2. Ecology is the study of living things in their surroundings.
A group of living things made up of the same species is a population.
A group of living things made up of more than one species is a community.
Ecosystem - all the organisms and non-living factors which affect the organisms.
Habitat is the place where an organism lives.   
Abiotic factors (non-living factors)
Sunlight
Shade
Wind
Temperature
Water currents
Nutrients
Soil
Weather
Humidity

3. Biotic factors (living factors)
Producers - produce their own food. (plants)
Bacteria (produce chemicals)
Consumers – can’t produce their own food. (animals)
Herbivores (eat plants)
Carnivores (eat meat)
Omnivores (eat both plants & meat)
Decomposers: breakdown organism remains and waste (e.g. fungi, bacteria)
Detritivores: eat decomposing remains (e.g. worms, crabs)
die
eaten by die
producers consumers decomposers
used by

4. Food chains
A food chain is a diagram, which shows how energy in the form of food is passed from one organism to another, e.g.
Grass Insect Frog Snake Hawk
The arrow ( ) in the chain means ‘is eaten by’.
Most food chains start with plants or algae. Plants are called producers as they make their own food through photosynthesis:
sunlight
carbon dioxide water glucose oxygen
(sugar/food)
Organisms which eat other organisms (plants or animals) are called consumers. They rely on other organisms for food.

6. Food Webs
There are many paths by which food can be cycled through an ecosystem. Food chains can be combined to form a food web.
Food webs show the feeding habits of all organisms that live together in a particular place.

8. Food Pyramids
A food pyramid shows the relative amounts of “food” one or more organisms must eat to support itself. To support one spider, there must be a lot of flies. Without flies the spider my need to shift to another area or eat different insects. Each level on the food pyramid feeds on and obtains energy from the one before it, then provides energy for the one above it.

9. Effects of Change
If any biotic or abiotic factors in an ecosystem are not in balance, many plants and animals will not be able to survive. As in food webs, all organisms are connected. Humans are the main cause of the lack of balance in nature.