Ecosystem - The interaction of a community of living organisms with the non-living parts of their
environment
What is a community made up of? - The populations of different species or organisms that are all
interdependent in a habitat
Habitat - The environment in which an organism lives
Popula...
7. AQA GCSE Biology: Ecology
Ecosystem - ✔✔✔The interaction of a community of living organisms with the non-living parts of their
environment
What is a community made up of? - ✔✔✔The populations of different species or organisms that are all
interdependent in a habitat
Habitat - ✔✔✔The environment in which an organism lives
Population - ✔✔✔The total number of organisms of the same species living in the same geographical
area
Interdependence - ✔✔✔The way in which each species within a community depends on other species
for food, shelter, pollination, seed dispersal etc
Competition - ✔✔✔The process by which living organisms compete with each other for limited
resources (such as food, light or reproductive partners)
What do organisms require to survive and reproduce? - ✔✔✔A supply of materials from their
surroundings and from the other living organisms there
What do plants often compete with each other for? (4) - ✔✔✔Light, space, water, and mineral ions
from the soil
What do animals compete with each other for? (3) - ✔✔✔Food, mates and territory
, Stable community - ✔✔✔Where all the species and environmental factors are in balance so that
population sizes remain fairly constant
What happens if one species is removed from a community? - ✔✔✔It can affect the whole community
Abiotic factors - ✔✔✔Non-living factors
Biotic factors - ✔✔✔Living factors
Name 7 abiotic factors and how they might affect a community - ✔✔✔Litmuswoc
1. Light intensity - photosynthesis, breeding cycles linked to day length
2. Temperature - photosynthesis/plant growth, therefore animals which can survive
3. Moisture levels - both plants and animals need water to survuve
4. Soil pH and mineral content - distribution of plants, most struggle to grow where there is few mineral
ions; low pH inhibits decay and therefore release of mineral ions
5. Wind intensity and direction - shape of trees and landscape, increases plant transpiration
6. Availability of oxygen - aquatic animals e.g. fish require high levels of dissolved oxygen
7. Availability of carbon dioxide - photosynthesis
Name 4 biotic factors and how they might affect a community - ✔✔✔FPOP
1. Availability of food - food allows animals to survive and breed successfully
2. New predators arriving - organisms with no defences against these predators may die out
3. One species outcompeting another so the numbers are no longer sufficient to breed - e.g. grey
squirrels in Britain
4. New pathogens - organisms have no resistance so populations can be wiped out
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