Ecosystem Ecology

Question 1

ecosystem ecology

Answer 1

ecosystem: all the organisms in a particular region, along with nonliving (abiotic)components
- ecosystem ecologists study how energy + nutrients move through the ecosystem

Question 2

3 broad categories of ecosystems

Answer 2

1. Terrestrial (grassland, Desert, Forest)
2. Marine
3. Freshwater

Question 3

trophic levels definition + categories

Answer 3

• eating levels

1. producers (autotrophs = self-feeding)
2. consumers (heterotrophs= eat others)

Question 4

producers

Answer 4

autotrophs
get their energy from the sun (via photosynthesis)
ie: algae, photosynthetic bacteria

Question 5

consumers

Answer 5

heterotrophs

• get energy by eating other organisms
• Primary, secondary, tertiary levels
  i. fox, eagles

Question 6

detritivores

not (too) important

Answer 6

internal digestion

ie. vultures, earthworms, some

Question 7

decomposers

not (too) important

Answer 7

external digestion

ie. bacteria, fungi

Question 8

food chain

Answer 8

the linear transfer of food energy from one trophic level to the next

**food web is more realistic

Question 9

primary productivity

Answer 9

the rate at which solar energy is converted into chemical energy/biomass (organic matter) via photosynthesis

Question 10

gross primary productivity (GPP)

Answer 10

the rate at which producers capture and store carbon as plant biomass (via photosynthesis) over some period of time

Question 11

Net primary productivity (NPP)

Answer 11

biomass/energy that remains after the plant has used the energy for its own needs

NPP= GPP - R
* THUS, not all solar energy plants convert to chemical energy is available to primary consumers

Question 12

10% rule

Answer 12

only 10% of the chemical energy available at one trophic level is transferred and stored in usable form in the bodies of organisms at the next trophic level
*but varies from 2-30%

Question 13

biomass

Answer 13

the combined weight of the living matter

Question 14

why is so much biomass/energy lost between trophic levels

Answer 14

1. not everything in the lower level gets eaten

2, not everything that’s eaten is digested or digestible

3.energy is always being lost as heat (a byproduct of metabolism)

Question 15

why is the transfer of energy from secondary to tertiary consumers less efficient than from producers to primary consumers?

what is a consequence of this?

Answer 15

consumers that are active predators expend a lot of energy acquiring food

• finding prey
• catching prey
• manipulating prey

Consequence: ecosystems need large #s of producers to sustain large numbers of consumers, especially secondary or tertiary consumers

Question 16

if producer biomass increases but, what is said to happen to the biomass of the entire ecosystem?

Answer 16

increases because:

higher producer biomass = high community biomass (bc producers are the largest trophic level)

Question 17

nutrient cycling

Answer 17

• nutrients: N, S, K, C, O
• needed for growth and maintenance of life
• chemical elements are recycled

Question 18

what supplies the earth’s ecosystem with continual input of energy

Answer 18

the sun

Question 19

carbon

Answer 19

• essential nutrient for growth + reproduction

- basic building block of organic molecules (nucleotide, amino acid, lipid, ATP, sugar)

Question 20

where is carbon stored?

Answer 20

main reservoir = ocean and atm

also remained of dead organisms(fossil fuels)

Question 21

how does carbon get into plants and animals?

Answer 21

plants: photosynthesis. plants remove CO2 from atm, incorporated the carbon into organic molecules
animals: passed along in food chain by consumers