Question

For each event or condition described below, match the correct answer to the following questions.? Populations evolve for many reasons. Suppose there is a population of plants that have either purple flowers or white flowers, and the allele for purple flowers is dominant. This means that plants with two purple alleles have purple flowers. Plants with one purple allele and one white allele also have purple...

Answer 1

Complete question;

Populations evolve for many reasons. Suppose there is a population of plants that have either purple flowers or white flowers, and the allele for purple flowers is dominant. This means that plants with two purple alleles have purple flowers. Plants with one purple allele and one white allele also have purple flowers. Only plants with two white alleles have white flowers. 

Which mechanism of evolution is at work? 
How does this event affect the population’s gene pool? Do the frequencies of the two alleles change, and if so, how? 



1.During an extreme heat wave, plants with white flowers survive better. 

2. Workers from a nearby greenhouse accidentally introduce white flower seeds into this population's habitat 

3.A storm kills many plants at random. 

4. A person uproots the five closest plants, all of which happen to have white flowers. 


A. Mechanism is gene flow and frequency of white allele increases 

B. Mechanism is genetic drift and allele frequencies stay the same 

C. The mechanism is genetic drift and allele frequencies change but not predictably. 

D. Mechanism is genetic drift and the frequency of the purple allele increases. 

E. Mechanism is Natural Selection and frequency of white allele increases 

F. Mechanism is gene flow and allele frequencies change but not predictably.

The answers are the below:

  Gene flow: genes from one population are transferred to a different population 
Genetic drift: random changes of allele frequency within a population from one generation to the next 
Natural Selection: a test of the fitness of an organism to survive and reproduce in a specific environment. 



1:E - Heat kills more purple plants, total white alleles increase. Natural selection because the white plants are more suited to their environment (ie they die less) than purple plants. 

2:A - Gene flow because genes from one population (the greenhouse) are introduced into another population (the general population). White alleles increase because now there are more white seeds than before. 

3:C - Genetic drift because the plants that die are random color. The frequency is likely to change (although it could stay the same, but it's unlikely) but you don't know how it changes unless you know which plants died. 

4:D - Genetic drift because (presumably) the plants were chosen at random. And the amount of white alleles decrease because it was white flowers that died.