Natural Selection Flashcards

1
Q

What two things are needed for evolution to occur

A

Needs to be a variation in traits within a population

Needs to be a variation in reproductive success among individuals

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2
Q

What % of behavioural traits are inherited

A

30

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3
Q

What % of physiological traits are inherited

A

33

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4
Q

What % of morphological traits are inherited

A

46

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5
Q

What things define fitness

A

Number of copies of allele passed on to next generation

Lifetime reproductive success

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6
Q

What is micro evolution

A

When natural selection causes changes in the relative frequencies of alleles in a population

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7
Q

Why is reproductive success more important than advantageous alleles

A

No point having advantageous alleles if can not reproduce as they are not passed on

Eg sparrows with long wings is more advantageous but short winged sparrows reproduce more often - short wing allele passed on so more short wings than long

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8
Q

What year did Darwin visit the Galapagos

A

1835

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9
Q

What species of finches was studied by Darwin

A

Geospiza fortis

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10
Q

Why did 1976-1977 drought on Isla Daphne Major cause

A

A decline in the population of geospiza fortis

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11
Q

Why did the number of seeds decrease during the drought

A

Plants focused on surviving rather than reproducing so produced less seeds

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12
Q

Why did long beaked geospiza birds eat more than small beaked geospiza birds during the drought

A

The seeds of plants hardened (thin in rainy season) meaning only long beaked birds were able to crack them and eat them

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13
Q

Why did bill depth of geospiza fortis increase after the drought

A

As the birds with the bigger bills were the only ones that could eat during the drought, they survived and reproduced meaning the offspring were born with bigger bills

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14
Q

Across how many generations did the microevolution of bill size

A

1

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15
Q

Directional selection

A

Shift in one direction either left or right

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16
Q

Diversifying selection

A

Extremes successful so dip in the middle

17
Q

Stabilising selection

A

Middle successful so mostly middle

18
Q

What a the three components of natural selection

A

Survival selection
Sexual selection
Kin selection

19
Q

What is survival selection

A

Selection for traits that maximises survival

20
Q

What is sexual selection

A

Selection for traits that enhance reproductive success

21
Q

What is kin selection

A

Selection for traits that maximise the fitness of close kin

22
Q

Why did Darwin consider sexual selection to be separate from natural selection

A

Sexual traits can increase fitness but reduce the individuals survival

Eg male peacocks have big tales to attract females - increases reproductive success and fitness - but makes them easy targets for predators - reduces individual survival

23
Q

What are the two types of sexual selection

A

Intra sexual selection

Inter sexual selection

24
Q

What is intra sexual selection between

A

Two males

25
Q

What does intra sexual selection lead to

A

Evolution of weapons and size dimorphism

26
Q

What is size dimorphism

A

One gender is bigger than the other

27
Q

What does inter sexual selection lead to and why

A

Leads to evolution of elaborate male ornaments that advertise male quality because inter sexual selection maximises traits that maximises the chances of breeding with females

28
Q

Why might Traits that lower the individuals survival rate be favourable

A

It increases the fitness of close kin

Kin selection

29
Q

When does adaptive evolution occur

A

When variation in heritable traits is correlated with differential reproductive success