Biodiversity and Evolution Flashcards
(52 cards)
Species richness
-Number of different species living in a habitat.
Species evenness
-A comparison of the number of individuals of each species living in a community.
Capture Recapture (Method)
-Capture a number of a species in a defined period of time.
-Mark then unobtrusively.
-Release them into the population.
-After a set period of time capture the same species over the same time as the first.
-Count how many are marked compared to not marked.
Pop size = Number in 1st x Number in 2nd/Number marked in 2nd.
Capture/Recapture limitations
-Assumes no death, births or migration.
-Marking may affect survival rate of animals.
Random Sampling (method)
-Mark out a grid at right angles.
-Pick x and y co-ordinates with a random number generator.
-Take a sample from that location.
Random sampling (Advantages and disadvantages)
-Data not biased by selective sampling.
-Each individual has an equal chance of being picked.
-May not cover all areas equally.
-Species with low presence may be missed.
Systematic sampling (methods)
-Samples taken at fixed intervals across the habitat.
-Can be done along a transect line, and then quadrats placed.
Systematic sampling (Advantages and disadvantages)
-Useful in clear gradient of environmental factors (eg coastline)
-Only species on the transect are recorded, leading to an underestimate.
Stratified sampling (method)
-Divide habitat into areas of different (eg grassland, forest, bare ground) and sample each section equally.
Stratified sampling (Advantages and disadvantages)
-All areas of habitat are sampled.
-Could have a disproportionate portion of samples taken in smaller areas.
Opportunistic sampling (method)
-Samples are taken based on prior knowledge of the area and the species inside it.
Opportunistic sampling (Advantages and disadvantages)
-Easier and faster.
-Data may be biased.
-Overestimate the biodiversity.
Simpson’s Index of Diversity
-A way to measure species diversity that takes into account species richness and evenness.
-Value closer to 1 equals a more diverse area.
Genetic diversity
-The biological variation of alleles that occurs within species.
-Makes it possible for species to adapt to environmental changes.
Calculating genetic diversity
Proportion of polymorphic (differing) gene loci = no of polymorphic gene loci/total no of loci.
Reasons for loss of biodiversity
-Deforestation.
-Agriculture (pesticides and monocultures)
-Climate change.
Conservation methods
-In Situ: marine zones and wildlife reserves.
-Ex Situ: seed banks, botanic gardens and zoos.
Millennium Seed Bank
-1 billion seeds.
-34,000 species.
-Provides a back up in case of extinction.
Convention on International Trade in Endangered Species (CITES)
-No killing of endangered species.
-Limit trade by licensing.
-Illegal to trade products from endangered species.
-Raise awareness of threats to biodiversity.
Rio Convention on Biological Diversity
-Develop international strategies for conservation.
-Using plant and animal products sustainably.
-Make conservation international law.
-Provide guidance to governments on conservation.
Countryside Stewardship Scheme
-In Britain.
-Promotes sustainable land management methods.
-Gives grant to landowners who uphold policies.
-Improve and extend habitats.
Taxonomic levels
-Domain
-Kingdom
-Phylum (body plan)
-Class (general traits)
-Order (nature of organism)
-Family
-Genus (closely related)
-Species
3 domains
-Archaea
-Eubacteria
-Eukaryote
5 kingdoms
-Plantae
-Animalia
-Fungi
-Protoctista
-Prokaryotae
