B4.1 Ecosystems

Question 1

abiotic factors

Answer 1

temperature
precipitation
soil pH
light intensity

Question 2

biotic factors

Answer 2

competition (for height/resources)
predation
Interdependence: mutualism, parasitism, commensalism

Question 3

temperature

Answer 3

warmth, enzyme reactions efficient for metabolism and growth

thermometer(oC)

Question 4

precipitation

Answer 4

needed for plant growth and to keep cells turgid
needed for animal cells and blood plasma
humidity sensor(%)

Question 5

light intensity

Answer 5

more light = more photosynthesis = more producers
light meter(lux)

Question 6

pH soil level

Answer 6

some plants grow better in acidic soils (ferns) or alkaline soils (cauliflower)
can harm some plants/trees
pH probe

Question 7

what do plants need to survive

Answer 7

light
water
carbon dioxide
minerals 
space

Question 8

what do animals need to survive

Answer 8

food
water
breeding mates
territory
shelter

Question 9

3 different types of organisms in a community

Answer 9

producer - makes own food via photosynthesis
consumer - eat something to get energy
decomposer - get energy by feeding on dead things, faeces and urine (cause of decay and rot)

Question 10

special terms

Answer 10

ecosystem = all organisms and conditions in an area
community - organisms in an exosystem
habitat - area where the organisms liv
population - total number of organisms in that species

Question 11

how is biomass transferred

Answer 11

the producer provides energy to the primary consumer

around 10% of that energy is transferred to increase the consumer’s biomass

Question 12

what are trophic levels

Answer 12

each step in the food chain

a food web is the interactions between different food chains.

Question 13

Pyramids of biomass and numbers

Answer 13

PofN: shows population of each trophic level
PofB: shows biomass of each trophic level
pyramids of biomass can be drawn by creating a suitable scale (i.e 10kg/cm)

Question 14

How is biomass calculated

Answer 14

biomass=number of organisms present x mass of one organism
the mass of the organism is weighed by killing it and drying it in a kiln, so the water content does not influence the mass

Question 15

what are detritivores

Answer 15

they are small animals that speed up decomposition by shredding the organic matter to create more SA for the decomposers

Question 16

how do decomposers get and release nutrients?

Answer 16

they release enzymes which break down the dead matter into soluble nutrients
they then absorb these nutrients for growth and as an energy store.
the nutrients are released when they are eaten, dead, naturally released into environment

Question 17

factors affecting decomposition rate

Answer 17

temperature
water levels
aerobic conditions
rate of decay = change in mass(g)/time(days)

Question 18

temperature on rate of decomposition

Answer 18

at high temperatures, the enzymes released denature

at low temperatures, the enzymes release operate slowly

Question 19

moisture levels

Answer 19

if not enough water is available, reactions withing the decomposer will slow down or be prevented

Question 20

oxygen levels

Answer 20

anaerobic conditions prevent decomposers from operating