13. How Populations Evolve

Gene trees are evolutionary trees that show the evolutionary lineages of specific genes separate from organisms. Below is a gene tree for the genes that code for opsins in humans. Opsins are the light sensitive proteins in the eyes. Humans have four opsins that are active in visual perception: long-wavelength sensitive (LWS or red-sensitive), medium-wavelength sensitive (MWS or green sensitive), short-wavelength sensitive (SWS or blue sensitive), and rhodopsin (RH, not color sensitive). Which mutational process would be most likely to create a gene tree like this?

Over short time periods, what would you expect to be responsible for creating the most genetic variation in humans?

The number of individuals in a population with each of the following genotypes is listed below. What is the frequency of the small t allele?

TT: 640

Tt: 200

tt: 160

Mutations that don’t impact the fitness of an allele can be called?

Natural selection is able to work independently on different genes that are found on the same chromosome because of which process?

Which of the following statements about mutations is correct?

Gia and Kojo collect a sample of beetles to calculate the frequency for the W allele. After genotyping the individuals in their sample, they count the following genotypes:

WW: 50

Ww: 170

ww: 120

Gia calculates the frequency by taking: $W=\frac{50+50+170}{680}$

Kojo calculates the frequency by taking: $W=\frac{2\left(50\right)+170}{50+170+120}$

Who calculated the frequency incorrectly, and what was their mistake?

When all the alleles in a population are considered together, independently of the individuals they come from, we call that the ___________.

Which process ensures that alleles are always found in new combinations?

Which of the following terms is correctly matched to its definition?