Biology ✿ Ecology

ecosystem

the interaction of living with the non-living organisms

what are 3 things plants compete for?

• space

• sunlight

• water/ minerals from soil

what are 3 things animals compete for?

• food

• mates

• territory

interdependence

when organisms within a community depend on each other for survival

what makes a community stable?

when all the living and non-living organisms are in balance so that population sizes are constant

abiotic factors

give 3 examples

non-living factors

• temperature

• soil pH

• light

biotic factors

give 3 examples

living factors

• food availability

• new predators

• new pathogens

explain how to do random sampling using a quadrat

• place quadrat in a random area

• record number of organisms (flowers) in the quadrat

• repeat atleast 10 times in random areas each time

• use equation:

  total population = total area / area sampled x no of organisms counted

extremophiles

organisms which live in extreme conditions

structural adaptation

features of an organisms body

e.g. thick fur

functional adaptation

features inside an organism

e.g. hibernation to slow metabolism

behavioural adaptation

the way an organism behaves

e.g. migration

Which two improvements would increase the validity of this method?

• repeat atleast 10 times

• use a random method to place the quadrats

what do food chains show?

• feeding relationships in a community

• the transfer of biomass

state the food chain order

producer → primary producer → secondary consumers → tertiary consumer → apex predator

Name the processes 1 to 5 shown on Figure 1

1. evaporation

2. condensation

3. precipitation

4. draining

5. transpiration

describe how the carbon cycle works

• CO₂ is removed by photosynthesis of plants

• CO₂ returns to the atmosphere when animals respire

• decomposers respire and return mineral ions by breaking down dead organisms

• CO₂ also returns to the atmosphere when fossil fuels are burnt (combustion)

why is high biodiversity important?

it ensures ecosystems are stable by reducing interdependence

state 5 ways humans are reducing biodiversity

• polluting waters by using chemical fertilisers

• taking up land for quarrying and building, reducing land for animals to stay in

• deforestation

• burning of peat bogs releases CO₂, increasing global warming

• destruction of peat bogs for compost reduces the area of habitat

Describe two ways to increase biodiversity in the UK.

• planting trees

• breeding programmes

what are 2 uses of peat bog

• used as fuel

• used for compost

what are decomposers? why are they important?

microorganisms that breakdown dead matter which releases nutrients back into the environment to be reused

explain how to do random sampling to estimate the number of dandelion plants in a field. [4]

• use a random number generator to generate co-ordinates

• place quadrats in the random co-ordinates and count the number of organisms in quadrat

• repeat this 10 times

• use equation (total area / quadrat area) x total no of organism counted

equation for total population size

(total area / quadrat area) x total no of organism counted

explain how to do random sampling using a transect line and quadrat to see how the factor of light intensity effects the distribution [6]

• place a tape measure on the ground perpendicular to tree/ river (transect line)

• place a quadrat at the start of the transect line

• record number of organisms in quadrat

• record the light intensity using a light meter

• move quadrat 1 metre along the transect line

• repeat along another transect

why might random sampling be unreliable?

• number of samples may not represent the entire field

• it is an estimate

biodiversity

the variety of different species

population

the number of species in a habitat

community

populations of different species in a habitat

producer

an organism which makes glucose by photosynthesising