Factors Affecting Genetic Variation-Standard Bio 4.3

Question 1

Complete the T-chart by categorizing each environmental factor as something that would most likely increase or decrease genetic variation. Some answers will fit in both columns depending on the situation. Predator-prey relationships Competition Toxins New habitat Disasters Increased food source

Revolt · Accepted Answer

Complete the T-chart by categorizing each environmental factor as something that would most likely increase or decrease genetic variation. Some answers will fit in both columns depending on the situat: Decrease; Complete the T-chart by categorizing each environmental factor as something that would most likely increase or decrease genetic variation. Some answers will fit in both columns depending on the situat: Increase

Question 2

Disasters Increase✔ DecreaseBoth

Revolt · Accepted Answer

B: Decrease

Question 3

Read each example and identify it with one of the mechanisms that influence gene pools. A zebra migrates to join a different herd of zebras. Competition for sunlight leads to taller trees. The DNA of a snake changes to make its venom stronger. A grassfire randomly sweeps through a population of buffalo and kills most of the animals.

Revolt · Accepted Answer

Selection 1: gene flow; Selection 2: natural selection; Selection 3: mutation; Selection 4: genetic drift

Question 4

A zebra migrates to join a different herd of zebras.

Revolt · Accepted Answer

B: brings new alleles from other populations

Question 5

Read each example and decide whether each would increase or decrease the genetic variation in the gene pool of that population. A zebra migrates to join a different herd of zebras. Competition for sunlight leads to taller trees. The DNA of a snake changes to make its venom stronger. A grassfire randomly sweeps through a population of buffalo and kills most of the animals.

Revolt · Accepted Answer

A: Increase

Question 6

Complete the T-chart by categorizing each statement as something that would most likely be relevant to gene flow or genetic drift. Some answers will fit in both columns depending on the situation. is random is a mechanism for evolution is often related to disasters is also called “migration” deals with movement between populations

Revolt · Accepted Answer

Selection 1: Genetic drift; Selection 2: Both; Selection 3: Genetic drift; Selection 4: Gene flow; Selection 5: Gene flow

Question 7

Describe an environmental factor that could influence natural selection and decrease genetic diversity. Pick a specific example to illustrate your point.

Revolt · Accepted Answer

One environmental factor that can influence natural selection and decrease genetic diversity is a severe, prolonged drought. This environmental change acts as a selective pressure, favoring individuals with specific traits that allow them to survive in arid conditions—such as plants with extremely deep root systems or animals with high water-retention capabilities. Individuals that lack these specific adaptations are less likely to survive and reproduce. As a result, the alleles responsible for the less-favorable traits are removed from the population's gene pool, which narrows the overall genetic variation. A specific example occurred with Darwin's finches on the island of Daphne Major; during a severe drought, finches with smaller beaks were unable to crack the large, hard seeds that were the only remaining food source. This led to a significant decrease in the population of small-beaked finches, reducing the genetic diversity of beak sizes within that population.

Question 8

Increased food source ✔ IncreaseDecreaseBoth

Revolt · Accepted Answer

A: Increase

Question 9

Question 9

Revolt · Accepted Answer

C

Question 10

Question 10

Revolt · Accepted Answer

B

Factors Affecting Genetic Variation-Standard Bio 4.3 Answers

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