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Evolutionary Ecology > Life Histories (DONE) > Flashcards

Life Histories (DONE) Flashcards

This is the main deck of flashcards for this topic

1
Q

What are life histories?

A

Life histories are the patterns of growth, reproduction & survival an organism undergoes in its lifetime

Influenced by genetics, environment & survival

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2
Q

What are the 3 main components of life histories?

A
  • Growth
  • Reproduction
  • Survival
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3
Q

How do guppies & whale sharks differ from cod in reproduction?

A

Guppies & whale sharks give birth to live young, while cod lay millions of eggs

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4
Q

What is r-selection?

A

A strategy where species “live fast, die young”, reproducing quickly in unstable environments

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5
Q

What is K-selection?

A

A strategy focussing on competition & slower growth in stable environments

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6
Q

What trade-offs do organisms face in resource allocation?

A

Between:

  • Current & future reproduction
  • Growth & reproduction
  • Reproduction & survival
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7
Q

Define semelparity:

A

A reproductive strategy where organisms reproduce once & then die

e.g. salmon

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8
Q

Define iteroparity:

A

A reproductive strategy where organisms reproduce multiple times throughout their life

e.g. humans

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9
Q

How do high-predation environments affect guppies’ life histories?

A

They mature faster & reproduce earlier to reduce time at risk or predation

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10
Q

What is senescence?

A

The process of ageing, marked by declining reproductive success & survival with age

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11
Q

What is mutation accumulation?

A

The build-up of harmful mutations that manifest later in life when natural selection is less effective

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12
Q

What is antagonistic pleiotropy?

A

When genes beneficial early in life have detrimental effects later in life

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13
Q

What constraints limit life history evolution?

A

Phylogenetic, biomechanical & developmental constraints

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14
Q

What does the reproductive value curve represent?

A

The expected number of offspring an individual will have over the rest of their life

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15
Q

What is the Darwinian Demon?

A

It is a hypothetical organism that starts reproducing immediately after birth - produces an infinite no. offspring & lives forever

Represents the theoretical “perfect” outcome of evolution - cannot exist tho

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16
Q

Why don’t organisms reach the “Darwinian Demon” ideal?

A

Bc they cannot reproduce from birth & face trade offs between growth & reproduction

17
Q

How does condition affect life history strategies?

A

Variation in resources & environment leads to differences in growth, reproduction & survival

18
Q

How do semelparous plants allocate energy compared to iteroparous plants?

A

Semelparous plants = invest more energy in a single reproductive event

Interoparous plants = spread investment over time

19
Q

What is Cole’s Paradox?

A

The question of why all organisms aren’t semelparous since producing one extra offspring seems advantageous

20
Q

What was observed in song sparrows regarding trade-offs?

A

Predicted trade-offs between reproduction & survival were not always supported

21
Q

How does extrinsic mortality affect senescence?

A

Higher external mortality leads to faster ageing since investing in future reproduction becomes less advantageous

22
Q

How do r- and K- strategists differ in unstable vs stable environments?

A

r- strategists thrive in unstable environments w rapid reproduction

K- strategists excel in stable environments w competition

23
Q

What example illustrate extreme senescence in vertabrates?

A

The Greenland shark –> can live over 400 years

24
Q

What study used anoles to demonstrate reproductive trade-offs?

A

An experiment showed that stopping reproduction allows greater growth & survival

25
Q

How do iteroparous species balance survival & reproduction?

A

By reproducing less intensely to maintain survival over multiple reproductive events

26
Q

How do phylogenetic constraints impact life histories?

A

Evolutionary history limits how much traits can adapt, such as mammals not reverting to fish

27
Q

What is the disposable soma theory?

A

The idea that organisms prioritise early reproduction, reducing long-term maintenance & survival

28
Q

What role does condition-dependent mortality play in life histories?

A

It shows that individuals in better condition can offset senescence & live longer

29
Q

What did Ricklefs (1998) observe about mortality in zoos?

A

Even in protected environments, senescence causes inc mortality late in life

30
Q

What trade offs were seen in high-predation guppy population?

A

High-predation fish reproduced earlier but continued reproducing longer than low-predation fish

31
Q

What is a key takeaway about life history trade-offs?

A

No strategy is perfect; all involve compromises between growth, reproduction & survival

Evolutionary Ecology (13 decks)

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