Module 4 Section 2 - Biodiversity Flashcards
Smithson
What are the three levels at which we can consider biodiversity? Describe them briefly.
- Species - types and abundance of different species
- Habitats - physical factors of living in a certain environment
- Genetics - variations in alleles
species richness
The number of different organisms in an area.
species evenness
The relative abundance of each species in an area.
habitat diversity
The number of different habitats in an area.
How do you calculate the species evenness?
The range in the number of each species there are in the area
taxonomic variety
Essentially the variety of taxonomic groups i.e. classified organisms in an area
I think, don’t quote me
Simpson’s Index of Diversity - what do n and N represent?
n = number of organisms in one specific species
N = total number of all organisms
Simpson’s Index of Diversity is always between ____ and ____.
0 and 1
The higher the Simpson’s Index of Diversity is to 1, the ____ diverse the habitat and the ____ able it is to cope with sudden changes.
more, more
A habitat with a Simpson’s diversity index of 0.2 is/isn’t dominated by one or a few species.
is
How has increasing population sizes affected food sources?
Current sources of food are being exploited faster than they can be replenished e.g. fish stocks
How has increasing population sizes affected waste & pollution? Give an example.
More waste and pollution is released (e.g. oxides of nitrogen from car exhausts) causing acid rain and lowering the pH of soil & water, killing trees and aquatic life
Apart from using more land for farming, how has agriculture increased to feed the growing population? Give two examples.
Land currently used for food is being exploited more intensely.
* Overgrazing by cattle can lead to soil erosion
* Farmers rely on monocultures more. This leads to an increased use of fertilisers (monocultures in particular make soil depletion occur faster)
Why is using lots of fertiliser bad for biodiversity?
Nutrient run-off can cause algal blooms in water, blocking sunlight from reaching the bottom of the bodies of water - aquatic plants die as they can no longer photosynthesise, closely followed by aquatic animals that can no longer respire
aesthetic reason to maintain biodiversity
Tourists may travel to see landscapes with high biodiversity for leisure and personal joy as biodiverse areas are attractive to look at
Why might you want to do non-random sampling? (2)
When you want to get samples from each of the different areas in a habitat, or to sample all the different species.
Three types of non-random sampling techniques
- Systematic sampling
- Opportunistic sampling
- Stratified sampling
When might you do systematic sampling?
Along a transect
How could you investigate crawling insects? (2)
Set up pitfall traps or use a pooter (essentially an insect vacuum)
Why can insects not escape a pitfall trap?
The contained has straight sides so insects can’t escape
What is important about the straws in a pooter?
There are two straws, but one of them is covered so you don’t accidentally suck the insect up
How could you investigate small animals? Explain how this works.
Use a Tullgren funnel (this is a funnel with a mesh, which is covered by soil/leaf litter) and a light is shone on top of it.
The light dries out the soil/leaf litter, drawing out any organisms inside - these then fall into the beaker below.
How could you investigate aquatic life?
Use kick sampling - kick/agitate the sediment in a river for a set amount of time and then use a net to collect any disturbed organisms downstream
How could you investigate organisms living in tall grass?
Use a sweep net - sweep once through the grass and empty the contents into a collection tray
