4.2.1 - Biodiversity Flashcards
Define biodiversity
The variety of living organisms in a present area
What does biodiversity include ?
Plants, animals, fungi and other living things
How is biodiversity essential ?
It is essential in maintaining a balanced ecosystem for all organisms
Why do we rely on balanced ecosystems ?
They provide us with the food, oxygen and other materials we need to survive
Which regions have the most biodiversity ?
Tropical mois regions
Which regions have the least biodiversity ?
- Very cold areas such as the arctic
- Very dry areas such as deserts
How are the equator and biodiversity linked ?
As you get closer to the equator the more biodiversity there is
Why does measuring biodiversity play an important role ?
- It informs scientists of the species that are present, thus providing a baseline for the level of biodiversity in an area
- The effect of any changes to an environment can be measured
What are the three levels of biodiversity ?
- Habitat
- Species
- Genetic
What is habitat biodiversity?
The number of different habitats
What is the correlation between habitat biodiversity and species biodiversity ?
In general, the greater the habitat biodiversity, the greater the species biodiversity will be within that area
What is species biodiversity?
The number of species and the abundance of each species in a particular location
What is species richness ?
The number of different species living in an area
What is species evenness ?
A comparison of the numbers of individuals of each species living in a community
Define community
The community is all the populations of living organisms in a particular habitat
What is genetic biodiversity?
The total number of genetic characteristics in the genetic make-up of a species
What is an allele ?
A different version of a gene
What does an allele lead to ?
It can lead to genetic biodiversity within a species
What does greater genetic biodiversity allow ?
- Better adaptation to a changing environment
- More likely to result in individuals who are resistant to diseases
What is sampling ?
The process of collecting data in a suitable way
Why is sampling important?
- It means data is representative is as it can be
- It makes data collection more manageable
What can sampling be used to estimate ?
The number of organisms in an area without having to count them all
What does abundance refer to ?
The number of individuals of a species present in an area
What can sampling be used to measure ?
- A particular characteristic of an organism
- e.g. height
What is random sampling?
Each individual in the population has an equal likelihood of selection
What is non-random sampling?
An alternative sampling method where the sample is not chosen at random
How could an area be randomly sampled?
- A grid could be laid out using two tape measures
- A random number generator is used to generate a grid reference
- A quadrat is placed at the grid reference
- A sample is collected
What are the 3 main non-random sampling techniques?
- Opportunistic
- Stratified
- Systematic
What is opportunistic sampling?
Sampling which uses organisms conveniently available
What is stratified sampling?
- Some populations can be divided into distinct groups
- A random sample is then taken from each of these groups proportional to its size
What is systematic sampling?
Samples are taken at regular intervals
Why wont a sample be entirely representative ?
- There may be :
- Sampling bias
- Chance
Sampling bias
- The selection process may be biased
- The effects of sampling bias can be reduced using random sampling, where human involvement in choosing the sample is removed
Chance
- The organism selected may not be representative of the whole population
- The greater the number of individuals studied, the lower the probability that chance will influence the result.
- Therefore the larger the sample size, the more reliable the result
What is a frame quadrat?
- A frame quadrat consists of a square frame divided into a grid of equal sections
What is a point quadrat?
- A point quadrat consists of a frame containing a horizontal bar, pins can be pushed down at set intervals to reach the ground.
- The plant which the pin touches is what is recorded
What is a line transect?
A line is marked along the ground between two points and samples are taken at specified points
What is a belt transect?
Two parallel lines are marked and samples are taken of the area between the two lines
What is an interrupted belt transect?
A transect is marked out and frame quadrats are placed at regular intervals along the transect
When would systematic sampling be useful?
When studying how biodiversity changes along an area
When would random sampling be useful?
If the study is only looking at biodiversity in one area
Give 5 methods of sampling animals
- Using pooters
- Sweep nets
- Pitfall trap
- Tree beating
- Kick sampling
What kind of animals are sampled using a pooter?
Small insects
What kind of animals are sampled using sweep nets ?
Insects, particularly those that live in long grassland
What kind of animals are sampled using pitfall traps?
Small crawling invertebrates
What kind of animals are sampled using tree beating?
Invertebrates which live in trees/bushes
What kind of animals are sampled using kick sampling?
Animals which inhabit river beds
Describe how pooters can be used to sample animals
By sucking on a mouthpiece insects are drawn into the holding chamber
Describe how pitfall traps can be used to sample animals
- A hole is dug and insects fall in
- This is left overnight so nocturnal species are also sampled
Why must a pitfall trap have a roof structure?
To prevent the hole filling with rainwater
Describe how tree beating can be used to sample animals
- A large white cloth is stretched out under the tree
- The tree is then shaken/beaten
- Animals fall onto the sheet where they can be collected
Describe how kick sampling can be used to sample animals
- The riverbank and bed are kicked to disturb substrate
- A net is held downstream to capture organisms that have been disturbed
Give the 2 ways plants can be sampled
- Frame quadrats
- Point quadrats
Define biotic factor
The living components of an ecosystem
Give 3 ways frame quadrats can be used to sample plants
Frame quadrats can be used to generate data on:
- density
- % cover
- frequency
Why would a temperature probe linked to a data logger be advantageous over a thermometer?
- Rapid changes can be detected
- Human error in taking reading reduced
- High degree of precision can be achieved
- Data can be stored and tracked on a computer
What are the 2 ways of measuring biodiversity?
- Species richness
- Species evenness
What is species richness?
A measure of the number of different species living in an area
What is species evenness?
How close in number the populations of each species in an environment are
What information is required to determine species richness?
Total number of species present
What information is required to determine species evenness?
Number of each species in an area
How can population size of a plant population be estimated?
Through the use of frame quadrats to find density or frequency
How can the size of an animal population be determined?
Mark-release-recapture
Outline the process of mark-release-recapture
- Organisms are captured and marked with a non-toxic marking
- Time is allowed for organisms to redistribute
- The organisms are recaptured and the number of marked animals is compared to the number of unmarked animals
What is the relationship between biodiversity of an ecosystem and stability of the ecosystem ?
Greater the species diversity, the greater the stability of an ecosystem (usually)
What is the usual effect of pollution on biodiversity ?
Pollution usually reduces biodiversity
Why can low species diversity indicate pollution is present?
Pollution usually results in harsh conditions, so few species tend to dominate, and biodiversity is reduced
What is Simpson’s index of diversity?
A measurement of biodiversity which takes into account both species richness and species evenness
What is the range of values for Simpson’s biodiversity index?
Simpsons biodiversity index always results in a value between 0 and 1
What does a higher result of Simpson’s diversity index indicate?
- A more diverse habitat
- The higher the value of the Simpson’s diversity index, the more diverse the habitat
What are the features of an area with low biodiversity ?
- Relatively few successful species
- Stressful or extreme conditions
- Few species live in habitat and those which do have very specific adaptations
- Relatively simple food webs
- Change to whole ecosystem has major effects
What are the features of an area with high biodiversity?
- A large number of successful species
- Relatively benign/not stressful conditionsmany species live in the habitat
- Complex food webs
- Often relatively small effect on ecosystem if there is a change to ecosystem
Why do scientists calculate the genetic biodiversity of a population of a species ?
To monitor the health of the population and ensure its long term survival
What is the same between all members of the same species ?
They share the same genes
What are alleles ?
Alleles are different versions of the same gene
What does the difference in alleles among individuals bring about ?
It brings about genetic biodiversity within the species
What can you say there is when there are more alleles in a population ?
The population is more genetically biodiverse
What are species with greater biodiversity likely to do ?
- They are likely to be able to adapt to changes in their environment
- Less likely to become extinct
Why are more genetically biodiverse species less likely to go extinct ?
- They are likely to carry an advantageous allele, which enables them to survive in the altered conditions
- Therefore they are able to live, reproduce and their species is able to survive
What needs to happen for genetic biodiversity to increase ?
The number of possible alleles in a population must also increase
How can the allele population increase ?
- Mutations
- Interbreeding
How can mutations increase the allele population ?
They can create a new allele
How can interbreeding increase the allele population ?
- When an individual migrates from one population and breeds with a member of another population, alleles are transferred between the two populations
- This is known as gene flow
How can the allele population decrease ?
- Selective breeding
- Captive breeding programmes
- Artificial cloning
- Natural selection
- Genetic drift
- Genetic bottlenecks
- The founder effect
How can selective breeding decrease the allele population ?
Only few individuals within a population are selected for their advantageous characteristics and bred
How can captive breeding programmes decrease the allele population ?
Only a small number of captive individuals of a species are available for breeding
How can breeding rare breeds decrease the allele population ?
When only a small number of individuals of a breed remain and are available for breeding, these animals will have been selected for their specific breed traits. The genetic diversity of the remaining population will be low
How can artificial cloning decrease the allele population ?
Asexual reproduction reduces the gene pool
How can natural selection decrease the allele population ?
- As a result, species will evolve to contain primarily the alleles which code for advantageous characteristics
- Over time, alleles coding for less advantageous characteristics will be lost from the population
How can genetic bottlenecks decrease the allele population ?
- This is where few individuals within a population survive an event or change, in turn reducing their gene pool
- Only the alleles of the surviving members of the population are available to be passed onto the offspring
How can the founder effect decrease the allele population ?
- This is where a small number of individuals creates a new colony, geographically isolated from the original.
How can genetic drift decrease the allele population ?
- Due to the random nature of alleles being passed on from parents to their offspring, the frequency of occurrence of an allele will vary
- In some cases, the existence of a particular allele can disappear from a population altogether
What are polymorphic genes?
They have more than one allele
What are monomorphic genes ?
A single allele exists for this gene
What do monomorphic genes ensure ?
They ensure that the basic structure of individuals within a species remains consistent
What are loci ?
Position of the gene on a chromosome
What is the relationship between the proportion of polymorphic gene loci and biodiversity ?
The greater the proportion of polymorphic gene loci, the greater the genetic biodiversity within the population
Why do humans rely on biodiversity ?
- Materials we need to survive
- Food, wood and oxygen
How are humans disrupting the ecology of areas ?
- Deforestation
- Agriculture
- Climate change
Why is this disruption taking place ?
To create enough space for housing, industry and farming to support the increasing population
Define deforestation
The permanent removal of large areas of forest to provide wood for building and fuel, and to create space for roads, buildings and agriculture
Define monoculture
Planting an area with a single crop
How can deforestation occur naturally ?
A result of forest fires caused by lightning or extreme heat and dry weather
How can deforestation occur indirectly ?
- Acid rain, it can form as a result of pollutants being released into the atmosphere
How does deforestation affect biodiversity ?
- It reduces the number of trees present in an area
- If only a specific type of tree is felled, the species diversity decreases
- It reduces the number of animal species present in an area as it destroys their habitat. This in turn reduces the number of other animal species that are present, by reducing or removing their food source.
- Animals are forced to migrate to other areas to ensure their survival. This may result in the biodiversity of neighbouring areas increasing
Why do famers only grow/rear specific plants/animals ?
- They select the species based on characteristics that give a high yield
- This significantly decreases the biodiversity of an area
What techniques do farmers use in order to produce as many of that desired species as possible ?
- Deforestation
- Removal of hedgerows
- Pesticides
- Herbicides
Why do farmers partake in deforestation ?
To increase the area of land available for growing crops or rearing animals
Why do farmers remove hedgerows ?
- To enable them to use large machinery to help them plant, fertilise and harvest crops
- Frees up extra land for crop growing
How does removing hedgerows decrease biodiversity ?
It reduces the number of plant species present in an area and destroys the habitat of the animals
Why do farmers use pesticides ?
To kill pests that would eat the crops or live on the animals
How do pesticides reduce biodiversity ?
They reduce species diversity as it destroys the pest species and destroys the food source of other organisms
Why do farmers use herbicides ?
To kill weeds
Why are weeds destroyed ?
This is because they compete with the cultivated plants for light, minerals and water
How does using herbicides decrease biodiversity ?
Plant diversity is reduced by destroying weeds and animal diversity may also be reduced by the removal of an important food source
How does monoculture decrease biodiversity ?
- Only one species of the plant is present
- As relatively few animal species will be supported by only one type of plant, this results in low overall biodiversity
Define global warming
It refers to a rise in the earths mean surface temperature
What have increased CO2 levels led to ?
Trapping more thermal energy in the atmosphere
What could happen if global warming carries on ?
Biodiversity will be affected
How will biodiversity be affected if global warming continues ?
- Melting of the polar ice caps could lead to the extinction of the few plant and animal species living in these regions
- Rising sea levels and the thermal expansion of oceans could flood low lying land, reducing the available terrestrial habitats
- Saltwater would flow further up rivers, reducing the habitats of freshwater plants and animals living in the river and surrounding areas
- Some plant species may no be able to survive because of higher temperatures and lower rainfall, xerophytes would become more dominant
- Insect life cycles and populations will change as they adapt to climate change. Due to the fact that they are pollinators it could affect the lives of the plants it leaves behind, causing extinction
What happens if climate change is slow ?
- Species will have more time to adapt or to migrate to new areas.
- This will lead to a loss of native species but in turn other species may move unto the area, so biodiversity would not necessarily be lost
What are the 3 categories of reasons for maintaining biodiversity ?
- Ecological
- Aesthetic
- Economic
Give an ecological reason why biodiversity should be maintained
All organisms are interdependent on others for survival, removal of one species may have significant effect on others
Give 2 aesthetic reasons why biodiversity should be maintained
- Natural world provides inspiration for people
- Studies have shown that patients recover more quickly when supported by the natural environment
Give 4 economic reasons why biodiversity should be maintained
- Species with potential economic importance may become extinct before they are discovered
- Continuous monoculture depletes soil of nutrients and so makes the ecosystem more fragile
- Greater biodiversity means greater potential for the manufacture of different products in the future
- High biodiversity provides protection against abiotic stress factors and disease
Define keystone species
A species that plays a key role in maintaining the structure of an ecological community
Define invasive species
An organism that is not native to an area and has negative effects on the economy, environment, or health
Describe the role of marine conservation zones in maintaining biodiversity
- Vital in protecting species rich areas e.g. coral reefs
- Doesn’t prevent fisherman in the area
- Creates area of refuge within which populations can build and repopulate adjacent areas
What is a downside of marine conservation zones?
Large areas are required
How are seeds stored in a seed bank?
The seeds are dried and stored at -20 degrees
Why are seed banks used?
- Seeds stored so new plants may be grown in the future
- Stores seeds for reintroduction and research for breeding and genetic engineering in the future
Give a problem with seed banks
Not all seeds are still viable after being frozen
Give 4 examples of active management of wildlife reserves
- Controlled grazing
- Restricting human access
- Controlling poaching
- Culling/removal of invasive species
Give 2 examples of in situ conservation
- Marine nature reserves
- Land nature reserves
Give an advantage of in situ conservation
It enables a species to adapt continually to changing environmental conditions
Give 3 examples of ex situ conservation
- Seed banks
- Botanic gardens
- Captive breeding programmes§
Give a disadvantage of ex situ conservation
It is very expensive, more expensive than in situ conservation
What are captive breeding programmes?
Offspring of endangered species are bred in a human controlled environment
How do captive breeding programmes try to maintain genetic diversity?
- An international catalogue of individuals’ genealogical data is maintained
- Mating can be arranged to ensure genetic diversity is maximised
Why might some captively bred organisms not be able to be released into the wild?
- Loss of resistance to local diseases
- Learned behaviour
- Genetic make-up of captive animals can become so different to original population they cannot interbreed
- Natural habitat must be restored before populations are introduced
What does IUCN stand for?
International union for conservation of nature
What does the IUCN do?
- Assist in securing agreements between nations
- Publishes the red list showing status of threatened animals
What does CITES stand for?
Convention on international trade in endangered species
What does CITES do?
Regulates international trade of wild plants and animals and their products
What was the Rio convention?
A meeting between 172 nations about how to maintain biodiversity
Give 2 examples of agreements the Rio convention resulted in
- CBD
- UNCCD
What does CBD stand for?
Convention on biological diversity
What does UNCCD stand for?
United nations convention to combat desertification
Give an example of a UK based conservation scheme
Countryside stewardship scheme
Outline the countryside stewardship scheme
- Governmental payments offered to farmers to enhance and conserve the English landscape
- Restoring neglected land
- Local conservation schemes
