4.2.1 Biodiversity Flashcards
What is biodiversity?
The variety of living organisms present in a certain area
What is habitat biodiversity?
Refers to the number of different habitats in an area. The greater the habitat biodiversity, the greater the general biodiversity
What is species biodiversity?
Refers to the number of different species present in an area.
Species evenness - the proportion of each of the different species within the area
Species richness - the abundance of different species in the area
What is genetic biodiversity?
Refers to the number of alleles within the population gene pool. High genetic biodiversity allows for greater variation & adaptation to a changing environment
Describe sampling techniques for plants.
- Frame quadrat - divide area into grid of particular size (quadrats), record amount of organisms in each quadrat
- Point quadrat - horizontal bar with pins stuck through at set intervals, record organisms that touch the pin
Describe sampling techniques for animals.
- Pooter
- Sweeping net
- Pitfall trap
- Capture-Mark-Release-Recapture (greater number of organisms at recapture without marks, the greater the population size)
- Tree beating - white cloth under tree, tree beaten to dislodge organisms
State and describe non-random sampling techniques.
- Opportunistic: organisms that are readily available are tested - not representative, convenient and quick
- Stratified: organisms split into groups based on characteristics then random sample taken of groups in relation to their size - time-consuming, but does do even coverage of area
- Systematic: samples taken at fixed intervals along the habitat - line transect: count organisms that touch the line, belt transect: two parallel lines marked, sample are between the lines - can miss out species
Why is it important to sample a range of organisms in a habitat?
So you can use the data to generalise to the whole population so you don’t have to analyse each organism in the habitat.
What are the three different ways of using quadrats?
Measure density: count number of visual plants in 1x1m quadrat for density per square metre - absolute measure
Measure frequency: count the number of squares a particular organism is in to find % occurrence
Measure percentage cover: estimate by eye the abundance of an organism in an area - used for speed
Why is Simpson’s Index of Biodiversity a better measure of biodiversity?
It takes into account both species evenness and species richness
What do low and high biodiversity index values tell us about the habitat?
Low biodiversity - UNSTABLE, few successful species, large effect from change in environment, very specific adaptations to their environment, few ecological niches
High biodiversity - STABLE, many successful species, more ecological niches, small effect from change in environment, few specific adaptations to environment
How do you calculate genetic biodiversity?
proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci
State and describe factors that increase genetic biodiversity.
- Mutations in DNA - different proteins synthesised
2. Interbreeding - individual migrates and breeds with another population, alleles are transferred (gene flow)
State and describe factors that decrease genetic biodiversity.
- Selective breeding/Artificial selection - few individuals selected due to desirable characteristics
- Captive breeding programmes - small number of individuals available for breeding, reduces allele variation
- Natural selection - those with advantageous characteristic out compete others, reduces variation
- Genetic drift - frequency occurrence of an allele decreases until it complete disappears from the population
- Founder effect - small number of individuals create colony isolated from original population - small gene pool
- Genetic bottleneck - only few individuals survive event - reduces gene pool
Explain agricultural factors that decrease biodiversity.
- Selection of species based on characteristics that give a high yield
- Deforestation
- Removal of hedgerows - support large diversity of species, are natural windbreakers - soil could be blown away if removed
- Chemicals - pesticides and insecticides
- Monoculture - only one species dedicated to an area
Explain the effect of global warming on biodiversity.
- Melting of polar caps - extinction of the species
- Rising sea-levels flood low land - reduce available habitats
- High temps and rainfall - non-xerophytes can’t survive, organisms that feed on them die
- Insect life cycles/populations change to adapt - affect organisms that rely on insects
How has the climate changed over the years?
- Warming trend in 50yrs twice that for previous 100yrs
- Average temp of ocean has increased since 1961 - seawater expanding, sea-level rising
- Fluctuations in the Earth’s surface temp
- CO2 levels significantly increased since industrial revolution
- Average amount of water vapour in atmosphere has increased significantly
State aesthetic reasons to maintain biodiversity.
- Humans feel joy from nature - inspires creativity
2. Studies show exposure to natural environments help patients recover quickly
State economic reasons to maintain biodiversity.
- Deforestation causes soil erosion - reduces crops to feed people
- Species with potential economic benefit may become extinct before discovery
- Continuous monoculture causes soil depletion (reduction in nutrient diversity) - weaker crops, dependent on chemicals
- Highly bio-diverse areas are more attractive for tourism
- Greater potential for manufacturing different products in the future
State ecological reasons to maintain biodiversity.
- Organisms are interdependent of each other (rely on each other) e.g. plants and bees
- Keystone species - have a dis-proportionally large effect on environment relative to their abundance, affect many organisms
State human activities that aim to maintain biodiversity,
Human intervention in creating a habitat manages ecosystems e.g. hedge planting, grazing. Without this, some species would begin to dominate within the area, lowering the biodiversity
Describe marine conservation zones as an ‘in situ’ method of maintaining biodiversity.
Marine conservation zones: vital for protecting areas rich in a species from unsustainable fishing. Creates refuge for population to build up for sustainable fishing - invasive species removed. Requires a large area
Describe captive breeding/zoos as an ‘ex situ’ method of maintaining biodiversity.
Zoos: endangered species bred to stable population size and released into natural habitat, suitable breeding partners/semen can be from other zoos. Difficult to maintain genetic biodiversity - few breeding partners, keep genetic record for individuals to ensure mating with greatest diversity. Organism may not be suitable for release if: lost resistance to disease, complacent behaviour, genetic divide, or an unsustainable habitat.
What is succession?
When a species is replaced over time until a stable population is achieved
What are reasons for unsuitable release to the wild?
- Disease - either loss of resistance or they haven’t developed resistance yet
- Behaviour - organisms could become complacent e.g don’t search for food
- Genetic races - genes could veer so far from original population that they can’t interbreed anymore
- Habitat - may not be large enough to support all - lead to tension over resources
What did the countryside stewardship scheme do?
Offered government payments to farmers and land managers to conserve English land to: sustain beauty and diversity, extend and create wildlife habitats, restore neglected land
What was agreed at CITES (Convention of International Trade in Endangered Species)?
Aimed to regulate trading with select species and encourage trade that doesn’t endanger species - resulted in more than 35,000 species being protected
What do the International Union for the conservation of nature (IUCN) do?
Publish ‘Red List’ of endangered species every year
What was agreed at the United Nations Framework convention on climate change (UNFCCC)?
Stabilise greenhouse gas concentrations
What was agreed at the United Nations convention to combat desertification (UNCCD)?
Prevent transformation of fertile land into desert and reduce drought effects
What are the aims of an Environmental Impact Assessment (EIA)?
- Avoid intense impact
- Help developers to develop their proposals to be more environmentally friendly
- Ensure local authorities are aware of potential environmental threats
Describe seed banks as an ‘ex situ’ method of maintaining biodiversity.
Seed bank: most temperate and tropical seeds stored this way, back-up if wild plants become extinct. Seeds dried and stored at -20c - slows rate of loss of ability to germinate. Some seeds die when dried/frozen - tropical rainforest trees
Describe botanic gardens as an ‘ex situ’ method of maintaining biodiversity.
Botanic gardens: provide best resources for growth (nutrients, watering, removal of pests). Many wild species are unrepresented within gardens (very low %) - could be potential genetic resources
Describe wildlife reserves as an ‘in situ’ method of maintaining biodiversity.
Wildlife reserves: actively managed through controlled grazing, restricted human access, removal of invasive species, and halting succession (through controlled grazing)
What was agreed at The Rio Convention on Biological Diversity (CBD)?
Three main goals: 1) protect biodiversity
2) use biodiversity without destruction
3) share benefits from genetic diversity equally
Lead to UNCCD and UNFCCC
