User:AMousou/Medium ground finch

Presentation Outline (Bullet Points):

What are the key topics that you plan to cover in your article (be specific!)?


 * Evolution:
 * Include the studies that have already been done on Medium Ground Finches from Charles Darwin that proposed evolution by natural selection.
 * Descriptions of the change in beak size and shape for Medium Ground Finches have been observed due to increased urbanization in Puerto Ayora will be included.
 * History of the urbanization of the islands that began the change in the Medium Ground Finches.
 * Habitat and Range:
 * write how they live in nests and how urbanization effects nest success.
 * Areas of increased urbanization will be included and a description of how those environments differ that may pose changes to Medium Ground finches.
 * Medium Ground Finch Change in Behaviors due to Urbanization (Indicated as “Behavior” on Wiki Page)
 * Medium Ground Finch.jpeg change in Medium Ground Finches in how social they are.
 * The change in behaviors for food preference.
 * The change in nesting sites.
 * The effect of urbanization on fitness for Medium Ground Finches.
 * Climate Change
 * Changing population size of medium ground finches and studies done in the past during El Nino years.
 * How changes in population are projected to change if climate change moves at the pace that it currently is moving.
 * Parasites
 * Add more information on the parasites and how some Medium Ground Finches have been able to co-exist with these parasites.

Lead:
The medium ground finch (Geospiza fortis) is a species of bird in the family Thraupidae. It is endemic to the Galapagos Islands. Its primary natural habitat is tropical shrubland. One of Darwin's finches, the species was the first which scientists have observed evolving in real-time.

Many studies and research has been conducted on medium ground finches; there are the most famous studies conducted by Charles Darwin and more recent studies conducted in relation to the changes revolving around the medium ground finches due to natural selection. Due to increase in urbanization on the Galapagos islands, medium ground finches have went through changes such as beak size, behavior in feeding, behavior in inbreeding, behaviors in nesting and more. The changes in the Galapagos islands are factors that affect the medium ground finches. There are also other factors that have been affecting the changes among medium ground finches, such as climate change and parasites.

Evolution:
The Galapagos island is famous for plant and animal life, it is now and has been for awhile an area of rapid urbanization. Since the 1990s, Galapagos tourism have increased by 9.4% per year and for resident population to about 6.4% per year. Rural areas on the islands which were privately owned, had wetlands which made it suitable for agriculture. This agriculture brought about invasive plant species, which included guava, passion fruit, and etc. The urban areas had more human activity like roads, shops and pollution. This area brought invasive species to the island like fire ants, black rats, etc. With these changes, medium ground finches that have short/stubby beaks adapted for eating seeds have shown change in their beak sizes and food preferences.

It is known that food is the main driver of beak size and shape in Darwin finches. Specifically in medium ground finches to be able to survive in urban areas, they had to adapt to new environments. Studies have shown that medium ground finches phenotypes have been more variable than of small ground finches on Santa Cruz Island, being consistent with previous findings that medium ground finches adapt more rapidly to local conditions than small ground finches. The speed of how medium ground finches have been able to change beaks sizes and shape may be centered around epigenetic. A research team run by Ms.McNew in Galapagos island have measured the physical traits of wild birds and the genetics and epigenetic of two Darwin finch species living at El Garrapatero, a rural area. They then compared the findings to urban finches living near Puerto Ayora, the two sites weren't far apart. Some of the earlier studies showed that only one female medium ground finch out of 300 that were marked and used in the research relocated between both sites. Later on, Ms.McNew then captured more than 1,000 small ground finch and medium ground finch species taking blood sample from females, sperm from males and physical characteristics from each finch.First they realized that a big difference between the finches was that the urban living finches dined on alot of human foods while the rural living finches didn't. They then discovered that medium ground finches from the urban living area were larger in beak size than those living in the rural area. As for the small ground finches living in urban areas, didn't have any morphological differences from the ones living in rural area. After performing this lab, Ms.McNew and her team looked for evidence through genetics and found no type of consistent evidence that can prove these phenotypic changes occurred through mutations. But when looking at epigenetic, there was significant evidence. In the finches studied, epigenetic alterations between the populations were dramatic, but minimal genetic changes were observed. The evidence showed in medium and small ground finches, most of the epigenetic mutations were related to beak size and shape.

In 1977, a severe drought reduced the supply of seeds in the Galapágos. The finch, which normally preferred small and soft seeds, was forced to turn to harder, larger seeds. This strong selective pressure favoring larger beaks, coupled with the high heritability of traits relating to beak size in finches, caused the medium ground finch population to experience evolution by natural selection, leading to an increase in average beak size in the subsequent generation. Evidence of evolution through character displacement has been found in a population of medium ground finches on the Galápagos island of Daphne Major. During a drought in 2004, overlap in the diets of the medium ground finch population and a recently settled population of large ground finches (Geospiza magnirostris) led to competition for a limited supply of seeds on which the medium ground finch population normally fed. Because the large ground finches were able to out-compete the medium ground finches for these seeds due to both a larger beak and body size, the medium ground finch population experienced a strong selective pressure against large beaks to avoid competition, ultimately leading to dramatic evolutionary change favoring smaller beaks in the subsequent generation.

Habitat and Range:
Endemic to the Galápagos, the medium ground finch is found on ten islands: Baltra, Floreana, Isabela, Fernandina, Seymour, Pinzón, San Cristóbal, Santa Cruz, Santa Fé, and Santiago. They are found on most of the main islands including the surrounding islets. They are found in semi-arid biomes. Medium ground finch make dome shaped nests, mainly in Opuntia cacti. These nests are made by the males.

Medium ground finches have a better chance of survival than small ground finches, due to their beak size. The beak size of medium ground finch can evolve in a relatively short period of time, depending on if it is a wet season or dry season. Survival and beak size of the birds are fueled by the environment. Weather conditions will favor one beak size over the other, causing birds of the unfavorable bill size to die off. The HMGA2 gene locus, is responsible for the evolution of beak size and plays an important role in natural selection.

The range size of a medium ground finch varies. It relies on many factors, such as the part of year it is, age, and the sex of the bird. Females that are incubating are more likely to remain in her nesting territory. Finches are 3.7 times more likely to travel to the brooding area than any other location.

Urbanization in the Galapagos is slowly increasing which directly affects the nesting success of the finches. Nests in urban areas are built using artificial materials, such as plastic, fishing lines, paper, and human hair. These materials cause death of the birds by strangulation, ingestion, and/or entanglement. Urban areas provide more reproductive success, however medium ground finches suffer by the usage of human-related debris. 97% of the Galapagos islands are protected nationals parks, however the increasing populations causes more dense urban areas. The islands are easily affected by anthropogenic changes, and urban development has a large impact on the environment, ecology, and evolution of the native species. The environmental changes such as increasing light pollution and noise directly affect the finches. Urbanization causes disruptions in ecological interactions, influencing selection pressures which causes phenotypes to be selectively modified. Areas of increased urbanization seem to have a less density of medium ground finches. as the abundance of humans leads to an abundance of food.

Behavior:

 * General Feeding & Changes in Feeding Behaviors:

The medium ground finch feeds primarily on seeds, although it is also known to eat flowers, buds, and young leaves, and the occasional insect. It forages either on the ground or in low vegetation. In urban areas, these birds exhibit a strong preference for human food items over their natural food sources. Scientists have found that due to urbanization, medium ground finches have access to a variety of food, such as human food Food has been a selecting agent for the various beak sizes present on the Galapagos islands. Scientists have found that due to urbanization, medium ground finches are showing changes in size and shape. Scientists conducted an experiment to observe the change in behaviors for feeding preferences among these finches; they found that the food the finches ate depended on the location those finches were in. The scientists observed feeding behaviors in four different locations of various levels of urbanization and tourist levels. Areas of high urbanization with high tourism showed that finches in these areas preferred to eat human food; whereas those finches located in more rural areas ate foods present in the area. The scientists also observed that these ground finches when given the preference between eating mainly human food or natural foods, they chose to each human food. Urbanization has caused an influence on feeding behaviors and preferences among medium ground finches. Further research has been conducted to determine why medium ground finches may be preferring human food rather than their natural food sources; scientists conducted an experiment to determine if their change and adaptive behaviors has a reason. Birds can detect bitter foods, sugar type and salty foods; each provides the bird with information. The bitter foods tell the birds that certain foods may be toxic; sugar type foods have high calorie gains, and salty foods have high contents of salt. With urbanization and the introduction of human food, scientists believe that preference for food may change as well. In a study conducted, beak wiping after eating human food indicated that the bird did not like the food that was just consumed; the study found that medium ground finches in remote areas wiped their beaks when given any human type foods, specifically oily type foods; ground finches in more urbanized areas fed more on sweet foods and wiped their beaks less than those medium ground finches in rural areas.

Studies conducted regarding feeding behaviors of medium ground finches in towns versus natural habitats with T. cistoides was also interesting. Medium ground finches are said to eat the seads from these types of plants; scientists did studies to see if urbanization would affect their behaviors on feeding on T. cistoides. Scientists found that there was a 1.25% increase on feeding on these seeds in more urbanized towns rather than natural habitats. This suggests that medium ground finches located in towns or urbanized areas had a phenotypic preference for small mericarps than did those finches in natural habitats. Those mericarps that were highly protected were more likely preyed upon by medium ground finches in urban areas. The results in this study found that with increased urbanization the interaction between medium ground finches and T. cistoides can be altered; where medium ground finches tend to prefer these small mericarps more than the finches in natural habitats. Scientists found that due to increased dispersal of the seeds of T. cistoides through birds and urbanization (such as seeds being dispersed by getting stuck underneath people's shoes or cars), there are more mericarps for medium ground finches in towns to forage from; this may be why more medium ground finches are foraging seeds from small mericarps. Due to urbanization, there has been an increase in an interaction between medium ground finches and T. cistoides due to the increased dispersal of seeds of this plant.


 * Inbreeding & Nesting Behaviors:

Inbreeding is said to affect medium ground finches; in years with low food availability inbreeding increases and this decreases reproductive success. In years with high food availability, inbreeding decreases and reproductive success increases. Finches in urban areas have more food availability than natural habitats due to human food; and due to this, reproductive success increases. This is how natural selection can occur; the birds' environment is influence the success of offspring and can possibly bring about evolution of finches in urban areas. Even though finches in urban areas have higher reproductive success they still exhibit mortality due to human pollutants such as plastic being trapped in nests. Overall, birds in urban ares have better outcomes for nesting than those birds in the natural habitat due to food availability. Birds in urban areas can become more adapted through having better reproductive and nesting success; this can influence a higher survival rate in urban areas.

Climate Change:
Due to climate change, El Niño and La Niña, are expected to occur more frequently. The amount of rainfall in the Galapagos is directly correlated to the amount of food. During dry years many finch will die of starvation, and individuals with the favorable traits will live on. In a La Niña year, low precipitations result in the scarcity of food for the finches causing low reproductive successes. During an El Niño year, higher precipitation leads to an increase in the food supply for medium ground finches. This food abundance leads to a fluctuation in breeding success, allowing the finch to produce up to twice as many eggs .The favorable conditions of an El Niño year, and the unfavorable conditions of a La Niña year influence the physical characteristics of the finches.

Medium ground finches are dependent on food for survival specifically seeds. If a change was to occur to the population it would be because of natural selection. A drought in 1977 led to a decrease in medium ground finches. The finches with the smaller beak size were able to live through the drought because of the rare small seeds available. It was the Grants that observed beak size had increased by 4% because only finches that knew how to eat larger seeds were able to survive and reproduce. In 1982, it rained heavily and there were an abundance of small seeds again. This led to a 2.5% decrease in beak size of medium ground finches, so it was easier and more efficient for the finches to eat the seeds. In this year large ground finches appeared. Then in 2004 there was a drought again, but the large ground finch species took over on the larger seeds that had became available and it led to competition with medium ground finches with large beaks. The large ground finches had a better advantage and alot of medium ground finches with large beaks died out and only the ones with smaller beaks were able to survive. With the climate changes occurring you would think medium ground finches would be able to survive because of their ability to adapt with droughts or heavy rain. The population of medium ground finches with a better chance would be with smaller beaks.

Parasites:
The medium ground finch has been under parasitism of the fly Philornis downsi as well as the avian pox virus (Poxvirus avium).

Philornis downsi:
The parasitic fly known as, Philomis downsi, was first documented in 1997; documentation of the parasite was found in the Galapagos Finches. The adult flies lay eggs in the nest of birds, when those eggs hatch larvae will feed off of the blood of offspring and mothers blood as well. 'The Philornis'' flies lay eggs in the nest including in the nestlings nostrils. The larvae feed on living tissue and in worst cases can perforate the bill. The larvae feed on living tissue and in worst cases can perforate the bill.''' Even with the data presenting that larvae do attempt to feed on adult female mothers, the feeding on adult mothers may fail. The feeding on adult females or its attempt to provides the female with exposure to the Philomis downsi antigens. Females are said to develop higher amounts of Philornis antibodies; this does correlate as females are mostly tending to the nestlings in the nest. Scientists require to do more studies, however, they have thought of possible advantages of adult females' exposure to such antigens as it may cause an advantage for their nestlings where antibodies can be transferred to their offspring. This can provide her offspring with an advantage and increase their survival. The survival of nestling birds from the fly will vary; sometimes Philomis downsi will have little effect on nestlings and sometimes Philomis downsi will cause none of the nestlings in a nest to survive. Studies conducted on medium ground finches on the island of Santa Cruz found that these finches are at risk. Scientists believe that within the next century, extinction of the medium ground finches can occur on the island of Santa Cruz; the Philomis downsi is showing a negative affect on the medium ground finches of Santa Cruz. '''Using a new mathematical model, a 2015 study suggested the population of 270,000 birds on Santa Cruz may become extinct in 50 years. In the Galapagos Islands there has been no indication of bird extinctions, however, this may become a possibility as more people begin to inhabit and visit the area, introducing parasites. Possible solutions include the introduction of parasitic wasps which would lay eggs on the larva, or cotton wool treated with a pesticide which the adult birds would use when constructing the nest.'''

Avian Pox Virus:
'''Although outbreaks of the virus have been historically rare, in 2008 there was an outbreak that showed to be present in 50% of the finches tested. As a result, the finches have developed antibodies to fight specific invasive parasites. The finches with the highest amount of antibodies tend to have the highest fitness, and therefore produce more viable offspring.'''