Example Of Disruptive Selection

Jessica Northey Exam Number 250104 1.Compare and contrast directional selection and disruptive selection, Provide and example of each. Directional selection and disruptive selection differ because instead of the subject only going in one direction it will split off and go two different ways for example if some flowers and their colors. The main colors may be red, pink and white primarily, and the more dominate color being a pink flower. But if we remove the pink flower completely from the equation then the flowers will shift toward the dominant white color over the red.

An example of this, is with the different species of mockingbirds that are located on the different islands. The mockingbirds’ beaks differ

We compared the level of difficulty for the bird to pick the food up and the amount. I found that the bigger the beak was the harder it was to pick up the food but gained a larger amount. The smaller the beak was the easier it was to pick up the food but gained a smaller

Directional selection and disruptive selection are two of the three types of natural selection. Although both of them result in a population adapting to biotic and abiotic environments, they differ in many ways. Directional selection occurs when one extreme phenotype is favored over the other phenotypes, whereas disruptive selection occurs when two or more phenotypes are favored over the others. Another difference is that disruptive selection favors polymorphism and directional selection causes species to evolve over time and leads to the extinction of those lacking the phenotypes causing the distribution curve to shift.

Natural selection is the process by which evolution occurs where organisms that are better suited to the environment (‘fittest’) survive and pass on favorable traits to the offspring. Organisms must adapt to the environment in order to survive. The stickleback fish adapted to the environment by keeping/removing the pelvic structures. For example, in Frog Lake, the all of the sticklebacks had complete pelvic structures because the lake was connected to a system of streams that allowed predators into the lake. The sticklebacks in Bear Paw Lake had reduced or absent pelvic structures because little/no predators are present in the lake.

Darwin noted that small different heritable traits in animals form from their chances of survival in natural selection. Darwin also believed in agenesis, the single transformation of a species and speciation, the isolated genetic changes in a species. The splitting and specializing phenomenon was another strong principle to Darwin's discovery of Evolution. The splitting and specializing phenomenon was the idea that two species could form from one species. The amount of shared characteristics between any species specifies how soon they have evolved from a shared lineage.

How long did it take for the populations to evolve into different populations with different colored coats? Did gene mutation cause a change in the coat color between populations of the Rock Pocket mouse? Hypothesis: Alternate hypothesis: Rock Pocket mice have different coat colors that help to their advantage that depend on their location through evolution. Null hypothesis: Rock Pocket mice don’t have different coat colors that help to their advantage that depend on location through evolution.

Directional selection means that natural selection is in favor of one extreme or another. An example of directional selection is that there is a green and red types of beetles. The predator in the area only likes green ones, this is a disadvantage for the green beetles. Another example, there are white rats and black rats. The predator, which is an eagle, the rats hide in mud; The eagle is able to see the white rats and eats them, that is an advantage to brown rats.

The reason for this is because the organisms with the least helpful phenotypes will be eaten by predators while the organisms with the better phenotypes will live on to breed, thus shifting the gene pool to go in a certain direction. I am able to move a total of 5 generations forward and each and every time I move the allele frequency will change to favor the superior phenotype, thus representing the

Organisms can evolve to enhance their ability to catch prey, or flee predators. Coevolution occurs in a predator-prey relationship when the prey evolves in response to pressures exerted by its predator. The predator then evolves in response to the changes in the prey (or vice versa). Inheritable adaptive traits evolve through natural selection, the process by which organisms that have developed favorable traits are capable of surviving and reproducing at greater rates, thus passing their adaptive traits to their offspring. Birds and caterpillars have a predator-prey

Depending on the conditions of the environment, the organisms may pass down selected traits to their offspring. These selected traits will allow for the next generation to better adapt and survive longer ["Natural Selection and Speciation - Biology."]. One example of evolution through the process of natural selection is that of the Viceroy butterfly. The Viceroy butterflies were facing extinction a little more than 100 years ago due to their inability to protect themselves or hide from their predators; mainly birds.

Some variations are favorable. Thick coats provide warmth to survive (thick coat advantage) More offspring are produced than survive. Half of the total cubs born survive Those that survive have favorable traits.

1. Explain why evolution often selects traits that promote genetic diversity. Evolution often selects traits that promote genetic diversity because genetic diversity boosts the chances that at least some members of the population will have a combination of traits that will allow them to survive and reproduce in a changing environment. Organisms that rely on asexual reproduction have virtually identical offspring, and they are successful in a stable environment; however, conditions rarely remain constant on Earth.

There are a least 14 species of Darwin’s finches that have developed over millions of years. When Darwin encountered the finches on the Galapagos Islands he noticed the diversity of the Finches beaks and size compared to each other. In Figure 1 you can see this. The diet of nuts and berries that the finches had access to on the island is greatly related to the size and function of the finches beaks (Grant, 2003). The larger beaked birds fed off of hard shelled nuts, while the smaller beaked birds fed off of smaller seeds and nectar from plants.

Compare with survival of the fittest. “The Hardy-Weinberg formulas allow scientists to determine whether evolution has occurred. Any changes in the gene frequencies in the population over time can be detected. The law essentially states that if no evolution is occurring, then an equilibrium of allele frequencies will remain in effect in each succeeding generation of sexually reproducing individuals. In order for equilibrium to remain in effect (i.e. that no evolution is occurring) then the following five conditions must be met: 1.