Ecosystems + Ecology

Question 1

what are the 5 elements of life?

Answer 1

Carbon, Nitrogen, Oxygen, Hydrogen, Phosphorus (95%)

Question 2

Carbon cycle

Answer 2

Carbon atoms travel from atmosphere to earth and back, auto factory emissions, plant respiration, animal respiration put C02 in the air, plants photosynthesize it.
Microbes drive carbon cycle.

Question 3

Nitrogen cycle

Answer 3

• Microbes drive this process
• Nitrogen fixation is very high energy demanding process
• Changes NH4 to NH2 to Nitrate (NO3) so it can now be absorbed by plants and animals

Question 4

What are the 4 types of ecology?

Answer 4

1) Behavioural ecology - animal behaviour
2) Population ecology - births/deaths/demographics
3) Community - interactions between species
4) Ecosystem - flow of energy and matter through biotic and abiotic ecosystems

Question 5

What is optimal foraging and 3 things to look out for?

Answer 5

• Optimal foraging: eat foods that maximize energy intake
  1) abundance of diff prey types
  2) catch-ability
  3) quality

Question 6

What are three complications when hunting for food?

Answer 6

1) competition
2) predation risk
3) essential nutrients

Question 7

Bottom up food control webs

Answer 7

• when abiotic factors (nutrients, sunlight, water) determines amount of primary producers
• Ex. In terrestrial environments nitrogen is limiting factor, air is 78% nitrogen but in N2 form which is unavailable to most organisms
• the nitrogen can be “fixed” by bacteria in soil/plants

Question 8

Top down food control webs

Answer 8

• predators control abundance (productivity) of “lower” trophic leaves

Question 9

Keystone species

Answer 9

• species that have large effect on environment relative to their abundance
• Ex. starfish, otter, beavers

Question 10

What are the two was to look at evolutionary change?

Answer 10

1) changes in allele frequency

2) changes in mean value of quantitative trait

Question 11

What are the five evolutionary mechanisms and describe them?

Answer 11

1) Mutation
- change in genetic code, generates new allele
2) Genetic drift
- random changes in allele frequency
- more effective in smaller population
3) Natural selection
- traits vary, heritable, adapt to environments for survival
4) Sexual selection
- intra-sexual: male-male competition
- inter-sexual: female choice
5) Gene flow
- 2 different populations exchange genes between them

Question 12

How do organisms respond to climate change?

Answer 12

• more locations

- stay but change traits = natural selection