Glossary 3052

Question 1

Acclimitisation

Answer 1

A gradual, reversible response of an organism to changes in its environment.

Question 2

Adaptation

Answer 2

An inherited trait with a current functional role in the life history of an organism. Adaptations are maintained and evolve by means of natural selection.

Question 3

Allele frequency

Answer 3

The proportion of all copies of a gene being of a particular type/version.

Question 4

Alleles

Answer 4

Version of a gene.

Question 5

Allopatric speciation

Answer 5

The process through which new species evolve from a single ancestral species while living in different geographic regions.

Question 6

Allopolyploidy

Answer 6

Cells with two or more complete sets of chromosmes derived from different species.

Question 7

Autopolyploidy

Answer 7

Cells with two or more complete sets of chromosmes derived from the same species.

Question 8

Bottleneck

Answer 8

The result of a sudden event when a significant proportion of individuals in a population/species are killed or not reproducing.

Question 9

Cline

Answer 9

A gradual change in a characteristic or feature across the geographic range of a species or population.

Question 10

Crossing over

Answer 10

The exchange of genetic material between homologous chromosomes.

Question 11

Deme

Answer 11

A local population that can interbreed with another population and therefore they share the same gene pool.

Question 12

Diploid

Answer 12

Cells with two copies of each chromosome.

Question 13

Directional selection

Answer 13

Type of natural selection where one of the two extremes of a trait is selected for/favoured.

Question 14

Disruptive selection

Answer 14

Type of natural selection where the two extremes of a trait are favoured.

Question 15

Emigration

Answer 15

When individuals leave a population.

Question 16

Endemic

Answer 16

Organisms that settled and evolved in a particular habitat and are found nowhere else in the world.

Question 17

Founder effect

Answer 17

When a new population is established by a very small number of individuals who will carry with them only a small proportion of all the alleles present in the population. The founder effect contributes, therefore, to the loss of genetic variation that follows colonisation.

Question 18

Gametes

Answer 18

Reproductive cells used in sexual reproduction.

Question 19

Gene flow

Answer 19

The transfer of alleles or genes from one population to another.

Question 20

Gene pool

Answer 20

All the alleles of a gene present in a population.

Question 21

Genetic drift

Answer 21

The change in the frequency of an allele in a population due to random sampling.

Question 22

Heterozygote

Answer 22

When the two versions/alleles of a gene are different.

Question 23

Homozygote

Answer 23

When the two versions/alleles of a gene are the same.

Question 24

Hybrid

Answer 24

Offspring from a cross between two different species.

Question 25

Immigration

Answer 25

When new individuals enter a population.

Question 26

Microsatellite

Answer 26

Simple, short repeating sequences of up to about six DNA base pairs.

Question 27

Mutation

Answer 27

Unrepaired change to the sequence of bases in the DNA.

Question 28

Natural selection

Answer 28

A process in which individuals with certain traits have a greater chance at surviving and producing offspring, than individuals without these traits.

Question 29

Non-disjunction

Answer 29

An error in cell division in which members of a pair of homologous chromosomes, or sister chromatids, fail to separate.

Question 30

Polymorphism

Answer 30

When two or more clearly different phenotypes exist in the same population/species.

Question 31

Polyploidy

Answer 31

Cells with more than two copies of each chromosome.

Question 32

Pre- and post- zygotic barriers

Answer 32

Pre-zygotic barriers prevent fertilisation and post-zygotic barriers prevent the development of the zygote (fertilised egg cell).

Question 33

Recombinant

Answer 33

An organism that contains a different combination of alleles from either of its parents.

Question 34

Ring species

Answer 34

A connected series of neighbouring populations, each of which can interbreed with closely sited populations, but no interbreeding occurs anymore between individuals from the two ‘ends of the ring’.

Question 35

Speciation

Answer 35

Formation of new species.

Question 36

Species

Answer 36

A group of organisms that interbreed and produce viable and fertile offspring.

Question 37

Stabilising selection

Answer 37

Type of natural selection where the two extremes of a trait are selected against.

Question 38

Subspecies

Answer 38

A group of organisms which, often due to geographic isolation, cannot interbreed with other members of the species.

Question 39

Sympatric speciation

Answer 39

The process through which new species evolve from a single ancestral species while living in the same geographic region.

Question 40

Tetraploid

Answer 40

Cells with four copies of each chromosome.

Question 41

Triploid

Answer 41

Cells with three copies of each chromosome.

Question 42

Population

Answer 42

Inidividuals of the same species living in a particular area and sharing the same gene pool

Question 43

Independent assortment

Answer 43

Purely random which chromosomes end up in a gamete