Ch17 Organisation of an ecosystem

Question 1

basic food chain

Answer 1

producer
primary consumer
secondary consumer
tertiary consumer

Question 2

Cycle or predators and prey

Answer 2

1. plenty of food available, so prey animals reproduce successfully, so numbers increase
2. increased prey numbers means more food available for the predators, so predators reproduce successfully and numbers increase
3. high numbers of predators eat a larger proportion of prey, so prey numbers decrease
4. fewer prey animals means less food for predators, so they are less successful and so predator numbers fall
5. with less predators, prey numbers go up

cycle continues

Question 3

decomposers

Answer 3

bacteria
fungi
detritus feeders
- maggots, beetles and worms

Question 4

conditions for decay

Answer 4

high moisture
- grow faster and helps digest food

temperature

• slow rate at cold night
• enzymes denature if too hot
• works best at 30°C

high levels of oxygen

• microorganisms respire aerobically
• in anaerobic conditions, they produce methane

Question 5

Decomposition process

Answer 5

digestion- releases enzymes amylase, protease and lipase
releases ions nitrate, magnesium and phosphate
Small soluble food molecules then diffuse into the microorganisms
respires aerobically which produces carbon dioxide

Question 6

biomass

Answer 6

produced by photosynthetic organism

the total dry mass

Question 7

biogas generators

Answer 7

decomposers
anaerobic conditions produce methane
used as fuel, electricity and heating

Question 8

producers

Answer 8

photosynthetic organisms that produce biomass(own food using sunlight)
synthesis molecules

e.g. alga or green plant

Question 9

Carbon cycle

Answer 9

1. Plants use CO2 from atmosphere for photosynthesis- carbon becomes part of complex molecules in the plants(proteins, fats and carbs)
2. animal eats a plant, carbon plant becomes part of the fats and proteins in animal.
3. Microorganisms and other animals feed on waste material or remains from animals- carbon then becomes part of these organisms
4. CO2 is released to the atmosphere through respiration by organisms, by the combustion of wood and fossil fuels or by decomposition/decay

Question 10

Water cycle

Answer 10

Evaporation
Condensation
Transport
Precipitation
Surface runoff
Infiltration
Transpiration

Question 11

Use of decay

Answer 11

compost produced is used as a
natural fertiliser for growing garden plants or crops

biogas