Biodiversity Flashcards
Define habitat
The area inhabited by a species
Define biodiversity
The variety of living organisms in an area
Explain how biodiversity may be considered at different levels
Habitat diversity- number of different habitats in an area
Species diversity- number of different species in an area
Genetic diversity- variation of alleles within a species (or population of a species)
Explain the importance of sampling in measuring the biodiversity of a habitat
Allows you to estimate the population of a certain species
Multiplying small area to larger scale
Saves a lot of time
Describe how random samples can be taken when measuring biodiversity
Take samples at regular distances across the habitat
Use random numbers to plot coordinates within a habitat on map
Use portable GPS to find exact positions
Methods of sampling plants
Random quadrats,
measure abundance with the ACFOR scale
Abundant, common, frequent, obvious, rare
Percentage cover- grad of string in quadrat or point frame over quadrat
Transect
Line across habitat with tape
Interrupted belt transept uses quadrats at set intervals
Continuous belt transect quadrats moved across
Methods for sampling animals
Sweep netting (stout net, wide arcs, white sheet, collect in pooter) Trees (stout stick, knock branch, white sheet underneath) Pitfall trap (set in soil, container buried, water or scrunched paper) Tullgren funnel (leaf litter light dries, funnel, mesh screen, jar under) Light trap (UV, vessel under with alcohol)
How to measure species richness of a habitat
Number of different species in an area
Qualitative, take samples
How to measure species evenness in a habitat
Number of individuals of each species in an area
Quantitative survey.
Plants- percentage cover smaller, count number of individuals per unit area for larger plants
Animals- mark and recapture, total population is (number captured in first capture times the number captured the second time) DIVIDED BY the number of marked animals recaptured in second time
Simpson’s index of Diversity
D=1-(sum(n/N)^2)
n is the number of individuals of a particular species in the area
N is the total number of individuals of all species in the area
Significance of high Simpson’s index
Diverse habitat
Dominated by many different species
Small change in environment may affect one species
Which is only a small part of the habitat, has a negligible effect on biodiversity as a whole
Significance of small Simpson’s index
Habitat dominated by only a few species Small change to environment affects one species Has a large effect on the biodiversity Could destroy the whole habitat Habitat easily damaged
Discuss current estimates of global diversity
14 million different species Global warming can have a large effect on global diversity Changes environmental conditions Changes spread of disease Changes agricultural patterns
This is not a measure of biodiversity because they do not take into account the number of individuals in each species, or give any indication of the variation between different species, or within a species. We cannot be sure how accurate they are because
They do not include any marine species
We cannot be sure that we have found all of the species on earth Evolution and speciation are continuing
Many species are endangered and some are becoming extinct
Define species
A group of similar organisms able to reproduce to give fertile offspring. It consists of individual organisms which are similar in appearance, anatomy, physiology, biochemistry and genetics
