2.2 communities and ecosystems

Question 1

ecology

Answer 1

• study of ecosystems
• major input/output is energy

Question 2

inputs

Answer 2

majority of ecosystems gain input of energy as light from the sun via photosynthesis
- carbon dioxide + water → glucose + oxygen

Question 3

outputs - heat energy

Answer 3

• living organisms can’t convert heat to other sources of energy –> lost bc of second law of thermodynamics
• energy leaves areas of high concentration (living things) and moves towards a more equal concentration (out into space)
• means that energy trapped by photosynthesis is lost at every trophic level; energy flows through ecosystems, not recycled

Question 4

trophic level

Answer 4

describes the role an organism plays in food chain

Question 5

trophic level one

Answer 5

primary producer: organism that nourishes itself using an inorganic form of energy (sunlight/chemical compounds)
- e.g: plants, chemosynthetic bacteria

Question 6

trophic level two

Answer 6

primary consumer: animal that feeds off primary producers
- e.g: deer, cow

Question 7

trophic level three

Answer 7

secondary consumer: animal that feeds off primary consumer
- e.g: lion, wolf, humans

Question 8

decomposers

Answer 8

consume dead and non-living material
- e.g: worms, maggots

Question 9

pyramids of energy

Answer 9

represent the energy that moves between trophic levels

Question 10

productivity

Answer 10

• conversion of energy into biomass over a period of time
• enables ecologists to compare the efficiency of photosynthesis between different biomes

Question 11

GPP - gross productivity

Answer 11

amount of energy that enters a trophic level

Question 12

NPP

Answer 12

• is GPP - R
• the amount of energy left over for growth and reproduction and available for consumers

Question 13

GSP - gross secondary productivity

Answer 13

• the total energy/biomass taken by consumers
• equation: food eaten - ‘fecal loss’

Question 14

NSP - net secondary production

Answer 14

equation: GSP - R

Question 15

MSY - maximum sustainable yield

Answer 15

max amount that can be taken (yield)

Question 16

bioaccumulation

Answer 16

• chemicals that aren’t broken down/expelled by the body
• typically associated with human made chemicals (e.g. dioxin pollution in lausanne)

Question 17

biomagnification

Answer 17

process where top predators incur higher concentrations of bioaccumulating toxins

e.g. methyl-mercury in people