Read the questions below carefully and provide the most accurate, complete answe
ID: 192845 • Letter: R
Question
Read the questions below carefully and provide the most accurate, complete answer. Use extra paper if needed. What are the five driving forces in evolution? Define and describe each one being sure to include specific examples of each. (8pts) 1.) B 2.) A population of lizards is separated into two populations due to rising water levels submerging a land bridge that has been there for thousands of years. The two populations adapt to their individual areas and we see signifanct differences in body size, coloration, and diet. Compare (5 pts) and contrast allopatric versus sympatric speciation and describe which one applies to the lizards.Explanation / Answer
1).
Evolution, as a scientific discipline, comprises 3 main field of research: the origin of life, evolution as a description of the history and evolution as an ongoing process. Since evolution is consider a genetic process in populations, there are 5 forces which play major roles in contributing to such genetic variations.
A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. Gene mutation can be classified in two major ways: hereditary and acquired.
Gene flow is a natural process that contributes significantly to the evolution of organisms. By a simple definition, gene floe indicates the movement of genetic material (genes or alleles) from one organisms to another. In population genetics, gene flow (also known as genet migration) refers to the transfer of alleles or genes from one population to another. Theoretically, there are 2 types of gene flow: vertical and horizontal gene flow.
Mutation and gene flow share one important quality; if they continue from generation to generation they can result in what appear to be progressive changes in gene frequencies that can give the appearance of directionality. In addition to mutation and gene flow are change that have no predictable constancy or direction from generation to generation. Genetic drift, one of the most important of such random or non-directional forces, is a consequence of random fluctuations in gene frequencies that arise in small populations. In larger populations, genetic drift is countered by selection.
While the observation that individual don’t mate randomly with respect to particular traits there is no clear definition of what exactly constitutes non-random mating. The term is applied to those situations in which the observed frequencies of various mating combinations cannot be predicted solely from the joint distribution of male and female phenotypes or genotypes.
Natural selection would produce or maintain adaptation as a matter of definition. Whatever gene is favorably selected is better adapted than its unfavored alternatives. This is a reliable outcome of such selection, the prevalence of well-adapted genes. The selection of such genes, of course, is mediated by the phenotype, and to be favorably selected, a gene must augment phenotypic reproductive success as the arithmetic mean effect of its activity in the population in which is selected.
2) Sympatric and Allopatric speciation: Comparison and contrast
Considering the definitions of both allopatric and sympatric speciation, the example mentioned can be considered as an example of allopatric speciation, which is separated by the level water causing geographic isolation and evolving in different directions.
3)
3.1
q2= 0.36
q= square root (0.36) =0.6
The frequency of “aa” = q2=0.36
3.2
Frequency of “a” allele:
q= square root (0.36) =0.6
3.3
Frequency of “A” allele:
p+q=1
p+.6=1
p=0.4
3.4
Frequency of “AA” = p2
P+0.6=1 then p=0.4
p2= 0.16
Frequency of “Aa”= 2pq
Frequency of “Aa”= 2(0.4)(0.6) =0.48
3.5
The frequency for “aa” phenotype will be still considered as 36% and since “A” is completely dominant over “a” the rest of the frequency for the other type of phenotype will 64%.
4)
Natural selection is a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
Sexual selection is a form of selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.
From the graphic that belongs to petal size, we observed a strong positive correlation with the selected success. This implies that the petal size is an important feature for the selection of the wildflower plant. On the other hand, leaf length graphic we observed a none correlation with the selected success of the wildflower plant. This species of mildflower is known that the flower structure has an invisible nectar guide pattern, which attracts its pollinators, moths, butterflies, and bees. From this, we can assume that the plant is selected by sexual selection.
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