7.4 Population in ecosystems Flashcards
What is a population?
A group of organisms of the same species, living in a habitat.
What is a habitat?
The place where an organism lives.
What is a community?
All the populations of different species in a habitat.
What is an ecosystem?
A community, and its biotic and abiotic factors.
What is a niche?
An organism’s role within an ecosystem.
What is the carrying capacity?
The maximum population size an ecosystem can support.
What are abiotic factors?
Non-living components in an ecosystem.
What are biotic factors?
Living components of an ecosystem.
What are the factors affecting population size?
Biotic + abiotic.
Examples of abiotic factors?
Temperature, oxygen + CO2 concentration, light intensity, pH and soil conditions.
Plants and animals are _______ to the abiotic factors within their ecosystem.
Adapted.
This develops through natural selection over many generations.
The less harsh the abiotic factors…
The larger the range of species, + the larger the population sizes.
What are the 2 types of competition?
Interspecific and intraspecific.
What is interspecific competition?
When members of different species are in competition for the same resource that is in limited supply.
What makes an individual more likely to succeed at competition?
If they are better adapted.
What is intraspecific competition?
When members of the same species are in competition for resources and a mate.
Regardless of the species, what trends does the predator-prey graph always follow?
- The size of the predator + prey populations both fluctuate.
- There will always be more prey than predators.
- The size of the populations will always change in the prey + the predators.
Why is sampling a good method?
It is more time efficient and can be more accurate.
How is it ensured that sampling accurately represents the population?
- Random sampling in uniform areas to eliminate bias.
- Line transect to examine a change over distance.
- Large number of samples (30+).
What method do you use if you’re measuring a slow-moving or non-motile organism?
Sampling using a quadrat.
What method do you use if you’re measuring a motile organism?
Mark, recapture, release.
When sampling using a quadrat, what do you do if there’s a uniform distribution?
Random sampling.
When sampling using a quadrat, what do you do if there’s an uneven distribution?
Line transect.
Random sampling method steps?
- Lie 2 tape measures at a right angle to create a gridded area.
- Use a random number generator to generate two coordinates.
- Place the quadrat and collect the data.
- Repeat at least 30 times + calculate a mean.