Lecture 12: Finite Resources and Strategy (Exam 2)

Question 1

How tradeoffs and changing environments produce the diversity of life we observe

Answer 1

-organisms have a finite energy “budget” so we make tradeoffs because resources are not infinite

Question 2

Categories of biological trade-offs

Answer 2

• allocation constraints
• functional conflicts
• shared biochemical pathways
• antagonistic pleiotropy
• ecological circumstances
• antagonism between survival and reproduction

Question 3

allocation constraints + example

Answer 3

• allocation to one component means decreasing to another
• ex: ?

Question 4

functional conflicts + example

Answer 4

• features enhance performance in one area, decrease in another
• ex: penguins are birds that cannot fly; physical trade-off between flight & diving efficiency

Question 5

shared biochemical pathways + example

Answer 5

• signaling molecules in multiple pathways yield multiple effects
• ex: testosterone can increase growth rate, muscle mass (positive), but also increase aggression; decrease parental care (negative)

Question 6

antagonistic pleiotropy

Answer 6

• genes have multiple antagonistic effects
• ex: ?

Question 7

ecological circumstances

Answer 7

• context-dependent relationships between traits and environment
• ex: ?

Question 8

antagonism between survival and reproduction

Answer 8

• traits that increase mating decrease survival or vice versa

Question 9

tradeoffs between the two components of natural selection

Answer 9

• two components: survival and reproduction
• survival : procure resources, structure or shelter, maintenance
• reproduction: find mates, produce offspring, care for offspring

Question 10

strategies for reproductive allocation and what environments would make each favorable

Answer 10

-** K-selection & R-selection**
- K-selection: selection for traits advantageous at high population densities; fewer offspring and greater parental investment (humans?)
- r-selection: selection for traits advantageous at low population densities; more offspring and less parental investment

Question 11

what two things yield a diversity of organisms

Answer 11

• environmental heterogeneity
• biological trade-offs