5.3 Energy and ecosystems

Question 1

What is Eutrofication?

Answer 1

Eutrophication occurs when there is an excess of nutrients, such as nitrogen, in an environment. This can happen when nitrogen from fertilizers or other sources washes into waterways, causing an overgrowth of plants and algae. This can lead to harmful algal blooms, dead zones, and fish kills
(Excess nutrients such as N in the environment)

Question 2

Describe how the biomass of some plants could be measured?

Answer 2

-dry dead sample put at 100 degrees in a calorimetor
-weigh and reweigh until mass is constant and does not change
-The sample of dry biomass is burnt and energy released is used to heat a known volume of water
-The change in temp of the water is used to calculate the chemical energy stored

Question 3

Give an example of ‘simplifying food webs to reduce energy loss to non-human food chains’

Answer 3

• pesticides

Question 4

Describe 2 ways in which farming practice can be changed in order to increase net production

Answer 4

• fertilisers
• ploughing to aerate the soil

Question 5

state the 2 things that contribute most to R (respiratory losses)

Answer 5

• movement
• maintaining body temp

Question 6

give equation for net production of consumers (N) in terms of I,F and R

Answer 6

N=I-(F+R)

Question 7

Which of GPP and NPP is the energy avaliable to herbivores?

Answer 7

NPP

Question 8

Define GPP

Answer 8

energy converted from lights by plants in a given area

Question 9

Define NPP

Answer 9

Energy avaliable to next trophic level (accounts for respiration)

Question 10

Is the amount of CO2 taken in by a plant an indicator of NPP or GPP?

Answer 10

GPP

Question 11

What is the benifit of root nodules

Answer 11

-mutualistic relationship
- contain nitrogen fixing bacteria that converts N2 from the atmosphere into nitrates the root nodules can absorb via active transport