Ecology

the study of interactions between organisms and the physical and chemical factors making up their external environment

study biotic(living environment) and abiotic(non-living environment)

Physical factors which make up the abiotic environment are :

Energy and nutrient flow in an ecosystem

Producers

make their own food by photosynthesis using chlorophyll

Decomposers

Consumers

Can affect the lives of other organisms because they provide them w/ energy and oxygen

Obtain their energy by feeding on other organisms

Obtain energy by breaking down dead organisms, faeces and excretory products

Ecological pyramids

Carbon Cycle

return nutrients to the environment

Food chain and food webs

Food chains

is a series of organisms through which energy is transferred in the form of food

Each stage in the food chain is known as a trophic level; usually not more than 4 levels in 1 food chain.

Food webs

consists of interlinked food webs

Pyramid of numbers

allows us to compare the number of organisms present in each trophic level at a particular time

Pyramid of biomass

allows us to compare the dry mass of organisms present in each trophic level at a particular time

Pyramids of energy

allows us to compare the total energy in each trophic level over a certain period of time

About 90% of energy is lost when it is transferred from 1 trophic level to the next

Heat is lost to the environment through respiration; uneaten parts or dead bodies; faeces and excretory products.

The concentration of CO in the environment remains relatively constant

Carbon is constantly removed from & released back into the environment, in the form of CO

Release of CO by: Respiration, Combustion and Decay

Removal of CO by: Photosynthesis, Preservation as fossil fuels

Carbon Sinks

Importance:

ensures there is a continuous supply of CO for plants to photosynthesize.

enables energy to flow through the ecosystem. Carbon compounds carry stored energy from organism to organism

maintains correct concentration of CO

area that stores carbon compounds for an indefinite period. It stores more carbon than it releases