Populations in ecosystems Flashcards
What is ecology?
The study of the inter-relationships between organisms and their environment. The environment being abiotic factors and biotic factors
What are abiotic and biotic factors?
Abiotic = non-living factors
Biotic factors = living factors
What is a population?
A group of individuals of one species that occupy the same habitat at the same time and are potentially able to interbreed.
What is a carrying capacity?
The size of population that the ecosystem can support.
What is a community?
All of the populations of different species living and interacting in a particular place at the same time.
What is a habitat?
The place an organism normally lives and is characterised by physical conditions and the other types of organisms present. Within each habitat there are microhabitats.
What is an ecological niche?
Describes how an organism fits into the environment referring to where an organism lives and what it does there.
What are organisms normally found?
In places where the local environment conditions fall within the range that their adaptation enable them to cope with.
Why does no population grow indefinitely?
Limiting factors eg, availability of food, light, oxygen and shelter.
Name 4 abiotic factors?
Temperature, light, pH and water/humidity
What is intraspecific competition?
Individuals of the same species compete with one another for resources.
What is interspecific competition?
Individuals of different species compete for resources.
What is abundance?
The number of individuals of a species in a given space.
Random sampling
Measure out a grid and choose random coordinates to take the sample from.
How do you calculate the estimated population size from the mark-release recapture technique?
(Individuals in first sample x individuals in second sample) / number if marked individuals recaptured
What assumptions must you make when doing the mark release recapture technique?
- The marked individuals distribute themselves evenly among the unmarked population.
- There is no emigration of immigration.
- There are no births or deaths.
- The mark is not toxic, make the organism vulnerable to predation or wear off.
What is a pioneer species?
Colonise an inhospitable environment in the first stage of succession.
Name 6 features of a pioneer species.
- Reproduce asexually,
- Dispersed by wind,
- Seeds germinate rapidly,
- Can photosynthesise,
- Fix nitrogen from the atmosphere as it is unavailable from the ground as their is no soil,
- Can tolerate extreme conditions.
What is a climax community?
One which remains stable over a long period of time.
Name 4 main reasons for conservation.
- personal,
- ethical,
- economic,
- cultural and aesthetic.
Name 5 stages of succession.
- The non-living environment become less hostile,
- A greater number of habitats and niches,
- Increased biodiversity,
- More complex food webs,
- Increased biomass.
What is conservation?
Maintenance of ecosystems and biodiversity by management of existing resources and restoring those lost.
