Evolution SJ 2

Question 1

define adaptation

Answer 1

the way each organism ‘fits’ its environment

Question 2

what are the 3 steps in developing a scientific method?

Answer 2

1) look for patterns: diversity/unity/adaptation
2) produce a testable theory for that pattern
3) test the theory(s) using repeatable methods that produce evidence that can disprove the idea

Question 3

what is the definition of evolution?

Answer 3

any change in gene frequency

Question 4

describe weismanns principle

Answer 4

• information transmitted from one organism to the next is in the germ cells (gametes)
• soma cells make up rest of organisms body
• any changes in the soma cannot be transmitted back into the germ line (arrows only in 1 direction)

Question 5

what is the modern equivalent to weismanns principle and what is the difference?

Answer 5

the central dogma where instead of soma and germ cells the example of DNA and protein is used

Question 6

what is genetic drift and why does it occur?

Answer 6

variation in the relative frequency of different genotypes in a population owing to the disappearance of particular genes are individuals die or don’t reproduce because mendelian inheritance is not exact

Question 7

what is meiotic drive?

Answer 7

genes distort segregation so that gametes that don’t carry the gene die during gametogenesis favouring the transmission of one or more alleles over another

Question 8

what is molecular drive?

Answer 8

molecular drive genes are able to convert slightly different genes into identical copies of themselves

Question 9

what are 3 ways to recognise an adaptation?

Answer 9

1) optimality approach - working out optimal to understand evolutionary characters in behaviours
2) comparative studies - similar lifestyles = similar traits?
3) experimentation - if a trait is adaptive, then changing the trait will change its adaptive value

Question 10

what are 3 ways to recognise an adaptation?

Answer 10

1) optimality approach
2) comparative studies
3) experimentation

Question 11

what is the difference between adaptation and mutation/genetic drift?

Answer 11

adaptation is directional the other 2 cause evolutionary change but are random

Question 12

what are 2 ways of detecting selection?

Answer 12

1) Look for correlations between characters and spatial or temporal variation in the environment
2) look directly for differences in fitness

Question 13

what are 2 ways of detecting selection?

Answer 13

1) Look for correlations between characters and spatial or temporal variation in the environment
2) look directly for differences in fitness

Question 14

what is an example of runaway sexual selection?

Answer 14

selection for long tails in peacocks is attractive so offspring have long tails and it carries on in a positive feedback loop until natural selection kicks in at optimal tail length

Question 15

what is an example of runaway sexual selection?

Answer 15

selection for long tails in peacocks is attractive so offspring have long tails and it carries on in a positive feedback loop until natural selection kicks in at optimal tail length

Question 16

what is a punctuated equilibrium in fossil records?

Answer 16

dramatic changes in differences in species due to gaps in fossil records

Question 17

what 2 things could also explain gaps in the fossil record?

Answer 17

1) rapid change

2) periods of stasis caused by stabilising selection

Question 18

what is orthogenesis?

Answer 18

evolution in which variations follow a particular direction and are not merely sporadic and fortuitous

Question 19

what was the permian extinction driven by?

Answer 19

environmental change - shallow marine habitats disappear and so do invertebrates in them

Question 20

what is kin selection?

Answer 20

altruistic behaviour to look after kin - if relatedness to target and benefit to target are bigger than cost to individual the altruistic act will be carried out

Question 21

4 causes of rapid evolutionary change

Answer 21

1) competition - between 2 species
2) exploitation - by humans
3) climate change - lack of resources
4) parasites - selection pressure

Question 22

2 uses of phylodynamic data?

Answer 22

1) tells us which lineages have gone extinct and when and which survived
2) can map on other data and look at phylodynamics

Question 23

2 uses of phylodynamic data?

Answer 23

1) tells us which lineages have gone extinct and when and which survived
2) can map on other data and look at phylodynamics

Question 24

3 reasons why evolution is important?

Answer 24

1) explains the history of life on Earth
2) helps us understand extinction and speciation
3) evolutionary principles help us decide which species and areas we should spend our limited resources conserving

Question 25

what are 3 consequences of phylogenetic niche conservatism?

Answer 25

1) closely related species share similar levels of threat
2) conservatism is a consequence of low rates of adaptability and evolution
3) improved knowledge of extinction risks