Biodiversity Flashcards
Definition of biodiversity
Biodiversity is the variety of species in an area
3 ways to measure biodiversity
- Quadrat
- Belt Transects
- Mark - recapture technique
How humans increase biodiversity
- Nature reserves
- Zoos
- Wildlife parks
- Breeding programmes
- Protected areas
- Restricted fishing zones
- Hunting bans
- Seed banks
- S.S.S.I. (sites of special scientific interest)
How humans decrease biodiversity
- Road building
- Mining
- Quarrying
- Deforestation
- Pollution
What is an alien species?
Animal/plant/microorganism from one part of the world that is transported to another part of the world to become established in a new area. Can happen accidentally or deliberately
Advantages of biological control
- Can be cost effective in the long run
- Specific to a particular pest
- self-sustaining system
Disadvantages of biological control
- Expensive at beginning
- Slow process
- Doesn’t completely destroy pest
- Predator could switch to different target and so disrupt food chains so can sometimes fail in specificity
Advantages of chemical control
- Fast acting
- Effective
- Leaves plants unharmed
- Often inexpensive
Disadvantages of chemical control
- Often requires reapplication to plants with each growing season
- Chemical pesticides can often persist in environment
- Over time, pest populations can build up resistance to pesticides
In order to find effect of a on dandelions, a sample was sprayed on a 10m^2 lawn. The number of plants was counted in a 1m^2 Quadrat. How would you use the Quadrat to estimate number of living dandelions before and after treatment? (QWC)
- Throw 1m^2 Quadrat randomly
- Count number of living dandelions in Quadrat
- Repeat these two steps at least 10 times
- Calculate average
- Multiply this number to calculate total number in whole lawn
- Do this before and 1 week after treatment
Advantages of Quadrat
- Quick and easy
- Accurate data if at least a quarter of total area is covered and enough samples taken
Disadvantages of Quadrat
- Not very accurate
- Possible to miss certain details/species completely or over-represent
Advantages of belt transects
- Best sampling method if investigating how distribution of species changes across habitat
Disadvantages of belt transects
- Longer
- More organisation needed
What is Chemical control?
Weed killers that are manually sprayed onto plants but can drift on wind and kill other plants
What is Biological control?
An invasive organism’s natural predator is used to control pest
Advantages of mark-recapture technique
- Estimate population of animals in an environment
Disadvantages of mark-recapture technique
- Need to be careful that mark doesn’t affect survival of animal, this reduces likelihood of scientists catching animal twice which would affect their results
