Biodiversity Flashcards
Habitat diversity
Habitat biodiversity refers to the number of different habitats within an area
Species biodiversity
Measured in 2 components
Species evenness- comparison of number the number of individuals of each species living in a community
Species richness- number of species living in an area
Genetic biodiversity
Refers to the variety of genes that make up a species
High levels of genetic diversity will lead to a lot of different characteristics being exhibited
Random sampling
Selecting individuals by chance, each individual in the population has an equal chance of being selected
1) Mark out grids on the grass using 2 tape measures laid at right angels
2) use random numbers to determine x and y co-ordinates
3) take a sample at each coordinate pairs generated
3 types of non random sampling
Opportunistic , stratified, systematic
Opportunistic sampling
Weakest form of sampling as it may not be representative of the population
Uses organisms conveniently available
Stratified sampling
Some populations can be divided into a number of strata based on characteristics
Random sample is then taken from each of these strata proportional to its size
Systematic sampling
Different areas within an overall habitat are identified, which are then sampled separately
E.g a line transect or a belt transect
describing how to distribution of organism changes as you move closer to the coast or across a field
Why may a sample not be reliable
Sampling bias - selection process may be biased
Chance- organisms selected may, by chance, not be representative
Ways to sample animals
Porter is used to catch small insects by sucking though a mouthpiece
Sweep nets are used to catch insects in long areas of grass
Pitfall traps are used to catch small, crawling invertebrates such as beetles, spiders and slugs
Tree beating is used to take samples of the invertebrates living in a tree or bush
Kick sampling is used to study organisms living in a river to disturb the substrate, net is held downstream to catch any organisms released
Point quadrats
Consist of a frame containing a horizontal bar
At set intervals along the bad, long pins can be pushed through the bar to reach the ground
Each species of plant the pin touches is recorded
Factors increasing genetic biodiversity
Mutations in DNA
Interbreeding between different populations, this is known as genetic flow
Factors that reduce genetic biodiversity
Selective breeding- where only a few individuals with the desired characteristics are selected to breed
Captive breeding programs
Natural selection- species evolve to contain primarily alleles which code for the advantages characteristics
Genetic bottlenecks- few individuals within a population survive an event or change in environment
The founder effect- where a small number of individuals create a new colony, geographically isolated from the original
Human influence on biodiversity
Deforestation - permeant removal of large areas of forest
Agriculture- increasing amounts of land has to be farmed in order to feed the growing population, this has resulted in large amounts of land being cleared and planted with one crop, reducing biodiversity
Climate change- there is much evidence that the release of carbon dioxide and other pollutants into the atmosphere from the burning of fossil fuels increasing global temp
Agricultural changes that effect biodiversity
Deforestation- to increase the area of land available
Removal hedgerows - as a result of mechanisation farmers remove hedgerows to give them more space to fertilise
Use of chemicals (pesticides and herbicides)
Pesticides- kill pests that would eat crops
Herbicides- kill weeds
Climate change
Temperature increasing at increasing rate
Increased water vapour in air
Temp of ocean has increased, contributing to sea level rise
Global average sea level rise increasing
Artic temperature increasing
Mountain glaciers melting due to heat increases
Long term upward trends in precipitation
How will biodiversity be effected due to climate change
Melting polar ice caps will lead to extinction
Riss sea levels will make land uninhabitable
Higher temp and less rainfall would effect hydrophytes and xerophytes
Insect life cycles and populations will change as they adapt to the new climate
3 reasons for maintain biodiversity
Aesthetic
Economic
Ecological
Aesthetic reasons
- the presence of different plants and animals in our environment enriches our lives
- natural world provides inspiration for artists
- studies have shown that patients recover more rapidly from stress and injury when they are supported by plants
Economic reasons for keeping biodiversity
- Soil erosion occur as a result of deforestation reduces the ability to grow crops
- sustainable methods of using raw materials otherwise economies will collapse
- large scale habitat and biodiversity loses means that species with potential economic importance may be lost
- continuous monoculture results in soil depletion, this reduces genetic diversity making the ecosystem more fragile as the plants are more susceptible to disease
Ecological reasons for maintain biodiversity
- all organisms are interdependent on each other
- species that play a key role in maintains the strider of an ecological community are called keystone species
In situ and ex situ conservation
In situ - Within the natural habitat
Ex situ - out of natural habitat
Positives of In situ conservation
Maintains genetic diversity
Maintains evolutionary adaptions by allowing species to interact with the environment
Cheaper than ex situ
Conservation agreements
Rio convention- (CBD) requires countries to deblop national strategies for sustainable development, (UNFCCC) is an agreement between nations to take steps to stabilise greenhouse gas concentrations within the atmosphere, (UNCCD) aims to prevent transformation of fertile land
Countryside stewardship scheme: sustain beauty, extending habitats, restoring neglected land (historical), improving opportunities for countryside enjoyment
CITES - convention on international trade in endangered species
Examples of in situ methods
Marine conservation
Wildlife reserves: controlled grazing, restricting human access, controlling poaching , feeding animals, reintroduction of species, removal of invasive species, halting succession ( succession is a natural process in which early colonising species are replaced overtime)
Ex situ conservation
Botanic gardens- plant species can be grown due to specific conditions
Seed banks- store generic material so new plants can be grown in the feature
Captive breeding programs- produce species in human controlled environment
Captive breeding
Provide animals with shelter and food
Marinating genetic diversity can be hard
Not suitable for wild releases because: not resistance to wild diseases, behaviour- some behaviour must be learned through experience, genetic- captive animals can become so different from the original population, habitat may not be there
how organic fertilisers improve the yield of plant crops
Fertilisers are broken down by decomposers
Fertilisers contain a large amount of nutrient
Lack of minerals is a limiting factor for growth meaning plant growth will increase
How do inorganic fertilisers effect farmland biodiversity
Promotes growth of one or few species
Reduces genetic diversity as some species are out competed
Advantages of using seed banks
Plants produce an excess of seeds meaning they can be collected without damaging
Take up little storage and can store large numbers
Cheap and easy to transport
importance of sampling to measure biodiversity
areas are too big to sample all organisms
by using a random sample you can get a representative estimate of the population
significance of a low value of Simpsons index of biodiversity
habitat dominated by a few species
habitat/ ecosystem is less likely to cope with change
reasons for conservation
idea of impact on food chain(s)
idea of right to exist / duty of humans to care for other
species / ethical reason / preserving species for
future generations
idea of aesthetic reason
economic reason / tourism / might provide useful
resource
why is it necessary to conserve some species ex situ
too many predators in natural habitat
habitat drastically changed due to climate or natural disaster, organisms is no longer suited to it
numbers are so low that sexual reproduction is unlikely
protection from pathogens
advantages of conserving as seeds rather than adults
easier to harvest without damage to the habitat
cheaper/ easier to transport
remain viable for longer periods of time
less susceptible to disease
implication for habitat if Simpsons index is low
Species diversity is low
implication for habitat if Simpsons index is low
if species is wiped out all others may not survive
whole habitat is likely to be effected by any changes
How excessive use of inorganic fertiliser can cause issues
Promotes the growth of 1 species
Other plant species are out competed
Reduction in soil quality
Why may a sample be never entirely representative
Sampling bias
Chance
What can you measure using a quadrat
Density
Frequency
Percentage cover
