Organisms In The Environment Flashcards
Define population
All the organisms of a particular species found in an ecosystem at any one time
Define community
The populations of all species found in a particular ecosystem at any one time
Define habitat
Places where specific organisms live
Some are provided by the physical environment and others by organisms themselves
Define ecosystem
A distinct, self-supporting system of organisms interacting with each other and with a physical environment
Define interspecific competition
A form of competition in which individuals of different species compete for the same resource in an ecosystem
Intraspecific competition
Where members of the same species compete for limited resources
Define predation
The preying of one animal on others
Describe the main stages in the water cycle
The sun evaporates water from the surface of the oceans lakes and rivers
Plant transpiration and respiration of organisms also releases water vapour into the air
When clouds rise over mountains and high ground they call and water condenses to form rain or snow
This precipitation falls on the earth
It is taken up by animals or plants or enters rivers and flows to the sea to start the cycle again
Describe the stages in the carbon cycle
Carbon enters the atmosphere as carbon dioxide from respiration
Photosynthesis ‘fixes’ carbon atoms from carbon dioxide into organic compounds
Feeding and assimilation pass carbon atoms along food chains
The animals and plants eventually die. The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide
Describe the effect of co2
Forms a layer in the atmosphere trapping wave radiation and heating up the planet
Causes of global warming
Cattle farming (chopping down large areas of rainforest)
Combustion of fossil fuels
Consequences of global warming
Polar ice caps melt
Sea levels rise
Change in the major ocean currents- warm water being redirected into previously cooler areas
Change in global rainfall patterns- extra water in seas-more evaporation-more rain
Change in the nature of many ecosystems- species could become extinct-no appropriate habitat
Pests become more abundant-higher temp-complete life cycles faster
Describe the stages in the nitrogen cycle
Nitrogen-fixing bacteria convert nitrogen into soluble ions such as nitrates
Plants absorb these nitrates from the soil and use them to make proteins
An animal ears the plant and nitrogen from plants proteins becomes proteins in the animal
Decomposers break down urea, egested material and dead bodies. This results in nitrogen being returned to the soil as ammonium ions, which nitrifying bacteria can convert into nitrates for plants to absorb
Denitrifying bacteria in the soil break down nitrates and return nitrogen gas to the air
