OCR Gateway GCSE Biology A community level systems (B4) overview quiz quiz

Ecosystem, community, population, organism

Population, organism, ecosystem, community

Organism, population, community, ecosystem

Community, ecosystem, organism, population

The number of predators

Competition for food

The presence of disease

Light intensity

Species rely on each other for things such as food, shelter and pollination, so a change in one affects the others

Each species lives completely on its own and does not rely on any of the other species in the whole community at all

Only the plants in the community depend on other organisms, while the animals are fully independent of them

All of the species living in the community happen to be roughly the same physical size as each other

An animal that hunts and eats other animals for its food

A green plant or alga that makes its own food by photosynthesis

An organism that breaks down dead and decaying material in the soil

An animal that eats only plants and never eats other animals

Energy is completely destroyed at each level of the food chain as it is passed on

The producers at the start keep almost all of the energy for themselves alone

Energy is lost as heat from respiration, and in movement, waste and uneaten parts

Energy only ever moves backwards down the food chain instead of upwards

The predators always die out completely a very long time before the prey population even begins to fall away in numbers

The two separate peaks on the graph always happen at exactly the same moment in time as each other

The predators do not depend on the prey numbers at all, so the two peaks are completely unrelated

More prey means more food, so predator numbers rise after the prey have increased; the predators then eat the prey down

19200

4800

1200

192000

To make the whole survey much quicker and easier to carry out

To avoid bias, so the sample fairly represents the whole area

Because random sampling needs no special equipment at all to do

To make absolutely sure that every single daisy is counted exactly

A single quadrat that is thrown down just once at random

A pooter, used to suck up small insects into a container

A transect, placing quadrats at intervals along a line across the habitat

A pitfall trap sunk down into the ground to catch the small crawling insects

Respiration removes the carbon dioxide; photosynthesis returns it to the air

Condensation removes the carbon dioxide; evaporation then returns it to the air

Nitrogen fixation removes the carbon dioxide; denitrification returns it again

Photosynthesis removes it; respiration and combustion return it

Nitrifying bacteria

Denitrifying bacteria

Nitrogen-fixing bacteria

Decomposing bacteria only

Warm, moist and well-aerated

Cold, dry and with little oxygen

Warm and well-aerated but dry

Moist and warm with plenty of oxygen