coevolution

Question 1

what is coevolution?

Answer 1

• how 2+ species will exert selective pressures on each other, and also evolve in response to each other
• the selective environment is constantly changing
• it is reciprocal evolution, where they are always responding to one another

Question 2

under what conditions does coevolution occur?

Answer 2

• when there are incredibly close ecological relationships between the species, usually specialists species,
• also predator/prey, host/parasite, mutualist, or competitors

Question 3

How do we identify coevolution?

Answer 3

• by looking at the adaptations of individuals, interactions between species, or broad evolutionary patterns

Question 4

what are co-phylogeny?

Answer 4

• phylogenetic trees that show similar patterns (cospeciation) between 2+ species,
• congruent phylogenies

Question 5

what is cospeciation?

Answer 5

congruent phylogenies that match one another, showing two species speciation reciprocally

Question 6

what is coadaption?

Answer 6

• reciprocal adaptations of two species

Question 7

describe plant-herbivore coevolution

Answer 7

• plants produce toxins and secondary chemicals to reduce herbivory, which increases their chance of survival
• some herbivores have evolved to detoxify the chemicals (especially herbivores that specialize on the host)
• herbivore overcomes plant defenses
• plant may respond in kind, resulting in coevolution

Question 8

what is the geographic mosaic theory of evolution?

Answer 8

• interactions coevolve as constantly changing geographic mosaics
• coevolution may be prominent in some areas, but not others
• the outcome of an interaction can vary between areas and gene flow can affect the outcome of interactions

Question 9

What is the red queen hypothesis? How does it relate to coevolution and escalation?

Answer 9

Red queen: running as fast as possible just to stay in the same space
- coadaptions are becoming increasingly powerful, yet species are not any better adapted because the selective environment is constantly changing

Question 10

how does coevolution lead to biodiversity?

Answer 10

• Coevolution is an evolutionary arms race, where one species is attempting to overcome another and vice versa
• this promotes diversity via antagonistic interactions
• which drives speciation

Question 11

what are the two models of evolution?

Answer 11

gradualism and punctuated equilibrium

Question 12

what is gradualism?

Answer 12

• large differences in phenotype evolves through many slightly different intermediate states

Question 13

What is punctuated equilibrium?

Answer 13

• provides a pattern of change in fossil record and a hypothesis about evolutionary processes
• pattern of rapid evolutionary change in phenotype separated by long periods of little change (stasis)

Question 14

what are difficulties when measuring rates of change in the fossil record?

Answer 14

• calculating change between fossilized end members almost always under-estimates the maximum rate of evolutionary change

Question 15

what is copes rule?

Answer 15

average body size in mammalian groups tends to increase over time