Unit 4 Topic 2: Chapters 8 and 9

Question 1

Define directional selection

Answer 1

A mode of natural selection where a single phenotype at one extreme of a trait’s range.

Question 2

What occurs during stabilising selection

Answer 2

The intermediate phenotype is favoured, leading to a strong decline to the upper and lower ranges.

Question 3

Defintion of morphology

Answer 3

The study of the size, shape, and structure of animals, plants, and microorganisms and of the relationships of their constituent parts.

Question 4

Gene pool definition

Answer 4

Consists of all genes including all different alleles present in a population.

Question 5

Microevolution Defintion

Answer 5

Small scale variations in allele frequencies within a species or population. The descendants are from the same taxonomic group as the ancestor.

Question 6

Macroevolution definition

Answer 6

The variation of allele frequencies that occurs at or above the species level.

Question 7

Consequences of macroevolution?

Answer 7

The divergence of taxonomic groups, with the descendant coming from a different taxonomic group to its ancestor.

Question 8

Define disruptive selection.

Answer 8

The natural selection process where extreme traits (phenotypes) are favoured over intermediate traits.

Question 9

What is one consequence of natural selection?

Answer 9

The development of a new species through speciation.

Question 10

Speciation definition

Answer 10

The process that creates a new plant or animal species. This separation means that the species develops its own characteristics.

Question 11

Definition of Evolution

Answer 11

The change in the genetic composition of a population during successive generations, which may result in development of new species.

Question 12

List 5 common drivers of evolution:

Answer 12

Sexual reproduction, mutation, genetic drift, gene flow, natural selection

Question 13

Explain when natural selection would occur?

Answer 13

When the pressures of environmental pressures of environmental selection confer a selection advantage on a specific phenotype. This enhances its survival (viability) and reproduction (fecundity).

Question 14

Define genetic drift

Answer 14

Genetic drift is a change in the frequency of an allele in a population due to random sampling. The alleles in the offspring are a sample of those in the parents.

Question 15

What can genetic drift cause?

Answer 15

Genetic drift can cause large changes in small populations.

Question 16

Natural selection is like genetic drift but with one major difference. Explain this difference.

Answer 16

It is not random. Unlike genetic drift which can be helpful, detrimental or have no effect, natural selection represents only positive change or adaptation.