4.2.1 Biodiversity Flashcards
Define biodiversity
measure of variation found in the living world
Define habitat biodiversity
range of habitats in which diff species live (sand dunes, woodland, meadow, streams)
Define species biodiversity
range of organisms found in a habitat (species richness and evenness)
What is species richness and species evenness?
richness: no. of species
evenness: no. of individuals in each species/the degree to which theyre represented.
Define genetic biodiversity
variation between individuals belonging to the same species -> breeds / number of different alleles in a population
Why is sampling important?
Impossible to count all fungi, bacteria and other single-celled organisms for example. So must SAMPLE -> select a small portion and then scale up
What is random sampling? State its advantages and disadvantages
randomly generating numbers as coordinates, or from a map
- ensures data aren’t biased
-low presence species might be missed = underestimate
- might not cover all areas equally
What is opportunistic sampling? State its advantages and disadvantages
- decisions based on prior knowledge - deliberate due to containing a species
- easier and quicker
-may be biased
-may be an overestimate due to large and colourful species
What is stratified sampling? State its advantages and disadvantages
- dividing a habitat into diff areas and sampling each separately
- ensures species aren’t under-represented and that all areas are sampled
- may lead to over-representation
What is systematic sampling? State its advantages and disadvantages
- samples taken at fixed intervals using line and belt transects
- useful when habitat shows a clear change in an environmental factor
- species may be missed if not on line = underestimate
Explain how you use a quadrat
used to define size of sample area
generate random numbers as coords and place it there. Identify plants found.
estimation: some have grid which make them more accurate since percentage cover can be estimated
point frame: no. of long needles, lower it into quadrat and record any plants touching. best to use it at regular intervals. use no.of readings etc to calculate a %.
Explain how to use a transect. What is an interrupted vs continuous belt transect?
- line taken across habitat, especially large ones
- can be line (just tape) or belt (with quadrats)
interrupted: at intervals
continuous: move quadrat along the line to study in detail - no gaps
Why is it hard to sample animals by observation?
animals hide and often move too quickly
What is involved in careful observation?
footprints, DNA sequencing of droppings, burrows, damage to trees -> can estimate population sizes
What is capture recapture?
LONGWORTH TRAP
1. Capture a sample and mark each individual (C1)
2. Release them and leave traps for a period of time
3. Number captured on 2nd occasion = C2
4. Number of already marked that are captured = C3
TOTAL POPULATION = C1 x C2 / C3
Why is capture and recapture sometimes inaccurate?
some know it contains food, some know it’s harmless, or some might stay away
How are birds and larger mammals kept track of?
birds: ringing
larger mammals tagged
What is Simpsons index of diversity? What does a high and low value indicate?
measure of diversity of a habitat -> takes into account species richness and evenness
high: diverse. tends to be stable and able to withstand environmental changes
low: habitat dominated by a few species, less stable
How do you calculate genetic diversity in small, isolated populations?
- Genetic diversity is found when there is more than one allele for a particular locus (position of a gene on a chromosome)
- Genetic diversity = proportion of polymorphic gene loci (more than 2 allele) = no.of polymophic loci / total no. of loci
Explain how human population growth affects biodiversity
alter ecosystems to get food, clearing land for agriculture or building, deforestation, pollution, using more resources , destroy and fragment habitats
leads to EXTINCTION - no more living members of a species. many believe we are at start of mass extinction
Explain how agriculture affects biodiversity
- clear vegetation = decreases habitat size and reduces genetic diversity
- reliance on monoculture -> one strain of species -> and selective breeding = decreasing genetic diversity
selecting for specific breeds means others may die out = genetic erosion
What is genetic erosion?
limited gene pool of an endangered species diminishes even more
Explain how climate change affects biodiversity
- species less able to adapt as climate changes
- extreme weather causes habitat destruction
- barriers to migration (agricultural land, mountain ranges, water)
- domesticated plants and animals very at risk due to little variation -> less food available
Explain the ecological reasons to maintain biodiversity
- Interdependence: due to food chains, an effect on one species will affect other species.
- Keystone species: disproportionate effect upon its environment relative to its abundance, many species rely on them e.g. predators that limit herbivores, plants, beavers (dams causes water flooding where species can live, water slows = good for aquatic; felled trees allow light to reach ground)
- Maintaining genetic resource: may be able to breed new crop varieties that can cope with climate change, and use plants and microorganisms for new medicines ; huge potential in wide range of extant species
Explain the economic reasons to maintain biodiversity
Food production:
Reducing soil depletion due to stopping monocultures = allows fertility and yields to increase
Biodiversity contributes to water purification, timber growth, recycling of nutrients, crop pollination, etc that food production relies on
Explain the aesthetic reasons to maintain biodiversity
- physical and emotional health
- forests protect soils from erosion, trees take up water
- protecting landscape for beautiful environments, e.g. by stopping soil exposure and severe flooding caused by deforestation
What is conservation in situ?
management to maintain biodiversity in the natural environment
What are wildlife reserves? What is the conflict?
- designated areas established for conservation of habitats and species
- animals raiding crops, poaching, tourists feeding/ littering
What are marine conservation zones?
Conserve biodiversity of nationally rare, endangered and representative habitats in our seas
What are other in situ methods?
National Parks (protected UK countryside), national nature reserves (protect sensitive features of environment) and local ones, SSSI’s (country’s best wildlife)
What is repopulation?
Reintroducing a species once their habitat is suitable
What are the advantages of in situ? (4)
Conservation in natural environment
Protect significant elements of natural and cultural heritage
Provide opportunities for sustainable land usage
Facilitates scientific research
What are the disadvantages of in situ? (4)
Habitats may become fragmented
Genetic diversity may be lost already
Harmful conditions might be present still
Might attract poachers and ecotourists who cause disturbance
What is conservation ex-situ?
management outside normal habitat of species
What takes place in zoos?
Captive breeding -> breeding endangered species and conducting research
Artificial insemination, in vitro fertilisation and embryo transfer with wild animals
Some carry out research on domestic species SIMILAR to target ones to avoid experimental research on endangered species
What are the advantages of zoos? (6)
protected from predation and poaching
genetic diversity can be measured
increased success of breeding due to reproductive tech
research made easier
education
attractions to raise funds
disadvantages of zoos? (5)
limited genetic diversity
exposed to diseases
abnormal behaviour
correct environmental conditions might be hard to achieve
difficulties when reintroducing to the wild
What are botanic gardens for?
Dormant plants = seeds.
Large numbers collected from wild, stored and germinated in protected surroundings
Huge numbers in little space
Often bred asexually
Individuals can be replanted in the wild
What are the problems with botanic gardens? (4)
Difficult to fund
Samples may not have representative levels of genetic diversity
Seeds may not be viable
Decreases genetic diversity due to asexual breeding
What are seed banks for? How are seeds stored?
Seeds that remain viable for decades. Provide them for crops, building materials and disease-resistant crops for agriculture. repopulation of endangered species + habitat reclamation
Storage: very dry and freezing conditions as they’re resistant to desiccation. tested at regular intervals to check their viability
What are the aims of CITES?
Convention on International Trade of Endangered Species of Wild Fauna and Flora = international
Overall: Ensure international trade of specimens does not threaten their survival in the wild
- ensure trade in wild plants for commercial purposes is inhibited
- restrict trade of endangered species
What are the aims of the Rio Convention on Biological Diversity?
- International
- promoting sustainable development
- conservation of diversity
- sustainable use of its components
-appropriate shared access to genetic resources - appropriate sharing of knowledge and tech
states partner states must adopt ex situ facilities to complement in situ measures
What were the aims of the Countryside Stewardship Scheme? What is it called now and what are its current aims?
- improve natural beauty of countryside, restore targeted landscapes, and improve public access. all at a local level
- Environmental Stewardship Scheme
- provides funding to farmers in England to deliver effective environmental management on their land
- help land managers to conserve and promote countryside by looking after wildlife, protecting natural resources, providing opportunities for learning
What’s sweep netting
Sweep netting: through vegetation, (suitable for low, can be used in water) empty onto white sheet. A POOTER uses straw to ensure insects dont fly away
Describe pitfall traps
Pitfall traps: in soil. any animals in plants/leaf litter will fall into container. Add water/scrunched paper to avoid them climbing up. Must be sheltered
Describe tullgren funnels
Tullgren funnel: light above drives animals downwards as it warms up -> fall through mesh and collected
Describe light traps
light trap: flying insects at night e.g. moths attracted to it and fall into collecting vessel with alcohol underneath
The Madidi National Park, in the South American rainforest, is home to a wide variety of species.
The largest predator in the area is the jaguar. These large cats are well camouflaged and hunt
mostly at night. A single individual can cover a very large area.
(a) In 2007 the Wildlife Conservation Society (WCS) attempted to estimate the population of
jaguars in the Madidi National Park.
* Digital camera traps were placed in areas that jaguars were likely to visit.
* If an infrared beam was broken by an animal, the camera was activated.
* The camera then took a photograph of the animal.
(i) Suggest why it was not appropriate to estimate the number of jaguars using the
capture-recapture technique. (2)
estimate will be inaccurate (because of low numbers)
dangerous (for collector or jaguar)
Most studies estimate the population density of jaguars in the South American rainforest
to be 5 individuals per 100km2.
In the 2007 study:
* 100 camera traps were set up covering an area of 271km2.
* 28 images of 9 different jaguars were recorded.
How well do these results support a population estimate of 5 individuals per 100km2? (4)
appropriate calculation of , observed / expected , population density
lower than estimate
so does not support
low / unknown , repeatability / reproducibility
(some) support because , figure / 3 , is close to estimate / 5
some individuals not photographed
idea that if many individuals not trapped population could be higher than estimate
