Adaptation

Question 1

What is Futuyma’s description of adaptation?

Answer 1

Characteristic that enhances the survival or reproduction of organisms that bear it, relative alternative character states

Question 2

What is the historical definition of adaptation?

Answer 2

Derived character evolved in response to a specific selective agent

Question 3

What is the ahistorical definition of adaptation?

Answer 3

Phenotypic variant resulting in highest fitness among a specified set of variants in a given environment

Question 4

What three things are needed for adaptation to occur?

Answer 4

Variation in phenotypic traits, fitness differences between different phenotypes, variation in traits have to be heritable.

Question 5

What happened between 1976-1978 that Peter and Rosemary Grant observed?

Answer 5

Severe drought, vegetation death, 90 survivors, beak depth average size 0.5mm deeper than before.

Question 6

What was the shift driven by?

Answer 6

Selection by loss of food resources as the only food left were very tough seeds and only strongest beaks able to utilise them

Question 7

What happens if a mutation creates an advantageous allele?

Answer 7

Shift from low frequency to high frequency, becomes polymorphic

Question 8

What happens if a mutation is disadvantageous?

Answer 8

Selected out, mutation-selection-balance, continual input of mutation, continually selected out

Question 9

What are the two types of balanced selection?

Answer 9

Heterozygote advantage and frequency dependent

Question 10

What is heterozygote advantage?

Answer 10

When the heterozygote has higher fitness compared to homozygote, will go to equilibrium and variation is maintained (sickle cell anaemia in malaria prevalent areas)

Question 11

What is frequency dependent selection?

Answer 11

Fitness depends on frequency (genes associated with host parasitic interactions, fitness for rare allele because parasite won’t be adapted)

Question 12

How did Darwin say eye might develop?

Answer 12

Through small steps

Question 13

What did Paley say regarding eyes?

Answer 13

Evidence for god

Question 14

What did Dawkins say regarding eyes?

Answer 14

Blind watchmaker, evolved without any foresight just driven by natural selection

Question 15

How many steps did it take to go from a small patch of cells with light sensing capability to a small concave dish?

Answer 15

362 steps

Question 16

What are the further steps for eye development?

Answer 16

Small concave dish, deeper pit, smaller and smaller aperture like a pinhole camera. Light forms semi resolved image on back surface. Optical properties of liquid inside pit make a higher resolution image.

Question 17

How many years to make a complex eye?

Answer 17

364,000

Question 18

What sort of eye does the Nautilus mollusc have?

Answer 18

Pinhole camera eye

Question 19

What animal shares a similar hearing mechanism to us?

Answer 19

Katydids (bush cricket)

Question 20

How do we hear?

Answer 20

External membrane where sound vibrations are transferred by a physical structure into an internal structure. A fluid filled medium is there and is filled with mechanical receptor cells (hair cells).

Question 21

Describe what happened with Atlantic Killifish?

Answer 21

Can persist in unusually toxic environments filled with PHA’s and PCA’s. An experiment involved taking sample populations from a non toxic environment and a toxic one and sequencing and comparing the genomes. Found that those in the toxic environment had the same genes involved in the metabolism of organic contaminants which allowed them to persist in polluted environments.

Question 22

Why did they adapt so quickly?

Answer 22

Because they have a large population size with high levels of genetic diversity, likely that already have the genetic variant that makes them adapted to the environment so can readily respond to the selection pressure.

Question 23

What did Gould and Lewontin say regarding adaptation?

Answer 23

Spandrels! Not everything has to have an adaptive explanation

Question 24

What are three examples of evolutionary spandrels?

Answer 24

Blood colour, due to Hb, doesn’t give any sort of fitness. Size of T.rex arms, when driving size increase arms didn’t increase proportionally. Pandas have useless projections on their feet with similar morphology to the ones on their hands they use to shear off bamboo, but they don’t use their feet to eat, so useless?

Question 25

What adaptations do marine mammals have that make them able to dive?

Answer 25

Increased myoglobin in muscles, myoglobin helps to store oxygen in the muscle. Also increased surface charge on myoglobin to prevent them from sticking together so they can still function correctly.

Question 26

How long could the whale ancestor dive and what was his name?

Answer 26

1.5 minutes Indohyus

Question 27

How long could Basillosaurus dive for?

Answer 27

15 minutes

Question 28

How long did it take to go from Indohyus time to sperm whale dive time (1.5 to 60 min)

Answer 28

43 million years - rate of 1.6 minutes per million years