Biodiversity Flashcards
What is meant by biodiveristy?
the variety of living organisms present in an area
What are the 3 different ways in which biodiversity can be studied?
- habitat biodiversity
- species biodiversity
- genetic biodiversity
What is species richness?
the number of different species living in a particular area
What is species evenness?
a comparison of individuals in each species in a community
What is meant by genetic biodiversity?
refers to the variety of genes that make up a species
What is sampling?
means taking measurements of a limited number of individuals in a certain area
What is the method for random sampling?
select individuals by chance:
- mark out a grid on the area, use a random no. generator to determine the x and y co-ordinates
- take a sample from the co-ordinates generated
What is opportunistic sampling?
(not representative of population) use organisms that are conveniently available
What is stratified sampling?
population divided into strata (sub-groups) based on particular characteristic (e.g. separating males and females)
What is systematic sampling?
diff areas within an overall habitat are identified, which are then samples separately
- line transect
- belt transect (sample taken from between the two lines)
What are the techniques used for sampling animals?
-pooter (used to catch small insects)
- sweep nets
- pitfall traps (trap small animals)
- tree beating
How does a point quadrat work?
frame with horizontal bar, push pins in at different intervals
record each species of plant in the pin touches
How does a frame quadrat work?
consists of a square frame, divided into equal sections
the type and number of each species within the sections is recorded
How do you collect the most valid representative sample?
quadrats, with random sampling technique
How can frame quadrats be used to sample a population of plants living in a habitat?
density
frequency
percentage cover
What are the six abiotic factors?
wind speed
light intensity
relative humidity
pH
temperature
o2 content in water
How is biodiversity calculated?
Using Simpson’s Index
D = 1 - total (total number of organisms of all species / total number of organisms in particular species)
What do the results of a Simpson’s index mean?
1 = infinite biodiversity
0 = no biodiversity
What are the factors that affect genetic biodiversity?
INCEASE:
1. mutations
2. interbreeding between different populations (alleles transferred known as gene flow)
DECREASE:
1. Selective breeding
2. rare breeding
3. natural selection
4. genetic bottlenecks
5. founder effect
What is meant by genetic bottleneck?
where only few individuals survive an event or change, reduces gene pool for further populations
What is meant by the founder effect?
where a small number of individuals create a new colony, geographically isolated
What are the three human influences on biodiversity?
- deforestation
- agriculture
- climate change
What are the aesthetic reasons for maintaining biodiversity?
