Mutualism (DONE) Flashcards

1
Q

Define parasitism:

A

One species benefits, while other suffers

e.g. ticks on mammals

(+,-)

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2
Q

Define commensalism:

A

One species benefits, while the other is unaffected

(Rare in nature)

(+,0)

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3
Q

Define mutualism:

A

Both species benefit from the interaction

e.g. pollination, nutrient exchange

(+,+) = cooperation

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4
Q

Define symbiosis:

A

A long-term, co-evolved relationship between species, not necessarily mutualistic

(Long-term, closely-evolved)

(+,-) (+,0) (+,+)

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5
Q

Are mutualistic relationships always mutual?

A

No

Mutualisms can fluctuate between mutual benefit & parasitism depending on environmental or contextual factors

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6
Q

Give an example of a relationship that was thought to be mutual, but was not after being studied

A

Relationship between Oxpeckers and Cattle

  • Oxpeckers originally thought to pick ticks (mutualistic)
  • Studies show they often open wounds, consume blood & inc earwax build up (parasitism)
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7
Q

Is mutualism typically altruistic?

A

No, mutualism is not normally altruistic

Both species act in their self interest & mutual benefits are a byproduct of maximising their fitness

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8
Q

Do both species always benefit from every interaction in a mutualistic relationship?

A

No, both parties may not benefit from every interaction

e.g. a pollinator may consume nectar w/o delivering pollen

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9
Q

How can fitness increases in one species affect the other in mutualism?

A

Fitness inc in one species are often at the expense of the other, reflecting trade-offs in the relationship

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10
Q

Why do conflicts of interest arise in mutualistic relationships?

A

Conflicts of interest arise bc each species has its own goals, such as plants maximising pollen dispersal while pollinators prioritise nectar collection

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11
Q

How is mutualism related to reciprocal exploitation?

A

Mutualism can be seen as reciprocal exploitation, where both species “use” each other to maximise their own gain, even if it comes at some cost to the other

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12
Q

How does the Prisoner’s Dilemma relate to mutualism?

A

The Prisoner’s Dilemma models how cooperation in mutualism can break down if both partners prioritise self-interest, leading to potential collapse of the relationship

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13
Q

Are mutual relationships static?

A

No, mutualisms are dynamic & can shift along a spectrum from mutualism to parasitism based on environmental conditions, resource availability & evolutionary pressures

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14
Q

What is visitor mutualism?

A

Temporary interactions where one species benefits during visits

e.g. pollinators visiting flowers, frugivore-plant, pollinator-plant & cleaner fish

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15
Q

What is obligate/symbiotic mutualism?

A

A long-term, speciealised relationship where species survival depends on the interaction

e..g figs & fig wasps, mycorrhizal associations, lichens & animal endosymbiosis

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16
Q

How dan mutualistic relationships drive coevolution?

A

They lead to coevolutionary arms races, where species evolve traits to maximise mutual benefits

17
Q

Provide an example of coevolution in mutualism:

A

Madagascan Star Orchis & Hawk moths

Orchid nectar spurs have nectar at the bottom –> longer spurs = more pollination as moth’s body must touch flower

Orchids evolved longer spurs & Moths evolved longer tongues to access nectar efficiently

Nectar tubes were shortened experimentally & reduced pollen success –> selection favours long spurs & tongues

18
Q

What mechanisms help maintain mutualism?

A

Mechanisms like sanctions or selective pressures prevent cheating or overexploitation

19
Q

What are 3 examples of interactions where sanctions are used?

A
  • Yucca & Yucca moths
  • Figs & fig wasps
  • Legume-rhizobia symbiosis
20
Q

How do yucca plants maintain balance in their mutualism w yucca moths?

A

Yucca plants abort flowers w excessive moth eggs to reduce exploitation

21
Q

How do figs and fig wasps maintain mutualism?

A

Figs abort fruit if pollination fails or if wasps overexploit

22
Q

Explain the legume-rhizobia symbiosis mechanism:

A

Plants reduce resources to non-fixing (cheating) bacteria, maintaining mutualistic balance

23
Q

What are specialist pollination syndromes?

A

Traits evolved in plants to match specific pollinators, like nectar spurs for long-tongued polliantors

24
Q

What general trend is observed in flower-pollinator interactions?

A

Red/yellow flowers attract hummingbirds, while white flowers attracts nocturnal hwakmoths (white produce nectar at night)

  • need to elaborate on this topic from notes
25
Q

How do mutualisms impact ecosystems?

A

They can have community-level effects, such as regulating populations

e.g. parasitoid wasps regulating pollinator wasps in fig ecosystems

26
Q

Provide an example of ant-plant mutualism:

A

Acacia trees provide food (nectaries) and shelter (hollow spines) to ants, which protect the trees from herbivores

27
Q

How do acacia trees ensure ant dependency?

A

They produce nectar with chitinase

The chitinase inhibits ant metabolism of sucrose, making ants reliant on glucose from the tree

28
Q

What is the relationship between fitness & mutualistic traits?

A

Fitness correlates positively w the effectiveness of mutualistic traits

Fitness ∝ Trait Effectiveness

29
Q

How do sanctions prevent overexploitation in mutualisms?

A

Sanctions, like flower or fruit abortion, increase in strength w the degree of overexploitation

Sanction Strength ∝ Degree of Overexploitation

30
Q

Summary:

A

Mutualisms are diverse interactions where both species benefit but often involve mechanisms to prevent exploitation. These relationships can be short-term or obligate, shaped by coevolutionary dynamics. Empirical examples (e.g., yucca moths, fig wasps) highlight how mutualisms maintain balance through adaptations like sanctions, dependency creation, or fitness trade-offs, playing vital roles in ecosystems.