Topic 7 - Revision Flashcards
How do you work out population density of an area?
Number of organisms / Area Sampled
What is the process/procedure to ensure samples are random and representative (when using a Quadrat)?
Divide area into a grid,
Use a random generator to pick co-ordinates, Place a quadrat at the top-left of each co-ordinate
Record the co-ordinate (to ensure co-ordinates aren’t repeated) and count (e.g. no of daisies)
Repeat the process (until a running mean is consistent)
What is a running mean?
Where you take the mean of each sample (as you sample) and repeat samples until the mean is consistent/stable
What would you use instead of a quadrat, for sampling moving organisms?
A pitfall trap or a net (to mark-release-recapture)
What is the definition of an Ecosystem?
All of the organisms in a community and the abiotic conditions in the area which they live
What is the definition of Interspecific Competition?
Competition between members of different species
What is the definition of Intraspecific Competition?
Competition between members of the same species
What is the definition of a Habitat?
The place were an organism lives (within an ecosystem)
What is the definition of Carrying Capacity?
The maximum stable population size of a species than an ecosystem can support
What is the definition of a Biotic Factor?
The living components of an Ecosystem
What is the definition of an Abiotic Factor?
The non-living components of an Ecosystem
What is the definition of Niche?
The role of an organism within it’s habitat
What is the definition of a Community?
All the populations of all of the different species living in a given area at a given time.
What does population size fluctuate around?
The Carrying Capacity
What is Conservation?
The protection and management of species and habitats in a sustainable way
What is an example of Conservation of Animals?
Captive breeding, Fishing Quotas and Protected areas
What is an example of Conservation of Plants?
A Seed Bank
What is a way of preventing succession in order to Conserve Habitats
Controlled Burning or Grazing
What is the definition of Sustainable?
Enough resources are taken to meet the needs of today, without it impacting future needs
What is the process of Mark-Release-Recapture?
1) Capture animals using an appropriate method (e.g. pitfall trap)
2) Mark those caught in a harmless way (won’t make them more susceptible to predators or effect their ability to breed etc) and record how many were marked.
3) Release them back into the environment and give them enough time to reintegrate/randomly distribute
4) Capture a second sample to estimate population size using
Population size = (1st Sample Size x 2nd Sample Size) / Number Marked in 2nd Sample)
What is an assumption of the Mark-release-recapture method?
Population size remains the same throughout, Marked individuals disperse evenly throughout the population,
Proportion of marked individuals is the same in Sample 1 and 2,
Mark is not lost throughout investigation
What is the definition of Succession
A series of events where life comes back
What is Primary Succession?
The stage of bare rock (no soil) - no plants can grow
What must happen (from Primary Succession) in order for the first species to colonise?
Erosion or Weathering
How does the rate of succession change between Primary and Secondary Succession
Secondary Succession occurs more rapidly as the abiotic conditions are less harsh than Primary
What is a Climax Community?
A community of organisms where the type of species/number of species is stable
What happens to the population size of the first species (in succession)?
It decreases as they are outcompeted when the abiotic factors change
What is the name given to the first species to colonise an Environment?
Pioneer Species
