Population Genetic Basis of Evolutionary Change

Question 1

Who are the two key figures associated with the theory of evolution by natural selection?

Answer 1

Charles Darwin and Alfred Russel Wallace.

Question 2

What is evolution in scientific terms?

Answer 2

A verified theory based on empirical evidence showing heritable change over time.

Question 3

Define ‘heritable’.

Answer 3

Traits that are passed from parents to offspring, usually through genetic material.

Question 4

What is anagenesis?

Answer 4

Evolution within a single lineage where the ancestral form is replaced.

Question 5

What is cladogenesis?

Answer 5

Evolution that results in the branching/splitting of a lineage into two or more distinct lineages.

Question 6

What is phylogenetics?

Answer 6

The study of evolutionary relationships and histories (phylogenies).

Question 7

Differentiate microevolution and macroevolution.

Answer 7

Microevolution occurs within species (populations); macroevolution occurs at or above the species level.

Question 8

What is a ‘character’ and a ‘character state’?

Answer 8

A character is any measurable trait; a character state is a variant of that trait.

Question 9

What is the genotype?

Answer 9

The genetic information stored in an individual’s DNA.

Question 10

Where is DNA located in a eukaryotic cell?

Answer 10

In the nucleus (linear chromosomes) and mitochondria (circular chromosomes).

Question 11

What is ‘junk’ DNA?

Answer 11

Non-coding regions of DNA, some of which have regulatory functions.

Question 12

What is a SNP?

Answer 12

Single Nucleotide Polymorphism—variation at a single nucleotide position.

Question 13

Define ‘allele’.

Answer 13

Different forms of a gene found at the same locus.

Question 14

What does ‘polymorphic’ mean in genetics?

Answer 14

A locus with multiple alleles present in a population.

Question 15

What is the phenotype?

Answer 15

Observable traits or characteristics of an organism.

Question 16

Why do scientists often study phenotypes?

Answer 16

Because they are easier to observe and often reflect genetic variation.

Question 17

What is an ‘extended phenotype’?

Answer 17

Traits like structures built by organisms (e.g. nests), influenced by their genotype.

Question 18

Give an example of non-heritable phenotypic variation.

Answer 18

Damage, disease, or somatic mutations.

Question 19

Why is genetic variation important for evolution?

Answer 19

It allows populations to adapt to changing environments and avoid extinction.

Question 20

What is microevolution?

Answer 20

Change in allele or genotype frequencies within a population over time.

Question 21

What processes generate genetic variation?

Answer 21

Mutation and recombination.

Question 22

What processes remove genetic variation?

Answer 22

Genetic drift and selection.

Question 23

What is genetic drift?

Answer 23

Random changes in allele frequencies, especially in small populations.

Question 24

What is a population bottleneck?

Answer 24

A sharp reduction in population size reducing genetic diversity.

Question 25

What is effective population size?

Answer 25

The number of individuals contributing genes to the next generation.

Question 26

Define inbreeding.

Answer 26

Mating between relatives, increasing homozygosity and risk of genetic disorders.

Question 27

What is linkage disequilibrium (LD)?

Answer 27

Non-random association of alleles at different loci.

Question 28

What is the Hardy-Weinberg Equation used for?

Answer 28

Estimating allele and genotype frequencies under no-evolution assumptions.

Question 29

What is adaptive evolution?

Answer 29

Evolution driven by natural or artificial selection that increases fitness.

Question 30

What is a selective advantage?

Answer 30

A trait that increases reproductive success in a given environment.

Question 31

Give an example of adaptive evolution.

Answer 31

Insecticide resistance in aphids.

Question 32

What is artificial selection?

Answer 32

Human-directed breeding selecting for desirable traits.

Question 33

What is a neutral gene?

Answer 33

A gene whose variation does not affect fitness and evolves by drift.

Question 34

Who developed the concept of neutral evolution?

Answer 34

Motoo Kimura.

Question 35

What is hitchhiking in genetics?

Answer 35

A neutral gene increases in frequency due to linkage with a beneficial gene.

Question 36

Can phenotypic traits be selectively neutral?

Answer 36

Yes, if they do not influence fitness.

Question 37

What is pleiotropy?

Answer 37

When a single gene affects multiple traits.

Question 38

What is antagonistic pleiotropy?

Answer 38

A gene that benefits early life but harms later life (e.g. testosterone and prostate issues).

Question 39

What is phenotypic plasticity?

Answer 39

The ability of a genotype to produce different phenotypes in different environments.

Question 40

Give an example of adaptive plasticity.

Answer 40

Skin tanning in response to UV exposure.

Question 41

What is a constraint in evolution?

Answer 41

A factor that limits or restricts evolutionary change.

Question 42

What is a blueprint constraint?

Answer 42

Limits on changes due to co-evolved, integrated genetic systems.

Question 43

Why can't insects grow very large?

Answer 43

Due to constraints in their exoskeleton and respiratory systems.

Question 44

What is the Red Queen Hypothesis?

Answer 44

Species must continuously adapt just to maintain their current fitness levels.

Question 45

Is evolution goal-directed?

Answer 45

No, it is not purposeful; it responds to environmental conditions.

Question 46

What is senescence?

Answer 46

The deterioration of function with age, often influenced by pleiotropy.

Question 47

What is phylogenetic constraint?

Answer 47

A limitation based on the evolutionary history of a lineage.

Question 48

Can the environment affect genotype expression?

Answer 48

Yes, this is the basis of phenotypic plasticity.

Question 49

What does 'fitness' mean in evolutionary terms?

Answer 49

The ability to survive and reproduce.

Question 50

What causes evolutionary change besides selection?

Answer 50

Genetic drift and mutation.

Question 51

What are the two fundamental patterns of evolutionary change?

Answer 51

Anagenesis (transformation) and cladogenesis (branching).

Question 52

What does 'consilience' mean in evolutionary biology?

Answer 52

Agreement among independent sources of evidence supporting a theory.

Question 53

What is meant by 'temporal change' in evolution?

Answer 53

Change in heritable traits over time.

Question 54

What is a phylogeny?

Answer 54

A branched evolutionary history of species or genes.

Question 55

What is the function of mitochondria in inheritance?

Answer 55

They contain mtDNA passed maternally, affecting traits and evolution.

Question 56

Why is 'junk DNA' considered useful in evolutionary biology?

Answer 56

Because it can mutate freely, offering a record of neutral evolution.

Question 57

What are two examples of crop diseases exacerbated by lack of genetic diversity?

Answer 57

Late Potato Blight and Black Sigatoka disease in bananas.

Question 58

What does SNP stand for?

Answer 58

Single Nucleotide Polymorphism.

Question 59

What is the difference between continuous and discontinuous variation?

Answer 59

Continuous has intermediate forms; discontinuous has distinct categories.

Question 60

How do you quantify variation in a population?

Answer 60

Using statistical measures like mean and standard deviation.

Question 61

Why are random samples important in studying populations?

Answer 61

To avoid bias and accurately represent genetic variation.

Question 62

What is genetic recombination?

Answer 62

The reshuffling of genetic material during meiosis, increasing diversity.

Question 63

What are examples of traits affected by artificial selection?

Answer 63

Plumage color in birds, size in crops or livestock.

Question 64

What is meant by 'effective population size'?

Answer 64

The number of individuals that contribute genes to the next generation.

Question 65

What is inbreeding depression?

Answer 65

Reduced fitness due to mating between relatives increasing harmful alleles.

Question 66

What is linkage equilibrium?

Answer 66

Random association of alleles at different loci.

Question 67

What is the formula for linkage disequilibrium (LD)?

Answer 67

D = f(AB) - f(A)f(B)

Question 68

What does r² measure in population genetics?

Answer 68

The correlation strength between alleles at two loci (LD measure).

Question 69

What kind of trait does selection act upon?

Answer 69

Heritable traits that affect fitness.

Question 70

What is fitness in evolutionary terms?

Answer 70

An organism’s ability to survive and reproduce.

Question 71

What does adaptive plasticity mean?

Answer 71

Environmentally-induced phenotypes that enhance fitness.

Question 72

Give an example of phenotypic plasticity.

Answer 72

Water buttercup leaves adapting to submerged or air-exposed environments.

Question 73

What limits maximum body size in insects?

Answer 73

Constraints due to their exoskeleton and tracheal respiration system.

Question 74

What does the Red Queen Hypothesis imply about evolution?

Answer 74

Organisms must keep evolving to maintain relative fitness.

Question 75

Define a phylogenetic constraint.

Answer 75

A limitation rooted in an organism’s evolutionary history.

Question 76

What are 'neutral traits' in evolution?

Answer 76

Traits not influenced by natural selection and subject to drift.

Question 77

What is antagonistic pleiotropy?

Answer 77

When a gene has both beneficial and harmful effects.

Question 78

What happens when selection pressures are removed from an adaptive trait?

Answer 78

The trait may become selectively neutral.

Question 79

What is the scientific view on evolution’s purpose?

Answer 79

Evolution is not goal-directed or purposeful.