Adaption, Life History And Behaviour

Question 1

What is clutch size?

Answer 1

Number of eggs laid

Question 2

What methodology do we follow in science?

Answer 2

Observation —> theory —> test

Question 3

X

Answer 3

Observation = great tit clutch size is 8 or 9 eggs.

Question 4

Testing adaption summary

Answer 4

1. Assume optimisation
2. Strategy set (options open to natural selection)
3. Fitness consequences of different options (costs and benefits - what trade offs drive this adaption)
4. What strategy yields the greatest fitness

Question 5

What does assume optimisation/maximisation mean?

Answer 5

What is a good measure of fitness?

In the grate tir example this might be how many offspring in the clutch size do they manage to pledge successfully

Question 6

Why does strategy set mean?

Answer 6

What are the different options of strategies that natural selection had to choose between?
(Eg. In great tits the different strategies natural selection could have taken are like it could have produced less eggs or more eggs in a clutch size etc) - 1-x eggs

Question 7

Flaws with idea of fitness

Answer 7

Fitness doesn’t take into account reproductive value (could have high reproductive success with lots of offspring but these offspring are very weak)

Question 8

How could you measure reproductive value in birds?

Answer 8

Look at how many offspring the mother managed to successfully fledge rather than how many offspring she produced at first

Question 9

What does fitness consequences refer to in the great tit example?
And what is this called

Answer 9

More eggs you lay = more offspring you have to feed = more chicks of lower quality
(This is a trade off between the number and quality of offspring)

Question 10

What is an evolutionary trade off?

Answer 10

When evolution cannot optimise one part of a biological system without compromising another part of it

Question 11

What is meant by

Answer 11

X

Question 12

Graph explanation

Answer 12

• survival doesn’t decrease much so great tit keeps producing more offspring
• eventually survival decreases so much that continuing to produce more offspring makes you do worse (I’m assuming because you just get lost of weak offspring so can’t pass on ur genes as well?)

Peak = maximum (3 is spring is maximum clutch size)

Question 13

What is the lack’s theory of clutch size?

Answer 13

That the clutch size has been adapted by natural selection to be the largest number of offspring which the parents can on average provide enough food

Question 14

More graphs

Answer 14

(a) as clutch size increases the average weights of chicks decreases
(b) = as chick weight decreases their survival decreases.

Question 15

X

Answer 15

Observed is similar to predicted

Natural selection

Question 16

X

Answer 16

X

Question 17

X

Answer 17

X

Question 18

X

Answer 18

X

Question 19

What is a hypothesis for why might birds lay less eggs than the lack clutch size? + example

Answer 19

Laying more eggs in one year might cost how many eggs you lay in future years

(Eg. Birds raise metabolism to feed their chicks so if they lay loads of chicks one year it may reduce their chance of surviving in future years because they are more physically exhausted Eg. Might become more prone to disease)

Question 20

What is the trade off involved in why birds might lay less eggs than the lack clutch size ?

Answer 20

Trade off between current reproductive effort and how much you will be able to reproduce in future years

Question 21

What kind of things can you experiment with, with great tits?

Answer 21

• how well a female survives if you add more eggs to her nest/ take away eggs
• ## add eggs earlier (adds cost of having to spend more energy incubating more eggs earlier)

Question 22

What length of fitness matters

Answer 22

Fitness over a LIFETIME

Question 23

What is a Darwinian demon?

Answer 23

Something amazing at everything:

• reproduced very young
• large
• reproduced lots of good quality offspring

Question 24

Why does a Darwinian demon not exist?

Answer 24

Because of trade offs

Question 25

What do you need to work out when you ask why something is how it is?

Answer 25

What the trade off is

Question 26

Fitness

Answer 26

Maybe eating a male provides better nutrition?
Maybe eating a male means the female can produce more eggs?
Turns out neither of these affect the number of offspring the female can produce

Question 27

Statistics of cannibalised male spiders and how it affects the female

Answer 27

When female spiders eat the male spider they are more likely to reject a second suitor

(Cannibalise male = 67% likelihood to reject suitor)

(Don’t cannabisme make = 4% likelihood to reject suitor)

Question 28

Disadvantage if two males mate a female

Answer 28

Sperm competition to fertilise their eggs

Question 29

Explain the statistics of offspring produced by female when the male is cannibalised vs not cannibalised

Answer 29

If the male allows himself to be cannibalised it means the female then doesn’t go on to mate a second suitor. This means that only that makes sperm fertilised the females egg so that 92% of her offspring are gathered by the male (have his sperm)

If the male isn’t cannibalised the female mates a second suitor meaning her offspring are a mix of both males’ sperm. The males not eaten only father 45% of the eggs (only 45% of the eggs were made with their sperm)

Question 30

What is the real benefit of not being cannibalised?

Answer 30

None - If you aren’t eaten by the female the likelihood you will reach another web is low anyway (16%).

So you might as well be cannibalised because when you’re cannibalised there’s a higher percentage of the females offspring that you father

Question 31

What is the winning strategy for spider mating?

Answer 31

Not Cannibalised = low (16%) likelihood you will reach another web and mate with a female

So you might as well just be cannibalised to maximise the number of offspring you produce (if cannibalised the female doesn’t mate with a second male so more of her offspring are made with your sperm)

Question 32

What’s being maximised
What’s the strategy set
What’s the cost and benefit (trade offs)

Blue head wrasse

Answer 32

1. Number of offspring produced will be maximised
2. Strategy set - should you be a male or a female and when should you change sex
3. What is the benefit of being a male or female at different ages?

Question 33

When do blue head wrasse’s change sex usually

Answer 33

When females are older and larger

Question 34

Female fecundity in the blue headed wrasse

Answer 34

Female fecundity (ability to produce abundance of fertile healthy offspring) increases with length

bigger is better when you are a female wrasse

Question 35

Males

Answer 35

Mating success depends on size and age more strongly than females.

Because bigger males can defend reef and get lots of females.

Question 36

Fitness consequences in the bluehead wrasse

Answer 36

Size and age have a huge fitness consequence

Question 37

Sneaky fucker

Answer 37

Male bluehead wrasse behaves like a female so they can chick their speed onto the eggs of females i

Question 38

Larger males have a ___ reproductive success compared to a small male

Answer 38

Larger (x40)

Question 39

Switching sex

Answer 39

Females switch sex and become a male when it’s optimal (get the best of both worlds)