Biology 1001A Lecture Notes - Lecture 17: Multicellular Organism, Semen
7 May 2018
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/- mutualistic, competitive and antagonistic relationships between species, given 'real world' examples
-factors that advantage one side or the other in an evolutionary arms race
-meaning of 'life-dinner principle'
-difference between prudent-parasite hypothesis and trade-off hypothesis, in terms of the evolution of
virulence
-factors that influence the optimal virulence of a given host/parasite relationship
-costs and benefits of being highly virulent (from the point of view of the parasite)
-why improving equipment for survival does not always translate into 'winning' an evolutionary arms
race
Lecture 22: Species Interaction and Evolutionary Arms Race
- mutually beneficial behavior between species is just cooperation, however, mutually beneficial
behavior between two organisms of different species is mutualistic behavior. Even humans engage in
mutualistic interactions We domesticate animals and crops. This benefits both the animals/crops and
us.
- When two species interact, one may use the other as a resource (exploiter benefits, resource suffers):
Antagonism (natural enemies)
Ex. A predator-prey interaction, also herbivores and plants, parasites reduce fitness of host but increase
their own fitness
- When two species interact, both may incur costs: Competition.
Ex. Big carnivores are often in competition with other carnivores for limited food. Ex. many
Even competition among different type of plants. Trees are in an evolutionary race for sunlight (this is
why they grow so tall when they are clustered together).
Evolutionary arms race: Adaptations and Counteradaptations
- Newts and Gardersnakes: Newts produce toxin that mean no other species can eat them. However,
gardersnakes can break down the toxins.
Evolutionary Arms Race: An escalating cycle of adaptation on one side that better allows it to deal with
adaptation on the other side.
Improved equipment for survival does not improve success Ex. lions and wildebeests both can run
faster through natural selection (improve equipment) but lions now do’t hae greater ailit of
catching wildebeests now as their ancestors did catching ancestral wildebeests because both get faster!
suess does’t iproe. E.2 Trees i forest Growing increases sunlight but it requires more energy
spent in trunk and less i akig speeds so trees’ suess does’t iproe.
Who wins the arms race? May keep escalating until costs of continuing to escalate outweigh the
benefits (Red Queen Equilibrium).
find more resources at oneclass.com
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Document Summary
/- mutualistic, competitive and antagonistic relationships between species, given "real world" examples. Factors that advantage one side or the other in an evolutionary arms race. Difference between prudent-parasite hypothesis and trade-off hypothesis, in terms of the evolution of virulence. Factors that influence the optimal virulence of a given host/parasite relationship. Costs and benefits of being highly virulent (from the point of view of the parasite) Why improving equipment for survival does not always translate into "winning" an evolutionary arms race. Lecture 22: species interaction and evolutionary arms race. Mutually beneficial behavior between species is just cooperation, however, mutually beneficial behavior between two organisms of different species is mutualistic behavior. Even humans engage in mutualistic interactions we domesticate animals and crops. When two species interact, one may use the other as a resource (exploiter benefits, resource suffers): A predator-prey interaction, also herbivores and plants, parasites reduce fitness of host but increase their own fitness.
