Populations in Ecosystems 7.1 Flashcards
What is the definition of a community?
-All the populations of all species occupying the same area at the same time
What is the definition of a population?
Individuals of the same species occupying one area at one time that can potentially interbreed
What is the definition of an ecosystem?
-Consists of the community and the non-living components of its environment
What is a Niche?
-The role an organism plays in the ecosystem and how it interacts with biotic and abiotic factors
What is the definition of an Abiotic factor?
-A non-living factor which affects the distribution of an organism
What is the definition of a biotic factor?
-A living factor which affects the distribution of an organism
What is a Species?
-Two organisms that can interbreed to produce fertile offspring are of the same species
What is Interspecific competition?
-Competition between members of different species. In general one species will outcompete the other if they have the same niche
What is Intraspecific competition?
-Competition between individuals of the same species
What is the advantage of two different species occupying different niches?
- The advantage of individuals occupying different niches is that is reduces interspecific competition between them
eg plants competition for light, water and nitrates is reduced
What is the definition of succession?
The gradual replacement of one plant community by another over a period of time through a series of several stages starting with a pioneer species and ending with a climax community (see revision page for detailed process)
What is Carrying capacity?
The maximum population size an ecosystem can support
What is habitat?
An area where an organism lives
What are the steps in succession?
Pioneer species colonise environment able to tolerate hostile conditions
Change abiotic factors creating a thin soil layer, die at nutrients eg nitrates and humus to soil
New species colonise less hostile environment which are better adapted outcompete pioneer species
Environment now less hostile new species such as trees colonise reaching climax community
Animals may migrate in
What are the steps in mark-release capture
-A sample of animals are captured the number is counted, marked with a eg non-toxic marker (marker does not affect survival ability) and released
-leave enough time for animals to reintegrate into the population
-capture a second sample and count the number marked
-equation: number caught in first sample x number caught in second sample / number marked in second sample
