12. Biodiversity Flashcards
What is biodiversity?
A measure of all the different plant, animal, fungus and other microorganism species, the genes they contain and the ecosystem in which they live.
What is a habitat?
The place where individuals in a species live.
What is habitat biodiversity?
The range of habitats in which species live.
What is a species?
Consists of individual organisms that are very similar in appearance, anatomy, physiology and genetics.
What is species richness?
The number of different plant, animal or other species in a certain habitat.
Does not take into account the number of individuals in each species.
What is species evenness?
How even the population of each species is.
The more even the numbers, the more diverse the area.
It is harder to calculate than species richness, a quantitative survey needs to be carried out.
What is genetic biodiversity?
Variation between individuals belonging to the same species.
This ensures that individuals within a species are not identical.
What are the different types of sampling?
Random and non-random.
Non-random sampling can be opportunistic, stratified or systematic.
How is random sampling carried out?
Sample sites within the habitat are randomly selected.
How is opportunistic (non-random) sampling carried out?
When a researcher makes sampling decisions based on prior knowledge.
They may choose an area they know contains a particular species.
How is stratified (non-random) sampling carried out?
Dividing a habitat into areas which appear different and sampling each separately.
How is systematic (non-random) sampling carried out?
When samples are taken at fixed intervals across a habitat.
e.g. Using line and belt transects.
What are the advantages of random sampling?
Ensures that the data are not biased by selective sampling.
What are the advantages of opportunistic sampling?
Easier and quicker than random sampling.
What are the advantages of stratified sampling?
Ensures that all different areas of a habitat are sampled and species are not under-represented from missing certain areas.
What are the advantages of systematic sampling?
Useful when the habitat shows a clear gradient in some environmental factor such as getting drier further from a pond.
What are the disadvantages of random sampling?
May not cover all areas of the habitat equally, leaving some species out.
What are the disadvantages opportunistic sampling?
The data may be biased.
The researcher may be drawn to include a particularly interesting species, leading to an overestimate of its importance.
What are the disadvantages of stratified sampling?
May lead to over-representation of some areas in a sample
What are the disadvantages of systematic sampling?
Only species along the line or within the belt can be recorded, others may be missed out.
What is a quadrat and how is it used?
A square frame used to define the size of the sampling area.
It can be placed along a transect or randomly in the habitat and the plants inside are identified and counted.
Percentage cover can then be calculated as a measure of their abundance.
What is a transect and how is it used?
A line stretched across the habitat along which samples are taken.
What are the different methods of catching invertebrates?
sweep netting, putting a sheet under a tree and shake the branch, a pitfall trap, a light trap for flying insects at night
How do you calculate the population of a species of small animals within a habitat?
Using Capture and Recapture.
Capture a sample of animals and mark them (the number captured will be C1).
Release the marked animals but leave the traps out.
The number captured on the second occasion will be C2 and the number of individuals already marked will be C3.
Calculate the total population using the formula…
(C1 x C2) ÷ C3
What factors can impact the calculation of a population when using capture recapture?
The estimate may be affected by animals who learn that the trap is harmless and contains food, or animals that don’t like the experience and keep away from the traps.
What is the Simpson’s index of diversity?
A measure of the diversity of a habitat. It takes into account species richness and evenness.
What is the formula for Simpson’s index of diversity?
D= 1- (Σ(n/N)^2) n= the number of individuals in one species. N= total number of individuals of all species.
What do you do with the Simpson’s index formula?
Do n/N for each species then square the result.
Add up all the results for each species.
Minus the final result from 1.
How do you interpret the result from the Simpson’s index?
A high value indicates a diverse habitat.
A low value indicates a habitat dominated by few species (low diversity).
What impact does a low and high diversity have on a habitat?
A high diversity means a small change to the environment may affect one species. But this is only a small percentage of the overall population so the impact is small.
The habitat is more stable.
Small changes to the environment in a non-diverse habitat could destroy the whole habitat.
How do you calculate genetic diversity?
If a species has 10,000 genes, if 2000 have more than one allele then genetic diversity would be
(2000/10,000) x 100% = 20%
You can also look at the observable features of the individuals.
A particular feature can show variation between species.
Where is genetic diversity found?
When there is more than one allele for a particular locus.
This means there will be more genetic differences between the gametes produced by individuals.
What is a locus?
The position of a particular gene on a chromosome.
What human processes impact other species?
Agriculture and Climate change
Both can lead to the extinction of species.
What impact does agriculture have?
Natural vegetation is cleared.
The size of both the habitats, the population and genetic diversity of any wild species in that habitat are reduced.
This means that the species has less capacity to adapt to changing conditions through evolution.
What is monoculture?
A crop consisting of one strain of one species. It has very limited genetic diversity. This makes the product easier to harvest.
e.g. The oil palm which is grown for palm oil.
What is the impact of monoculture?
Areas such as rainforests with a huge natural biodiversity get destroyed and replaced by large areas of a single strain of one species.
Genetic diversity is also reduced as farmers usually prioritise rapid growth etc. over other characteristics which are ignored.
What is genetic erosion?
Loss of genetic diversity of a species.
How does climate change impact species?
As the climate changes, species are less able to adapt to the changes in temperature and weather. Therefore, species often migrate nearer the poles. Domesticated species (selectively bred to provide the best yield in certain conditions) have less genetic diversity so are unable to adapt and are vulnerable to disease.
What is extinction?
Occurs when the last living member of a species dies and the species ceases to exist.
What are the main reasons to maintain biodiversity?
Aesthetic reasons, economic benefits, food from plants and animals, medical resource, Interdependence of organisms and Genetic resource
What is interdependence of organisms?
All organisms within a habitat are linked together in a food chain or food web.
The range of relationships includes predator-prey, intra- and inter-species competition and parasitic and mutualistic relationships.
What is a keystone species?
One that has a disproportionate effect upon its environment relative to its abundance.
They can be plants or animals.
How are wild animals and plants a genetic resource?
Organisms adapt to overcome the problems presented by the environment, pests and disease.
Selective breeding may be able to produce crop varieties that can cope with new conditions created by climate change.
New medicines can be found in plants, animals, fungi and bacteria.
What are the economic reasons to maintain biodiversity?
Ecosystems perform processes that impact on food production…
recycling of nutrients
crop pollination
formation and fertilisation of soil
purification and retention of fresh water
What is soil depletion?
Crops take minerals out of the soil.
When the crop is harvested these minerals are removed from the ecosystem.
A monoculture takes all the same minerals, so soil depletion occurs more quickly.
If these minerals are not replaced, the soil is no longer fertile and plants can no longer grow.
What is in situ conservation?
Conservation of a species in their natural habitat
What are the different methods of in situ conservation?
legislation, wildlife reserves, repopulation
What is legislation?
Legislation can be passed to stop activities such as hunting, logging, and clearing land for agriculture.
What are wildlife reserves?
Designated areas for the conservation of habitats and species
Choosing wildlife reserves must take into account…
Comprehensiveness (how many species are within the area)
Adequacy (an area large enough to provide long-term survival)
Representativeness (A full range of diversity within each species)
Must also take into account the lives and rituals of the indigenous people
What are marine conservation zones?
Areas of the sea set aside to conserve the diversity of species and habitats
What are the advantages of in situ conservation?
Organisms protected in their natural environment.
Allows management of these areas to ensure the ecological integrity is maintained.
It facilitates scientific research.
What are the disadvantages of in situ conservation?
Endangered habitats may be fragmented and each small area may not be large enough to ensure survival.
The population may already have lost much of its genetic diversity.
The conditions that caused the habitat or species to become endangered may still be present.
The areas are perfect hunting grounds for poachers and attract tourists that cause a disturbance.
What is repopulation?
When areas that have lost their biodiversity are rebuilt.
What is ex situ conservation?
The conservation of an endangered species outside of its normal habitat.
What are the different methods of ex situ conservation?
Zoos, Botanic gardens, Seed banks
How do zoos help towards conservation?
Many concentrate on captive breeding, breeding endangered species and conducting research to protect them.
Modern technology such as freezing sperm, eggs or embryos allows them to carry out artificial insemination, in vitro fertilisation and embryo transfer.
How do botanic gardens help towards conservation?
Seeds are produced in large numbers by plants and collected without disturbing the ecosystem.
These seeds are stored and germinated in protected surroundings and are bred asexually.
The number of plants increase rapidly and are returned to the wild.
How do seed banks help towards conservation?
They collect seed samples of endangered plants.
The seeds remain viable for decades and are used for repopulation, production of disease resistant crops for agriculture etc.
What are the advantages of ex situ conservation?
Organisms are protected from predation and poaching, The health of organisms can be monitored and medically assisted, Genetic diversity of the population can be measured, Selective breeding can be used to increase genetic diversity, Conservation sites can be used for education and research.
What are the disadvantages of ex situ conservation?
A captive population has limited diversity, Disease can spread quickly amongst the population, The organisms are not in their natural habitat, It may be expensive, The organisms may find it hard to re-integrate into their natural environment.
What is CITES?
The Convention on International Trade in Endangered Species
What does CITES aim to do?
Regulate and monitor international trade in plants and animals, Ensure international trade does not endanger species in the wild, Ensure that trade in wild plants for commercial purposes is prohibited.
