Exam 21: Evolution: How Genotypes and Phenotypes Change Over Time

In New Mexico, large expanses of black lava create patches of unique habitat. If, in every generation, selection favors the darkest colored pocket mice in those habitats because they are best hidden from predators, this would be an example of:

The rate differences between molecular clocks are due largely to differences in _____. Thus, the extreme case of a fast molecular clock is derived from a _____.

What is a possible explanation for why a population may NOT be in Hardy-Weinberg equilibrium?

Inbreeding depression is a serious concern in small populations of endangered organisms. Why is inbreeding depression a concern for such populations?

You have been sequencing a gene that codes for a protein in the mitochondrial electron transport chain. If it is discovered that your gene is not responsible for an inability to interbreed between individuals in two different population of the same species, why might you still see an accumulation of genetic differences between individuals from the two different populations?

If two males compete directly with one another over access to a group of females, this is a form of:

Alfred Russel Wallace also developed a theory of evolution by natural selection (independently) around the same time as Charles Darwin.

Why is Hardy-Weinberg such a valuable tool when examining populations?

A population that is in Hardy-Weinberg equilibrium is evolving.

What is the frequency of the LLT-s allele in the population?

One key principle of natural selection is that there is competition for resources.

Why are mutation and recombination the only processes that can increase genetic variation?

In a given population, all humans have the same blood type O. If no other alleles for blood type exist in this population, this population is "fixed" for the O allele.

Why can't we measure genetic variation in a population using observable traits (phenotypes)?

A former protein-coding gene that no longer performs any useful function will accumulate how many mutations relative to a gene that encodes a protein that is functionally important?

A population that exhibits only one allele at a particular gene is:

Black-bellied seedcrackers are a species of bird found in central Africa. They live in various habitats where individuals eat either hard, large seeds or small soft seeds. Individuals with thick, shorter beaks can eat the harder seeds. Individuals with thin, longer beaks can eat softer seeds. Individuals with beaks of intermediate thickness and length cannot really eat either type of seed very well. If you measured beak width and length in populations of black-bellied seedcrackers, what type of selection would you expect to find?

In a hypothetical population of 1000 frogs there exists a gene with two alleles. 280 of the frogs are homozygous dominant (DD), and 220 are homozygous recessive (dd). What is the frequency of the D allele in the population?

Which of the following statements is TRUE regarding molecular clocks?

Evolution typically occurs when all conditions are at Hardy-Weinberg equilibrium.