World Population and Beak Size

According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.

The documentary, “Darwin’s Dangerous Idea” tells the story of Charles Darwin’s conception of his theory of natural selection, and how it explains the evolutionary process and species adaptation. The story begins with a brief overview of his 5-year stint on the HMS Beagle as the ship's naturalist, during her South American voyage. The film shows how Mr. Darwin collected fossils and many species of animals and birds from many different regions especially the Galapagos Islands. It portrays Mr. Darwin’s return to England and his struggle between the mainstream religious beliefs and his personal beliefs of how different species came to be. Additionally, the documentary covers his presentation of fossils and ideas to the scientific community,

Over the last several years, evolution has been playing an increasingly important role in determining how various species are evolving. This is because ecology will have an impact on how quickly a particular organism is able to adapt (with: the unique challenges for a particular environment). To determine the effect that this is having requires carefully examining different species over the course of many years. This will be accomplished by comparing these changes on Darwin and Wallace Islands. Once this occurs, is when specific insights will be provided that are highlighting the underlying challenges affecting the development of organisms. This is the point that these transformations will be evident among the various life forms. (Fasolo, 2011, pp. 53 68)

The reason for doing this lab is to study evolution using small population of finches on two different islands. I used different charts and graphs to find limitations on natural selection. Then find the effect evolution will have on beak and population over a certain time period. Using three different assignments I have to develop different hypothesis comparing and contrasting the average beak size and population size changing rain fall, beak sizes, population and island size on Darwin’s and Wallace experiments.

The Beak of the Finch by Jonathan Weiner explores evolution through the most famous examples in history—the finches of the Galápagos Islands. Charles Darwin’s theory of natural selection and the process of evolution are applied directly to what scientists refer to as Darwin’s Finches. Weiner follows scientists Peter and Rosemary Grant as they study the finches in real time on the Galápagos. Years of previous work, study and data is collected and analyzed. Different species of animals are observed and explained throughout history. The Grants have one goal, and that is to find the origin of the species, how organisms first began. They find that it really is about the “survival of the

The Evolution Lab simulates environmental situations to determine effects on evolution over periods of time. This lab experiments with the evolution of finches on two different islands over 100, 200, and 300 years. By manipulating parameters that influence natural selection, the effects that natural selection have on the evolution process can be studied.

1. Define evolution. There are many parameters and conditions that need to be in place in order for evolution to occur. One such parameter is that the population trait in question must be variable. i.e., there will be variations of a trait found in the population. What are some additional parameters and conditions necessary for evolution to take place?

The Galapagos Islands consists of thirteen major islands and over a hundred smaller islands located along the Ecuadorian coast. The islands are home to a variety of unique species such as sea lions, sharks, rays, and 26 different species of native birds. Thirteen of these birds are Darwin’s finches. These finches are known to be the “world’s fastest-evolving vertebrates” due to their bodies quickly adapting to the rapidly changing environment (Robertson, N.D. , para.1). Their DNA chemical makeup causes these adaptations to occur. The finch’s most noticeable feature is their evolutionary adaptations, due to the briskly changing environments.

In 1977 a drought reduced the number of small seeds available for the birds, forcing them to rely on larger seeds and nuts, which were difficult for birds with smaller beaks to open. The number of birds unable to eat reduced as they died and gave way to harder beaked finches. Within a couple of generations they had evolved larger beaks. In 2003 another drought struck the Galapagos and as there were many large beaked finches, the food source of nuts dwindled, making the ability to eat smaller seeds an asset. The numbers of larger beaked birds dwindled as food became scarce, leaving the smaller birds to survive and reproduce. Darwin’s theory was not well received when first written in On the Origin of Species, though many scientists today use it as a basis for research in evolution.

In the Galapagos Islands there is an island named, Daphne Major, this island plays as the host of the Galapagos finches. In 1976 - 1977 there was an absolute near extinction of these finches. This is because of the drought of 1976 and 1977 (see figure 1). While the drought made the Finch population dwindle there was a hidden trait that was helping some survive, and that is beak size. Why did the larger beaks help those fortunate Finches survive? Because the only plants that survived where plants like the Tribulus, which produces hard shelled seeds. While there was an abundance of hard shelled seeds there was a shortage of soft shelled seeds. The finches that had the larger beaks weighed more, for example, survivors weighed approx. 12.5g to 17.5g with beak sizes going from 10.5 to 13.6(for evidence see figure 2. This reduced the population because the Finch’s with the smaller beaks couldn't open the harder seeds and had to scavenge for soft seeds which were very rare. The finches with small beaks, then died from starvation

He finally observed that overtime these birds developed different physical characteristics to help them be able to survive and adapt to their surroundings. Darwin developed the “Natural Selection” theory that stated that plants and animals adapt to their surroundings and environments in order to survive. He also stated that older generations of these species would eventually die out, because they do not have the newer characteristics that needed to be developed in order to live.

When that happens over many generations a species’ gene pool changes to only include the traits that are a best fit for ensuring survival of that species, and a new species may evolve. In the case of the Galapagos finches Darwin studied, biologists have since found that one of the differences was their beak size, which were adapted to the specific seeds available to the finches as food on the different islands. This would support this principle as only the birds able to eat the local seeds would be able to survive to reproduce, thus over many generations, new finches with a variety of different beak sizes would “evolve”. The

In observing the fossils, Darwin also noted similarities between the earth, the swimming and the flying animals. An example of this is pentadactyl limb. This is a homologous structure that can be found in humans, cats, bats and whales. During Darwin's journey on the Beagle, he met the Galapagos Islands. He not only noticed that the species in the Galapagos Islands deviated from the permeable islands, but that the species differed on the island itself. As he watched the turtles, Darwin noted similarities and differences that turtles had. The different qualities these creatures had were the shape, size and color of the shell. These features were all similar, but they had small changes as if they had been adjusted. Darwin also noted similarities and differences found in a group of birds. These birds are more famous than Darwin's finches. Like the turtles, the finches had many similarities, but they also varied in size and shape, color, and had aesthetic differences, such as the shape of the beak. The fossils found in an area are usually the deceased of the species that currently live there.

From there, the newly inhabited populations performed the process of specialization in which they adapted to their individual resources and environments. This differentiated the populations and confirmed the process of speciation as they became their own species in isolation. Specialization can be found in the different beaks of the finch species. The different sizes and shapes of the beaks are a result of the different sizes and shapes of the seeds that the populations feed on in their own niches. For example, bigger and bulkier beaks can help crack open harder seeds, whereas smaller beaks can be more successful in obtaining smaller seeds. And longer and thinner beaks can help reach into flowers, whereas medium sized can be more successful in obtaining insects. Because of this separation in characteristics, these different finches do not continue to breed with each other, resulting in fully separated species with their own traits. The specialization found between and within the species is a direct result of the geographic isolation that occurs from adaptive radiation.

It had a beginning, but it has no ending. Creation is always busy making new scenes, new things and new Worlds” (Weiner 3). In the bible it states that all living things were created at the hands of God. No one has ever desired to challenge the Catholic Church of this belief. Until a man by the name of Charles Darwin discovered the wonders on Daphne Major. After his survey of the island, he concluded that there was something about the finches beaks that made them unique to each of the islands. Making meticulous observations of the beaks he saw that each finch had a specific set of beaks. This allowed them to adapt to a specific niche in their environment. “What is more. the tame little birds that Darwin had found hopping around beneath the bushes were unique too. They were not relatives of blackbirds, walders, wrens, and finches, as Darwin had thought when he bagged them” (Weiner 28). Darwin speculated about how natural selection is one of the main concepts for biological evolution. Natural selection consisted of descent with modification, known as a gradual process over time, heritable biological traits become either more or less common in a population. When the next generation of that species gains that dominant trait in the population, this is known as descent with modification. Observing descent with modification is still prominent during that time period. According to the Variation Lab, natural selection was the driving mechanism for biological evolution.