User:Malik8U/notes

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Biology is the study of living things.

A term which is very commonly used in biology should be introduced at this point. Whenever we talk about an individual thing which is alive, we can refer to it as an organism.

If we were to talk about a number of organisms of one kind, we could refer to them as a species. (All races of modern man belong to one species.)

A living organism has the unique ability to take non-living components and incorporate them into something which is living or organic.

This has broadened the definition of organic matter to include any matter in which carbon plays a major building role. The organic matter in our bodies is generally organized into carbohydrates, fats or lipids, and proteins. These substances are very important in the structure and functioning of living things.

Similar building units called “cells”. The cells in the two organisms shown are similar in many ways (including size), although obviously one has many more cells than the other. This is not to say that all cells are identical in size and structure. Consider that while we cannot ordinarily even see individual cells without a microscope, we can certainly see or handle a chicken or duck egg, which is really one cell if it is not fertilized.

It was in 1665 that English scientist Robert Hooke first saw the empty cavities, which were the remains of once-living cells, in a slice of cork. It was not until about two hundred years later (1838) that two German scientists, Schleiden and

Schwann, independently concluded that all living things were formed of cells and that all essential life processes took place in these cells.

Tissue = Similar cells, which together perform the same type of job, are called tissues. (i.e. nerve tissue, muscle tissue).

Organ = Different tissues grouped together to perform one function become an organ. (i.e. kidney, heart, liver, stomach).

System = Organs are then grouped into specialized (organ) systems. (i.e. digestive, circulatory, respiratory).

Organism = Finally when all organ systems are functioning together, there is a complete organism.

Functions or Processes Common to Living Things

1.   Obtaining and using raw materials or food

2.     Controlling life or body processes 3.     Responding to the environment – IRRITABILITY 4.     Reproduction

Total Magnification = Magnification of Ocular X Magnification of objective

The environmental (or internal) condition which could cause a response is called a stimulus.

Some insects go through a very distinct four stage cycle (egg, larva, chrysalis/pupa, adult). This is called complete metamorphosis. In other organisms, the changes are more gradual over their life span. This is called incomplete metamorphosis. It includes the egg, nymph (miniature adult without wings), adult (with wings) that can fly, eat, and reproduce.

Many individual processes occurring in plant and animal bodies come under the general term of metabolism. This includes all actions in the body involving energy and using that energy to keep the body running properly. SUCH AS 1. Respiration2. Ingestion3. Digestion4. Excretion - Egestion

Another activity, which is often more noticeable in animals than plants is movement.

Finally, a process which may be considered to be related to reproduction, is growth. Some non-living things could be regarded as capable of growing, as with an icicle growing in size as water continues to be added on the outside.

Anatomy Study of the gross structure of plant and animal organs.

Bacteriology Study of microscopic non-green organisms, some of which cause disease.

Cytology Study of the structure and functions of cells.

Ecology Study of the environmental relations and distribution of organisms.

Embryology Study of the early development of organisms.

Entomology Study of insects.

Eugenics Branch of genetics dealing with human heredity.

Genetics Study of heredity.

Herpetology Study of reptiles.

Histology Study of the structure of tissues.

Ichthyology Study of fish.

Morphology Study of the total form or structure of organisms.

Mycology Study of fungi.

Ornithology Study of birds.

Paleontology Study of the life of past geological periods.

Parasitology Study of organisms which live on or in the bodies of other organisms and derive their nourishment from those organisms.

Pathology Study of diseases of organisms.

Phycology Study of algae.

Physiology Study of the functions of organisms, or of the functions which occur in their bodies or body parts.

Space biology Study of survival problems of living things in outer space.

Taxonomy Naming, grouping, and classifying of organisms.

Virology Study of viruses

Biotechnology, which is the application of biological knowledge toward practical purposes, is receiving a great deal of attention at the present time. Part of the reason for this may be due to one area of biotechnology where fairly dramatic results have been occurring and still have potential for great changes.

LESSON TWO

a) Qualitative – the observations are described in words, they describe changes. (See the example in # 5 above).

b) Quantitative – Observations that answer “How much?” The outcomes are recorded as numbers in charts, graphs are made, may involve calculations.

Technical method: Acting

Research method: reading, studying

In 1675, Dutchman Anton van Leeuwenhoek worked with “refining” microscopes. His accounts of the many micro-organisms present created more arguments between those favouring spontaneous generation (abiogenesis) and those opposed.

The theory of abiogensis: This centred on the idea that some forms of life could develop from nonliving things. Aristotle SPONTANEOUS GENERATION

It was not until 1668, when an Italian scientist by the name of Francesco Redi carried out some experiments on decaying meat, that some doubt was placed on the idea of spontaneous generation. By excluding flies from some decomposing meat while permitting other meat to be exposed to them, his results showed maggots as coming from flies – even though many still disputed this.

Around this time (1665) another discovery occurred which was to have some important consequences approximately two hundred years later. English scientist Robert Hooke used a simple microscope to observe cavities in cork, which he called cells. Unknown to him at the time, these were just the remaining signs of once-living cells

The viewing of a nucleus in a cell by Robert Brown.

The almost simultaneous discovery by German scientists Matthias Schleiden and Theodor Schwann that plant and animal bodies are made up of cells.

Rudolf Virchow's studies and statement that all cells come from other living cells

Led to:

The Cell Theory stated that all organisms are made up of cells; each cell is a basic unit of function; and, all cells come from other cells.

In 1864, Louis Pasteur set up an experiment to further help contradict spontaneous generation. By preparing flasks in certain ways, he demonstrated that nutrients would not have micro organisms appearing in them unless they came from other living sources. In the flasks prepared by Pasteur, micro-organisms only appeared if there was direct access to the outside air which already contained micro-organisms. Closed flasks with the S-shaped tubes remained organism-free. Pasteur's experiment and Virchow's third statement of the Cell Theory, which stated that all cells come from other living cells, finally proved the theory of spontaneous generation to be false.

Theory of Biogensis: all living cells or organisms are produced from other living cells or organisms.

The idea of natural selection, put forward by Darwin and Wallace, is one of a present number of theories trying to provide reasons for species changes or evolution.

Six steps of the scientific method include:

1.     Curiosity towards a situation of some sort.

2.     Recognizing the problem, obtaining knowledge that will help you to furtherly identify the problem.

3.     Setting up an experiment, and generating a hypothesis, predicting the outcome of the experiment.

4.     Carrying out the controlled experiment, meaning there exists a control in the experiment.

5.     Recording and organizing the data/results obtained from the controlled experiment.

6.     Formulate the conclusion, and update the hypothesis if it was proven to be incorrect

LESSON THREE

Ecology is a study of the relationships or interactions which exist in particular environments or ecosystems. These relationships involve both living and non-living things.

The biosphere is the “layer of life” surrounding the earth – a layer that supports life. It extends from the outer edge of the atmosphere to the depths of the oceans.

The biosphere consists of many smaller units or ecosystems. Each ecosystem, or unit of the biosphere, can be variable in size depending on how each one of us looks upon it.

A biome is a larger geographical region characterized by a distinctive, climax vegetation.

􀂃 The pelagic biome - the open sea.

􀂃 The benthic biome - the actual ocean floor. This is divided into:

fi The littoral benthic which can be reached by light

fi The dark, deep sea benthic.

􀂃 Plants adapt in interidal zones by having:

􀃠 Thick cell walls or cuticles to prevent water loss or,

􀃠 By growing in masses, they may hold quantities of water between their bodies.

The tundra (which is a Finnish word for treeless plain) has a fairly flat landscape. The warm summer temperatures melt the upper soil or gravel layers; but, rarely more than a metre below the surface is a layer which is permanently frozen – the permafrost. This permafrost has a number of effects on the land, such as soils become infertile, and plant roots cannot penentrate completely.

CONEROUS FORESTS:The round or triangular-shaped needle leaves, along with their waxy outer layers, are able to withstand colder temperatures and also to reduce transpiration or water loss in the cold months. At the same time, photosynthesis can resume and continue under cool conditions. The triangular shapes of the trees themselves enable the plants to shed accumulations of snow better and to reduce breakage of limbs.

Characterized by less severe winters and a much longer growing season with more fertile soils. B. Deciduous Forests

Has "evergreen" trees with large broad - shaped leaves, that are replaced throughout the year   D. Tropical Rain Forests--- A matter of grave concern about this is that the rainforests normally contribute greatly to the oxygen layer surrounding our earth's surface.

Some of the climax organisms are moose, beaver, black spruce, jackpine, ravens and Canada Jays. A. Coniferous Forest

A grassland biome experiences high evaporation and periodic droughts. Most people in Saskatchewan are familiar with the warm summer temperatures and the winds which help to bring these about.

Eastern and northern areas of the biome are classed as tall grass prairies. Here, natural grasses used to be of the sod-forming variety where plants would grow close together with intertwining roots. Moving southwest or south, precipitation amounts decrease, leading to the short grass prairies or the Great Plains as they are called in the United States. In these drier locations grasses grow farther apart and are referred to as bunch grasses.

In earlier times, the grassland biome supported the highest densities of herbivores of any biome.

There are two regions of Saskatchewan that are referred to as Ecotones. Ecotones are transition zones between two different biomes. The two Ecotones are:

The Aspen Parkland     – this is an area of      transition between the grasslands of the south and the forests of      the north (The main plant life is that of aspen      poplar-willow-grass combinations.) The second ecotone is The Taiga. A transition zone between the     tundra and the coniferous forest.There is little plant      diversity in the taiga due to severe cold and the very short      growing season.

Visible desert vegetation consists mainly of xerophyte plants. These are plants adapted to survive under dry conditions.

The tundra biome is found in the north and high up in the mountains. If one was to travel between the equator and the poles, there would be a strong possibility of seeing a progression of most of the biomes described. The changes in both the climatic and biotic characteristics, in this direction of travel, are part of the term latitudinal gradient. Another means of seeing similar types of changes would be to travel between the base and summit of a mountain. If a mountain exists in a tropical area and is high enough, it is possible to go from a tropical rainforest at the base to tundra or alpine conditions at the summit. In this instance, the climatic and biotic changes make up an altitudinal gradient.

Changes which begin and then occur in an area which had not experienced any living forms previously are part of a primary succession.

Secondary succession occurs in areas where there was some form of previous life.

Climax species do not change: individual plants and animals which die or are killed are replaced by others of their own kind.

􀂃 In processes of succession there may be other common characteristics:

􀂅 organic matter usually increases

􀂅 food webs may become more complex

􀂅 organisms appear which are larger in size.

Ozone can screen or prevent the passage of some ultraviolet radiation. With less ozone and ozone "holes" (where ozone is greatly reduced), much more ultraviolet radiation can reach the earth's surface.

The study of the geographical distribution of living things is biogeography. Within this field are attempts to understand why organisms are found where they are (and not in other areas).

(A corridor could be regarded as a major route or means of movement between two areas.)

1. Physical or geographical barriers

Example: such as oceans, mountains or even rivers limit the movements of organisms between continents or on continents.

2. Climatic barriers also prevent movements.

Example: the very dry conditions of deserts are major climatic barriers for amphibians and other animals.

3. Biotic barriers are represented by other living organisms.

Example:

􀂃 The lack of plant growth in a desert could be a biotic barrier to a herbivore.

􀂃 A predator could also serve as a biotic barrier, as a hawk could be to a mouse trying to cross a fairly open field.

Most organisms are located where they are now because they are adapted or able to cope with the conditions of their present environments. This ability is called tolerance. Example: A frog has a low tolerance for dry conditions and this is why it is unlikely that one would be seen in a desert area or survive very long if put there.

A limiting factor is anything necessary for the continued survival of an organism and which may be in limited or short supply.

A process which brings minerals and other matter from the ocean depths to the surface is called ***.

Selected Answer:

b. upwelling

As succession goes on in a forest area where a fire had gone through a number of years before, insects, birds and mammals would likely ***.

Selected Answer:

d. change in kind, as certain species   leave and others move in

Tolerance to variations in critical living requirements would have to be high for organisms living in a(n) ***.

Selected Answer:

d. intertidal zone

LESSON FOUR

A relationship where two different kinds of organisms live close together or actually with each other is called symbiosis.

Mutualism is a relationship between two organisms where both benefit.

Parasitism occurs when an organism lives on the surface, or inside the body, of another living organism called a host. The parasite benefits by feeding on some part of the host. The host is naturally harmed but not usually to the point of direct death.

Commensalism is a symbiotic relationship that exists when one kind of organism benefits while another is unaffected.

There are also micro-organisms which can break down some inorganic chemical compounds to yield energy for food synthesis. They are still autotrophs but are called chemosynthetic to distinguish them from the larger photosynthetic plant group. Both photosynthetic and chemosynthetic organisms are considered as independent. All others are dependent.

Saprophytes (the plant equivalent of scavengers)

The lengths of food chains or the total numbers of organisms in food webs vary. They can depend on:

􀂃 Location or type of ecosystem

􀂃 Temperatures or season of the year

􀂃 Precipitation amounts

Photosynthetic activity in the plant converts light energy to chemical energy.

Much of the energy taken in by any organism is needed just to maintain the body. Some of the processes going on within our bodies at this moment which require energy are: muscular movements; breathing or respiration; digestion; transmission of nerve impulses; and, movement of materials in the body.

In plant bodies many life-maintaining activities occurring are: synthesis of cell parts, cell repairs and active transport. Growth and reproduction are other plant and animal activities which use up energy.

Rapid reproductive rate by the producers.

To feed plants to animals in order to produce animal products such as milk or meat, would really be "wasting" energy. Not only would the animals use up much of the energy for themselves, but significant amounts of energy would remain in such things as animal wastes, intestines, bones, hides or hair and other normally inedible items.

Nitrogen-fixing bacteria, either free-living in the soil or located in root nodules of certain plants (especially legumes), convert free nitrogen into the nitrate form which can be used by most plants.

Several kinds of nitrifying bacteria can eventually change ammonia into the also useful nitrate form. The relationship involving those bacteria living in the root nodules of legumes is mutualistic. Bacteria derive sugars from the plants while providing nitrates to the plants.

Another group of bacteria, active in oxygen-deficient soils, can convert these gases back to free nitrogen form. These are known as denitrifying bacteria.

Green plants are able to incorporate carbon, during the process of photosynthesis, into complex molecules such as sugars, starches, amino acids and oils.

Oxygen is required by both plants and animals for the process of (cellular) respiration when molecules are broken down and energy and carbon-dioxide are released.

Phosphorous is a key in plant and animal metabolism which requires energy transfer. It is also instrumental in the transfer of traits from parents to offspring during reproduction.

From the point of view of living things, the flow of energy and the cycling of materials, which both occur through food chains and webs, are the key actions.

Lesson Five

Any grouping where a number of organisms of one particular species occupy a certain area or habitat is referred to as a population.

Six studies of populations are:

Population numbers

Population densities: Density is the number of organisms of a particular species in a definite area and time. Example: Three gophers per square kilometre in the Swift Current region in July, 1999.

Distribution: Based on tolerance, methods of dispersal (either by natural or human aided methods)

Age ratio or Structure: A group with a greater ratio or number of old individuals compared to the young or reproductive, will show future declines. In animals or plants, such a continuing trend could lead to extinction.

Sex Ratio: One to one are more desirable

Behavior

The highest rate of reproduction for a population under ideal conditions is called its biotic potential.

Environments have limiting factors which eventually slow growth, perhaps stop it and may even cause decreases. Any single factor usually has an upper and a lower limit, or range of tolerance within which an organism can function.

The sum of all limiting factors is sometimes called environmental resistance.

The carrying capacity is the population limit which an environment can support at a particular time.

Factors affecting population growth ARE:

1. Birth rate – referred to as natality.

2. Death rate – referred to as mortality.

3. Immigration - referring to movement into an area.

4. Emigration – referring to movement out of an area FOR THE PURPOSE OF SEARCHING FOR FOOD

Birth and immigration can lead to population increases, while death and emigration can do the opposite.

Some populations are considered to be closed populations. This means that in or out movements (immigration and emigration) of individuals do not occur. Such populations are usually not typical.

Most populations are open populations, where individuals do have opportunities to move in or out of areas.

Another type of movement, not to be confused with either immigration or emigration, is migration. The first two movements are one-directional, for the most part. Migrations are carried out by such organisms as caribou, monarch butterflies and many birds.

Whether populations increase or decrease depends on the relationships among the four major factors just discussed:

􀂃 The difference between birth rate and death rate.

􀂃 The net balance between immigration and emigration.

Environmental factors can have effects on population sizes without themselves being affected by the populations' numbers. These are density-independent controls.

There are many kinds of factors which can affect the sizes of populations, but in so doing are themselves affected by the population sizes. These are density dependent controls. ARE: PPPP

PARASITES

PATHOGENS

PEERS

PREDATORS

There are many kinds of factors which can affect the sizes of populations, but in so doing are themselves affected by the population sizes. These are density dependent controls. The idea of complete competitors not being able to co-exist is part of what some biologists call the Competitive Exclusion Principle.

Competition is often greatest between members of the same species. This is intraspecific competition.

Population controls, whether they are density-independent or density-dependent, are part of all the limiting factors in particular environments. Taken altogether, they determine an area's carrying capacity or the population limit which it can support at a certain time.

The large rates of increases have been due to a number of underlying causes. Some of these are:

􀂃 Better sanitation and personal hygiene.

􀂃 Better medicine and disease prevention have been prime factors in reducing death rates among people. Initially, when such conditions have been developed or are introduced in particular areas, a very high birth rate will still remain after the death rate drops. This results in large population increases in short periods of time.

􀂃 Food supply appears to be one of the major limiting factors to human numbers.

􀂃 A related factor centres on the earth's reserves of energy, in the form of coal, oil and gas, since these are related to food production.

In recent times, the introduction of better health care and food aid to non-industrial areas, has resulted in a ***.

Correct Answer:

d. greater difference between natality and   mortality

In most natural populations, the highest mortality rates occur among the ***.

Selected Answer:

b. unborn or young

J - curve graph   f. A graph showing exponential growth of a population

Biotic Potential   g. Highest rate of reproduction for a population under ideal conditions

Different species being found in the same area and being complete competitors (for exactly the same needs) are not really that common. Slight differences are possible in the kinds of foods, eating habits or kinds of territories preferred. Summer diets of moose centre on water plants or wetland vegetation. Elk are grazers – on grasses and sedges. Deer are primarily browsers, on shoots, twigs or other woody-stemmed plants. Therefore, even if all three species are found in the same general area, unless there is an extreme food shortage, competition among them is limited.\

In simpler words, two possible behavioral changes, when the amount of space is decreased are:

1.     An increase in aggression (for both humans and animals)

2.     A less willingness to associate with or help other people (in humans)

LESSON SIX

Studies dealing with interactions or interrelationships between humans and their environments are considered human ecology.

From a biological point of view, soil is a vital link to the continued life on this planet.

Rocks are eroded by rain or wind or broken down by other physical or chemical processes to form the tiny mineral particles making up a large part of any soil. Sizes of the mineral particles are important in determining the characteristics and classifications of soils. Clays consist of the smallest or finest particles while sands and gravels are at the other extreme with the largest.

Irregular spaces within the soil allow either atmospheric gases (oxygen, carbon dioxide and nitrogen) or water and water vapour to fill them.

This darkly-coloured humus, which helps to make up topsoil, is important in a number of ways:

􀂃 It provides many of the nutrients which plants require.

􀂃 It loosens up and aerates some soils.

􀂃 It can also act somewhat like a sponge in helping to absorb and hold water.

The presence or amount of the soil components and just how they make up the vertical arrangement of a soil type makes up what is called a soil profile. A soil profile generally shows distinct layers or horizons. The horizons are a result of:

􀂃 The amount of decomposition at the top and

􀂃 The movements and leaching of materials and nutrients.

The soil zones are closely related to the climatic and vegetation belts, as these are two of the factors playing a role in soil formation.

The major factors affecting soil fertility are:

􀂃 Climate (temperature and precipitation)

􀂃 Vegetation

Four main ways humans have affected the soil are:

1.     Clearing and breaking of the land – brought about by cultivation processes

2.     With the disappearance of natural grass covers and a reduction of anchoring material incultivated top soils, another damaging effect began to occur: Erosion water wind - Water-sheet erosion can take place in times of high water. Water covering larger areas of relatively flat land will dissolve matter from the upper soil layers and then carry it away when the land finally drains.

3.     Soil salinity, with more salts in the upper soil layers, has been increasing in large partdue to cultivation. IN AREAS WHERE POOR DRAINAGE AND ALSO HIGH WATERS BESIDE LAND.

4.     Another problem, which is not yet as serious as those already mentioned, is the increasing acidity of some soils. In some situations this is a result of decomposition of organic matter, when carbon-dioxide is released and carbonic acid forms. Presently, the increased use of ammonia or nitrogen fertilizers in inappropriate amounts or unsuitable proportions is also leading to greater acidity.

Hillsides or slopes are contour cultivated, or worked across the slope to create furrows, ridges or plant strips opposing downward movement of water. Some gullies or other likely pathways for water movement are seeded to grasses. Sheet erosion on frequently submerged lowlands can also be prevented by seeding the areas to grasses.

Strip cropping is commonly used to reduce the effects of wind erosion. This technique has crops alternating with summer fallow or grass.

Dealing with wind erosion also involves other attempts to decrease wind velocity or its effects. Another such method is the establishment of shelterbelts around farmyards or (tree) windbreaks in fields and along roadsides.

Minimum tillage is also used to reduce soil erosion.

Using cultivators instead of discers leaves stubble upright and also enables it to trap more snow.

Maintaining a trash cover on the soil surface keeps the soil moist longer. In addition, the stubble or straw residue helps to keep or hold the soil in place. The use of straw spreaders, choppers or bunchers after combines, rather than burning stubble, helps to maintain the cover.

Cereal crop – Wheat, barley, oats, Rye Oilseed – Canola, Mustard, Rapseed, Flax Pulse legume – Fababeans, green pease, lentils

Forage legumes – Clover alfafa trefoil

Forage grasses – grasses

The field of oceanography, which involves marine/salt water studies

The field of limnology (freshwater studies) concentrates on two types of aquatic conditions: STANDING WATER AND FLOWING WATER.

This is the characteristic landscape with the circular depressions or sloughs common to so many farmers' fields. Many of these were formed by blocks of ice left in the soil and rock material deposited by the glacier. The depressions were formed after the glacier retreated and the ice blocks melted. As the glacier was melting backward or retreating, melt water was being trapped in lakes between the glacier's original forward position and its retreating position.

The density of water becomes higher as the temperature falls to 4 0 Celcius and then decreases from 4 0 to 0 0

These nutrients can then be absorbed by microscopic water plants or phytoplankton. Ample amounts of sunlight and warm water temperatures could result in a population explosion or an algal bloom. Once the organisms die, they settle to the bottom and are acted upon by decomposing bacteria. Decomposition and respiration by bacteria and other organisms uses up oxygen. In some lakes, conditions could develop where water layers next to the bottom have no oxygen.

Once this happens to a lake and it begins to experience summers where oxygen depletions occur in the lower depths, that lake is said to be in a state of eutrophication. These lakes contain a great deal of organic matter. Many people commonly associate the term eutrophication with pollution and "dying" lakes.

"Swamps" are often used for areas located in forests while "marshes" apply to wetlands located in more open or grassland areas. Swamps or marshes are characterized by poor water circulation. In the autumn or during dry years, the soil or mud may be exposed in places. Decomposition and respiration actions by bacteria and other microorganisms lead to low oxygen levels near the bottom. Anaerobic bacteria, the type which can function in such conditions, are very plentiful. Their actions result in incomplete decomposition of organic matter and the release of such gases as hydrogen sulfides and methanes.

Plant life in standing waters includes:

Micrscopic: microscopic Phytoplantkton

Submergent: With roots, chara, milfoil, fanwort

Emergent: cattails, water lily

Animal life in standing waters:

Zooplankton, paramecia Daphnia, Cyclops amphipod

Loss of natural habitat is the major cause of endangerment today.

Some pollutants are biodegradable in that they will decompose or break down over time into harmless components. Canada or Saskatchewan Agriculture actually prefers to use the term persistent rather than non-biodegradable.

By-products of combustion, such as carbon, sulphur and nitrogen compounds, are gases responsible for many detrimental effects (i.e. acid rain) on our planet's surface.

Although they were greatly reduced, fluorocarbon and freon gases cause changes in the atmosphere itself – particularly to a special oxygen or ozone layer. The fluorocarbons, used mainly as propellants in spray cans such as those for hairsprays and antiperspirants, and the freon gases from air conditioners and freezers, cause ozone to break down.

Mercury and another chemical, PCP (pentachlorophenol), had been used as fungicides in treating seeds and pulpwood. Many Saskatchewan waters still contain more than the desirable limits of mercury.

Nitrogen and phosphorous, which make up a large part of the fertilizers applied to crops, can also increase algae growth rates. Nitrates and phosphates from the land fertilizers are carried by runoff water or leached into water bodies.

Cultural controls are those related to working land and the regulation of seeding and harvesting dates and planning crop rotations which may include plants which can crowd out weeds or are resistant to insects. Increasing use is being made of bio controls, which involve living organisms, rather than synthetic chemicals.

Biological Oxygen Demand is ***.

Selected Answer:

c. a way of testing the purity of a water   sample

A gas which is produced by decaying matter, as in garbage dumps and manure pits, and which could be used for energy is ***.

Selected Answer:

c. methane

A soil profile forms mainly as a result of the ***.

Selected Answer:

d. kinds of decomposition occurring in the   upper layer and down or up movements of nutrients and minerals

phytoplankton   d. microscopic autotrophs

Green manuring can help in soil management by acting as a sponge to try to reduce the upward movements of salt-carrying waters or drawing-off excess water in areas of poor drainage. By doing so; the production of plants near that particular soil increases, and the quality increases as well (organic soil matter).

Planting cover crops is mostly done over areas of light, sandy soils, and is done in order to reduce the effects of both wind and water erosion which occurs in the spring. Rye is a good example of a cover crop used in Saskatchewan in such areas.

LESSON EIGHT

Scientists estimate that there are anywhere from two million to five million (2 000 000 – 5 000 000) different kinds of organisms present on this earth

The science of classifying organisms is taxonomy. (Taxonomy can also show relationships between organisms.)

The work of a Swedish botanist, Carl von Linné (Linnaeus), 1707-1778, in trying to develop a better classification system, served as an important base for the development of taxonomy as we know it today.

Kingdom

Phylum

Class

Order

Family

Genus

Species

as you proceed down the list, you are continually narrowing down both the characteristics and different kinds (or numbers) of organisms. When you come to the species level, there is only one kind of organism.

LATIN HAS MANY DESCRIPTIVE WORDS, AND BECAUSE THE LANGUAGE WAS NO LONGER IN EXTENSIVE USE, IT COULDN’T BE CHANGED.

Linnaeus promoted the idea of using a two-word naming system to name an individual organism. This system is called binomial nomenclature (meaning a two-word naming system). To use the scientific name of an organism both names – genus and species – must be used. To write the scientific name it is always either italicized or underlined.

Basis of classification:

1.                 homologous structures. These are structures or organs in different organisms which have similar origins, but appear somewhat different and possibly having different uses.

2.                 Such similarly used organs, even though their structure and development are different, are said to be analogous. – fish fin, whale paddle

3.                 Embryology – the study of embryo development

4.                 These similarities are referred to as biochemical homologies. – body compounds

5.                 Chromosome or genetic similarity – DNA RNA similarity

6.                 Behavioral patterns

A species is usually any naturally occurring group of individuals which can interbreed to produce fertile offspring.

A dichotomous key consists of statements in pairs which give characteristics of

organisms. Each pair allows you to make one choice. The choice you make can possibly give you the organism's identity, or the number of the next pair of statements to continue your search.

KINGDOM MONERA::::::::::::::::::

A "true" nucleus is one which is considered as having nuclear material enclosed within a definite membrane. Monerans either have nuclear material scattered throughout cells, or located in smaller, generalized areas – but still without surrounding membranes. Cells which lack true nuclei are classed as prokaryotes

􀂃 They lack the definite cell bodies or organelles (mitochondria, plastids, etc.) normally found in the cells of organisms of other kingdoms.

􀂃 They all reproduce asexually by binary fission. A simple form of sexual reproduction called conjugation may occur.

UNICELLULAR OR COLLONIAL, ARE NOT MULTICELLULAR

Two groups of organisms make up this kingdom. They are:

􀂃 Archaebacteria (meaning ancient or primitive bacteria).

􀂃 Eubacteria (meaning true bacteria).

Classification of monerans:

􀂃 Shape: 1.spherical or coccus (plural: cocci) which occur singly, in pairs, in a chain, or in a cluster. 2.rod-shaped or bacillus (plural: bacilli) which occur singly, in pairs or in a chain. 3.twisted or spirillum (plural: spirilla) which are always found singly.

􀂃 Nutrition: 1. Saprophytes (Decomposers) – these organisms feed on dead plant and animal matter. They are used in sewage treatment. 2.Parasites – some heterotrophic bacteria get their food from living cells. Many of these bacteria are disease-causing, as their enzymes will often kill or damage a host's cells.

􀂃 Reaction to Gram stain: Gram positive – These bacteria hold the dye and appear purple. Or Gram negative – These bacteria release the dye and appear pink in colour.

􀂃 Respiration: OBLIGATE FACULTATIVE

􀂃 Reproduction: Asexual reproduction – binary fission, and spore formation

Sexual reproduction – Conjugation Transduction (virus wrecking DNA) and Transformation (DNA entering medium)

Viruses possess an outer protein shell called a capsid (which makes up

approximately ninety-five percent of the entire virus).

Virulent Viruses are aggressive and invade the host cell’s DNA and inject some of their own – virus protein, virus nuclear matter, viral DNA.

Latent or Lysogenic Viruses: Viruses which utilize the host’s processes to duplicate its viral DNA/protein.

Viruses can invade cells of bacteria (where they are known as bacteriophages)

Microcystis   g. a cyanobacteria that forms a scum on a water surface and can release a poisonous toxin

Two ways that cyanobacteria are a beneficial influence on our environment are:

1.     In the earth's atmosphere, a considerable portion of the oxygen and even natural waters are really a by-product of the photosynthetic activities carried out by cyanobacteria.

2.     Cyanobacteria are an important factor in the nitrogen cycle as some forms of these blue-green bacteria can form nitrates which are through time, eventually released into waters/soils. These nitrates are essential needs by green plants, and are absorbed for tissue (protein) buildup. These nitrates have also found to be "fertilizers" in areas where people cannot afford chemical fertilizers.

One example of a cyanobacteria species is that of the spherically shaped celled Nostoc specie.

LESSON NINE:

KINGDOM PROTISTA:::::::::::::::::::::::;

Most of these microscopic organisms are unicellular, but colonial and multicellular varieties do exist. Since most are unicellular, this means that protists lack the specialized tissues and organs which begin to be found in plants and animals. This lack of specialization does not mean that these small organisms do not have the ability to carry out many life functions. On the contrary, a microscopic, single-celled protist can carry out all the necessary life functions which are common to complex, multicellular organisms (like ourselves). Protists do have organelles such as a mitochondrion, which is a structure that releases energy for cell activities.

Characteristics common to all protists are:

1. Small or microscopic.

2. Eukaryotic - that is they have a distinct nucleus.

3. Unicellular but colonial and multicellular organisms also exist.

Animal like. Cannot make their food, protists are known as protozoans. Protozoans that engulf their food are referred to as holozoic organisms, whereas those that absorb food that has been already digested directly through their cell membranes are called saprozoic organisms. The four main phyla of the protozoans are divided into their respective groups based on their mode of movement. Other classifying characteristics that will be looked at are:

The main feature of sarcodinans is the presence of pseudopods or "false feet."

Sarcodinans may form hard, protective, inactive cysts when conditions become unfavourable (drought, lack of nutrients, heat…)

Inclusions (which are vacuoles which may contain oil droplets or solid particles).

Oxygen enters and carbon-dioxide leaves Sarcodinans by the process of diffusion.

PARTS OF THE PARAMECIUM:

TRICHOCYSTS: used in defense or allowing it to stick to some surface

CILIA: Aid in movement

PELLICLE: AID IN BREATHING, BY THE PROCESS OF DIFFUSION

RADIATING CANALS: expels liquid/gas wastes into contractile vacuoles

CONTRACTIle VACUOLES: The amount of water inside the bodies of freshwater protists is usually regulated by the ***.

Selected Answer:

d. contractile vacuoles

expels the wastes into the anal pore

ANAL PORE: expels the wastes

ORAL GROOVE: directs food particles to mouth

FOOD VACUOLES: encircles food particles, where they will then be broken down by enzymes

MOUTH: it’s a mouth.

MACRONUCLEAS: directs cellular processes in the organism

MICRONUCLEAS: Is more invlovled in the actual reproduction process

Structures common to both Amoeba and Paramecia are ***.

Selected Answer:

d. contractile vacuoles

One thing which algal protists can supply to other organisms, which protozoans cannot is ***.

Selected Answer:

c. oxygen

Streaming of cytoplasm forms pseudopods in ***.

Selected Answer:

d. Amoeba

The protist which "captures" its food by surrounding and then engulfing it, is a(n) ***.

Selected Answer:

a. Amoeba

PLANT LIKE PROTISTS: ALGEA

The major difference between this group and the Protozoans involves their relationship to food. Almost all algal protists possess various kinds of chlorophylls enabling them to photosynthesize and produce their own food.

General Characteristics of the Plant-like Protists

􀂃 Algae can be unicellular, colonial, or multicellular.

􀂃 They are autotrophic. This means that they contain chlorophyll and are able to photosynthesize to make their own food.

􀂃 They are found in all types of environments, from a drop of water to soils to marine environments.

􀂃 They are grouped according to several factors. These factors are: the pigments present, the type of compound that makes up their cell wall, or the molecule that food is stored as.

PHYLUMS – Euglena

Euglenas are sometimes studied as a possible link between plants and animals mainly because of their distinct characteristics, depending on their surrounding environments, For example, in favorable sunny condition, where light is in abundance, euglenas utilize photosynthesis and produce their own food through the usage of their chlorophylls, making them autotrophic. During periods of darkness, however, euglenas act as heterotrophs taking in solid food, and thus, making them more animal like in that manner.

Most members of this phylum are found in fresh waters. Water which tends to be stagnant and has a higher concentration of nitrates and phosphates (possibly from pollution) provides especially favourable growth and reproductive conditions. Rapid asexual reproduction by fission could lead to such high numbers that the waters could turn green and have surface scum.

The euglenoid movement by contraction and then elongating it.

Coloured or euglenoid flagellates are significant producers or sources of food in many food chains or webs, which may also include humans.

Phylum Pyrrophyta (Dinoflagellates)

Whereas euglenoid flagellates are mainly freshwater, the majority of dinoflagellates are marine – especially common in warmer seas.

Dinoflagellates often have more rigid, cellulose outer walls instead of flexible pellicles. The cellulose wall is often made up of small, overlapping plates resulting in intricate and often beautiful patterns.

Phylum Chrysophyta (Yellow-Green and Golden Algae or Diatoms)

The largest part of planktonic life is made up of this phylum. It is also a very widespread group, being found in freshwaters, oceans and on land.

Diatoms often have cell walls made of calcium or silica, arranged in elaborate patterns. When diatoms die and decompose, these "skeletons" form layers which compact to form diatomaceous earth. Ancient lake or sea beds, which are now exposed on land, are sometimes used to supply commercial companies with diatomaceous earth. This is an ingredient or part of many uses: scouring powders for polishing silverware or metals; a filtering medium for sugars, gasoline or oils; a part of some toothpastes; insulation for steam or refrigeration pipes; and, an absorbent for nitroglycerin in dynamite.

The main reason that they have been moved to the plant-like protists is that although they are multicellular, they do not contain tissues where as plants are multicellular and do contain tissues.

The algae are divided according to the following characteristics: pigment types, manner of reproduction, thallus size and form and method of food storage.

Phylum Chlorophyta (Green Algae)

Plankton refers to both very small aquatic plants and animals. More specifically, phytoplankton refers to the very small plant like (algae) protists.

The bodies of some varieties are one-celled or unicellular. Others have a body or thallus consisting of filaments of identical cells, formed asexually by fission. Most varieties are colonial, where unicellular individuals form groups of millions of cells.

Chlorophyta are the largest and most diverse of the algal groups. Members of this particular group are common in freshwater, such as in our prairie lakes and potholes or sloughs, and also in marine and on land environments.

Phylum Rhodophyta (Red Algae)

The possession of a particular red pigment, which can absorb deeper penetrating blue light, allows some varieties to grow at depths up to several hundred metres. Most red algae have many-celled, branching or threadlike thalli (body), although they do not tend to be long – usually not longer than half a metre.

Another substance, called carrageen, is used in such preparations as preserves, ice creams, puddings, chocolate milk and salad dressings.

Phylum Phaeophyta (Brown Algae)

Another mainly marine alga variety, this group seems to prefer colder waters – unlike Rhodophytes which thrive in warm waters. Brown algae have many-celled bodies which include individuals with the largest bodies of any algae. Some types reach lengths of approximately fifty metres.

Fungi-like Protists

Phylum Myxomycota (Slime Molds)

In cold and dry conditions, Spore formation and release is part of the life cycle which is very similar to that of fungi. Spores can remain dormant in unfavourable conditions or environments for considerable lengths of time. If conditions become, or are, good for growth, a spore will undergo meiosis to produce varying numbers of haploid (n) sex cells.

slime molds   C. life cycle at certain stages resembles protozoans and at other stages resembles fungi

Slime molds have many characteristics  which would seem to make them belong with protists except that they

d. produce spores as a means of   reproduction

Under favourable conditions (warm and moist), slime molds are tiny bits of "naked" protoplasm ranging from a microscopic size to several square centimetres and over, depending on the variety. Bacteria, yeast cells, other small living micro-organisms and bits of dead organic matter are engulfed and enclosed in food vacuoles. (Slime molds are primarily decomposers.)

KINGDOM FUNGI

Groupings of fungi into various divisions or phyla are usually made on the basis of the types of reproductive structures they have.

The most outstanding feature of all fungi is that they lack chlorophyll. This means that all fungi are nutritionally dependent on other organisms or are heterotrophic.

Some fungi are parasitic by deriving nourishment from living cells or organisms.

Most are saprophytic in that they "feed" or live on non-living organic matter.

In fact, most fungi are made up of many fine, branching, thread-like structures called hyphae, which may or may not have cross-walls. The massing together of the hyphae forms a tangled network called a mycelium. Depending on how closely together hyphae are interwoven, or whether or not there is cellulose in the cell walls of some hyphae, mycelia could range from soft, fluffy masses to more solid structures, like mushrooms and bracket fungi.

Fungi have extra-cellular digestion - that is - enzymes are secreted that break down the food so it is digested externally before it is absorbed. In this way fungi decompose dead organisms.

Phylum Zygomycota – Conjugating fungi

This is a grouping of what are considered to be the simplest of fungi. This group includes bread molds and drug molds.

Where the projections (+ AND -) meet, the cell walls disintegrate allowing nuclei from the two hyphae to come together and fuse into one body called a zygote. A thick wall forms around the zygote creating a zygospore, which can withstand poor growing conditions.

Phylum Ascomycota (Sac Fungi)

Asexual reproduction in this phylum can occur in two ways. BUDDING AND SPORE FORMATION

CLUB FUNGI::Fairy rings are mushrooms of certain types which grow in circles. These circles generally expand outward as mycelia use up organic matter in the centre. Grasses just inside the ring tend to be a little greener as decaying mycelia release nitrates which are used by plants for leaf growth and chlorophyll formation.

Phylum Deuteromycota (Fungi Imperfecti)

If fungi appear to be able to only reproduce asexually (usually by conidia) they are called imperfect.

In the mutualistic relationships with fungi, the fungi seem to assist the plants in absorbing water, nitrates and especially some important minerals such as phosphorous and potassium. In return, hyphae of fungi growing out from the plant roots can help in the absorption.

Mycorrhizae are relationships of plant roots and fungi – usually Ascomycetes and Basidiomycetes. Many kinds of plants have hyphae from soil-living fungi growing into them, or some fungi growing right in the roots with their hyphae growing out into the soil.

LICHENS: Another symbiotic relationship of two kinds of organisms is illustrated by lichens. Lichens are algae-fungi combinations. Once more the fungi are parasitic by sending their hyphae into algal cells for nourishment. Algae possess chlorophyll and are able to produce food by means of photosynthesis. In many varieties of lichens, fungi may "pay back" the algae for their food by helping to provide them with minerals and water, as well as support, as the algae live embedded in the fungi.

Establishment of a protist kingdom first occurred when it became difficult to determine whether some organisms were plants or whether they were animals. In general, protists' microscopic sizes added to this problem.

Unicellular organisms: Unicellular organisms are independent of other cells (they only contain one cell that carries out all the necessary body functions), independently, not relying on any other type of cell for assistance.

Colonial organisms: Though they live in colonies, the cells in these organisms are also independent of each other, in the sense that they (the cells) can carry out all the necessary body function that even the most complex of organisms carry out.

Multi-cellular organisms: Multi-cellular organisms are different than colonial and unicellular organisms mainly because their cells are dependant on fellow cells to carry out the bodily functions. This is because they are made up of so many cells that they unite together to carry out the function in an orderly manner, each cell doing its specific job for the completion of the process.

LESSON TEN::::::::

Any organism capable of causing a disease or disorder is known as a pathogen. The major groups of pathogens are:

1. Bacteria.

2. Viruses.

3. Protists.

4. Fungi.

5. Parasitic worms.

bacteria and fungal spores in the atmosphere) on page 7; point 2 has two other ways of contracting diseases (food and water).

These poisons are called toxins – compounds produced by bacteria and/or fungi. If these should be released by still-living bacterial cells, they are called exotoxins. Some toxins are released only when the bacterial cells die and their walls disintegrate. In this instance they are called endotoxins.

Defense mechanisms in organism bodies:

Hair-like cilia are present on some mucous membranes, especially those lining respiratory passages. These cilia beat, or have a wave-like motion, in one direction. This motion carries mucus and any foreign material trapped in it to the nose or throat where it can eventually be expelled or swallowed.

Mucous membranes continue as physical barriers and the mucus produced serves to entrap and also to destroy some bacteria. There are some enzymes in mucus which break down the cell walls of some bacteria.

Perspiration or sweat on skin surfaces of humans or animals is also protective. The salty and slightly acid sweat is not very favourable towards the survival and growth of many kinds of bacteria.

Cellular defenses:

Plants will sometimes demonstrate a reaction called hypertrophy, where there appears to be an unregulated growth of cells called tumours or galls. Insects or fungal attacks seem to trigger these, and some insects appear to use these galls as shelters for their eggs or larva. Small pea-sized galls can often be noticed on the leaves of willow trees.

First, damaged cells release a substance called histamine. This chemical causes any nearby blood vessels to expand in size and become "leaky." That is, blood cells can pass through the vessel walls more readily to enter the tissues around the wound. (This results in the redness and swelling.) Special white blood cells called phagocytes and lymphocytes, which enter the area, begin engulfing bacteria and destroying them with enzyme action.

Higher temperatures slow down the growth and development of some bacteria while speeding up body defense reactions. (Too high a body temperature for too long, however, will begin destroying blood cells.)

If any strange protein enters a body, then that body attempts to get rid of it. These foreign proteins called antigen(s)

White blood cells called lymphocytes eventually encounter the foreign particle. These lymphocytes which contain this new antibody are called B-cells or T-cells, depending on how they attack the invader. The T-cell, for instance, will attack an entire cell if there is a foreign protein inside; a Bcell attacks just the foreign protein - such as a bacterial or viral cell outside of a body cell.

The main difference between active and passive immunity is that Passive immunity results from the introduction of ready-made antibodies whereas active immunity is the introduction of an antigen (foreign protein) that is the later cause of the body forming an antibody to confront it. In simpler words passive immunity is the direct introduction of an antibody whereas active immunity is the indirect method of forming antibodies.

A macrophage is a type of white blood cell that acts in the destruction of (foreign) antigens such as bacteria and viruses.

Epithelial cells are those which line the surfaces of some body cavities and secretory canals.

Human immunodeficiency deficiency virus enters mainly T-cells, but can also enter macrophage cells and epithelial cells. Once inside the cell, the virus directs the cells to produce virus proteins. Such protein can be attached into white blood cell's nuclear membrane, or set free to infect other cells. This is the "dormant" stage of HIV (lasts about 8 years from infection).When HIV does become active; the hosts’ T-cells are eventually destroyed as they are taken over by the production of the viral proteins. The loss of T- and macrophage cells, in addition to the loss of directing influence of the protein; usually conducted by the T-cells (now destroyed), leads to AIDS. Once reaching the stage of AIDS, the immune system of the body begins to deteriorate at a continuous pace until most of the bodies defenses have been obliterated by the virus. With the fall of the immune system, the body is now open to all sorts of diseases, and even the smallest of diseases/infections can mean death in an AIDS patient (the body cannot fight back anymore, the immune system is destroyed.

Sexually transmitted infections can be caused by bacteria, viruses, or parasites.

Antibiotics inject antigens into organisms, and each antigen results in a specific antibody being formed to combat it. Antibodies, on the other hand are the bodies’ natural special protein that attacks such foreign proteins.

LESSON ELEVEN:

KINGDOM PLANTAE:::::::::::::::::::::;

Most plants are non motile

They all have chlorophyll

All plants are independent

The majority of individual plants are multi cellular meaning that they have a specialization of cells, nad vascular tissue.

Asexual methods of reproduction include, spore formation and also vegetative reproduction where parts of the plant can cause new plants to be formed.

Sexual methods through A special division process, called meiosis, produces cells (gametes) with one-half the chromosome number ordinarily found in the "body" cells. These gametes, or eggs and sperm, can then unite to form a zygote and eventually a new individual.

MOSSES:

Mosses reproduce asexually by fragmentation or by the release of gemmae which are cup shaped structures that contain haploid photosynthetic cells. These structures are found on the gametophyte plant. They can be knocked off the plant by drops of rain where upon they will begin to grow into a new plant.

Sexual reproduction occurs by alternation of generations where male and female gametes are produced.

The water could come from dew, rainfall or spray mists and is a very important condition for sperm movement and the life cycle to be carried out. This is a major reason why deserts and other dry areas are unlikely areas for moss growth.

Moss growths help to anchor soil and could prevent or slow soil erosion.

􀂃 In some areas where there have been thick layers of moss, blocks of peat could be cut and dried and used as a fuel or as gardeners' "soil." Gardeners can buy bags of peat moss to incorporate into their soils or use as starters for seed.

The gametophyte is the more prominent stage of the mosses.

Tracheophytes are plants that have a vascular system - that is the plants have a series of vessels and tubes that conduct water, nutrients and food to the various parts of the plant. These groups would be the spore producers and the seed producers (plants).

Small size is necessary as the processes of osmosis and diffusion, by which materials move in these organisms, are not efficient over long distances. Cells that are far removed from the absorbing rhizoids may not receive enough water or minerals. With the addition of special conducting tubes, which could move needed substances fairly quickly to all cells, the limitation to size has been mainly removed.

Spore Producers:

Movement to different land environments and the accumulation of millions of cells has also resulted in plant cell specialization or differentiation.

One has to do with the inability of many ferns to prevent excessive water loss. Many of these plants have thin epidermal cells and a thin, or absent, waxy cuticle layer. These conditions could permit a high water loss if the plants were located in sunny, dry areas.

􀂃 Another necessity for moist conditions involves the reproductive cycle. Ferns, like mosses, need water in order that sperm reach eggs for fertilization.

Fronds or leaves of ferns consist of a stipe or stalk and a blade.

Any plants which include sexual reproduction in their life cycles feature alternation of generations.

The sporophyte stage, with the roots, rhizomes and especially the leaves, becomes the most visible part of the fern life cycle.

Ferns play important roles in ecological succession. They are viewed as being “pioneer plants” as are mosses. Ferns grow in areas as diverse as on rocks, ground left after a forest fire, in bogs and marshes. They grow in the shade. Each year they grow and die back thus adding organic matter or creating material for other plants to grow in. As they do this, the soil conditions become such that they can no longer survive and are replaced by the next kinds ofplants in the ecological succession.

IN MOSSES:Gametophyte most prominent while sporophyte is less noticeable but is supported by the gametophyte during its life

IN FERNS:Sporophyte most prominent, gametophyte is reduced and dies shortly after sporophyte appears

Seed Producers

Cell differentiation or specialization - a cell that has developed special characteristics to enable it to perform particular functions. In animals - bones, nervous tissue; in plants - Xylem, phloem.

􀂃 Xylem which conducts water and dissolved minerals upward from the roots

􀂃 Phloem which transports food from the leaves or green stems.

Unlike xylem cells, which carry out their conducting functions after they are dead, phloem cells transport material while they are still alive.

Destruction of the cambium and phloem stops the downward movement of food. The roots will eventually die of starvation, resulting in the death of the entire plant.

The four organ of plants are:

Stems

Roots

Leaves

Flowers

Flowers are involved in the sexual reproduction of many of the plants we are familiar with on the prairies.

"Gymnosperm" means "naked seed," which illustrates one of the major characteristics of this group of seed plants. These plants produce seeds which are carried on the surfaces of some scales or appendages, with very little to cover them.

􀂃 Angiosperms are flowering plants. Even though some groups such as angiosperm trees and grasses appear not to have them, there are indeed flowers present.

􀂃 Seeds are covered or enclosed. Where gymnosperms produced "naked" seeds, angiosperms have their ovules or seeds enclosed in an ovary or ovaries.

􀂃 An enlarged ovary or fruit, mentioned in the last statement, is also a structure found only in this group.

􀂃 Another unique feature, related to the life cycle, is double fertilization. This involves a union of two different pairs of nuclei.

Of all plants which experience alternation of generations, this group has the most reduced, or least obvious, gametophyte stage. The structures involved are somewhat different, but reproduction is similar to gymnosperms.

The pollen grains are the male gametophytes.

Angiosperms are furtherly divided into:

Monocotyledons and Dicotyledons, this is because of the four differences:

Number of cotyledons (supply food to the embryo)     developed by the embryo, mono=1, dico=2

Flower parts, number of pedals – 4/6 or     multiples of = dico, and 3’s or multiples of = mono

Leaf Venation – how veins are     arranged in the leaves. Netted = dico, paralled = mono

Vascular tissue

Root Types Another distinction between the two     classes is that dicotyledons have a tendency to possess tap roots while      monocotyledons have fibrous roots.

A prothallus is used to refer to a ***.

Selected Answer:

a small green body, capable of  photosynthesis, that develops from a spore

Alternation of generations in plants means that ***.

Selected Answer:

asexual and  sexual reporduction alternate with one another

The phylum name of Tracheophyta refers to the presence of ***.

Selected Answer:

conducting  tissue

Of the following characterisitics, the one that ferns share with mosses is that they

Selected Answer:

a. require water for fertilization

Girdling eventually destroys a tree by ***.

Selected Answer:

b. cutting off the food supply to the root   system

One structure common only to angiosperms is a ***.

Selected Answer:

c. flower

apical meristem   c. embryonic cells found at the tips of plants that are responsible for increases in length

differentiation   e. specialization of cells to a specific function

spore   g. haploid reproductive cell that has an outer covering

Gemmae are cup shaped structures that contain haploid photosynthetic cells. The function of gemmae is in the process of asexual reproduction where the gemmae are “knocked” off of the parent plants and then grow independently into new gametophyte plants. Mosses are a plant where one could find gemmae present.

LESSON TWLEVE

KINGDOM ANIMALIA:

Alltogether, mammals and vertebrates only represent 5% of all animals.

Animals are multicellular. The terms metazoa or metazoans are sometimes used to denote this. If you recall, protozoans was applied to single-celled, microscopic organisms which sometimes had both plant and animal characteristics.

Animal cells are surrounded by a cell membrane. The absence of a rigid cell wall (with cellulose), as found in plants, allows animal cells some degree of flexibility.

All animals can reproduce sexually and some can also carry out asexual reproduction. Many animals are of separate sexes – that is, either female or male. Some species (such as earthworms) are hermaphroditic, where individuals possess both female and male sex organs.

Compared to plants, animal bodies are usually more highly differentiated, especially with the development of nerves and muscles. This means that animals are more responsive than plants to external stimuli.

One method involves making a comparison of body developments and structures.

The ectoderm, endoderm and mesoderm are called germ layers because they do give rise to the different tissues and organs

Endoderm cells are frequently associated with digestive structures.

Ectoderm cells may give rise to outer body coverings, nerves, brain and spinal cord.

The mesoderm forms a large part of the main body such as muscles, skeletons and major organs.

Organisms that show bilateral symmetry also show cephalization – that is the concentration of nerve cells are in the head end. These organisms have a greater awareness of their surroundings and are able to move more quickly.

Animal Phyla

THE INVERTEBRATES:

Phylum Porifera (Sponges)

Members of Porifera have four types of cells organized into two layers. Because these cells are mixed together without any apparent co-ordination and with seemingly little interdependence between them, sponges are said to lack tissues and organs. Some scientists do call the outer covering cells tissues; however, because they do not act in a co-ordinated way, they are not generally considered as such. A jelly-like material bonds the outer layers of covering cells and an inward facing layer of collar cells. Mixed into the jelly-like material are also pore cells and needle-like cells called spicules.

Ameobocyte cells can pick up some of the digested matter and transfer it to other cells. Waste products may also be picked up by the amoebocyte cells and taken back to the collar cells for excretion. Scattered throughout the cell layers are needle-like structures called spicules. These are believed to offer support for a sponge and also possible protection from organisms which may attempt to eat it.

Sponge reproduction could be asexual or sexual.

Asexually, the organisms can give rise to outgrowths or buds which eventually break off, fasten themselves to a support and continue life as another individual. Sponge colonies can develop in this way. Some marine and many freshwater varieties could produce gemmules in the fall. These are masses of mainly amoebocyte cells enclosed by thick walls. These eventually break away from an individual and start life on their own.

Sexually, some amoebocyte or collar cells can produce egg and sperm cells by meiosis. These egg and sperm cells may be produced by different individuals or by the same one, which is then known as a hermaphrodite. Zygotes, which result from the union of sperm and eggs, develop into flagellated larvae which can swim about freely for a while before becoming sessile.

Phylum Cnidaria (Coelenterata)

Cnidarians are somewhat like sponges in that they are made up of two distinct cell layers. In cnidarians, however, there are a greater number of specialized cells in these two cell layers. Included among these are nerve cells which are organized into a simple nerve network. Muscle fibres extend in different directions through both cell layers. The nerves and the muscles enable cnidarians to actively respond to various stimuli in the environments.

The organization and functioning of cells such as the nerves and muscles means that this phylum has the beginnings of tissue systems.

Cnidarians may show one of two body forms and many actually have both types during their life cycles. These two forms are the polyp hydra and the medusa. Both show a radial type of symmetry. The polyp has a tubular body with a basal disk (for fastening to some surface) and tentacles around the mouth. The medusa is bell-shaped and free-swimming. Descriptions of the body characteristics of a member of each group follow.

Hydra = Stinging capsules or nematocysts are the main facility used by the hydra to obtain food. Such tentacles apply the prey with a paralyzing poison can be shot from these nematocysts into another organism. If the “shot” organism be a source of food, the Hydra's tentacles will then push it through its mouth and into the gastro vascular cavity. Asexual - Outgrowths or buds can develop from the sides of organisms into complete (although smaller) individuals. These buds eventually separate and become independent.

Sexual - Ovaries and testes, which may both be found on the same individuals in some varieties, produce the eggs and sperm involved in sexual reproduction. Although not considered as a natural form of reproduction, Hydra can reproduce or regenerate lost or injured parts. An individual which may have lost some of its tentacles could regenerate new ones.

Aurelia is one jellyfish variety which shows both a medusa and polyp form in its life cycle. In a way, this is really a form of alternation of generations: Medusae reproduce sexually to produce polyp forms and these polyps then reproduce asexually, creating the medusae.

Worms: 1. All of the worms exhibit a bilateral symmetry. (This is a form where, if you imagine cutting an organism in one direction along a central axis, there would be an identical or very similar left and right half.) Such a form is commonly associated with, and assists, organisms which move in particular (forward) directions.

2. The development of three germ or body layers, with the ectoderm, endoderm and mesoderm, enables the worms to develop not only tissues (which cnidarians have) but organs as well.

3. The worm phyla all show cephalization and the beginnings of a central nervous system. Cephalization is the concentration of nerves and certain senses at one particular end (head) of an organism. This, along with the development of nerve concentrations or "brain" and major nerve pathways, increases the awareness and responsiveness of an organism to its environment.

PARASITIC WORMS: They have a small body size. This characteristic helps to avoid detection and possible removal by a host. Also, despite a parasite taking nutrients from a host, the parasite's well-being depends on its host. A successful parasite is one which really does the least harm to its host. The death of a host often means death for a parasite.

􀂃 The outer skin is a thick cuticle – especially for parasites living in digestive systems. This prevents the digestion of the parasites by their hosts.

􀂃 There is a degeneration of various systems. Compared to the free-living forms, parasites have some systems poorly developed or missing completely. Sensory nerves and the digestive systems are generally the most reduced. There is less need for these inside a host's body. Reduction of these systems increases the space for reproductive organs.

Phylum Platyhelminthes (Flatworms)

Planarians exhibit bilateral symmetry which allows them to have greater awareness of their surroundings.

On the grass, larvae can form thick, outer walls or cysts which can protect them for several months. If they are eaten by cattle or sheep within that time, they are released from their capsules in the digestive systems and make their way into blood vessels and eventually, into particular organs.

Phylum Nematoda – Roundworms

Of all multicellular animals, roundworms are the most numerous.

Two major body developments, which can be considered as significant advances over previous phyla, consistently occur in nematodes.

􀂃 The digestive system includes a tube which runs the length of the organism and has openings at both ends – the mouth and the anus. This allows food matter to be more efficiently digested as it moves through the tube.

􀂃 Another development is a fluid-filled cavity or pseudocoelom between the digestive tube and the mesoderm. Circulation of the fluids around the tube increases the efficiency of food and oxygen movements, as well as waste removal.

Phylum Annelida – Segmented Worms

The most complex of the worm phyla is the annelids.

􀂃 Segments - Segmentation permits organisms to have certain parts of their bodies adapted for specific functions.

􀂃 Coelom. A coelom is a cavity within the mesoderm rather than between the endoderm and mesoderm. What has happened is that part of the mesoderm has surrounded the digestive tube, to become layer of muscle to push food along, while the rest continues around the coelom to form a lining.

The development of a coelom is important to organisms in two ways. First, the separation between the outer body wall and the digestive tube allows the muscles of each to act more freely without interfering with each other. Another major advantage of a coelom is that the extra space of the cavity allows for coiling and looping of intestines. This adds extra area for more efficient digestion and absorption.

Phylum Mollusca

"Mollusca" means soft body.

A trocophore larva. This is a larval     form with a distinct structure and shape common to all mollusks in the      early stages. Usually show a bilaterally     symmetrical body. Three main body parts consisting of a     head-"foot," dorsal visceral organs and a mantle. The "foot"     is a muscular organ used for movement. The visceral organs include     a gut, a kidney, a heart and reproductive organs. The mantle is an     outer membrane, which in some mollusks, produces a hard shell or rod. Gills also exist in aquatic species and arise out of the mantle.

A slug, which you may occasionally see around the foundation walls of buildings, under boards or cement blocks, lacks any kind of shell, snails have shells.

This system, where the blood is not always confined to vessels, is called an open circulatory system. Gastropods are often hermaphroditic, although cross-fertilization is generally involved in sexual reproduction. Fertilization of eggs can occur internally or externally when eggs and sperm are released into the water.

Their active way of life is supported by a more efficient closed circulatory system. Continually enclosed in vessels, mixing of oxygenated and deoxygenated blood does not have to occur and movement, in general, is faster.

Phylum Echinodermata

Echinoderms are a group of "spiny-skinned" marine organisms common to shallow waters or tidal areas.

Adult echinoderms exhibit radial symmetry – five similar body segments arranged around a central core.

Unlike the adult forms, larvae hatched from eggs have a bilateral symmetry.

Unique to this phylum is a water vascular system. Each arm has many tube feet connected by a radial canal leading to a central ring canal. The ring canal has an external opening or sieve plate on the dorsal surface. When tube feet are placed on a surface and the organism forces some water out of the system, suction is created at the end of each tube foot allowing it to hold onto the surface. This enables the organism to move along the bottom by alternately holding on and then releasing with each of its arms. It also assists the tentacles in opening the shells of clams and oysters.

SUMMARY:

1. Porifera

􀂃 Two cell layers

􀂃 Differentiated cells but no co-ordination (No tissues)

2. Cnidaria (Coelenterata)

􀂃 Two cell layers

􀂃 Differentiated cells with co-ordination. Presence of tissues

􀂃 Digestive cavity with one opening

3. Platyhelminthes

􀂃 Beginning of bilateral symmetry

􀂃 Beginning of three cell layers. Presence of tissues and organs\

􀂃 Beginning of cephalization and a central nervous system

4. Nematoda

a. Digestive tube with two openings – a mouth and an anus

b. Presence of pseudocoelom

5. Annelida

􀂃 Beginning of segmentation

􀂃 Beginning of the coelom.

6. Mollusca

􀂃 Free-swimming trocophore larvae

􀂃 Prominent exoskeleton in some groups

7. Echinoderms

􀂃 Bipinnaria larvae (similar to chordates)

􀂃 Coelomic cavity development similar to chordates

􀂃 Water vascular system

What advantage is there to having a mesoderm?

Selected Answer:

The advantage of having a mesoderm is  that it (the mesoderm) gives rise to vital parts of   the body such as bone (skeleton), muscle, connective tissue, and   major organs.

Correct Answer:

[None]

Feedback:

in other words it allows for the  specialization of cells to the differnet body parts.

The unusual thing about a starfish stomach is that it ***.

Selected Answer:

c. can be pushed out of the body through   the mouth

A sponge seems to behave more like a colony of cells rather than a complete individual because ***.

Correct Answer:

c. the cells do not seem to work with each   other

Parasites which are commonly located inside the bodies of hosts seem to have few sensory developments. This would seem to be related to ***.

Selected Answer:

b. degeneration

The development of body segmentation in organisms is probably most important in that it ***.

Selected Answer:

a. permits different body areas to become   specialized for different functions

Cysts in parasitic worms are a means of ***.

Selected Answer:

a. remaining unchanged and inactive until   the life cycles can continue in other hosts

metazoa   g. multicellular

open circulatory system   c. blood is not always confined to vessels and there is mixing of oxygenated and deoxygenated blood

polyp form   b. a tubular body with a basal disk and tentacles around the mouth

What are three benefits to organisms in having coelomic cavities?



The coelomic cavity provides       separation between the outer body wall and the digestive tube, which        will consequently allow the muscles of each to act more freely        without interfering with each other.

Another major advantage of a       coelom is that the extra space of the coelomic cavity allows for the        coiling and looping of intestines. This also adds extra area for       more efficient digestion and absorption.

"The coelom is a fluid filled cavity that helps       absorb shock and provides a hydrostatic skeleton. It also allows        organs to grow independently of the body wall."

Small size is necessary as the processes of osmosis and diffusion, by which materials move in these organisms, are not efficient over long distances.

Indicate two ways that sponges reproduce asexually.

Selected Answer:

Sponges can give rise to       outgrowths or buds which eventually break off, fasten themselves to a        support and continue life as another individual. Sponge colonies are       developed in this manner. Some marine and many freshwater       sponge varieties could produce gemmules in the fall. These are       masses of mainly amoebocyte cells enclosed by thick walls. Like the       buds, these amoebocyte cells eventually break off the sponge and begin        life as a new individual.

LESSON THIRTEEN:::

This lesson concludes the examination of invertebrates with the phylum Arthropoda. Approximately four-fifths or 80 percent of all animal species, both invertebrates and vertebrates, are Arthropods. This very successful phylum has species located in oceans, fresh waters and all kinds of land environments. Organisms exist as free-living individuals, in colonies, as parasites, as agents of disease and in a multitude of other forms and relationships.

CHARACTERISTICS OF ARTHROPODS:

A prominent exoskeleton or     outer body covering, which serves to protect inner body parts and acts as      an attachment for body muscles. A major part of the exoskeleton is a     strong, flexible, carbohydrate material called chitin. Jointed Appendages A dorsal heart delivers blood though out     the body through arteries and sinuses. A ventral nervous system. These last two     characteristics are "backward" to ours. That is, mammals have     their hearts located in the ventral or lower halves (or fronts) of the      bodies while nervous systems are along the backs or upper halves.

􀂃 Chelicerata – The best known group in this sub-phylum is the Arachnida which includes spiders, scorpions, ticks, mites and other smaller groups.

􀂃 Crustacea – This sub-phylum includes lobsters, crab shrimp, krill, copepods and

Daphnia (water flea).

􀂃 Uniramia – This sub-phylum consists of the insects, the centipedes and millipedes. This group is considered uniramous which is explained later in this lesson.

SubPhyla Chelicerata

Class Arachnida

Arachnids are distinguished mainly by the way the appendages immediately around the mouth are shaped. Such arachnids as spiders, scorpions, mites and ticks have their first two pair of appendages, called chelicerae, modified for handling food and sensing. All arachnids lack antennae. They do have four pairs of walking legs. Many have two major body parts – a cephalothorax and an abdomen. The cephalothorax may be considered as a fusion of a head and thorax area.

Book lung. Connected with one opening to the outside on the ventral side of the abdomen, the book lung is responsible for respiration.

SubPhylum Crustacea

Movement of the legs also moves the gills which aids in gas exchange. Crayfish can remain alive out of water for a time as some water is trapped around the gills by the exoskeleton. Blood cavities or sinuses surround the gills, enabling gases to pass between the gills and the circulatory system.

NERVOUS SYSTEMZ: This is accomplished by rapid contractions and relaxations of the abdominal muscles and the help of the flipper like telson and uropods.

Uniramous refers to appendages (legs) that are unbranched (as opposed to biramous). Arthropods that display this feature are insects, centipedes and millipedes

Biramous refers to legs that have an outer branch which often forms a feather-like gill and an inner branch that is used for walking or modified for some other function. This feature is displayed in all other arthropods.

SUBPHYLA: UNIRAMOUS:

CLASS INSECTA:

The most varied and numerous animal grouping is that of insects. Entomologists, or people who specialize in insect studies.

Small size Complex sense organs and brain Jointed and modified appendages Special adaptations

Three body parts. The word "insect" is     derived from a Latin word referring to a sharp division. This is evident     in the distinct head, thorax and abdominal regions. Even though greatly reduced in some species,     insects have one pair of antennae. Adult insects have three pairs of legs, which     are attached to the thorax. Most insects possess one pair or, more commonly,     two pair of wings which also attach to the thorax. Some species have only     certain individuals develop wings or only at certain times (such as with      some termites and ants).

Breathing or respiration is accomplished by means of body tubes called tracheae with openings to the outside called spiracles.

A tympanum or ear is usually located a little above each of the last pair of legs (or jumping legs in the grasshopper).

Malpighian tubules clean an insect's blood and absorb nitrogen wastes from the blood which enters the sinus. The Malpighian tubules then transfers these nitrogen wastes into the intestines.

A form of reproduction called parthenogenesis occurs in some varieties – particularly in colonies. This type of reproduction involves the development of unfertilized eggs into individuals. In bees, for example, fertilized eggs (2n) develop into females while unfertilized eggs (n) develop through parthenogenesis into males.

Incomplete metamorphosis is a type of development where an insect hatches from an egg and acquires adult features and behaviors in a gradual manner through a series of molts (usually five to seven molts). Complete metamorphosis, on the other hand, is a type of development where an insect will (commonly) go through four development stages of egg, larva, pupa (chrysalis) and adult, with the larva and adult looking and behaving very differently (in the incomplete metamorphosis, the larva and adult did not change in general form, but did in size (the nymph or young in incomplete metamorphosis is really only a miniature form of its adult’s structure.).

Timing of egg laying, larval growth and pupa development seem to be regulated by chemicals produced in certain body parts. Other chemicals called pheromones are produced within the bodies and are released to the exterior surface. These appear to act as chemical messengers in helping organisms to locate each other, particularly during mating.

INSECT ORDERS ARE BASED ON DIFFERENCES IN:

􀂃 Types of mouth parts

􀂃 Kinds of metamorphosis

􀂃 Numbers of wings and types

Class Chilopoda

Centipedes - poisonous

Class Diplopoda

Millipedes

Differences between the two:

The first few segments of     millipedes bear a single pair of legs, with the remaining segments having      two pair each. In centipedes, however, each segment in their body bears     only one pair of legs.

The body structure of centipedes     is more flat, whereas millipedes are characterized by possessing more      "roundly-shaped" bodies.

Terrestrial crustaceans such as the sowbugs, sometimes found in basements or around foundation walls, require wet or moist environments because ***.

Selected Answer:

b. internal gills must be kept moist for   respiration to occur

Parthenogenesis generally results in, or produces, ***.

Selected Answer:

c. a new individual from an unfertilized   egg

Spiders eat prey by ***.

Selected Answer:

b. injecting enzymes into their bodies and   then sucking out the fluids

Arthropod bodies are usually restricted in size by their exoskeletons and by their systems for ***.

Selected Answer:

a. respiration

The kinds of habitats and food associated with most arthropods are usually related to ***.

Selected Answer:

a. the kinds, numbers or various   specializations of their appendages

Prairie grain and oilseed producers must use contact (rather than stomach) poisons to control insects which ***.

Selected Answer:

b. have sucking mouth parts

cephalothorax   d. fusion of the head and thorax area

ganglion   b. concentration of nerve fibres to form a "brain"

LESSON FOURTEEN:

CHORDATE SUBPHYLA:

1.   Urochordata (Sea squirts)

Cephalochordata Vertebrata

Vertebrata:

They have an endoskeleton, which is opposite from the exoskeleton in the sense that it is from the inside, guarding the major organs. The endoskeleton is not as restrictive to body growth or to mobility.

Closed circulatory system.

Larger bodies and increased or faster movements among vertebrates require a more efficient circulatory system than the open type characteristic of many invertebrates. Efficiency is improved by confining much of the movement of blood to closed vessels. This not only speeds up circulation but prevents the mixing of oxygenated and deoxygenated blood. Hearts in vertebrates become more ventral while the single nerve cord is dorsally located. (These positions are opposite to those of invertebrates.)

Class Agnatha

The general group of fish is a varied one, with members found in both fresh and salt waters.

Class Agnatha possesses what are considered primitive fish characteristics. Some of these are:

They are jawless. There are no paired      fins – they have single fins The presence of a      notochord remains throughout these organisms' lives. The skull and      skeleton are quite simple and lack bones, as cartilage is the skeletal       tissue. Members of Agnatha have      anywhere from 6 to 14 pairs of gill slits and gill pouches along the body       sides. Water enters the pharynx and the gill pouches where gas exchanges      occur between the water       and numerous blood vessels or gills. In the absence of      scales the smooth skin of these organisms possesses mucous glands which       can make the fish quite slimy.

Class Chondrichthyes

Rays and skates are flattened, triangular-shaped fish of this class.

1. They have a cartilaginous skeleton (which is the main distinguishing feature). This cartilage skeleton is retained throughout an individual's life. As with Agnatha, a notochord is retained as well.

2. They have two sets of paired fins: pectoral and pelvic. In rays and skates the pectorals are enlarged and extend around most of the body while the pelvic fins are greatly reduced.

3. They have placoid scales. These small "skin teeth" are made of the same material as the actual teeth in the jaws. Triangular-shaped, they are very sharp and can be quite abrasive. (At one time, cabinet makers used sharkskin as "sandpaper.")

Chondrichthyes lack of an air bladder. This internal structure is common in bony fish and is used to regulate buoyancy in the water. Its absence in a shark means that, with a body which is heavier than water, as soon as the fish stops swimming it sinks to the bottom. Some sharks do gulp air into their stomachs to increase their buoyancy.

Class Osteichthyes – bony fish

Fish have the same number of scales from the time they develop them. These scales increase in size as the fish grow.

Mucous glands are located in the skin among the scales. People who have handled pike ("jack"), trout and other fish, are probably familiar with the mucus or slime which forms and covers these fish. This mucus is valuable to the fish, not only in aiding movement, but serving to protect the fish from organisms such as bacteria, fungi and parasitic worms. The mucus helps to prevent their entry and acts almost like an antiseptic in killing the micro-organisms.

Osteichthyes have a number of pairs of gills and gill structures for respiration. Unlike the cartilage fish, however, there is only one external gill opening. This is covered by a protective plate called an operculum. Many of the external features common to most fish could be seen in the common perch in the next diagram.

DIFFERENCES BETWEEN CHONDRI’S AND OSTEICH’S:

By incorporating some minerals, their skeletons have become largely bone.

Most also possess a swim (or gas or air) bladder just under the spinal column. In some earlier, primitive fish, this was believed to be a type of lung. A presently existing lungfish in Africa has a connection between this and the fish's pharynx, allowing it to swallow bubbles of air at the water's surface. These fish can also form chambers in the mud in which they can survive if a water body dries out. In most fish, the connection with the pharynx has disappeared. Gases enter and leave the bladder by diffusing out of or into adjoining blood vessels.

The swim or air bladder in a fish such as a lake trout helps the fish by ***.

Correct Answer:

b. enabling the fish to better maintain   itself at particular depths

All senses are connected to a brain which has essentially the same parts as other vertebrate animals, including ourselves. This means that fish are quite good at interpreting senses and controlling body actions.

Separate sexes and external fertilization are characteristics of most bony fishes. External fertilization, which occurs in a process called spawning, is not a very efficient process. During spawning, a male releases milt (liquid with sperm) simultaneously with a female laying her eggs. Many of the eggs are not fertilized. The success rate of reproduction is further decreased when other organisms feed on the eggs and young fish.

Class Amphibia

Amphibians are somewhat of an in-between group in terms of a water and land existence. They are not completely independent of either environment. Almost all are dependent on water in part of their life cycle, even though much of the time may be spent on land. Most young amphibians are similar to, and have the characteristics of, fish. A metamorphosis, or change in body form, often results in adults with many body features suitable for a land existence.

CHARACTERISTICS:

The number of heart chambers varies from two (in larvae) to three (in adults).

Larvae are usually vegetarian and adults are carnivorous.

A thin, smooth, moist skin. In many amphibians this is permeable to water. Organisms can absorb water (and dissolved oxygen) through it and just as easily dry up in direct sunlight and warm temperature. (You may have seen shrivelled-up frogs or salamanders enclosed or trapped under such conditions.)

Fertilization is external. A male frog or toad often firmly clasps a female and pushes against her sides and abdomen helping to force the eggs out. (This clasping is called amplexus.) As the eggs are expelled from the female, the male fertilizes them.

The digestive system has the same parts which we have but ends in a common receptacle and opening for solid and liquid wastes as well as reproductive cells. This is called a cloaca.

Class Reptilia

characteristics

A thick, tough, dry skin covered with scales made of material similar to our own fingernails. This type of body covering limits the loss of water from the body and enables organisms to live under dry conditions if they have to. A characteristic which accompanies this is a pair of relatively well-developed lungs with internal folding to increase their area. This characteristic is made necessary as reptiles can no longer carry on respiration through the skin as amphibians and some other organisms were able to do.

Limbs better adapted to movement on land. The reptiles that have legs have them, are more directly under the body. (Amphibian legs extend sideways more and then down.)

One significant characteristic of body development that allows reptiles to make a move away from water is internal fertilization (which does not require water for sperm transfer) and an amniotic egg. The eggs have leathery or hard shells which are impenetrable to sperm. This means that eggs must be (internally) fertilized before the shells are formed.

The amniotic egg has a structure which enables it to be deposited in a land or dry environment without drying up, thus enabling organisms to not only reproduce inside the water but on the land as well.

Yolk sack provides nuritment for the embryo within the egg.

Most reptiles are oviparous, in that they lay their eggs.

A few varieties are ovoviviparous with eggs hatching internally and young being born alive. Garter snakes, which are common in Saskatchewan, reproduce in this way. (Mammals, such as us, are viviparous with young born alive after being nourished internally by means of a placenta.)

CROCODILES ARE REPTILES, HOWEVER, THEY HAVE A FOUR CHAMBERED HEART UNLIKE THE THREE CHAMBERED WITH A PARTIAL SEPTUM HEART OF REPTILIAS.

Class Aves

Fossils of the early Archaeopteryx would easily have passed for those of reptiles except for the clear imprints of feathers.

Probably the most distinctive feature about birds is the presence of feathers.

If you were an ornithologist or a person who studies birds, you would not have much difficulty finding subjects for studies whatever your surface location on this planet.

CHARACTERISTICS:

THE PRESENCE OF FEATHERS

Special modifications for flight

Weight reduction and a streamlining effect are also accomplished in some flying birds by a decrease in leg size and their placement farther back on the body.

Foot Characteristics

􀂃 The arrangement of toes

􀂃 Types of claws

􀂃 Whether or not there are webs

Beak Characteristics

􀂃 The type or shape of beak is an indicator of food diet

Three differences between altricial birds and precoccial birds are:

Altricial Birds lay from two to     six eggs, while precoccial birds lay anywhere from 8 to 20 eggs.

Altricial Birds’ incubation period     varies from ten days to two weeks, while the incubation period of      precoccial birds ranges from three to four weeks.

Altricial Birds who have just     hatched will promptly need the support of their parents for their vital      survival while precoccial birds are generally capable of movement      and feeding themselves after hatching.

Class Mammalia

The most distinguishing feature about all mammals is that they feed their young with milk produced by mammary glands in the skin. (This is how the class name originated.)

Around the nose and eyes of many animals are longer, thicker, tactile hairs or "whiskers" which assist the animals in "feeling."

The greater development at birth comes about due to a viviparous form of reproduction among most mammals.

Mammals are endotherms or warm-blooded.

Placental Mammals –

(This is not an order of mammals in itself but rather a grouping of orders that have the same ‘method of reproduction’).

This membrane or placenta is supplied with many blood vessels which function in the transfer of materials between the embryo and the mother. (The actual movement between the embryo and the placenta occurs through the umbilical cord.)

IN CLASS MAMMALIA, The most immediate features used for classifications are tooth and foot structures.

The body temperature and heartbeat rate of birds is so different (higher) than in other animals mainly because of their way of living. Birds must remain active in order to stay alive and hence, the maintenance of high body temperatures and heartbeat rate is very necessary. They are also characterized by having a high metabolic rate, which also is necessary for vigorous activities, such s flying over high altitudes during migrations.

Osteichthyes have a number of     pairs of gills and gill structures for respiration. Unlike the cartilage     fish, however, there is only one external gill opening -      Chondrichthyes fish have pairs of separate gill slits (or openings),      usually numbering five, located along the sides of the organism

Chondrichthye fish are     characterized by having a cartilaginous skeleton, while      Osteichthyes have skeletons composed from bone (giving them their      name, bony fish)

The common characteristic that these organisms share with each other, and thus places them into phylum chordate is the presence of a dorsal notochord (a flexible, rod like tissue which extends most of an animal's length).