Bio writtne assignment 1

Bio writtne assignment 1 - Logan Chastain Ben Clegg IB 150...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Logan Chastain Ben Clegg IB 150 Written Assignment 1. Directional selection can lead to the fixation of favored alleles. When this occurs, genetic variation is zero and evolution stops. Explain why this rarely occurs in nature. Fixation of favored alleles rarely ever occurs in nature for several reasons. The first and most important reason is random environmental factors that cause the “favored” alleles to change. Habitats and populations rarely have enough time to evolve to the point of fixed alleles before a new environmental factor (i.e. drought, a new predator is introduced, habitat changed by humans….etc.) is introduced that changes what the “best” allele for survival is. When this happens it causes the evolutionary pathway to change and move toward a different type of allele being the favored one. Another reason that this rarely ever happens is that natural selection is more based on which allele is better than which is the overall best. There is always room for genetic improvement, because there is hardly ever a perfect allele. The last reason that that evolution hardly ever stops is random mutations. Random mutations while mostly being harmful can sometimes introduce a new allele that is better for the organism. This starts the whole process of moving toward fixed alleles all over again. 2. When a population colonizes a new geographic location, why would genetic drift be an especially important process causing divergence during the colonization event? If the colonist occupy a different habitat from that of the source population, why would natural selection also be an important process causing divergence? When a population colonizes a new geographic location genetic drift is a
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

Bio writtne assignment 1 - Logan Chastain Ben Clegg IB 150...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online