Evolution- (6) Speciation

Question 1

What is a species?

Answer 1

Population whos members can interbreed and produce viable + fertile offspring

Question 2

2 types of speciation?

Answer 2

Sympatric speciation and allopatric speciation

Question 3

What is sympatric speciation?

Answer 3

Same geographical area, but reproductivley isolated.

Question 4

What is allopatric speciation?

Answer 4

Caused by a geographical barrier. Ex) ocean levels, natural disasters, glacier flow

Question 5

Name the 5 prezygotic isolating methods

Answer 5

Behavioural, habitat, temporal, mechanical, gametic

Question 6

Whats a prezygotic isolating mechanism

Answer 6

Pre fertilization barriers - stopping zygote formation + development between different species

Question 7

Explain behavioural isolating methods

Answer 7

Any special signals or behaviours that are species specific. ie) bird song

Question 8

Explain habitat isolating mechanisms

Answer 8

Species that live in same region but different habitats.

Question 9

Give an example of habitat isolating mechanisms

Answer 9

ie) common garter snakes live near water and northwest garter snakes live in open feilds. both in same region.

Question 10

Explain temporal isolating mechanisms

Answer 10

Timing barriers- may occupy same habitat but may mate/flower at different times

Question 11

give an example of temporal isolating mechanisms

Answer 11

Orchids blooming for a single day each in response to stimuli. But, one blooms 8 days after.. 9 days after… etc

Question 12

Explain mechanical isolating mechanisms

Answer 12

May mate, but fail to acheive fertilization due to anatomical incompatibility

Question 13

Example of mechanical isolating mechanisms

Answer 13

Insects and their lock + key systems

Question 14

Explain Gametic isolating mechanisms

Answer 14

Gametes are prevented from meeting after mating.

Question 15

Example of gametic isolating mechanisms

Answer 15

Reproductive tract of females destroy gametes of other species.

Question 16

Whats a post zygotic isolating method?

Answer 16

If zygote forms, barriers prevent hybrid zygotes from developing viable + fertile individuals.

Question 17

Name the 3 post zygotic isolating methods

Answer 17

Hybrid inviability, hybrid sterility, hybrid breakdown

Question 18

Explain hybrid inviability

Answer 18

Genetic incompatibility- no zygote development. Result of a polar body

Question 19

Explain hybrid sterility

Answer 19

Offspring viable, but not fertile- no further reproduction. ie) mule

Question 20

Explain hybrid breakdown

Answer 20

sometimes hybrids are viable and fertile for 1 gen, but the next gen is sterile and weak. ie) rice

Question 21

What is adaptive radiation?

Answer 21

the diversification of a group of organisms into forms filling different ecological niches.

Question 22

Explain the connection of darwins finches and adaptive radiation

Answer 22

Development of different functional structures from a common ancestral form is called adaptive radiation. Darwin’s finches had common ancestors and now have 13 species of birds with different types of modified beaks according to their food habits.

Question 23

Explain divergent evolution

Answer 23

Common ancestor becomes increasingly different

Question 24

Explain convergent evolution

Answer 24

2 unrelated species become similar based on selective pressures

Question 25

Explain the theory of gradualism

Answer 25

Slow and steady changes after divergence from ancestor. Major changes is a result of small changes accumulating

Question 26

Explain the theory of punctuated equilibrium

Answer 26

Long periods of stasis periodically interrupted by periods of divergence. Major changes occur when they first diverge from common ancestors.

Question 27

How do humans contribute to speciation?

Answer 27

We cause allopatric speciation. We build infastructure, relocate individuals within a species, and flood land for dams