4.2 - Biodiversity Flashcards
Explain the importance of sampling in measuring the biodiversity of a habitat(model answer - 2 marks)
- It is impossible to count every individual in a species’ population
- So sampling provides an estimate of the population that is representative of the whole area/habitat
What is the significance of a low Simpson’s Biodiversity Index?
- The habitat is dominated by one species
- So the habitat is less likely to be able to cope with change
Sampling in ANIMALS model answer mechanisms
• set grid/area to be sampled
• use random numbers generated by a computer to locate the areas you will
randomly sample
• pick appropriate capture method CHOSE ONE e.g. sweep nets, pooters,
pitfalls etc
• identify each sp. using a key and count the numbers of each sp.
• repeat this several times in each habitat, using the same technique each
time to show repeatability and identify anomalies
- extrapolate the data to estimate biodiversity in the entire habitat
Sampling in plants model answer
- set grid/area to be sampled
- use belt transect to sample
- use 50cmx50cm quadrats
- at regular 5m intervals ‐ systematic sampling
- identify plant species using keys
- record the presence/absence of sp. in each quadrat
- estimate the % cover of each species in your quadrat
- repeat this using several different transects to show repeatability and identify anomalies
- extrapolate the data to estimate biodiversity in the entire habitat
Reasons for maintaining biodiversity
- Ecological reasons
- plants form habitats for other organisms
- protect keystone species
- genetic diversity for genetic resources, e.g. medicine, selective breeding, genetic engineering
- Economic reasons
- tourism
- source of medicines or resources
- Aesthetic reasons
- e.g. different breeds of dog
Ethical reasons:
- we should protect animals as it is our duty to protect and preserve biodiversity of other organisms
Three biodiversity agreements and conferences
- CITES - Convention on International Trade in Endangered Species of Wild Flora
- Rio Convention on Biological Diversity
- Countryside Stewardship Scheme
Aim of CITES
- conservation of biodiversity
- regulate, monitor and prevent trade in endangered species
- ensure trade does not endanger wild populations
- prohibit commercial trade in wild plants
- allow some trade in less endangered plants and animals
- allow trade in artificially propagated plants
How does CITES help save endangered species?
- countries in agreement make it illegal to poach species
- place ban on trade of endangered species
- increase cooperation between countries
- increase awareness of impact of illegal trade
Aims for Rio Convention on Biological Diversity
- conservation of biodiversity
- sustainable use of organisms / habitats / ecosystems
- share genetic resources
- share access to scientific knowledge
- promoting ex situ conservation methods (to complement in situ measures)
- raising profile of biodiversity with governments / general public
- international cooperation on biodiversity issues
Biodiversity def
-The range of habitats, the number of different species and their relative abundance, and the genetic diversity within a species within an area.
Species biodiversity def
- The number of different species living in a habitat (species richness) and their relative abundance (species evenness).
Factors affecting biodiversity
- Human Population Growth:
- more food and land needed = alter ecosystems and destroy habitats
- Using up more natural resources, e.g. crude oil is finite
- More energy sources and materials needed = more pollution
- Over hunting/fishing decreases biodiversity
- Agriculture and monoculture:
- monoculture will have reduced genetic diversity
- More land and natural habitats are cleared for land monoculture - reduces size of habitats and of wild species populations
- reducing population sizes reduces genetic diversity - less able to survive changes in conditions and leads to extinction
- Climate Change:
- Species with low genetic diversity are unable to adapt to the climate changes
- So species may have to migrate, which is risky as it is not always possible and could lead to extinction of a species
Habitat def
The place where an organisms lives
Habitat biodiversity def
-The range of habitats in which different species live within an area
Species def
-A group of organisms similar in appearance, physiology and genetics whose members are able to interbreed to produce fertile offspring
Genetic biodiversity def
-Variation between individuals of the same species e.g. breeds of dog.
2 types of sampling
- Random
- Non-random
Types of non-random sampling
- Opportunistic
- Stratified
- Systematic
Info about opportunistic sampling
-Pros and cons
- Prior knowledge of a site determines the sample site.
- You may deliberately sample an area where you know an organism is present.
Pros:
-Quicker than random sampling
Cons:
- This may introduce bias to the data
- you are sampling in a place you already know has a certain species or organism present
- Could lead to an overestimation of biodiversity or abundance of a species in habitat
Info about stratified sampling
-Pros and cons
Stratified sampling is sampling areas in a habitat which seem very different, separately
Pros:
- Ensures all different areas in the habitat are sampled
- ensures no under representation of different areas in habitats (random sampling may miss areas)
Cons:
-If too many samples are taken in proportionally smaller areas, it could lead to over representation of some areas.
Systematic sampling info
-Pros and cons
Samples are taken at regular, predetermined intervals across a habitat e.g. belt or line transects.
Pros:
- If there is a clear gradual change in an environmental factor across an environment, a transect can show how species abundance changes with it
- therefore shows the effect of the factor on the different plant species.
Cons:
- Species which do not fall on the line or in the belt may be missed
- Therefore the sample would not be representative and there would be an underestimation in biodiversity of a species
Two types of conservation
- In-situ
- Ex-situ
Examples of ex-situ conservation
- Seed banks
- Zoos
Examples of in-situ conservation
- Wildlife reserves
- Marine Conservation Areas
Importance of seed banks
- To maintain genetic diversity
- To maintain plants for future or currently unknown uses
- To counteract extinction or prevent inbreeding
How seeds are kept viable in seed banks
- ensure that seeds are germinated from time to time
- ensure new seeds are produced
- freeze seeds
- dehydrate seeds
How genetic variation is ensured in seed banks
- ensure you have many seeds
- collect seeds from many areas
- ensure the seeds have a mixture of genotypes
Advantages of using seed bank rather than adult plants to conserve endangered plant species
- most plants produce excess of seeds
- so can be collected from wild without damaging wild population
- take up little space
- able to store large numbers
- easy and cheap to transport
- remaining viable for long periods
- less susceptible to disease / pests
Disadvantages of using seed banks rather than adult plants to conserve endangered plant species
- collection of wild seeds may disturb environment
- collected samples may not be representative of genetic diversity of species
- seeds from one area may not survive in different area
- seeds stored for a long time may not stay viable
- asexually bred plants will have no genetic variation – reducing biodiversity
Definition of in-situ conservation
-Conserving a species in its normal habitat. Attempting to minimise human impact on the natural environment and protecting the natural environment.
Def of ex-situ conservation
-Conserving an endangered species by activities that take place outside its normal environment.
Advantages of in-situ conservation
- Conserving species in their natural habitat
- Conditions and food etc. that they require for survival already present – ??
- cheaper than ex situ
- Species are already well adapted to living in habitat
- No special provisions need to be made
- Can create protected reserves
- Can ensure sustainable use of environment including land and resources
- Allows for scientific research of ecosystem etc.
- Permanently protects biodiversity in area and whole ecosystems
- Creates areas of interest for ecotourists
Disadvantages of in-situ conservation
- There may be threats to the survival of the species in this area e.g. predation, hunting
- Human activity could threaten species in wild e.g. hunting deforestation
- Disease could threaten survival of species
- Species could be outcompeted by other species
Advantages of ex-situ conservation
- health of individuals can be monitored and treated for disease to ensure survival
- young can be hand reared which reduces mortality of young
- provision of mates for breeding can be manipulated
- protection from hunting and predation
- competition reduced between individuals
Disadvantages of ex-situ conservation
- Expensive
- Can be difficult to reintroduce species to the wild after ex-situ conservation, e.g. zoos
- Due to predation, or inability to adapt and reintegrate into the habitat and ecosystems
- Space is limited in zoos and other facilities
- Animals may not breed successfully - due to captive stress or cannot find a compatible mate
Measures to help preserve species in the wild
- ban hunting
- create protected reserves
- provide breeding sites
- prevent habitat destruction
- monitoring of species e.g. with tagging
- feeding programmes
- educate tourists on not feeding wild animals and not dropping litter etc.
- promotion of ecotourism to generate money to help with preservation in case the population falls again
- create sperm and egg banks
Species richness def
The number of different species living in a habitat
Species evenness def
The relative abundance of a specific species in a habitat
Functions of different statistical tests
Chi-Squared:
- to see if results gathered during an observed experiment are what we expected to find
(Unpaired/Student) T-test:
- compare the means between two sets of data
Explain the difference between species richness and species evenness and why both measurements are needed to assess biodiversity.
(4 Marks)
- Species richness - number of species within a habitat
- Species evenness - abundance of each species within a habitat
- Both species richness and evenness are needed to reveal dominance of each species within the habitat
- high biodiversity associated with a species richness and high species evenness
Before any major development can take place, an Environmental Impact Assessment (EIA) needs to be carried out.
One such development is the proposed extension to the M27 motorway in Hampshire. This extension would cut through an important heathland ecosystem.
Suggest three aspects of this development that would need to be considered when carrying out the EIA.
(3 Marks)
Scientists have identified approximately 1.8 million different species. The number of species that actually exist is likely to be significantly higher than 1.8 million.
Suggest two reasons why the number of species identified is likely to be lower than the actual number of species present on Earth
Not all areas of world explored - some species not yet discovered
Some species microscopic/camouflaged - difficult to see with naked eye
Sampling may miss rare species
Methods of sampling animals
