Speciation

Question 1

Adaptive radiation

Answer 1

Pattern of evolution; a large number of species form to occupy different ecological niches.

Question 2

Allopatric speciation

Answer 2

A result of geographical isolation.

Question 3

Allele frequency

Answer 3

Relative proportion of alleles in a population.

Question 4

Behavioural isolation

Answer 4

Animals won’t reproduce due to differences in courtship, etc.

Question 5

Biogeography

Answer 5

Evidence for evolution; organisms separated by geography become increasingly different.

Question 6

Co-evolution

Answer 6

Pattern of evolution; one species or group changes its genetic composition in response to a genetic change in another.

Question 7

Comparative anatomy

Answer 7

Evidence for evolution; homologous structures (related species), analogous structures (unrelated species).

Question 8

Convergent evolution

Answer 8

Different species living in a similar environment come to look similar.

Question 9

Deme

Answer 9

A localised population.

Question 10

Directional selection

Answer 10

When one extreme is selected for.

Question 11

Disruptive selection

Answer 11

Where both extremes are selected for against the middle range. This ultimately produces two new species.

Question 12

Divergent evolution

Answer 12

When one species branches to form two or more species.

Question 13

Ecological isolation

Answer 13

Organisms don’t interbreed because of niche differences.

Question 14

Fossil evidence

Answer 14

Evidence for evolution; geological layers show species increasingly different to modern species the deeper (older) you go.

Question 15

Gene flow

Answer 15

Caused by reproduction between populations.

Question 16

Gene pool

Answer 16

All the genes in a reproducing population.

Question 17

Genetic drift

Answer 17

Random changes in allele frequencies because of small population size.

Question 18

Geographical isolation

Answer 18

Organisms can’t reproduce due to physical separation.

Question 19

Gradualism

Answer 19

Pattern of evolution; slow changes between populations occur as a result of slightly different selection pressures.

Question 20

Homologous structure

Answer 20

Structures with common ancestry, now used for differing functions.

Question 21

Instant speciation

Answer 21

Speciation resulting from polyploidy.

Question 22

Molecular biology

Answer 22

Evidence for evolution; DNA (& therefore proteins) are more similar, the more similar (& more recently diverged) two species are.

Question 23

Mutation

Answer 23

An unrepaired change in DNA - the origin of all variation.

Question 24

Natural selection

Answer 24

The best adapted individuals have a greater chance of reproductive success.

Question 25

Polyploidy

Answer 25

When cells have more than 2n chromosomes. Results from mutation (non-disjunction), can result in instant speciation.

Question 26

Post-zygotic isolation

Answer 26

Factors that prevent a hybrid persisting as a new species – includes hybrid inviability, hybrid infertility and hybrid breakdown.

Question 27

Pre-zygotic isolation

Answer 27

Factors that prevent a hybrid from being conceived – includes behaviour, structure, temporal, gamete incompatibility, geographical.

Question 28

Punctuated equilibrium

Answer 28

Pattern of evolution; consists of long periods of stability, followed by rapid changes as a result of critical selection pressures.

Question 29

Reproductive isolation

Answer 29

Populations unable to interbreed.

Question 30

Selection pressure

Answer 30

The environmental factors that favour certain phenotypes.

Question 31

Speciation

Answer 31

Formation of a new species.

Question 32

Species

Answer 32

A group of individuals that will interbreed in nature to produce fertile offspring.

Question 33

Stabilising selection

Answer 33

Selection for the middle range against the extremes.

Question 34

Structural isolation

Answer 34

Organisms are unable to reproduce due to differences in their genital organs.

Question 35

Subspecies

Answer 35

Groups that are very different from each other, but can still interbreed.

Question 36

Sympatric speciation

Answer 36

Due to isolating mechanisms other than geography - happens in the same place (due to a number of niches).

Question 37

Temporal isolation

Answer 37

Organisms don’t reproduce due to differences in timing (active/breeding at different times).

Question 38

Analogous structures

Answer 38

Structures which have the same job but have different bone make-up. Do not share a common ancestor.

Question 39

Cline

Answer 39

A gradual variation in the characteristics of a species or population over a geographical range.

Question 40

Embryology

Answer 40

The study of how embryos develop, looking at which genes are turned on and when.

Question 41

Endemic

Answer 41

Only found naturally in a certain country or area.

Question 42

Evolution

Answer 42

Gradual process by which the present diversity of plants and animals arose from earliest and most primitive organisms.

Question 43

Genetic drift (2)

Answer 43

Random fluctuation in the frequency of alleles due to chance events.

Question 44

Selective pressure

Answer 44

Environmental factor that selects certain phenotypes.

Question 45

Autopolyploid

Answer 45

Having more than two haploid sets of chromosomes that are derived from the same ancestral species.

Question 46

Allopolyploid

Answer 46

Having three or more complete sets of chromosomes derived from different species.

Question 47

Hybrid

Answer 47

An individual formed by mating between genetically different populations or species.

Question 48

DNA comparison

Answer 48

Comparison of the DNA sequences allows organisms to be grouped and show relativeness.