Question

. Forest logging removes trees, leaving behind only smaller bushes. Some rats in a depleted forest have an allele that makes them smaller than normal rats. It is easier for the small rats to hide from predators in the bushes.

a) Give three reasons that the rat population is not at Hardy-Weinberg equilibrium. (6 points)
There is gene flow between populations, mating is assortative and natural selection is taking place from the variations offered and by recombination and mutation. Alleles are changing frequency in the population of rats and negating Hardy-Weinberg constraints.

b) How will the allele frequency change in the rat population? (3 points)

c) Is this an example of natural selection? Explain. (4 points)

d) Has genetic diversity helped or hurt the survival of the rat population? Explain. (4 points)

e) The allele for small size is recessive, and the allele for normal size is dominant. The frequency for the normal-size allele is 0.72. What percentage of the rats are normal sized? (3 points)

Answer 1

.)
1.* Population must have random mating, Assortive mating is probably occurring as there are probably increasing rates of smaller rats to mate with, and the smaller rats are able to reproduce because they have the bushes for shelter whereas the big rats have no shelter and no protection from predators.*
2. *There can’t be selection leading to loss/gain of alleles-This population is losing alleles because selection is pressing on the larger rats, while the smaller ones are reproducing effectively.*
3. Mutation can’t occur-you don’t know this
4. Migration can’t occur, linking populations- you don’t know this
5. Small population size causing sampling effect- you know nothing about the population size.

b.)the smaller rats have protection from the elements and from predators. They are being selected for , not the large rats because they have become more vulnerable with the change in environment.

c.) You would expect more small rat alleles in the gene pool because they are in their environmental niche, where as the larger rats are having a more difficult time in this environment.

d.) This is an example of Natural selection selecting for the smaller rats. The animals that struggle in the new environment,or with the new environmental changes are being selected against. According to Darwin, this can lead to an opportunity for evolution of the species.

e.) Having diversity gives at least some of the species the opportunity to adapt and survive to the new environment. Having the smaller rats in addition to larger rats has given them the ability to adapt to different niches. If the bushes had died but the bigger trees that only the big rats could access had survived, the larger rats would have been selected for. Having this diversity has helped the population.

Answer 2

^The first letter was supposed to be an A ;)

Answer 3

Soooo

Answer 4

.)
1.* Population must have random mating, Assortive mating is probably occurring as there are probably increasing rates of smaller rats to mate with, and the smaller rats are able to reproduce because they have the bushes for shelter whereas the big rats have no shelter and no protection from predators.*
2. *There can’t be selection leading to loss/gain of alleles-This population is losing alleles because selection is pressing on the larger rats, while the smaller ones are reproducing effectively.*
3. Mutation can’t occur-you don’t know this
4. Migration can’t occur, linking populations- you don’t know this
5. Small population size causing sampling effect- you know nothing about the population size.

Answer 5

All of this is A?

Answer 6

@krisssssssssssss