1What are two cycles vital for life on Earth by maintaining habitats, fresh water, and the flow of nutrients?
The carbon and water cycles
2How is carbon dioxide removed from the air in the carbon cycle?
By photosynthesis in green plants and algae
3How is carbon dioxide returned to the air by plants, algae, and animals?
Through respiration
4What group of microorganisms breaks down dead organisms and waste while returning mineral ions to the soil?
Decomposers
5How is carbon dioxide returned to the air during the burning of wood and fossil fuels?
Combustion
6What causes water to evaporate from the sea and lakes to form water vapour in the water cycle?
The sun's energy
7What process in plants also forms water vapour in the water cycle?
Transpiration
8What process causes water vapour to rise and form clouds?
Condensation
9By what process is water returned from clouds to the land?
Precipitation
10What is decomposition?
The breakdown of dead matter, fallen leaves, or animal droppings by decomposers
11What types of organisms can act as decomposers?
Bacteria or fungi
12How do decomposers break down dead matter?
By secreting enzymes to break it down into smaller soluble food molecules
13Which of the following affects the rate of decomposition?
- Temperature
- Water
- Availability of oxygen
- Wind speed
14How does temperature affect chemical reactions in decomposition?
Chemical reactions generally work faster in warmer conditions
15What happens to enzymes if it becomes too hot during decomposition?
They can denature and stop decomposition
16Why do microorganisms grow faster in conditions with water during decomposition?
Water is needed for respiration and makes food easier to digest
17Do most decomposers respire aerobically or anaerobically?
Aerobically
18What biological material is produced when biological material decays?
Compost
19What is compost used for by gardeners and farmers?
As a natural fertiliser
20What gas do decomposers respire with when more oxygen is available in a compost heap?
Oxygen
21What does aerobic respiration in a compost heap produce besides carbon dioxide?
Heat
22What can be drawn based on what each organism eats?
A food chain
23What is created when multiple food chains are linked together?
A food web
24What do food chains always begin with?
A producer
25What is a producer in a food chain typically?
A photosynthetic organism such as a green plant or algae
26What do producers produce that starts the food chain?
Glucose
27What are organisms that eat producers called?
Primary consumers
28What are organisms that eat primary consumers called?
Secondary consumers
29Generally, do food chains continue past tertiary consumers?
No
30What type of community shows population cycles between predators and prey?
A stable community
31If the population of prey increases, what will happen to the population of predators?
It will increase
32What happens to the population of prey after the predator population increases?
It decreases
33What happens to the population of predators when there isn't enough prey to feed them?
It decreases
34What is an individual part of a species living in its habitat within a population called?
An ecosystem
35What is the interaction of a community with the non-living parts of the environment called?
An ecosystem
36What are non-living factors in an environment called?
Abiotic factors
37What are living factors in an environment called?
Biotic factors
38Which of the following is an abiotic factor?
- Light intensity
- Temperature
- Moisture levels
- New predators
39Which of the following is a biotic factor?
- Food availability
- New predators
- New pathogens
- Soil pH
40Why is light required by plants?
For photosynthesis
41How does soil pH affect plants and soil?
It affects the rate of decay and how fast mineral ions return to the soil
42What happens to an organism's population when food availability increases?
It can increase in numbers because organisms can breed more successfully
43What happens when a new pathogen arises in a population with no resistance to it?
They can be wiped out quickly
44What happens if one species is better adapted to the environment than another during competition?
It will outcompete the lesser adapted species until their numbers are insufficient to breed
45What do plants compete for?
- Light
- Space
- Water
- Mineral ions
46What do animals compete for?
- Space
- Food
- Water
- Mating partners
47What term describes how organisms in a community depend on other organisms for vital services like food, shelter, and reproduction?
Interdependence
48What is a stable community?
One where all the biotic and abiotic factors are in balance so population sizes remain roughly constant
49Give an example of a stable community.
Tropical rainforests, oak woodlands, or coral reefs
50What level of trophic levels do producers represent?
Level 1
51What level of trophic levels do primary consumers represent?
Level 2
52What level of trophic levels do secondary consumers represent?
Level 3
53What level of trophic levels do tertiary consumers represent?
Level 4
54What are carnivores that eat other carnivores, have no predators, and sit at the top of the food chain called?
Apex predators
55What do pyramids of biomass show?
The relative biomass at each trophic level
56What happens to biomass as you move up the trophic levels?
There is less biomass
57What percentage of incident energy from light do producers transfer for photosynthesis?
About 1%
58Approximately what percentage of biomass is transferred from each trophic level to the next?
10%
59What waste substance is released in urine by animals?
Urea
60Why is biomass lost as faeces in herbivores?
Herbivores do not have all the enzymes to digest all the material they eat
61What is the formula for calculating the efficiency of biomass transfers?
(Biomass transferred to the next level / Biomass available at the previous level) x 100