Evolution: Speciation And Adaptation

Question 1

What is structural adaptation?

Answer 1

Adaptation that affects the appearance or arrangement of particular physical features.

Question 2

What are the 3 kinds of structural adaptation?

Answer 2

1: Mimicry
2: Cryptic Colouration
3: Warning Colouration

Question 3

What is Mimicry?

Answer 3

Structural adaptation allowing one species to resemble another species or part of another species. Often to look more dangerous.

Question 4

What is Cryptic Colouration?

Answer 4

Structural adaptation characterized by camouflaging shape and colouring for the purpose of blending in. Allows species to hide from predators.

Question 5

What is Warning colouration?

Answer 5

Bright colours that announce danger to predators.

Question 6

What are physiological adaptations?

Answer 6

Adaptations associated with functions in organisms. (Eg; Enzymes for blood clotting, chemical defences of plants, immunity)

Question 7

What are behavioural adaptations?

Answer 7

Adaptations associated with the ways in which organisms respond to their environment. (Eg: migration, foraging, hibernating, hiding)

Question 8

What is a biological species? Speciation?

Answer 8

Biological species: Population that is reporductively compatible. Members of the population can interbreed and produce viable, fertile offspring.

Speciation: The formation of a species.

Question 9

What are the two ways in which speciation may occur?

Answer 9

1: Transformation - A species may result from accumulated changes over a long period of time, transforming one species into another.

2: Divergence - One or more species arise from a parent species that continues to exist.

Question 10

What has to happen for speciation to occur? What ensures this?

Answer 10

Two populations must be prevented from interbreeding. (They must be isolated) This is achieved through geographical and biological barriers.

Question 11

What are geographical barriers?

Answer 11

Prohibits interbreeding due to keeping populations physically separated. May help adapt to different environments over long time periods. These separated popultions will no longer be capable of mating with original population.

Question 12

What are biological barriers?

Answer 12

Keeps species reproductively isolated even when their ranges overlap. They may act before or after fertilization.

Question 13

What are prezygotic barriers and their 5 types?

Answer 13

Impedes mating between species by preventing fertilization of the ova from different species.

1: Behavioural isolation
2: Habitat isolation
3: Temporal isolation
4: Mechanical isolation
5: Gametic isolatin

Question 14

What is behavioural isolation?

Answer 14

Species specific mating signals that don’t attract other species.

Question 15

What is habitat isolation?

Answer 15

Two species rarely encountering each other because of habitats, even while living in the same general region.

Question 16

What is temporal isolation?

Answer 16

Species who occupy the same habitat may mate/flower at different times of day, preventing mating.

Question 17

What is mechanical isolation?

Answer 17

Species being anatomically incompatible with different species, preventing mating.

Question 18

What is gametic isolation?

Answer 18

This ensures that if two different species’ gametes meet, they will not form a zygote.

Question 19

What are postzygotic barriers and their 3 types?

Answer 19

Barriers that prevent zygotes from developing into normal, fertile individuals.

1: Hybrid inviability
2: Hybrid sterility
3: Hybrid breakdown

Question 20

What is hybrid inviability?

Answer 20

Prevents normal mitosis after fusion of the nuclei in gametes. Causes hybrid to stop developing at some point in embryonic development.

Question 21

What is hybrid sterility?

Answer 21

Two species may mate and produce offspring, but the offspring are born sterile. Comes into effect when meiosis fails to take produce normal gametes in the hybrid due to parents differing chromosomes number/structure.

Question 22

What is hybrid breakdown?

Answer 22

First generation hybrids may be fertile/viable, but after mating with each other or a parent species member, the offspring are sterile/weak.

Question 23

What are the 2 types of speciation?

Answer 23

1: Sympatric speciation
2: Allopatric speciation

Question 24

What is sympatric speciation?

Answer 24

Differentiation of populations within the same geographic area into species. Reproductive isolation occurs without physical separation.

Question 25

What is allopatric speciation?

Answer 25

Formation of a new species occuring when populations are split into two+ isolated groups by geographical barriers. Gene pools become so distinct, species' may no longer mate even if reunited. Geo isolation -> Repro isolation.

Question 26

What is adaptive radiation?

Answer 26

Parent species has offspring which split up and go to other areas. Areas being ecologically different enough means different selective pressures acting on the offspring, resulting in different evolutions. (Type of Allopatric speciation)