Biology Paper 2 - 4.2 Biodiversity

A measure of variation found in the living world.

Where an organism lives.

A group of organisms that can breed together to produce fertile offspring. They share similar physical characteristics, anatomy, biochemistry and genetics.

The number of species and abundance of each species that live in a particular location.

The number of different species found in a habitat.

The degree to which each species is represented. If each species is found in similar numbers biodiversity is even. If each species is found in differing numbers it is uneven.

The number of individuals of a species.

The variation within individuals of the same species. Genetic variation accounts for the differences within species - why we don’t all look the same. Genetic variation creates breeds within species e.g. spaniels and labradors.

Random: select habitat at random using randomly generated coordinates. Removes bias from data collected but may not be representative - rare/infrequent species may be missed, so biodiversity may be underestimated.
Non-random opportunistic: habitat chosen deliberately. Quicker - no random coordinates needed but can lead to bias, so biodiversity may be underestimated or overestimated.
Non-random stratified: habitat divided into areas and sampled separately. Sampling within areas may be random. Ensures all habitats of interest are sampled but areas of differing sizes may be under/over sampled.
Non-random systematic: samples taken at fixed intervals across habitats, sampling for change over distance, e.g. from shore to dunes. Shows change in biodiversity with change in conditions but only species along belt transect recorded.

By individual numbers of each species
Percentage cover.
Abundance using the ACFOR scale - Abundant, Common, Frequent, Occasional, Rare.

Grid area and randomly select area to be sampled.
Set up grid using tape measures at right angles.
Generate random coordinates using a random number generator.
Place left hand corner of quadrat at coordinate.
Record the number of individuals of each species in the quadrat, use 50% rule.
Repeat multiple times so that 1% of area is covered.
Percentage cover can be used for frame quadrats when frequency is hard to measure.

Misidentification of plant species - use a key to reduce error.
50% in rule is subjective - may lead to under/over estimation.
% cover count is subjective - may lead to under/over estimation.
Can be difficult placing quadrat in rough terrain - could use point frame quadrat.
Placing of quadrat at coordinate may be inaccurate - grid area within sample area or use GPS.

Decide on area to be sampled using research/prior knowledge - this depends on factor being investigated, e.g. shade to light in a woodland.
Place tape to span area of interest.
Line transect - count plants touching tape.
Belt transect - use left hand rule to place quadrat on tape. Continuous belt transect - move quadrat along tape. Interrupted belt transect - place quadrat at determined intervals along tape e.g. every 1m.

Only plants along line counted.
May be biased.
Misidentification of plant species - use a key to reduce error.
50% in rule is subjective - may lead to under/over estimation.
% cover count is subjective - may lead to under/over estimation.
Can be difficult placing quadrat in rough terrain - could use point frame quadrat.

Sweep net - move net with figure of eight motion, tip net contents onto white sheet for identification. +: catch small invertebrates hidden in long plants; catch flying insects. -: disturbance causes invertebrates to fly/flee misidentification.
Pooter - place tube over invertebrate, suck through second tube, drawing invertebrate into chamber. +: individual collection of organism. -: limited to size of tube.
Tree knocking - place white sheet under tree and knock firmly, invertebrates fall onto sheet. +: can collect samples from areas that are not suitable for net. -: invertebrates by fly/jump off/hold on; care with damage to trees.
Pitfall trap - dig hole in ground and place collecting cup in hole; may contain water to prevent insects crawling out; cover to prevent flooding. +: traps can be set and left to collect data over time. -: chance if organism falls in; organisms may prey on one another; organism may drown in water.
Tullgren funnel - place soil sample in funnel, switch on lamp, invertebrates move away from heat and light and fall into collecting cup; may contain ethanol to kill samples. +: can collect difficult to find invertebbrates. -: inhumane killing samples.

A known number of individuals are captured, marked and released, C1.
Appropriate method of marking is used so that it doesn’t harm the organism.
A second random known number of individuals are captured, C2.
The number of marked individuals recaptured, C3, is recorded and then they are released.
Population size can then be calculated from this data using the formula: Total population = (C1x C2)/ C3.

Marking not removed.
No immigration/emigration.
Sufficient time for marked individuals to mix with the population.
No births/deaths.
Sampling method is the same for each collection.

Random samples – no bias involved.

Larger sample size.

Larger sample area.

Smaller quadrat when sampling plants.

Same technique in each habitat.

Random number generator generating coordinates for quadrat placement.

Control/note abiotic variables.

Different version of a gene.

The position along a chromosome at which a gene is located.

A locus that has more than two alleles.

Species richness and species evenness.

D= 1 - [ ∑(n/N)2 where n = number of individuals of a species and N is the total number of the population (all the n’s added together).
The diversity of a habitat.
Takes account of species richness and evenness.
A high index value (closer to 1) is more diverse than a low index value.
The richer and more even a habitat, the more stable it is.

More habitats for organisms to live in.
More food sources.
More breeding sites.
More inter and intraspecific interactions.

Increase in naturally occurring mutations may confer selection pressure.
Protects individuals from disease/death, e.g. Ash dieback - all trees genetically identical so no natural immunity to fungus.

Count number of loci of interest - this is number of individuals in population x2 (because each individual has two alleles for each gene).
Count number of heterozygotes in population (heterozygotes have two different alleles at a locus and so are more genetically diverse than homozygotes who have the same allele).
Genetic diversity = Number of heterozygous loci/total number of loci in population.
The closer the value to 100%, the greater the genetic diversity.

Count population and multiply by number of loci of interest.
Count number of individual heterozygous for each allele.
Calculate mean of heterozygous population.
Divide by total allele population.

Significant and long lasting changes in weather patterns - do not refer to global warming!

A crop consisting of one strain of a species, e.g. palm oil trees.

Agriculture - farming to produce more food.
Destruction and fragmentation of habitats - farming, housing, road networks, logging.
Overuse of Earth’s resources - water, minerals, fossil fuels.
Pollution.
Overpopulation.

Habitat destruction for farming, logging etc. Reduction in biodiversity - fewer habitats, fewer food sources, fewer inter-/intraspecies interactions.
Monocultures - large scale plating of single crop. Reduction in biodiversity. Reduction in genetic diversity, reduction in naturally occurring resistance to pests and disease, increased susceptibility to disease e.g. Ash dieback.
Selective breeding. Reduction in biodiversity. Reduction in genetic diversity, reduction in naturally occurring resistance to pests and disease. Leads to genetic erosion.

Species are less able to adapt to changes in climate -
remember that individuals that already carry a favourable adaptation survive; it is NOT the change that causes the adaptation.
Inbreeding leads to further loss of genetic diversity.
Natural resistance to disease is lost; susceptibility to disease is increased.
Reduction in biodiversity.
Loss of different habitats.
Loss of food sources.

Increase/decrease in rainfall.
Increase/decrease in temperature.
Increase in violent climatic events e.g. flooding, hurricanes.
Mobile species unable to adapt are forced to migrate away from changing ecosystems - sooner or later they will run out of space to move.

Major human developments and infrastructures.
Agricultural land.
Large bodies of water- reservoirs, dams.

One that has a disproportionate effect upon its environment despite its abundance e.g. wolves of Yellowstone Park.

Loss of soil fertility.

| Caused by removal of minerals by continuous cropping.

Complex natural ecosystems take millions of years to evolve.
Intra species interaction occur within species e.g. blue tits compete for nesting sites in a tree.
Interspecific interaction occur between species e.g. cheetahs hunt antelopes.
If these interactions are disturbed, food webs are altered and may collapse.
Biodiversity is reduced. Habitats become unstable. Extinction occurs.

Keystone species may be a predator and limit populations of prey, e.g. sea otter and anemones.
Keystone species may be a plant eg sugar maple tree has deep roots, stabilise soil and prevent soil erosion.
Loss of keystone alters habitats, allows other species to predominate, food webs altered.
Or food webs collapse and species may become extinct.

Decline of genetic diversity.

Plants, fungi or animals that may hold solutions to problems are lost e.g. medicinal uses.
Species less able to withstand climate change are reduced in abundance or become extinct.
Reduction in gene pool reduces genomes available for beneficial genetic modification/cross breeding/ selective breeding.

Contributes to many natural cycles that cannot be done by Man. Regulation of atmosphere and climate. Nutrient recycling- carbon and nitrogen cycles. Detoxification and purification of wastes - plants used to collate waste chemical spills, toxins removed when plants removed. Formation and fertilization of soils.
Crop pollination.
Crops such as timber, food and fuel.
Molecules as potential medicines.
Maintenance of landscapes and ecosystems.
Reduction in erosion, flooding etc.
And because we like it - chlorophyllia. Tourism. Recovery - mental and physical. Reduction in stress.

Species are at risk of becoming extinct because their population has fallen so low that the numbers are at a critical level for continued survival.

Poaching. Their habitat is being destroyed.

Protecting species in their natural habitat.

Establishing protected areas such as national parks & wildlife reserves.
Marine conservation zones - where fishing is controlled.
Controlling or preventing the introduction of species that threaten local biodiversity.
Legal protection to endangered species.

Both species & habitat are conserved.
Large populations can be protected.
Less disruptive than removing organisms from their habitats.

Some factors that are threatening a species may be difficult to control, such as poaching, predators, disease or climate change.

Protecting species by removing part of the population from a threatened habitat.

Relocating organisms to a safer place - free from poachers.
Breeding organisms in captivity then reintroducing them to the wild.
Botanic gardens grow a rare plants and reintroduce them into suitable habitats.
Seed banks provide a useful store of seeds if natural reserves are destroyed.

Can protect individual animals in a controlled environment - predation & hunting can be managed more easily.
Can be used to reintroduce species to an area.

Small numbers of individuals cared for.
Difficult & expensive to create & sustain the right environment.
Animals that are habituated to human contact may be less likely to exhibit natural behaviour & may catch a human disease.
Many species cannot breed successfully in captivity.

Convention on International Trade in Endangered Species.

Regulate trade in endangered species.
Allow trade of less endangered species.
Ensure that trade does not endanger wild populations.
Prohibit trade in wild plants.
Allow trade in artificially propagated plants.

Permits to hunt are only issued to certain people.

| Different countries cooperate to deal with poachers and illegal trade.

(Rio) Convention on Biological Diversity.

Sustainable use of ecosystems.
Promote ex situ conservation methods.
Share access to scientific knowledge relating to biodiversity & share genetic resources.
Raise the profile of biodiversity to governments & encourage international c

The Country Stewardship Scheme (CSS).

Pay landowners to use regenerate hedgerows & grow wildflowers around the edges of fields to increase species habitats and food sources.

Reduce soil erosion.
Attract beneficial insects and reduce pests.
Increase plant diversity.
Provide habitat.

Selective breeding reduces genetic diversity & results the whole crop/herd to an outbreak of disease.
A wild plant could have resistance to this disease.
If the wild plant was bred with the crop plant, some of the offspring may have the good characteristics of both plants.
These would then be selected and bred from again so that new stocks of plants can be built up.