Sub 1: Energy Fixation and Flow

Question 1

what is photosynthesis?

Answer 1

a process where light energy is converted to chemical energy by primary producers

Question 2

why are autotrophs important?

Answer 2

the capture of energy and its conversion into stored chemical energy by autotrophs provide ecosystems with their primary energy source.

Question 3

what is primary productivity?

Answer 3

the level of light energy converted to chemical energy by photoautotrophs in an ecosystem in a given period of time

Question 4

what is the total primary productivity (net primary productivity)?

Answer 4

Gross primary productivity - total yield of organic matter from photosynthesis (GPP - R)
this is the energy available to the next trophic level

Question 5

what are the units of primary productivity?

Answer 5

g/m2/year

Question 6

why is biomass usually expressed as dry weight?

Answer 6

because the water content of plants is a variable factor both daily and seasonally

Question 7

what is meant by ecological niche?

Answer 7

the sum of all the characteristics that determine the position of an organism in its ecosystem . This includes the biotic and abiotic factors required for the survival of that species and which limits the distribution and growth

Question 8

what are each link in a food chain called?

Answer 8

trophic levels

Question 9

what is a heterotroph?

Answer 9

any organism that has to gain energy and nutrients by consuming complex organic molecules

Question 10

what is a saprotroph?

Answer 10

group of heterotroph that gets its energy by feeding on dead organisms or waste material

Question 11

name two kinds of saprotrophs

Answer 11

detritivores and decomposers