2. Biodiversity Flashcards
Biodiversity
measure of variation within the living world
3 types of. Biodiversity
Habitat, species, genetic
Habitat biodiversity
where an organism lives
Species biodiversity
Organisms that can interbreed to produce fertile offspring
Genetic biodiversity
Within the same species there’s variation of alleles
Random sampling
- number generator, coordinate generator
- Advantage = not biased
- Disadvantage = may not cover all areas of habitat equally
3 types of non random sampling
Opportunistic, stratified, systematic
Opportunistic
based on previous knowledge, know exactly where to sample. Adv = easier and quicker than random sampling. Dis = data is biased + can lead to overrepresentation something
Stratified
dividing habitat into segments of things that look different. Adv = allows you to sample everything that looks different = representative. Disadv = data is biased + can lead to overrepresentation
Systematic
when samples are taken at fixed intervals across habitat. Done w/ belt transect and line transect. Adv = clear gradient is visible. Disadv = data is biased + can lead to underestimation because only samples along the line will be measured
How to sample plants
To sample plants you use quadrats = everything that touches the grid you count. Point frame lowered after quadrat = same square and everything that touches the grid you count.
Quadrats can be places above transects as well
Observation to sample animals
if you can see them or droplets or footprints you can count them for larger animals
Pitfall trap
placed in ground with a little water to drown small invertebrates. May be more likely to come the second time of capture and release bc they know there’s food or may be less likely to come bc they known it’s a trap = influencing their behaviour.
Pooter
suck in small invertebrates to capture them
Using pitfall trap
- dig hole and place container in soil
- Make top of container level w soil level
- Cover to protect from rain
- Leave overnight
- Count invertebrates
Tullgren funnel
traps insects that are light sensitive = moves away from heat and goes into collecting pot. Ethanol in collecting pot underneath to kill the insects bc some may be predators some prey so if alive u won’t get an accurate representation.
Kick sampling
kicking the ground allowing the species to come out (small invertebrates in streams + rivers). Number of kicks + how vigorous kicks are. Disturbs organisms in the habitat
Sweepnet
catches invertebrates. standardised by controlling how many times you sweep and how high you sweep from the ground. Disturbs organisms in the habitat
What can be a limitation of a sampling technique
disturbing the organisms in the habitat
Capture and release formula
Everything you’ve captured you mark as c1. Let them go and put the trap there again and check who came back and which ones are unmarked. The ones that were already marked you mark as c3 and the ones that aren’t marked you mark as c2. Use equation (c1xc2)/c3 = total population.
Capture and release
The period between the first trap and the second trap should be quite short to stop animals from moving far away from the region. Animals may condition themselves to not come back because they think it’s a trap or they might think the trap isn’t harmless and will come back. Only people with a license can perform this experiment. You don’t want the marking to be toxic to the animal.
Species richness
a measure of how many different species there are
Species evenness
a measure of how many of each species there are
Species richness and evenness in a place w good biodiversity
High
Simpsons index
The value can be between 1 and 0 and the closer it is to one, the more diverse it is.