4.2.2: biodiversity Flashcards
what is meant by biodiversity?
the variety of living organisms present in an area
what are the 3 different ways in which biodiversity can be studied?
- habitat biodiversity (sand duns, woodland, meadows, streams)
- species biodiversity (species richness and species evenness)
- genetic biodiversity (different breeds within a species)
what is species richness?
the number of different species living in a particular area
what is species evenness?
a comparison of individuals in each species in a community
what is meant by genetic biodiversity?
refers to the variety of genes that make up a species
what is sampling?
taking measurements of a limited number of individuals in a certain area
what is the method for random sampling?
selecting individuals by chance:
- mark out a grid on the area, use a random no. generator to determine the x and y co-ordinates
- take a sample from the co-ordinates generated
what is opportunistic sampling?
(not representative of population) use organisms that are conveniently available
what is stratified sampling?
population divided into strata (sub-groups) based on particular characteristic (e.g. separating males and females)
what is systematic sampling?
diff areas within an overall habitat are identified, which are then samples separately
- line transect
- belt transect (sample taken from between the two lines)
how does a point quadrat work?
- frame with horizontal bar, push pins in at different intervals
- record each species of plant in the pin touches
how does a frame quadrat work?
consists of a square frame, divided into equal sections
the type and number of each species within the sections is recorded
what are 6 abiotic factors?
- wind speed
- light intensity
- relative humidity
- ph
- temperature
- oxygen content in water
how is biodiversity calculated?
- Using Simpson’s Index
- D = 1 - total (total number of organisms of all species / total number of organisms in particular species
- 1 = infinite biodiversity
- 0 = no biodiversity
what are the factors that affect genetic biodiversity?
increase:
- mutations
- interbreeding between different populations
decrease:
- selective breeding
- rare breeding
- natural selection
- genetic bottleneck
- founder effect
what is meant by genetic bottleneck?
where only few individuals survive an event or change, reduces gene pool for further populations
what is meant by the founder effect?
where a small number of individuals create a new colony, geographically isolated
how does deforestation effect biodiversity?
- reduces the number of trees
- if only a specific type of tree is felled
- destroys habitats and food sources for other animals
- animals migrate = increase biodiversity in other areas
how does agriculture affect biodiversity?
- deforestation to clear land
- removal of hedgerows = less plant species
- pesticides reduce pests
- herbicides reduce plant species in an area
- monoculture = less biodiversity
how does climate change affect biodiversity?
- melting of polar ice caps = loss of plant and animals species
- rising sea levels = reducing terrestrial habitats
- higher temperatures and less rainfall = less plants survive
- insect life cycles will change (important pollinators)
what are 2 aesthetic reasons for maintaining biodiversity?
- enriches our lives
- patients recover more rapidly from stress and injury when supported by plants
what are 2 economic reasons for maintaining biodiversity?
- soil erosion and desertification of land = can’t grow crops
- some species of plant may be medically useful
what are 2 ecological reasons for maintaining biodiversity?
- all organisms are interdependent
- some species are keystone species (maintain structure of an ecological community)
what is in situ conservation?
takes place within an organisms natural habitat
- wildlife reserves
- marine conservation zones
