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
