Evolution & Natural Selection

Question 1

What 3 things can cause mutations

Answer 1

Radiation
Viruses
Carcinogens

Question 2

What affect do mutations have on a gene pool

Answer 2

They increase variation

Question 3

Give an example of an advantageous mutation

Answer 3

Peppered moth - darker pigment helped camouflage to trees in industrial revolution

Question 4

Give an example of a disadvantageous mutation

Answer 4

Yellow mice - less camouflaged therefore more vulnerable to predation

Question 5

What is an example of microevolution

Answer 5

dog breeds

Question 6

What is an example of macroevolution

Answer 6

speciation - Galapagos finches

Question 7

what is polymorphism and give an example

Answer 7

the occurrence of different forms among the members of a population of colony

i.e: hair colour, eye colour, fur texture, wing shape

Question 8

Name 3 pieces of evidence for evolution

Answer 8

Any from:

1. Fossil record showing change over time of species
2. Transitional forms in the fossil record
3. Comparative anatomy (similarities in anatomy)
4. Homology
5. Vestigial structures
6. Biochemistry (molecules and genes)
7. Antibiotic resistance – natural selection in action
8. Geographic distribution of related species

Question 9

What is homology ?

Answer 9

The similarity of a structure or function of parts of different origins based on their descent from a common evolutionary ancestor

Question 10

What are Vestigial structures

Answer 10

Structures that have no apparent function - i.e; appendix in humans

Question 11

What is a human appendix an example of?

Answer 11

A Vestigial structure

Question 12

briefly outline Darwin’s theory of natural selection

Answer 12

There is variation between individuals in a species
Individuals compete with each other for resources
Those with better characteristics are more likely to survive and reproduce
The less successful individuals die out

Question 13

What 4 factors does Darwin’s theory of natural selection observe

Answer 13

• High reproductive potential - organisms produce more offspring than will survive
• population size remains constant (despite multiple offspring being born)
• Resources are limited
• competition is inevitable

Question 14

What are the 4 key points of Darwin’s theory

Answer 14

Natural selection is NOT random

It only works on heritable traits

Environmental factors are variable (right time, right place for ‘good’ traits)

Individuals with better traits survive

Question 15

What are the 3 types of natural selection

Answer 15

Directional
Stabilising
Disruptive

Question 16

What is directional selection

Answer 16

a mode of natural selection in which a single phenotype is favoured, causing the allele frequency to continuously shift in one direction
- occurs when environmental conditions favour one extreme of the phenotype

Question 17

When does directional selection often occur?

Answer 17

When environment changes / individuals change location

Question 18

What is stabilising selection?

Answer 18

opposite of directional selection – genetic diversity decreases as the population stabilizes on a particular trait value
- intermediate traits are favoured and extreme phenotypes are eliminated

Question 19

What does stabilising selection do to a population’s gene pool

Answer 19

Reduces genetic variation because there are less extreme phenotypes

Question 20

What is disruptive selection

Answer 20

when extreme values for a trait are favoured over intermediate values
- extremes at either end of the spectrum (so the mean is selected against = is reduced)

Question 21

When may disruptive selection occur?

Answer 21

when environmental conditions take distinct forms that selects for individuals with traits at either end of the phenotypic range

Question 22

Which type of selection can lead to speciation?

Answer 22

Disruptive

Question 23

Which is the rarest type of selection?

Answer 23

Disruptive

Question 24

What is artificial selection

Answer 24

the intentional breeding of plants or animals for particular traits or characteristics.

Question 25

What is sexual selection

Answer 25

where one sex prefers a specific characteristic in an individual of the other sex

Question 26

What is inTRAsexual selection

Answer 26

competition within one sex for mating opportunities – i.e: male-male fights

Question 27

What is inTERsexual selection

Answer 27

likelihood to mate is affected by interactions between members of each sex – i.e: as a result of female choice

Question 28

What are male ornaments? Give an example

Answer 28

Male characteristics of visual aesthetics to attract a mate

• peacock feathers, bright colours, longer tails, antlers

Question 29

Which type of sexual selection are male ornaments used for

Answer 29

IntERsexual selection (to attract a female)

Question 30

Which type of sexual selection will antlers be used for

Answer 30

InTRAsexual selection (to fight off other males)