Biodiversity Flashcards
What is biodiversity?
The variety and complexity of life. It is an important indicator in the study of habitats.
What is species diversity?
The number of different species and individuals within each species in an ecosystem and the evenness of abundance across the different species present.
What is genetic diversity?
The variety of genes and alleles in the genome of one species.
What is habitat diversity?
The range of different habitats
What is species richness?
This goes under species diversity. It is the number of species in an ecosytem
What is the effect of reduced genetic diversity?
Less alleles mean the population is less likely to survive and adapt to changes via natural selection.
What are the 3 things that can reduce genetic diversity?
1.Captive breeding in zoos = small number of individuals breeding. So smaller gene pools and the same alleles will keep being passed on.
2. Bottle neck effect = A small number of a population survived an event so gene pool is decreased. Only those alleles will be passed on.
3.Founder effect - of original population a small number migrate to an isolated area, Inbreeding is more likely. Limited genetic pool so same alleles passed on.
How can genetic diversity be measured?
By examining polymorphic genes in isolated populations like zoos, rare breeds and pedigree animals where selective breeding has been used. You can measure polymorphism via:
Proportion of polymorphic gene loci =
no. polymorphic gene loci / total no. gene loci
The higher the proportion of polymorphic gene loci, the larger the genetic diversity in the population.
What is a polymorphic gene?
One that has more than one allele. Most genes have one allele = monomorphic.
How is biodiversity (species diversity) measured?
Using Sampsons index of diversity.
n = total no. of organisms for a single species
N = total no. of organisms for all species
Values near 1 indicate high levels of biodiversity
Values near 0 indicate low levels of biodiversity
What is sampling and why is it used?
A technique used while measuring a habitat’s biodiversity because it would take too long to count every individual in an area. This allows you to get a representative estimation of the population.
How do you make sure your sample is representative?
- Large sample, calculate mean and do a statistical test to see if any differences or correlations you see are significant.
- Randomly sample to avoid bias
Give examples of random sampling techniques.
Quadrats, sweep nets, pitfall
traps and pooters.
How are quadrats used in random sampling?
- Quadrats (0.5m x 0.5m) are used to observe abundance of plants or slow-moving organisms. Laid randomly in an area.
- E.g converting sampling area into a grid format and a random number generator picks the sample points/coordinates. Abundance-percentage cover of different species recorded.
Density = counting how many organisms present.
Frequency = fast. Count how many squares out of the hundred the organism is present in to get a percentage frequency.
Percentage cover = estimate % of entire quadrat covered by species being investigated. Quick but subjective and low accuracy
- E.g converting sampling area into a grid format and a random number generator picks the sample points/coordinates. Abundance-percentage cover of different species recorded.
How are pooters used in random sampling?
Pooter = small containers with 2 tubes that suck up small insects and invertebrates.
How are pitfall traps used in random sampling?
cans or jars that are buried in the ground that are used to catch ground-dwelling (often nocturnal) insects and other invertebrates as they fall into the trap
How are sweeping nets used in random sampling?
These are large, strong nets with a fine material (very small holes) that are used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass
Why is non-random sampling used?
Because random sampling can take impractically long or just be impossoble.
What are the 3 types of non-random sampling?
Opportunistic, stratified and systematic.
What is opportunistic sampling?
Unlikely to result in accurate data as only organisms that are conviniently available are sampled = bias.
What is stratified sampling?
Populations or habitats are separated into groups to then randomly sample. Eg, in a pond you split it into surface, shallow and deep water regions and take a sample from each one (strata)
What is systematic sampling?
Best used when you want to identify a change in the distribution of species in a habitat. Involves a belt transect.
- Plave single tape measure along the sample area and at regular distance along the tape place quadrat and record data.
Can identify change in species richness and evenness.
How is Tllgren funnel used in random sampling?
these are funnels with a light bulb above and a container below. It collects invertebrates that live in leaf litter or soil. The leaf litter or soil is placed in the funnel and the light and heat forces the invertebrates to move down until they drop into the container
How is kick-sampling used in random sampling?
It is used to catch freshwater invertebrates living in streams or rivers. A net in placed on the stream-bed so that the water is flowing into it and the stream-bed just above the net is churned up by the scientist (using their foot) for a set period of time. The invertebrates are carried by the stream into the net
