Module 6

Question 1

2 Steps of evolution

Answer 1

1. the production and distribution of genetic variation (inherited differences among individuals), which are contributed by sexual reproduction and mutation.
2. Natural selection acts upon the variation among individuals, differentially causing some individuals to have more reproductive success than others. As a result over time, successful/beneficial traits become more common within the population, while unsuccessful/deleterious traits drop out.

Question 2

Genetic Definition of Evolution

Answer 2

A change in allele frequencies of traits from one generation to another.

Question 3

Allele Frequencies

Answer 3

Indicators of the genetic make-up of a population.

Question 4

Population

Answer 4

An interbreeding group of individuals (a.k.a. species).

Question 5

Microevolution

Answer 5

Changes in the allele frequencies of traits from one generation to the next, within a few generations.

Question 6

Macroevolution

Answer 6

The long-term effects of allele frequency change of traits which accumulate over many generations, that eventually result in the development of a new species(also known as Speciation).

Question 7

Mutation Notes

Answer 7

1. Mutation must occur in a gamete if they are going to have an effect on the evolutionary process.
2. Mutations are rare, random, and the only way to produce new genes (variation).

Question 8

Gene Flow

Answer 8

The exchange of genes between populations.
NOTE: Large-scale movements are not required, significant changes in allele frequencies can occur over time through gradual or sporadic introduction of genetic material from other populations.

Question 9

Genetic Drift

Answer 9

As a result of small population size, some individuals contribute a disproportionate share of genes to succeeding generations. Alleles with low frequencies simply may not get passed on to offspring, so they eventually disappear from the population.

Question 10

Founders Effect

Answer 10

A type of genetic drift. When a small migrant band of “founders” colonizers a new region away from its parent group. As long as mates are chosen only from this population, all of its members will be descended from its original founders.

Question 11

Gene Pool

Answer 11

The total complement of genes shared by reproductive members of a population.

Question 12

Genetic Bottleneck

Answer 12

A type of genetic drift. If a population is severely decreased (due to disease, over predation, scarce food resources, drastic change in environment, etc.), the few survivors of the group possess only a sample of all of the alleles that were present in the population before the ravaging event. By chance alone, some alleles may be completely removed from the gene pool. The outcome is a decrease in genetic diversity and the allele frequencies of the succeeding generations may be very different from the original large population.

Question 13

Directional Selection

Answer 13

When natural selection provides directional change in allele frequency according to specific environmental factors - leading to adaption.