Speciation

Question 1

Evolution

Answer 1

A change in the gene pool of a population over time.

Question 2

Genetic drift

Answer 2

The random fluctuations of allele frequencies over time due to chance.

Question 3

Allele frequency

Answer 3

The number of one allele relative to the total number of all alleles for that gene, or the proportion of one allele.,

Question 4

Gene pool

Answer 4

The total set of alleles that are present within a population.

Question 5

Founder effect

Answer 5

Involves a small group of individuals moving away from the main population, and therefore establishing their own gene pool.

Question 6

Bottleneck effect

Answer 6

Involves an event which greatly reduces the population size. Often, this changes the make-up of the gene pool and the resulting population is more vulnerable to genetic drift.

Question 7

Migration

Answer 7

The movement of individuals from one population to another.

Question 8

Stabilizing selection

Answer 8

Both extremes of the phenotypic range are selected against, while the middle phenotype (or the average) is selected for.

Question 9

Disruptive selection

Answer 9

Both extremes of the phenotypic range are selected for, while the middle phenotype (or the average) is selected against.

Question 10

Directional selection

Answer 10

A single extreme phenotype is selected for.

Question 11

Polyploidy

Answer 11

Polyploidy refers to variation in the number of chromosome sets.

Question 12

Non-disjunction

Answer 12

Chromosomes fail to separate (disjoin) during division. Instead of moving to opposite poles of the cell, a pair of chromosomes move to the same pole.

Question 13

Natural selection

Answer 13

The process whereby better adapted alleles are selected for against disadvantageous alleles.

Question 14

Autopolyploidy

Answer 14

Autopolyploidy is where the genome is multiplied within a single species.

Question 15

Allopolyploidy

Answer 15

Allopolyploidy results from the hybridization between species.

Question 16

Post-zygotic RIMs (Reproductive Isolating Mechanism)

Answer 16

Anything that prevents species from forming fertile offspring. (e.g. hybrid inviability, hybrid sterility and hybrid “breakdown”)

Question 17

Pre-zygotic RIMs (Reproductive Isolating Mechanism)

Answer 17

Anything that prevents mating or fertilization. (e.g. habitat isolation, temporal isolation, mechanical isolation etc.)

Question 18

Speciation

Answer 18

The formation of new species as populations become reproductively isolated, preventing gene flow.

Question 19

Allopatric speciation

Answer 19

Speciation occurring due to geographical barriers, or geographic isolation. (e.g. formation of rivers, mountains etc.)

Question 20

Sympatric speciation

Answer 20

Speciation occurring within the same geographic location. This occurs due to selection pressures which were a result of competition, or preference.

Question 21

Temporal isolation

Answer 21

Differences in breeding behaviour, such as breeding times or breeding seasons.

Question 22

Behavioural Isolation

Answer 22

A reproductive barrier due to differences in mating behaviours.

Question 23

Hybrid inviability

Answer 23

The hybrid produced from the mating between different species is inviable and dies early in development.

Question 24

Ecological isolation

Answer 24

Due to differences in the habitat within the same geographical location that prevent populations from coming into contact.