Ecology

The distribution, diversity and number of plants and animals found in ecosystems are determined by biotic and abiotic factors. 


Ecology is the study of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment.
These are a few important forms that need to be defined prior to understanding the study of ecology.
biotic: living things
abiotic: non living features--chemical and physical factors e.g: temperature, rainfall, salinity etc.
These chemical factors are (for abiotic):
-- rainfall
-- salinity
-- soil type
-- water
-- air composition
-- PH
These physical factors are (for abiotic):
-- temperature
-- pressure
-- sunlight
-- light and heat intensity


AGAIN (for better understanding): 
Here is a list of some abiotic and biotic factors of ecosystems:
Chemical factors-- water, oxygen, nitrogen, carbon dioxide, pH, salinity.
Physical factors-- light, temperature, humidity, tide, wind.
Plants-- grasses, algae, shrubs, trees.
Animals-- micro-organisms, fish, birds, reptiles, mammals.
Fungus-- yeast, mushrooms, toadstools.
Bacteria-- Rhizobium sp, Escherichia coli.


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Biomes: are made up of habitats.

Community: made up of a variety of organisms. 

Habitats: containing a community.

Populations: made up of one type of organism.

Biosphere -> ecosystems -> communities -> populations -> individuals.


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COMPONENTS OF ECOSYSTEMS:
An ecosystem is the combination of all organisms (biotic factors) living in a community and all the non-living features (abiotic factors) with which they interact. There is a fine balance between the biotic and abiotic factors in ecosystems. The distribution of the different Australian ecosystems is due to the variation in biotic and abiotic factors found within each particular area.

Terrestrial and aquatic ecosystems:

Terrestrial environments are those found on land, for example desert or rainforest ecosystems. 

There are two main types of aquatic (water) environments:

Saltwater or marine environments (e.g coral reefs) and freshwater environments (e.g lakes).

However some aquatic environments are exposed to freshwater and saltwater, such as an estuarine environment affected by tidal changes. The major types of organisms found in aquatic environments are influenced by the level of water salinity.

Abiotic factors in aquatic and terrestrial environments:
Biotic and abiotic factors differ greatly between aquatic and terrestrial environments. biotic factors create various conditions which suit different types of organisms and hence affect biotic factors (abiotic factors affect biotic factors).
Abiotic factors of water environments differ depending on whether the water is saltwater or freshwater.


Examples of aquatic ecosystems include: wetlands and mangrove swamps, rock platforms--bare rock and littoral zones; estuaries, rivers and lakes; oceans and coral reefs. 
Examples of common terrestrial ecosystems found in australia include: desert, grassland, shrub land, woodland, temperate forest, rainforest. 


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POPULATION:


A population is a group of similar organisms living in a given area at a given time.
Populations can never be 100 percent accurately counted this is because of the difficulty of describing in detail large areas also it would be too time consuming and damaging to the environment.
Populations are estimated using sampling techniques. These make an estimate, which is roughly accurate of the population.


LIMITING FACTORS CONTROLLING POPULATION:


Populations will increase in number until they are confronted by a limiting factor. limiting factors include:
--lack of space
--predators
--disease
--competition for food between members of the same species
--competition from members of other species
--physical factors (weather conditions)


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GLOSSARY (USEFUL TERMS):
Abiotic: non-living features--physical and chemical factors (e.g temperature, rainfall, and salinity).
Aquatic environment: an environment existing mainly in water either freshwater, saltwater or both.
Biome: large regional system characterised by major vegetation type (e.g. desert); region of earth with similar ecosystems grouped together.
Biosphere: the part of the earth and atmosphere in which living organisms are found.
Biotic: living features--all living things (e.g. numbers, distribution, interactions).
Community: groups of different populations in an area or habitat. 
Ecology: study of the relationships living organisms have with each other and their environment.
Ecosystems: a community together with its environment: any environment containing organisms interacting with each other and the non-living parts of the environment (e.g. rainforest, freshwater pond).
Environment: both living (biotic) and non-living (abiotic) surroundings of an organism. 
Habitat: place where an organism lives.
Niche: place of a species within a community involving relationship wit other species. 
Organism: living thing (e.g: plant, animal).
Population: group of organisms of the same species living in the same area at a particular time.
Species: groups of similar individuals that can reproduce fertile offspring (e.g. kookaburra, snow gum)
Terrestrial environment: an environment existing mainly on land. 


Notes:
Compare requires a discussion of both the similarities and differences in abiotic characteristics of the two environments.

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