What is the result of natural selection?

Question

a. the entry of alleles into a population due to immigration

b. the loss of alleles from a population due to emigration

c. a change in the gene pool of a population due to differential reproductive success

d. a change in allelic frequencies due to mutation

e. a chance change in the gene pool of a small population

Answer 1

Natural selection is the process by which a population adapts to its environment.  It ensures that genotypes which are more suited to a given environment will increase in relative frequency over the generations.  Individuals during their life span can on the other hand, adapt to the environmental changes.  Such adaptation is not genetically transmissible.  It may be called physiological or individual adaptation.  To cite an example, the darkening of skin a few weeks after exposure to the sun is a physiological non transmissible individual adaptation

Natural selection is the result of favourable variation in a population.  Individuals endowed with the favourable variation will inevitably have an advantage  over others  and a greater percentage of such individuals survive  and create off springs.  Gradually the frequency of this variation  increases.  In the long run, the desirable variation which was rare on its first appearance will turn to be a  trait by which  a population is specially marked.  Eventually contrasts between populations isolated ecologically or geographically ever widen due to continuous mutations and selection process so that mating is no longer possible between them and are apt to be christened separately.  Thus new species are formed  over years and very randomly.

Answer 2

I have to ask, did you pay attention at all in class this year?

Answer 3

c.

The biological definition of evolution is "change in allelle frequency in a population over time." Whenever you are asked a question about a part of evolution (natural selection, sexual selection, etc.) you should ask yourself "could this change the allelle frequencies (in plain english: the percentages of genes) in a population (a group) over time?"

An example would be if there was a disease that only struck black cows dead- the frequency of the black cow gene would change (go down) over time.

Answer 4

C

Answer 5

C.