Biodiversity Flashcards
what is the definition of biodiversity?
the variety of living organisms in an area, including:
- habitat biodiversity
- species biodiversity
- genetic biodiversity
what the definition of a habitat?
the area inhibited by a species
what is habitat biodiversity?
the number of different habitats in an area
what factors does habitat biodiversity include? (include examples)
- physical factors (e.g. soil, temperature range)
- living (biotic) factors (e.g. the availability of food, the presence of predators)
name 4 examples that could contribute towards habitat biodiversity
- sand dunes
- woodland
- meadows
- streams
what is the definition of a species?
a group of similar organisms able to reproduce to give fertile offspring
what is species biodiversity?
a measure of species richness and species evenness in an area
what is the definition of species richness?
the number of different species present in an area
what is the definition of species evenness?
the number of each species present in an area
what does high species richness and evenness tell us about a habitat?
it has high biodiversity
name a habitat that has species biodiversity (high species richness and evenness)
a woodland (could contain many species of plants, insects, birds and mammals)
how do you calculate species biodiversity?
Simpson’s Index of Diversity
what is Simpson’s Index of Diversity?
- a measure of species biodiversity within 1 habitat
- it usually includes both species richness and evenness so is considered pretty accurate
- it is always a value between 0 and 1
- the closer the index is to 1, the more diverse the habitat is and the greater its ability to withstand change - it has higher species richness and evenness
what is the formula of Simpson’s Index of Diversity?
D = 1-(Σ(n/N)²)
D - Simpson’s Diversity Index value (always a value between 0 and 1)
Σ - sum of
n - number of individuals of a species
N - total number of all individuals of all species present
what is genetic biodiversity?
the variation of alleles within a species or a population of a species (how varied the gene pool is)
what is the definition of an allele?
a version of a gene
what is an example of genetic biodiversity?
different breeds of dog (due to a variation in alleles)
what is the importance of genetic diversity?
- it increases the likelihood of a population adapting to and surviving a change in environment
- it reduces the likelihood of the entire population being wiped out because of a single event (e.g. disease, natural disaster)
- it reduces the vulnerability of a population and increases how robust it is
- it reduces inbreeding (reducing risk of genetic diseases)
- it increases the gene pool and therefore different alleles that could be useful
name 4 examples of low genetic diversity
- Irish potato famine - airborne fungus wiped them out for 6 years
- pedigree dogs - bred for desirable characteristics, narrowing the gene pool via selective breeding
- Amish people
- ‘blue Fugates’ family (blue people) - inbreeding and intermarriage increases homozygosity, creating a genetic blood condition (blood is chocolate brown causing skin to appear blue)
what is the definition of polymorphism?
a locus that has 2 or more alleles with a frequency of over 5% in the population
what is the definition of a locus?
*
a position on a chromosome where alleles of the same gene are found
what can polymorphism indicate?
it is a great indicator of diversity
(the higher the level of polymorphism, the more frequently different alleles are found within the population, the more genetic diversity)
name an example of polymorphism
the Heliconius Erato butterfly has a high degree of polymorphism for genes encoding wing colour
how can polymorphism be maintained?
by a balance between variation, created by new mutations and natural selection
how do you measure genetic diversity?
by the proportion of polymorphic gene loci in a population
what is the formula for calculating the proportion of polymorphic gene loci?
P = number of polymorphic gene loci ÷ total number of loci investigated (x100 for a %)
what is the definition of a genetic drift?
a variation in the frequency of different genotypes in a small population, because of random fluctuations in allele frequency
what can a genetic drift cause?
- the disappearance of certain alleles (usually rarer ones), especially after an event such as a natural disaster or a genetic bottleneck
- a new population which is genetically distinct from the original population (possibly evolving to new species)
what is the genetic bottleneck effect?
where a sudden event drastically reduces population size, usually resulting in a new population that is much more vulnerable to distinction that the previous
name 4 events that could occur, leading to the bottleneck effect
- disease
- a change in environment
- famine (loss of food)
- a natural disaster
name 7 pieces of equipment that can be used to collect data on moving organisms and what organism it can be used on
- tree sampling = organisms that live in trees
- pitfall trap = nocturnal invertebrates
- tullgren funnel = organisms found in soil
- light trap = nocturnal flying insects
- sweep netting = insects
- pooters = terrestrial invertebrates
- mark and recapture
how do you carry out tree sampling?
shake the tree and see what organisms fall
how do you carry out a pitfall trap?
- dig a hole and place a trap (bucket/container) below ground level
- cover with a piece of wood (so that water and predators cant enter)
- leave overnight and count number of organisms
how does a tullgren funnel work?
a light is placed above leaf litter which covers a filter, leading to a collecting pot
small organisms move away from the heat/light and land in the collecting pot for investigators to count
how does a light trap work?
nocturnal flying insects (e.g. moths) are drawn to light which allows them to gather in one place, ready to be counted