Genetic diversity

Question 1

What is genetic diversity?

Answer 1

Genetic diversity is the number of different alleles within a species.

Question 2

Why is genetic diversity important?

Answer 2

The greater the genetic diversity, the more likely a species can survive changes in the environment.

Question 3

What is selective breeding?

Answer 3

Selective breeding is when individuals with desired characteristics are chosen to breed, increasing the frequency of desired alleles in the population.

Question 4

What happens to individuals without desired characteristics in selective breeding?

Answer 4

Individuals without desired traits are killed or prevented from breeding to eliminate unwanted alleles.

Question 5

What is the founder effect?

Answer 5

The founder effect occurs when a few individuals colonise a new region, leading to reduced genetic diversity due to limited allele variation.

Question 6

What is a genetic bottleneck?

Answer 6

A genetic bottleneck is a sharp reduction in population size where only a few members survive, reducing genetic diversity.

Question 7

What is natural selection?

Answer 7

Natural selection is the process where individuals with advantageous alleles are more likely to survive, reproduce, and pass on these alleles to the next generation.

Question 8

How does natural selection work?

Answer 8

1. Variation exists due to mutation. 2. Those with advantageous alleles survive and reproduce. 3. These alleles increase in frequency over generations.

Question 9

What is stabilising selection?

Answer 9

Stabilising selection occurs in stable environments where individuals with phenotypes close to the mean are favoured, reducing variation.

Question 10

Give an example of stabilising selection.

Answer 10

An example is human birth weight, where extreme weights are selected against.

Question 11

What is directional selection?

Answer 11

Directional selection occurs when the environment changes, favouring individuals with extreme phenotypes that best suit the new conditions.

Question 12

Give an example of directional selection.

Answer 12

An example is antibiotic resistance in bacteria.

Question 13

What is the definition of a species?

Answer 13

A species is a group of organisms that can interbreed and produce fertile offspring.

Question 14

How do new species arise?

Answer 14

New species arise through variation caused by different alleles, selective pressures, and eventual reproductive isolation preventing interbreeding.

Question 15

What is courtship behaviour, and why is it important?

Answer 15

Courtship behaviour is specific to a species and ensures successful mating by recognising mates, forming bonds, and synchronising mating.

Question 16

How does courtship increase the probability of successful mating?

Answer 16

Courtship increases successful mating by recognising the same species, assessing fertility, and forming pair bonds.

Question 17

What is diversity, and how can it be investigated?

Answer 17

Diversity can be investigated by comparing DNA base sequences, amino acid sequences, proteins (immunological comparison), and fossil records.

Question 18

What is interbreeding, and how does it confirm species?

Answer 18

Interbreeding occurs when individuals of the same species produce fertile offspring, confirming they belong to the same species.

Question 19

What is phylogeny?

Answer 19

Phylogeny is the study of how closely related species are by analysing their evolutionary descent and relationships.

Question 20

What does a phylogenetic tree show?

Answer 20

A phylogenetic tree shows points of divergence and common ancestry between species.

Question 21

What is DNA hybridisation?

Answer 21

DNA hybridisation involves combining single-stranded DNA from two species to see how closely they match based on complementary base pairing.

Question 22

What does the degree of DNA hybridisation tell us?

Answer 22

The more closely related species are, the more complementary bases they share, and the higher the temperature needed to separate hybrid strands.

Question 23

What is immunological comparison of proteins?

Answer 23

Immunological comparison measures how antibodies react to antigens from different species. Greater precipitation indicates closer relatedness.

Question 24

What is classification?

Answer 24

Classification is the grouping of organisms based on shared characteristics.

Question 25

What is hierarchical classification?

Answer 25

Hierarchical classification splits larger groups into smaller non-overlapping groups based on shared characteristics.

Question 26

What is taxonomy?

Answer 26

Taxonomy is the theory and practice of biological classification.

Question 27

What is the taxonomic hierarchy?

Answer 27

The taxonomic hierarchy includes Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Question 28

What is speciation?

Answer 28

Speciation is when new species arise from existing species due to reproductive isolation and different selective pressures.

Question 29

What is allopatric speciation?

Answer 29

Allopatric speciation occurs when populations are geographically separated, preventing interbreeding and leading to the evolution of new species.

Question 30

What causes allopatric speciation?

Answer 30

Geographical isolation, different environments, mutations, and selective pressures lead to changes in allele frequencies over time.

Question 31

What is sympatric speciation?

Answer 31

Sympatric speciation occurs within the same habitat due to mutations or behavioural changes that prevent interbreeding.

Question 32

What is reproductive isolation?

Answer 32

Reproductive isolation prevents individuals from breeding successfully due to changes in alleles, phenotype, or behaviour.

Question 33

What are examples of reproductive isolation?

Answer 33

Examples include temporal changes (breeding seasons), mechanical changes (reproductive organs), and behavioural changes (courtship).

Question 34

What is genetic drift?

Answer 34

Genetic drift is a change in allele frequency due to random chance, where some alleles are passed on more than others.

Question 35

How does genetic drift affect populations?

Answer 35

Genetic drift increases certain allele frequencies, especially in small populations, potentially leading to reproductive isolation and speciation.