Biology Mrs J- Start July Flashcards
What is the definition of a population?
All the organisms of one species in a particular area at one time, that can potentially interbreed.
What is the definition of a community ?
All organisms of all species within a given area at the same time.
What is the definition of a habitat?
Where an organism lives
What is the definition of an ecosystem?
All organisms and interactions with the abiotic factors.
What is the definition of a niche?
Where an organism lives and the specific role it has
What is the definition of biotic and abiotic factors?
Biotic = living factors E.g organisms
Abiotic= non-living factors E.g PH, Temp ect.
What is the competitive inclusion principle?
When 2 organisms try and occupy the same Niche, the best adapted will survive, and the other will die out
What is the definition of species richness?
The number of different species
What is the definition of species diversity?
The number of different species and the number of organisms within each of these species.
What is the definition of carrying capacity?
The maximum size of a population that can be supported by an area
What is the carrying capacity affected by?
- abiotic factors (NL)
- and interactions between biotic factors
What are some examples of biotic factors that could affect the carrying capacity?
- Competition for resources
- Intraspecific predation
-Interspecific predation
What is intraspecific predation?
Within species predation e.g canabalism
What is interspecific predation?
Between species E.g lynx eats the rabbit
For the previous example: if the rabbit population were to increase, would the lynx population increase or decrease?
The lynx population would also increase
What technique would I use for sampling non-motile organisms?
Quadrats!
What are the key elements/steps to using a quadrat?
- Tapes at right angles
- Random no. generator to get random coordinates
- Place quadrat at coordinate
- Count number of organisms within quadrat/ use percentage cover of each square
- Repeat 20x minimum
- Calculate the mean from all data collected for each repeated quadrat
- Use the calculation to give an estimate for the target area.
What is the calculation used to estimate the total population size of a target area when using a quadrat?
(Total area m^2 / area of quadrat m^2) x mean no. Of organisms per quadrat x mean no.
per quadrat
What 2 things must I control when using a quadrat?
- Same sized quadrat
- Same specific time of year
How would I measure the distribution of organisms?
By using a transect
What is the benefit of using % cover instead of counting each organism?
It is less time consuming, so more efficient
What must I also measure when using transects?
Abiotic Factors (PH/Temp)
What technique should I use to estimate the population size of motile organisms?
Capture, Mark, Re-capture
I hat are the steps in this technique? (5 steps)
- For fixed time collect species in a specific location
- Mark them so not to disadvantage them I.E not easily identifiable to predators!
- Release them and give them time to mix
- Collect a second time- over the exact same time period and the same time of day.
Then note down the total number collected. (Ones already marked have been re-captured) - Use the estimate equation:
(N1 x N2 ) / N3
