2.2 ORGANISMS

Question 1

What is evolution?

Answer 1

A change over time in the proportion of individuals in a population differing in one or more inherited traits

Question 2

Evolution occurs through which processes?

Answer 2

Random and non-random processes

Question 3

Give an example of a random evolutionary process.

Answer 3

Genetic drift

Question 4

What is genetic drift?

Answer 4

The random change in the frequency of a particular allele within a population

Question 5

In which type of population is genetic drift more important?

Answer 5

Small populations

Question 6

Why is genetic drift important to small populations?

Answer 6

Alleles are more likely to be lost from the gene pool

Question 7

Give two examples of a non-random evolutionary process.

Answer 7

Natural selection, sexual selection

Question 8

Why are natural and sexual selection described as non-random processes?

Answer 8

Certain alleles become more frequent in the population because they confer a selective advantage

Question 9

What is mutation?

Answer 9

The original source of new DNA sequences

Question 10

What is the result of mutation?

Answer 10

Variation in traits arises as novel alleles are formed

Question 11

Mutations can be?

Answer 11

Neutral, harmful or beneficial to the evolutionary fitness of an individual

Question 12

What are the two types of fitness?

Answer 12

Absolute fitness, relative fitness

Question 13

What is absolute fitness?

Answer 13

Ratio of frequencies of a particular genotype from one generation to the next

Question 14

What is relative fitness?

Answer 14

Ratio of surviving offspring of one genotype compared with other genotypes

Question 15

What happens when organisms produce more offspring than the environment can support?

Answer 15

Individuals with variations more suited to the environment are more likely to survive and breed

Question 16

What happens to selected alleles?

Answer 16

They become more frequent in subsequent generations through inheritance

Question 17

What is the result of high selection pressures?

Answer 17

Rate of evolution becomes rapid

Question 18

Name four ways to increase the rate of evolution.

Answer 18

High selection pressures, shorter generation times, warmer environments, sharing of beneficial DNA

Question 19

How is DNA shared?

Answer 19

Through sexual reproduction and horizontal gene transfer

Question 20

What is horizontal gene transfer?

Answer 20

Transfer of DNA sequences using plasmids

Question 21

What is co-evolution?

Answer 21

When a change in traits of one species acts as a natural selection pressure on the other species and vice versa

Question 22

When does co-evolution occur?

Answer 22

When pairs of species interact frequently or closely

Question 23

Give four examples of co-evolutionary relationships.

Answer 23

Herbivores and plants, pollinators and plants, predators and prey, parasites and hosts

Question 24

What is the term given to ongoing co-evolution?

Answer 24

Red Queen Hypothesis

Question 25

What does the Red Queen Hypothesis state?

Answer 25

Both organisms must “keep running in order to stay still”

Question 26

What does the Red Queen Hypothesis explain?

Answer 26

Sexual reproduction evolved as a way to produce variation more readily than relying on mutation alone

Question 27

Co-evolution can be described as?

Answer 27

An ‘arms race’

Question 28

How can parasites increase their fitness?

Answer 28

Better their ability to feed, reproduce and find new hosts

Question 29

How can hosts increase their fitness?

Answer 29

Better their ability to resist and tolerate parasitism