Topic 5 (Unit 4) Flashcards
Give examples of abiotic factors affecting habitats
Solar energy input Climate Oxygen availability Pollution Topography Edaphic
Give examples of biotic factors affecting habitats
Interspecific competition Intraspecific competition Predators Mutualism Grazing Catastrophes
What does “edaphic” mean?
Relating to the soil.
Eg. pH, mineral content
What does “mutualism” mean?
Species benefiting each other.
Eg a squirrel buries nuts/seeds. The squirrel has a food supply for the winter, and has helped to disperse the nuts/seeds.
What are anthropogenic factors?
Factors specifically relating to humans. Can be biotic or abiotic.
What is a habitat?
An area that
a) differs significantly from adjacent areas eg a lake is a separate habitat to the adjacent land
b) is geographically separate from similar habitats eg two sides of a lake may be similar but are still separated by the lake
What is a community?
Different species living in a habitat make up a community.
What is an ecosystem?
A biological community of interacting organisms and their physical environment.
When would you use random sampling?
When the habitat looks fairly uniform and there is little variation.
How would you randomly place a quadrat?
Divide the habitat/area into a scaled grid and use a random number generator to pick a section.
How do you measure the abundance of a species in a quadrat?
For larger species, count the number of organisms present. Set criteria for whether organisms half-in the area count as in or out beforehand and stay consistent.
For smaller species, where it would take too long to count, estimate percentage cover. There is a distinct possibility of human error here.
How would you measure an abiotic factor when looking at how it affects the distribution or abundance of a named species?
In the same square of the quadrat each time. Eg the centre square.
Why would you use systematic sampling?
To measure variation across a habitat.
What is a line transect?
One string/tape. Shows the distribution of species present along the transect.
What is a belt transect?
Two strings/tapes defining an area between them, the same width all along (eg the width of a quadrat).
Only look at species within the area.
Good for measuring abundance as well as distribution.
