Ecology
- Created by: Sophie
- Created on: 25-09-14 09:20
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- Ecology
- Community= A group of populations of different interacting species living in the same area at the same time
- Habitata= The particular locality in which an organism lives.
- Microhabitat= A very small habitat
- Biosphere= The part of the Earth in which organisms live and are active
- Niche= the function or role of an organism in a community
- Species= A group of organisms with similar features that are able to breed to produce viable and fertile offspring
- An environmental factor that results from the activities of living organisms e.g disease.
- Abiotic factors= A non living factor that forms a non-biological part of the environment e.g climate.
- Environment= The surroundings of an organism including biotic and abiotic factors.
- Population= A group of organisms, all of the same species, occupying a particular area
- Biome= The natural grouping of organisms over a large area, e.g desert
- Ecosystem= A community of organisms with its associated physical environment e.g a pond.
- Quadrats- consider size, # of quadrats used and the position of each quadrat in each study area.
- Avoid bias= valid data
- Estimated mean density= total # of individuals / # of quadrats * area of quadrat
- Estimated pop. size= Total # of individuals in sample 1 * total # of individuals in sample 2 / # of marked individuals recaptured
- Catch mark release relies on assumptions that there are no births or deaths, definite boundary
- Pop. size limited by environment, e.g food soucre
- Stable equilibrium phase is reached when the pop. is at the environment's carrying capacity
- Abiotic factors= temp, ilght, pH, H20
- Interspecific= different
- Intracpecific= same
- catch mark release relies on the assumption that organisms distribute themselves evenly on release
- Predation= interspecific competition
- Succession= directional change to the plant species in a community over time due to changes in environmental factors caused by species present.
- Primary= Bare rock/sand e.g after volcanic erruption
- Secondary= Bare soil, e.g after forest clearing
- Bare rock, few H20 and nutrients so lichens colonise, mosses grow on lichen, thin layer of soil forms as lichen decomposes, pioneer species like grasses grown on soil, larger species outcompete pioneer species, trees, climax community
- Pioneer species= a species that can colonise bare rock or ground
- Each species modifies habitat by creating oppurtunities for new species
- Less hostile environment, more stable, more diverse community
- Plagioclimax community= Human interference that permanently alters/ stops natural vegetation so climax vegetation doesn't occur
- Example of plagioclimax community is herbicide use.
- Conservation= maintaining biodiversity
- Other species around before us so ethical to allow us to coexist
- large gene pool for economic reasons
- Cultural= variety inspires us
- Pop growth = births + immigration - deaths - emmigration
- Birth rate= # of births per year / total pop. in that year * 1000
- Factors affecting birth rate= economy, religion/culture, social pressures, birth control, political factors
- factors affecting death rate= age profile, life expectancy, food supply, water, sanitation, medicine, war
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