Process of Evolution (9.2)

Question 1

Describe evolution

Answer 1

Change in genetic composition of populations over time

Question 2

State how evolution can be observed

Answer 2

Changes in allele frequencies in a population over time

Question 3

State what is the driving force of evolution

Answer 3

Natural selection

Question 4

State what natural selection causes

Answer 4

Changes in allele frequencies within a population

Question 5

State whether or not individuals evolve

Answer 5

No. Only populations or species

Question 6

State whether mutations in an individual serve as evidence of evolution

Answer 6

No. Only changes in the overall gene pool

Question 7

Describe species

Answer 7

Group of genetically similar individuals that can produce fertile & viable offspring when interbreeding

Question 8

Describe the 2 classifications of genetic isolation causing mechanisms

Answer 8

1. prezygotic

2. postzygotic

Question 9

Describe prezygotic isolating mechanisms

Answer 9

Those that typically prevent individuals from different populations from interbreeding

Question 10

State whether or not prezygotic isolating mechanisms prevent fertilisation from occuring

Answer 10

Yes.

Question 11

State what prezygotic isolation mechanisms commonly prevent

Answer 11

Mating

Question 12

List the 6 prezygotic isolating mechanisms

Answer 12

1. geographical isolation
2. ecological isolation
3. temporal isolation
4. behavioural isolation
5. morphological isolation
6. gamete mortality

Question 13

Describe geographical isolation as a prezygotic mechanism

Answer 13

Populations are separated by physical and geographical barriers (e.g. oceans)

Question 14

Describe ecological isolation as a prezygotic mechanism

Answer 14

Populations occupy different niches within the same ecosystem

Question 15

Describe niches

Answer 15

Role/place in ecosystem

Question 16

Describe temporal isolation as a prezygotic mechanism

Answer 16

The breeding cycles or active times of populations do not overlap

Question 17

Describe behavioural isolation as a prezygotic mechanism

Answer 17

This occurs when mating calls and courtship ritual are highly specific (only possible in animals)

Question 18

Describe morphological isolation as a prezygotic mechanism

Answer 18

The reproductive organs of different species are physically incompatible and prevent individuals from mating

Question 19

Describe gamete mortality as a prezygotic mechanism

Answer 19

Egg and sperm fail to fuse in fertilisation

Question 20

Describe sexual selection

Answer 20

The difference in the ability of individuals to acquire mates

Question 21

Describe the effect of sexual selection on evolution

Answer 21

Increase the likelihood of ‘fitter’ alleles being inherited by the next generation and the presence of favourable alleles in the gene pool

Question 22

Describe postzygotic isolating mechanisms

Answer 22

Those that typically prevent a zygote of two different species from developing into a fertile adult

Question 23

State what the offspring resulting from interbreeding between individuals from different species are called

Answer 23

Hybrids

Question 24

Describe hybrid inviability

Answer 24

Reproductive isolation - sperm from one species fertilises egg of another species to form hybrid zygote (but unmatched chromosomes prevent embryonic development)

Question 25

Describe reduced hybrid viability

Answer 25

Postzygotic isolation - offspring of different species survive to birth/germination but do not reach reproductive maturity

Question 26

Describe hybrid sterility

Answer 26

Postzygotic isolation - hybrid offspring are reproductively mature but incapable of reproducing

Question 27

State what hybrid sterility is usually a result of

Answer 27

Problems encountered during gamete formation

Question 28

Provide 1 example of a hybrid

Answer 28

Mule

Question 29

State whether or not hybrids have homologous chromosomes

Answer 29

No

Question 30

State why hybrids do not have homologous chromosomes

Answer 30

Genetic material comes from different species

Question 31

Describe hybrid breakdown

Answer 31

Postzygotic isolation - first-generation hybrid cannot reliably produce viable second-generation offspring when interbred with other hybrids

Question 32

Describe endemic

Answer 32

Native species

Question 33

Describe speciation

Answer 33

Evolution of new species from an ancestral species

Question 34

State what the most common form of speciation is

Answer 34

Allopatric speciation

Question 35

Describe allopatric speciation

Answer 35

Divergent evolution of two new species from an ancestral species resulting from separation by a geographical barrier

Question 36

State when allopatric speciation occurs

Answer 36

When a population becomes divided by a geographical barrier

Question 37

State what spatial isolation prevent individuals of separated sub-populations from doing

Answer 37

Interbreeding

Question 38

Describe niche

Answer 38

A role assumed by a particular organism within its' community

Question 39

What name is given to the process in which one species evolves to closely resemble another?

Answer 39

Mimicry

Question 40

Describe gene pool

Answer 40

All alleles possessed by members of a population, which may potentially be passed to next generation.

Question 41

Describe the relationship between gene pool and genetic diversity

Answer 41

A gene pool is the total genetic diversity found within a population or a species.

Question 42

Describe the relationship between large gene pool and genetic diversity

Answer 42

Large gene pool that has great genetic diversity.

Question 43

Describe adaptive radiation

Answer 43

Process in which organisms diversify rapidly from ancestral species

Question 44

State what low heterozygous presence in a population indicates

Answer 44

Low genetic diversity

Question 45

Describe how a mass extinction results in new species evolving

Answer 45

Reduces competition for resources and leaves many vacant niches, which surviving lineages can evolve into.

Question 46

Describe transitional fossils

Answer 46

Any fossil that exhibits traits common to both an ancestral group and its derived descendant group.