Module 1

Question 1

What is genetic drift

Answer 1

Genetic drift is the change in allele frequency of a population due to CHANCE.

Question 2

What is the Bottleneck effect and the Founder effect?

Answer 2

Bottleneck effect - a sudden reduction in population size due to environmental events such as fire, earthquakes, or floods.
Founder effect - when a new population is established by a smaller number of population from a large population - and is unrepresentative of the original population.

Question 3

What is gene flow

Answer 3

Gene flow is the change in alleles from one population to another. This results in new alleles to a population, but reduces variation among a population over time

Question 4

What were Aristotle’s main points on evolution?

Answer 4

• viewed species as being fixed and unchanging
• arranged into a hierarchy of perfection

Question 5

What were Carolus Linnaeus’ main points on evolution?

Answer 5

• Interpreted organismal adaptations as evidence each species was designed for a specific purpose.
• He was the founder of taxonomy, classifying life’s diversity “for the greater glory of God”.
• he developed the binomial format for naming species.

Question 6

What were Georges Cuvier’s main points on evolution?

Answer 6

• Recognised extinctions as common
• Opposed the idea of evolutionary change
• And instead advocated catastrophism, the idea that sudden, short-lived, and violent events lead to the extinction of many organisms.
• Largely developed palaeontology, the study of fossils

Question 7

What were James Hutton’s main points on evolution?

Answer 7

• Hutton perceived that huge changes in Earth’s surface can result from slow continuous actions
• This view, known as gradualism, exerted a strong influence on Darwin’s thinking eg, a river cuts through a rock, slowly cutting through the valley

Question 7

What were Lamarck’s main points on evolution?

Answer 7

He proposed the idea that evolution is based on the inheritance of acquired characteristics. He suggested that life evolved, however, his ideas were largely regarded as wrong, as he had no evidence to support.

Question 8

What is it meaning by ‘descent with modification’?

Answer 8

It explains that all organisms are related through descent from an ancestor that lived in the remote past

Question 9

True/False: Individuals evolve

Answer 9

FALSE: Individuals do not evolve - populations do

Question 10

What are analogous structures?

Answer 10

Structures that have similar form or function but were not present inthe last common ancestor of those groups. The groups evolved have evolved independently from one another.
It occurs when two groups of largely unrelated organisms are exposed to very similar environments and develop similar adaptations to survive.

Question 11

What are homologous structures?

Answer 11

Physical structures that are similar, due to common ancestry. However, the features serve completely different functions.

Question 12

What were Charles Lyell’s main points on evolution?

Answer 12

• he developed the idea of uniformitarianism, which states that the mechanisms of change are constant over time.

Question 13

What are Darwin’s main two observations?

Answer 13

1. Members of a population often vary in their inherited traits
2. All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce.

Question 14

What were Thomas Malthus’ main points on evolution?

Answer 14

• some inheritable traits are advantageous, and these will accumulate in a population over time, resulting in the increase in frequency of individuals with these traits.

Question 15

Define Phylogeny

Answer 15

Phylogeny is the evolutionary history of a species or group of related species.

Question 16

Define Systematics

Answer 16

Systematics is the classification of organisms using their evolutionary relationships.

Question 17

What is the correct way to write a binomial nomenclature

Answer 17

The first letter of the genus is capitalised, while the specific epithet is lower case.
They are both italicised.

Question 18

What does each point (node0 on the phylogenetic tree represent?

Answer 18

Represents the divergence of two evolutionary lineages from a common ancestor.

Question 19

What are sister taxa?

Answer 19

Sister taxa are groups that share an immediate common ancestor that is not shared by any other group.

Question 20

What is convergent evolution?

Answer 20

convergent evolution occurs when natural selection (under similar environmental pressures) produce similar (analogous) adaptations in different organisms.

Question 21

What is Monophyly?

Answer 21

A single common ancestor and all of its descendants

Question 22

What is Paraphyly?

Answer 22

A common ancestor and some of its descendants

Question 23

What is Polyphyly?

Answer 23

A grouping with no recent common ancestor

Question 24

What are the requirements of evolution (there are 4 main ones)

Answer 24

1. Competition
2. Variation
3. Heredity
4. Differential Reproduction

Question 25

What are the 4 sources of genetic variation?

Answer 25

1. Formation of new alleles
2. Altering gene number or position
3. Rapid reproduction
4. Sexual reproduction

Question 26

What is the neutral theory?

Answer 26

many changes in genes and proteins have no effect on fitness and therefore are not influenced by Darwinian selection. The rate of molecular change that is neutral is fairly constant (like a clock)

Question 27

A change in allele frequency within a population over time is best described as…

Answer 27

Evolution

Question 28

What are the 5 conditions for the Hardy-Weinberg equation?

Answer 28

• large population
• no gene flow
• no mutation
• random mating
• no natural selection

Question 29

What causes populations to evolve?

Answer 29

Genetic drift, gene flow and natural selection can alter allele frequencies in a population ad bring about evolutionary change.

Question 30

In a Hardy-Weinberg population with two alleles, A and a, the frequency of allele a is 0.4. What is the frequency of heterozygous individuals? (use calculator)

Answer 30

0.48

working out:
p2 + 2pq + q2 = 1
p + q = 1
p+ 0.4 = 1
p=0.6
therefore 2 x 0.6 x 0.4 = 0.48

Question 31

What are the modes of selection? Explain

Answer 31

Stabilising selection - removes the extreme variants from the population and preserves the intermediate (middle of curve) types.

Directional selection - shifts the overall makeup of the population by favouring variants at one extreme of the distribution.

Disruptive selection - favours the variants at both ends of the distribution.

Question 32

What is the fitness coefficient (W)

Answer 32

Its the adaptive value of a particular individual’s phenotype. It is measured relative to the most successful genotype - meaning that individuals that produce the most offspring within a population have a fitness of 1 (100%).

Question 33

What is the selection coefficient (s)

Answer 33

A measure of selective pressure against a particular phenotype, relative to the others in the population. It is calculated as 1-W.

Question 34

What is artificial selection?

Answer 34

Artificial selection is the process by which humans choose individual organisms with certain phenotypic trait values for breeding.

Question 35

What is sexual selection?

Answer 35

Sexual selection is the process by which individuals compete for access to mates and fertilization opportunities.
It is a form of natural selection, and leads to individuals with certain inherited traits being more likely to be successful in reproduction and obtaining mates.

Question 36

What is the difference between intersexual and intrasexual selection?

Answer 36

Intersexual selection occurs when one sex chooses which members of the opposite sex to mate with (choice), while intrasexual selection occurs when members of the same sex compete for mates (competition)

Question 37

What is punctuated equilibrium?

Answer 37

Long periods of stasis with little activity in terms of extinctions or emergence of new species are interrupted by intermittent bursts of activity.

Question 38

What is morphological stasis?

Answer 38

The maintenance of a standard morphology over vast periods of time during which much environmental change has taken place.

Question 39

What is adaptive radiation?

Answer 39

When 2 or more different species arise from the same ancestor in a short time, adaptive radiation can rapidly result in morphological diversity.

Question 40

What is heterochrony?

Answer 40

An evolutionary change in the relative rate and timing of developmental events - it can have a huge impact of the body shape. Heterochrony can alter the timing of reproductive development relative to the timing of non-reproductive organs.

Question 41

What is Allometry?

Answer 41

The relationship between an organism’s size and shape, it refers to the different rates at which different organs grow.

Question 42

What is meant by ‘evolution is not goal orientated’?

Answer 42

There is no intrinsic drive toward a particular phenotype - therefore evolution is not goal orientated. Rather, it is a process of trial and error, of experimentation and adaptation. This is how new species arise and how existing species change over time.

Question 43

What is gradualism?

Answer 43

A slow, steady change through time which leads to drastic morphological changes.

Question 44

What are the differences between Autopolyploidy and Allopolyploidy?

Answer 44

Autopolyploidy- a type of polyploidy when the individuals have more than 2 copies of chromosomes from the same species.

Allopolyploidy - A type of polyploidy when individuals have more than 2 copies of chromosomes from different species.