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