T7 organisation of an ecosystem

Question 1

define population

Answer 1

species that occupy the same habitat

Question 2

define habitat

Answer 2

place in which an organism lives

Question 3

define community

Answer 3

populations of different species interacting

Question 4

define ecosystem

Answer 4

interactions between biotic and abiotic factors in an area

Question 5

what do food chains show

Answer 5

feeding relationships of different organisms and the flow of energy between the organisms

Question 6

define biomass

Answer 6

total mass of living material

Question 7

what are trophic levels

Answer 7

stages in a food chain

Question 8

what do arrows in a food chain represent

Answer 8

direction of biomass transfer

Question 9

describe a simple food chain

Answer 9

producer > primary consumer > secondary consumer > tertiary consumer

Question 10

what is a producer

Answer 10

organism that makes its own food

Question 11

what types of organisms are primary producers

Answer 11

photosynthetic organisms like green plants and algae that trap energy from the sun

Question 12

what is a primary consumer

Answer 12

organism that feeds on producers

Question 13

what is a secondary consumer

Answer 13

organism that feeds on primary consumers

Question 14

what is a tertiary consumer

Answer 14

organism that feeds on secondary consumers

Question 15

what is a predator

Answer 15

consumer that kills and eats other animals

Question 16

what is prey

Answer 16

animal that is killed and eaten by another animal

Question 17

describe the pattern of predators and prey in a stable community

Answer 17

number of predators and prey rise and fall in cycles

Question 18

why are producers the first trophic level

Answer 18

provide all biomass for the food chain (production of glucose via photosynthesis)

rest of the food chain involves the transfer of this biomass

Question 19

piece of apparatus used to measure the abundance and distribution of organisms in an area

Answer 19

quadrat

Question 20

piece of apparatus used to study the distribution of organisms across a gradient

Answer 20

belt transect

Question 21

describe how materials cycle through the living and non-living components of an ecosystem

Answer 21

organisms take in elements from their surroundings

elements converted to complex molecules which become biomass

elements transferred along food chains

elements returned to environment during excretion and decomposition of dead organisms

Question 22

give 3 molecules which are cycled through ecosystems

Answer 22

oxygen
carbon dioxide
water

Question 23

describe the carbon cycle

Answer 23

plants fix CO2 into organic molecules during photosynthesis

organic carbon-containing molecules are passed onto organisms that eat the plants

CO2 is released back into the atmosphere by respiration from animals and plants

burning fossil fuels also releases CO2

Question 24

why is the carbon cycle important

Answer 24

carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells

Question 25

describe the water cycle

Answer 25

water from lakes and oceans evaporates evaporated water condenses into clouds and returns to earth as precipitation water from precipitation is useful for life on land water then returns to rivers and oceans through surface runoff

Question 26

why is the water cycle important

Answer 26

living organisms require water and the water cycle provides organisms on land with a continuous supply of water

Question 27

why are microorganisms important for the cycling of materials through an ecosystem

Answer 27

return carbon to the environment by releasing CO2 through respiration while they decompose dead matter decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use

Question 28

what is meant by decomposition

Answer 28

breakdown of dead materials into simpler organic matter

Question 29

how do decomposers break down dead matter

Answer 29

release enzymes which catalyse the breakdown of dead material into smaller molecules

Question 30

two types of decomposition

Answer 30

``` aerobic decomposition (with oxygen) anaerobic decomposition (not w oxygen) ```

Question 31

what factors affect the rate of decomposition

Answer 31

oxygen availability temperature water content

Question 32

why is oxygen required for decomposition

Answer 32

aerobic respiration

Question 33

how does the availability of oxygen affect the rate of decomposition

Answer 33

as O2 levels increase, rate increases as O2 levels decrease, rate decreases

Question 34

why can decomposition still occur in the absence of oxygen

Answer 34

some decomposers respire anaerobically however, rate is slower as anaerobic respiration produces less energy

Question 35

how does soil water content affect the rate of decomposition

Answer 35

decomposers require water to survive in moist conditions, rate is high in waterlogged soils there is little oxygen for respiration so the rate decreases

Question 36

why does decomposition require water

Answer 36

water is required for secretion of enzymes and absorption of dissolved molecules

Question 37

how does temperature affect the rate of decomposition

Answer 37

decomposers release enzymes: rate highest at 50C lower temp, enzymes work too slowly, rate decreases higher temp. enzymes denature, decomposition stops

Question 38

how is the rate of change calculated when considering the decay of biological material

Answer 38

rate of change = change in value / change in time value is a measurable variable associated with the decay of the material

Question 39

what is compost

Answer 39

nutrient-rich product of the rapid decay of waste biological material in optimum conditions set by gardeners and farmers

Question 40

how is compost used

Answer 40

natural fertiliser to promote growth of crops or garden plants

Question 41

describe how biogas generators work

Answer 41

provide methane gas for fuel through anaerobic decomposition that occurs in animal waste

Question 42

describe how environmental conditions affect communities

Answer 42

affect the abundance and distribution of organisms within communities eg. rising global temp have been linked to extinction of frog species

Question 43

how can different temperatures be bad for certain communities

Answer 43

temp too low = growth will be slower as organisms will use more energy to stay warm temp too high = organisms can die and water will become limited as evaporation increases

Question 44

how can change in water levels affect ecosystems

Answer 44

animals may have to migrate to find water melting ice caps may destroy the habitats of some animals

Question 45

how can atmospheric gases affect ecosystems

Answer 45

some organisms can't survive when certain gases are present polluted water can cause illness to animals that drink it

Question 46

what impacts can sulfur dioxide have on the environment

Answer 46

formed when fossil fuels containing impurities are burnt sulfur dioxide can dissolve in water to form acid rain which can erode buildings and pollute water sources

Question 47

what impacts can carbon monoxide have on the environment

Answer 47

formed from the incomplete combustion of fossil fuels binds irreversibly to haemoglobin which prevents it from carrying oxygen too much exposure can cause unconsciousness and death

Question 48

name 5 greenhouse gases

Answer 48

``` water vapour carbon dioxide nitrous oxide methane CFCs ```

Question 49

give 3 human activities that contribute to greenhouse gases

Answer 49

burning fossil fuels deforestation large scale livestock farming

Question 50

how do greenhouse gases lead to global warming

Answer 50

allow heat from the sun to enter the atmosphere gases act as blanket and trap the heat in the atmosphere

Question 51

3 consequences of global warming

Answer 51

sea level rise due to melting icebergs disrupted farming and agriculture increased spread of diseases in warmer climates