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Final 7th Grade Science Report Theory of Evolution Amber Lopez 4th period 5/31/07

The purpose of this paper is to restate that we have learned this year. Theory of Evolution is Darwin thought, the species gradually changed over the years over many generations. Natural Selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. Survival of the Fittest is since food and other resources are limited, the offspring must compete with each other to survive.

Homologous structures are body parts that are structurally similar in related species; provide evidence that the structures were inherited from a common ancestor. DNA is deoxyribonucleic acid; the genetic material that carries information about an organism and is passed from parent of offspring. Common physical characteristics – fishes, amphibians, reptiles, birds, and mammals, for example, all have a similar body structure-an internal skeleton with a backbone. Common fetal characteristics (development before birth), during early development is these three organisms that go through same/similar stages. Fossils are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms.

The theory of evolution is it what Darwin found organisms evolved over millions of years into more complex creatures. Perhaps, Darwin thought, the species gradually changed over many generations and became better adapted to the new conditions. It was clear that Darwin that evolution had occurred on the Galapagos Islands. He did not know, however, how this process had occurred. Darwin had to draw on other examples of changes in living things to help him understand how evolution occurs. Natural selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. Most species produce far more offspring than can possibly survive. Since food and other resources are limited, the offspring must compete with each other to survive. Over a long period of time, natural selection can lead to evolution. Helpful variations gradually accumulate in a species, while unfavorable ones disappear.

Species is a group of similar organisms that can mate with each other and produce fertile offspring. A new species can form when a group of individuals remains separated from the rest of its species long enough to evolve different traits. The longer the group remains isolated from the rest of the species, the more likely it is to evolve into a new species.

Fossil is the preserved remains or traces of an organism that lived in the past. Most fossils form when organisms that die become buried in sediments. Most of what scientists know about extinct species is based on the fossil record. The fossil record also provides clues about how and when new groups of orgasm evolved.

Individual’s alleles control the inheritance of traits. Some alleles are dominant, while other alleles are recessive. Geneticists use Punnett squares to show all the possible outcomes of a genetic cross and to determine the probability of a particular outcome.

Some human traits show a large number of phenotypes because the traits are controlled by many genes. The genes act together as a group to produce single trait. Because males only have one X chromosome, males are more likely than a sex-linked trait that is controlled by a recessive. The main goal of the Human Genome Project is to identify the DNA sequence of every gene in the human genome. Over a long period of time, natural selection can lead to evolution. Helpful variations gradually accumulate in a species, while unfavorable ones disappear. A new species can form when a group of individuals remains separated from the rest of its species long enough to evolve different traits.

The rock cycle is the series of processes on and beneath Earth’s surface that changes rocks from one type of rock to another. The major types of fossils include petrified remains, molds, casts, carbon films, trace fossils, and preserved remains. The extinction of dinosaurs at thy end of the “Mesozoic Era” made an opening for mammals, which evolved to live in most environments on land, in water, and in thy air.

Modern classification systems are based on evolutionary history. All living things must satisfy their basic needs for energy, water, living space, and stable internal conditions. Organisms are classified in seven levels: kingdom, phylum, class, order, family, genus, and species. Species with similar evolutionary histories are classified more closely together.

The first forms of life on Earth were similar to bacteria. Bacteria are prokaryotes. Their cells do not have nuclei that contain the cell’s genetic material. Instead, the genetic material floats freely in the cytoplasm. Bacteria reproduce asexually by binary fission, which results in the production of two cells exactly have a simple from of sexual reproduction called conjugation. This process results in a cell with a new combination of genetic information.

Land plants evolved from green algae. Vascular plants are better suited to drier conditions than are nonvascular plants. Plants are autotrophs. All plants are also multicellular eukaryotes. Green algae is a larger form of algae

Gymnosperms were the first group of seed plants to evolve. Angiosperms first appeared about 100 million years ago. See plants have evolved adaptations to different environments. All gymnosperms produce naked seeds. Many gymnosperms also have needle like or scalelike leaves, and grow deep root systems. Two characteristics of angiosperms are that they produce flowers and fruits.

A diagram of an evolution tree shows the major animal phyla are related. Animals are multicellular organisms that obtain food by eating other organisms. Animals can move. Most reproduce sexually. The bodies of complex animals all have either radial or bilateral symmetry.

The natural history of mollusks is recorded by fossils. Arthropods arose in the oceans. Most mollusks have shells, soft bodies, a mantle covering internal organs, and a muscular foot. Major groups of mollusks include gastropods, bivalves, and cephalopods. Arthropods have an exoskeleton, jointed appendages, and a segmented body. While some insects are harmful to humans, the vast majority are harmless or beneficial.

An evolution-tree diagram shows relationships among major vertebrate groups.