Lecture 9: Mechanisms of adaptation

Question 1

Evolution:

Answer 1

ANY change in gene frequency

Question 2

Adaption:

Answer 2

evolutionary change that fits an animal to its habit or habitat

Question 3

3 ways to revers adaption:

Answer 3

• optimality studies
• comparitive studies
• experimental studies

Question 4

Optimality studies; example

Answer 4

Bee-eaters that forage for honey bees & large dragon flies.

• 2 circles; inner circle no bees taken beyond this range. outer circle dragonflies only taken.
• By looking at flight time (always in flight when foraging)
• returning to perch
• & whats been caught

Question 5

Comparative method e.g; Do animals with similar lifestyles have similar traits?

Answer 5

• BATS & OIL BIRD
• Bats; echo location. Send out clicks when in flight towards prey. Click return & can give information regarding size of prey & direction of prey
• Oil bird; Sends clicks as lives in a cave against walls to find nest.
• -> Similar traits but no recent common ancestor

Question 6

If a trait is an adaption then changing the trait will

Answer 6

change its adaptive value - peppered moth

Question 7

What makes an experiment an experiment?

Answer 7

must have a CONTROL & something must be MANIPULATED

Question 8

What mechanisms produce adaptations?

Answer 8

Adaptation involves evolutionary change. Mechanisms that produce evolutionary change might also produce adaptation.

Question 9

Whats common between?

• Genetic drift
• mutation
• meiotic drive
• molecular drive

Answer 9

Can cause evolutionary change but change is random ADAPTATIONS ARE DIRECTIONAL

Question 10

Inheritance of acquired characteristics can produce

Answer 10

adaptive change but only by chance, just as likely to produce non-adaptive change.
-Also adaptive changes cannot be passed on.

Question 11

Better adapted individuals _____ ____ & mate ___ ___ so leave _____ offspring

Answer 11

survive longer
more frequently
more
& vice versa with poorly adapted individuals

Question 12

3 factors necessary for selection:

Answer 12

• Multiplication
• Variation
• Inheritance

Question 13

multiplication

Answer 13

leads to a struggle for existence. With one male and one female 700 years = 19 million elephants. More elephants less resources to go round

Question 14

variation + struggle for existence

Answer 14

• -> differential survival & reproduction (selection)

- important for identification, human faces

Question 15

selection + inheritance –>

Answer 15

adaptation

Question 16

Charles Darwin & Alfred Russel Wallace

Answer 16

Both looked at evolution.

darwin didn’t know the mechanism for inheritance

Question 17

Charles Darwins book=

Answer 17

‘The Theory of Evolution by Natural Selection’ in 1858

Question 18

Discontinuous characters;

Answer 18

e.g. colour morphs

determined by one set of genes

Question 19

Continuous characters;

Answer 19

e. g. body size

- determined by multiple set of genes (POLYGENIC INHERITANCE)

Question 20

Where does NEW variation come from?

Answer 20

1) RECOMBINATION; (crossing over) but NO change gene frequencies
2) MUTATION; mutation creates variation which is random in direction. Selection provides direction to adaptive changes.

Question 21

Ultimate source of variation is

Answer 21

MUTATION

Inheritance must be particulate not BLENDING

Question 22

Darwinian Natural Selection + Mendelian Inheritance =

Answer 22

Neodarwinism