4.2 Biodiversity Flashcards
what is biodiversity
the variety of living organisms in an area
what is species
a group of similar organisms able to reproduce to give fertile offspring
what is habitat
the area inhabited by a species, including physical factors (soil and temperature range) and living factors ( availability of food and presence of predators)
what would an area with high biodiversity have
lots of different species
what are the 3 different levels of biodiversity
habitat, species and genetic
what is habitat biodiversity
the number of different habitats in an area
- in general, area with higher habitat biodiversity will have higher species biodiversity
- high diversity would have many habitats, e.g. sand dunes, meadows, woodland and streams
what is species biodiversity
the number of different species and the abundance of each species in an area ( richness and evenness)
what is genetic diversity
the variation of alleles within a species (or a population of a species)
- this leads to different characteristics being exhibited within the same species, e.g. breed of dogs
- good as can better adapt for changing environment and more likely to arise in individuals resistant to disease
why are sampling techniques used
in most cases, too time-consuming to count every individual organism in a habitat, so samples of a population are taken
- estimates of whole population is then based on the samples
- also estimate particular characteristics of a population by taking averages
how would you carry out a sampling technique
1) choose area to be sampled
2) count the number of individuals of each species
3) repeat the process, taking as many samples as possible
4) use results to estimate the total number of individuals or different species in the habitat being studied
- if sampling different habitats and comparing, always use SAME sampling technique
how would you alter your sampling techniques based on the organism
- for crawling insects, use a pitfall trap (a small pit that insects can’t get out of) or a pooter (allows you to safely suck insects into a jar)
- for small organisms in soil or leaf litter, use Tullgren funnel
- for aquatic organisms, use kick sampling, where you kick bottom of stream and collect insects
- for long grass, use a sweep net
explain a random sample
- needed to avoid bias in your results
- e.g. dividing field into a grid and using random number generator to choose coordinates
why may you sometimes need to use a non-random sample
- if there is a lot of variety in the distribution of species in a habitat, and you want to make sure all the different areas have been sampled
what are the 3 types of non-random samples
SYSTEMATIC: where the samples are taken at fixed intervals, along a line, for example using quadrats placed along a transect line
OPPORTUNISTIC: where samples are chosen by the investigator, is simple to carry out but will be biased
STRATIFIED: different areas are identified and sampled separately in proportion to their part of the habitat as a whole, e.g. areas of heath and gorse would be sampled separately in a heathland depending on how much they take up of a habitat
what is species richness
the number of different species in an area, higher the number, greater the richness
- count the number of species
what is species evenness
the relative abundance of each species in an area, more similar the population size of each species, the greater the evenness
- count the number of individuals in a species
what is Simpson’s Index of Diversity
statistical test that takes into account both species richness and evenness
what will the SIoD always be
a value between 0 and 1
- the closer to 1, the more diverse an area is
what is the formula for SIoD
D = 1-(Σ(n/N)²)
n= the total number of individuals of one species
N= the total number of organisms of all species
why is it important to identify a population’s genetic diversity
- if a population has low genetic diversity
- they may not be able to adapt to a change in the environment
- and the whole population can be wiped out by a single event
- include isolated populations, e.g. those bred in captivity ( zoos, pedigree ( animal bred purely from animals of the same breed) and rare breeds (not used in large-scale farming))
how can you control animals with low genetic diversity
- use calculations to monitor the genetic diversity of populations over time
- can increase diversity if needed, e.g through breeding programmes in zoos
what are alleles
different versions of a gene, and alleles of the same gene are found at the same point (locus) on a chromosome
what is polymorphism
a locus that has two or more alleles
how can you find out the genetic diversity of a species
- working out the proportion of polymorphic gene loci in an organism ( the points on a chromosome with more than one allele)
via: proportion of polymorphic gene loci=
NUMBER OF POLYMORPHIC GENE LOCI/TOTAL NUMBER OF LOCI
what are the factors that affect biodiversity
1) human population growth
2) monoculture in agriculture
3) climate change
how does human population growth effect biodiversity
1) HABITAT LOSS: human development is destroying habitats, e.g. deforestation to make way for grazing and agriculture - decreases habitat diversity
2) OVER-EXPLOITATION: greater demand for resources (food, water and energy) means that things are being used up faster than they can be replenished - decreases genetic and species diversity, extinction
3) URBANISATION: cities and major road developments can isolate species, so unable to interbreed - decrease genetic diversity
4) POLLUTION: high amounts of pollutants can kill species and destroy habitats, e.g. fertiliser in rivers can decrease fish species - decrease biodiversity
how does monoculture in agriculture decrease biodiversity
- to feed large amounts of people, large areas of land are devoted to monoculture
- means growing of single variety of a single crop
- leads to a decline in global biodiversity
1) habitats are lost as land is cleared for large fields
2) local and naturally occurring plants and animals are seen as weeds and pests, so destroyed using pesticides and herbicides
3) heritage (traditional) varieties of crops are lost because they don’t make enough money, so aren’t planted anymore
what is climate change
variation in the Earth’s climate, e.g. changes in temperature and rainfall pattern
how does climate change come about
- occurs naturally
- but scientific consensus is that the climate change experiencing now is caused by humans
- increased emissions of greenhouse gases (e.g. CO2)
- the GG cause global warming (increasing the global average temperature), which causes other types of climate change
- affect different areas in different ways
how does climate change affect global biodiversity
- most species need a particular climate to survive
- change in climate means that areas previously habitable become inhabitable, and vice versa
- causes an increase or decrease in the range of some species in area where they live
- some species may be forced to migrate from area in which they live , changing species distribution
- decrease biodiversity in areas they come from, and increase it in areas they go to
- if no suitable area to migrate to, species is a plant and can’t migrate or change is too fast, species will go extinct
what are the ecological reasons for maintaining biodiversity
- protect keystone species
- maintain genetic resources
what is it meant by species being interdependent in an ecosystem
they depend on each other to survive
- means that the loss of just one species can have pretty drastic effects on whole ecosystem
what can a loss of species do to an ecosystem
1) disruption of food chains
2) disruption of nutrients cycles, e.g. decomposers like worms improve the quality of soil by recycling nutrients, if they decrease so does soil quality, effecting growth of plants and amount of food for animals
what are keystone species
species that many other species in an ecosystem depend one and without which the ecosystem would change dramatically
- often predators, keeping the population of prey in check
- can also be modifiers, maintaining the environment needed for the ecosystem (e.g. beavers building dams)
- could be hosts, e.g. plants providing particular environment
what are genetic resources
any material from plants, animals or microorganisms containing genes that we find valuable
why do we need to maintain genetic resources
1) they provide us with a variety of everyday products: food, drink, clothing (many fibres and fabrics are made from plants and animals) , drugs (morphine made from poppies), fuels (organisms used to produce renewable fuels, e.g. biogas and ethanol, which beats non-renewable fossil fuels), and other industrial materials, such as wood, dyes, adhesives
- important for global economy
2) they allow us to adapt to changes in the environment: e.g. because of climate change, some crops can’t grow in the same areas as now, but we can use the genes from plants resistant to changes to genetically engineer crops
what are the economic reasons to maintain biodiversity
to reduce soil depletion:
- monoculture is growing a single variety of a single crop
- continuous monoculture is planting the same crop in the same field without disruption
- this causes soil depletion, as the nutrients required by the crop are gradually used up (traditionally crops would be rotated with other types so that nutrients and organic matter can be replaced)
- economic cost of soil depletion include increased spending on fertilisers and decreased yields
what are aesthetic reasons of maintaining biodiversity
- areas with high biodiversity provide pleasant, attractive landscapes for people to enjoy - so protecting landscapes
- more biodiversity, more visitors attracted, so economical advantages too
what does in situ conservation mean
on site conservation
- involves protecting a species in their natural habitat
why is conservation important
- ensuring the survival of endangered species, species at the risk of extinction because of low population or threatened habitat
what are examples of in situ conservation
1) protected areas such as NATIONAL PARKS and WILDLIFE RESERVES:
- protects wildlife in these areas as urban development is restricted, as well as industrial development and farming
- also used in sea ecosystems with MARINE CONSERVATION ZONES, where human activities, e.g. fishing, is controlled
2) controlling and preventing INTRODUCTION OF SPECIES WHICH THREATEN LOCAL BIODIVERSITY:
- e.g. grey squirrels are not native to britain, but have competed with red squirrels and caused the population to decline, so controlled in some areas
3) PROTECTING HABITATS:
- controlling water levels to conserve wetlands and coppicing (trimming trees) to conserve woodlands
- this allows organisms to continue living in their natural habitat
4) PROMOTING PARTICULAR SPECIES:
- via protecting their food sources or nesting sites
5) giving LEGAL PROTECTION to endangered species, so illegal to kill e.g.
what is an advantage to in situ conservation
- both the species and habitat is conserved
- large populations can be protected
- and less disruptive than removing organisms from habitat
- greater chances of population recovering
what are disadvantages to in situ conservation
its difficult to control some factors that threaten a species, e.g. poaching, predators, disease and climate change
what is ex situ conservation
off site conservation
- protecting a species by removing part of the population from a threatened habitat and placing it into a new location
- often the last resort
what are the methods of ex situ conservation
1) relocating an organism to a safer area
2) breeding organisms in captivity and then reintroducing them into the wild when they are strong enough - breeding can be carried out in animal sanctuaries or zoos
3) BOTANIC GARDENS are controlled environments used to grow a variety of rare plants for conservation, research, display and education - endangered or extinct species in the wild can be grown and reintroduced
4) SEED BANKS: seeds can be frozen and stored in banks for over a century without losing fertility - provide a useful store of seeds if natural reserves are destroyed, e.g. via disease or natural disaster
what are the disadvantaged to ex situ conservation
- usually only a small number of individuals can be cared for
- can be difficult and expensive to create and sustain the right environment
- animals that are habituated (used to) human contact are less likely to exhibit natural behaviours and more likely to catch a disease from humans
- usually less successful than in situ, many species can’t breed successfully in captivity or don’t adapt to the new environment when moved to new location
what are the advantages to ex situ conservation
used to protect individual animals in a controlled environment, so predation and hunting can be managed better
- also be used to reintroduce species that have left an area
what are examples of international and local conservation agreements
Rio Convention on Biological Diversity (CBD) (inter)
CITES agreement (inter)
The Countryside Stewardship Scheme (local)
what is the rio convention
- aims to develop international strategies on the conservation of biodiversity and how to use plant and animal resources in a sustainable way
- made it a part of international law that conserving biodiversity is everyone’s responsibility
- provides guidance to governments on how to conserve biodiversity
what is the CITES agreement
- Convention on International Trade in Endangered Species
- agreement designed to increase international cooperation in regulating the trade in wild animals and plant specimens
- made it illegal to kill endangered species
- conserves species by limiting trade through licensing, and made it illegal to trade products made from endangered animals
- raises awareness of threats to biodiversity through education
what is the CSS
- the Countryside Stewardship Scheme UK
- introduced in 1991
- conserve wildlife and biodiversity, and to improve and extend wildlife habitats by promoting specific management techniques to landowners
- offered 10 year agreements to pay landowners who followed the management techniques suggested
- e.g. to regenerate hedgerows, leave grassy margins around fields for wildflowers to grow and to graze upland areas to keep down bracken
- in 2000, there were 10,000 agreements in the UK
- various species have been able to rebuild in numbers, such as birds like bittern, stone curlew and black grouse
