Lecture 6

Question 1

Biological magnification occurs because

Answer 1

Biological magnification occurs because the biomass at any given trophic level is produced from a much larger toxin-containing biomass ingested from the trophic level below. eg DDT

Question 2

POPs

Answer 2

persistent organic pollutants

Question 3

POP effects:

Answer 3

increased incidence of cancer,
reduced immunity,
decreased learning ability in children,
lower infant birth weights

Question 4

Cold Condensation Theory

Answer 4

Many of these POPs are still in use in agricultural settings in the tropics

In the tropics, at warm temperatures, POPs vaporize into the air and are carried thousands of kilometres in air currents

If they reach cold environments, they condense, collect in snow and ice and melt out in spring to eventually enter Arctic food webs

Question 5

Biogeochemical cycles

Answer 5

processes by which matter cycles from the living world to the nonliving physical environment and back again

Reminder: how is this different from energy flow in ecosystems?
Organisms constantly dissipate energy, but they recycle materials

Question 6

Why are these cycles called Biogeochemical cycles?

Answer 6

They involve biological, geological and chemical interactions and pathways

Question 7

CO2 in atmosphere

Answer 7

0.03% of atmospheric gases, or 385 mg L-1

Question 8

Carbon in aquatic systems and soils

Answer 8

carbon di oxide
carbonate
bicarbonate and
as dissolved organic matter (DOM)

Question 9

_______ returns CO2 back to the abiotic environment (e.g., atmosphere or dissolved in water)

Answer 9

Cellular respiration returns CO2 back to the abiotic environment (e.g., atmosphere or dissolved in water)

Question 10

Large quantities of inorganic carbon are also stored in _________ for millions of years

Answer 10

Large quantities of inorganic carbon are also stored in limestone rock (CaCO3) for millions of years