Lecture 16: Mutualism, competition, and exploitation (Exam 3)

Question 1

How species interactions influence evolution and how they are classified

Answer 1

• intraspecies interaction - within species
• interspecies interaction - across species
• symbiotic: 2 species interact, can be good or bad
• mutualism: both organisms benefit

Question 2

the six kinds of species interactions and their effects on fitness

Answer 2

1. competition (both negative)
2. predation (herbivory): + for A, - for B
3. parasitism: + for A, - for B
4. commensalism: + for A, no effect on B
5. amensalism: no effect, - for B
6. mutualism: + for A, + for B

Question 3

the difference between mutualism and altruism, and why altruism poses problems for long-term persistance

Answer 3

• in mutualism, both organisms experience benefits; in altruism, the fitness of another organism increases but the self-fitness decreases
• these kinds of interactions were not stable and thus would not persist

Question 4

The diference between facultative and obligate

Answer 4

facultative: not necessary for survival, improves fitness
obligate: necessary for survival, improves fitness

Question 5

What evolutionary game theory is and how iterative
games solve the “problem” of mutualisms

Answer 5

• strategies of survival and reproduction
• it showed that “tit for tat” is the winning stage; cooperate on the first move, but thereafter copy player B’s move

Question 6

exploitation and examples

Answer 6

• any type of interaction in which one organism kills and consumes another species
• ex: (predation, herbivory)