Ecosystems

Question 1

What is an ecosystem

Answer 1

all the organisms living in a certain area and all the non - living conditions found there

Question 2

why are ecosystems described as dynamic

Answer 2

changing all the time

Question 3

what are biotic factors and abiotic factors and give examples

Answer 3

living features of an ecosystem: presence of predators or food
non living features of an ecosystem such as temp, rainfall

Question 4

what is biomass

Answer 4

the mass of living material

Question 5

describe how biomass is transferred between trophic levels

Answer 5

producers eaten by primary consumers then secondary consumers then tertiary consumers

Question 6

how can you show biomass transfer and measure efficiency

Answer 6

food webs and food chains

Question 7

what is a trophic level

Answer 7

a stage in a food chain that is occupied by a group of organisms

Question 8

what are decomposers

Answer 8

organisms that break down dead or undigested organic material

Question 9

how do you calculate efficiency

Answer 9

biomass transferred/ biomass intake x 100

Question 10

what is gross productivity

Answer 10

rest of available energy

Question 11

why is some available energy never taken in by the organism in the first place

Answer 11

plants can’t use all the light that reaches their leaves
some light hit parts of plant that cannot photosynthesise
some parts of organism aren’t eaten by predators
some parts of food are indigestible

Question 12

when energy is lost to the environment during energy production what is this called

Answer 12

respiratory loss

Question 13

what is net productivity

Answer 13

the total amount of energy available to the next trophic level

Question 14

what are the relative energy transfer efficiencies between each trophic level

Answer 14

sun to prodcuer- 2-3%
producer to consumer- 5-10%
consumer to consumer- 15-20%

Question 15

how can you measure the amount of energy in an organism

Answer 15

measure dry mass

Question 16

what are the issues with using dry mass to measure amount of energy in an organism

Answer 16

consumers absorb energy from other sources than the producer, so difference between two calculated wouldn’t be accurate

Question 17

how do farmers try and reduce energy loss in food chains

Answer 17

herbicides- kill weeds which compete with crops for resources
fungicides- kill fungal infections
insecticides- kill pests that damage crops
fertilisers- provide minerals for growth
rearing livestock- controlling their living conditions to ensure most energy is used for growth

Question 18

draw a diagram of the carbon cycle

Question 19

what processes are present in the carbon cycle

Answer 19

photosynthesis, decomposition, respiration, combustion, weathering

Question 20

what happens to carbon in photosynthesis

Answer 20

absorbed by plants which carry out photosynthesis, carbon passed onto primary consumers when eaten by plants

Question 21

what happens to carbon during decomposition

Answer 21

organisms die and are broken down by decomposers which secrete enzymes and absorb the products of digestion, processes is called saprobiontic nutrition

Question 22

what happens to carbon during respiration

Answer 22

carbon is returned to air as all living organisms respire and produce CO2

Question 23

what happens to carbon during combustion

Answer 23

if dead organic matter ends up in a place without decomposers it can be turned into fossil fuels, carbon is released when they’re burnt

Question 24

what happens to carbon in volcanoes

Answer 24

rocks like limestone can be drawn into earths crust by movement of tectonic plates and they undergo chemical changes which is released into air via volcanoes

Question 25

what happens to carbon during weathering

Answer 25

rocks broken down by rainwater,