Evolution Leading to Speciation

Question 1

What is a species?

Answer 1

A group of interbreeding individuals that give rise to fertile offspring

Question 2

What is speciation?

Answer 2

The process by which populations of the same species evolve into seperate species → becoming reproductively isolated

Question 3

what is sympatric speciation?

Answer 3

Speciation that occurs due to lack of gene flow between populations as a result of factors other than geographic barriers

Question 4

what is allopatric speciation?

Answer 4

Speciation that occurs due to geographic isolation preventing gene flow between populations

Question 5

Reproductive Isolating Mechanisms (RIMS)

Answer 5

RIMs are factors that prevent that successful reproduction between two individuals

Question 6

Pre-zygotic Isolating Mechanisms

Answer 6

i.e gametic, behavioural, geographical, temporal/habitat

Question 7

Post-zygotic Isolating Mechanisms

Answer 7

Hybrid inviability or sterility

Question 8

What do RIMs do?

Answer 8

RIMS prevent groups from reproducing. This can lead to two groups to change due to no gene flow

Question 9

What is a ring species?

Answer 9

arrangement of populations with one boundary characterised by reproductive isolation, but intergradation among populations elsewhere.

Question 10

What is a Polyploidy?

Answer 10

Polyploidy is a CONDITION of having more than TWO full sets of chromosomes. it occurs when an individual inherits additional chromosome sets

Question 11

what is non-disjunction?

Answer 11

Homologous chromosomes/sister chromatids DO NOT SEPERATE during meiosis. ONE DAUGHTER CELL has twice the number of chromosomes as the parent.

Question 12

what is autopolyploidy

Answer 12

when an organism that has more than two sets of chromosomes that are derived from a single parental species

Question 13

Triploid Offspring

Answer 13

When a diploid gamete fertilises haploid gamete → results in triploid offspring → NOT FERTILE OFFSPRING because can’t produce gametes with odd number of chromosome sets

Question 14

tetraploid offspring

Answer 14

many plants can self-fertilise → if two diploid gametes fertilise they can produce a TETRAPLOID ZYGOTE → can be viable → tetraploid offspring

Question 15

allopolyploidy

Answer 15

when organisms have more than two chromosome sets that come from two different species → occurs when two closely related species mate and produce HYBRID

Question 16

hybrid offspring

Answer 16

allopolyploids often get their start when gametes from two different species combine → making a hybrid