part 2 (new)

• extinct


  when a species no longer exists
• endangered


  population is critically low, due to humans, so close to being extinct

  • population increase
  • agriculture
  • deforestation
  • pollution increase
  • killing animals for protection (anopheles mosquito)
• critically endangered


  likely to go extinct as numbers are not sustainable and too low for the survival of the species
• how do humans influence biodiversity

  agriculture

  deforestation

  climate change
• what is deforestation


  permanent removal of large areas of wood/forest and habitat destruction to provide space for houses, industry, agriculture, roads

  • directly reduces the number of trees present in an area
  • if only a specific type of tree is felled, it reduces species diversity
  • reduces number of animal species in an area due to the destruction of their habitat/food source - forces to migrate elsewhere in order to survive
• AGRICULTURE


  removal of hedgerows to allow farmers to use large machinery and free up land reduces the number of plant species in an area, thus destroying the habitat of animal species such as blackbirds/mice

  HEDGEROWS GOOD:

  • food and shelter for important species
  • pest control - predators live in them
  • control water levels and run off
  • pollination of crops by insects
• PESTICIDES


  indiscriminate spraying of pesticides reduces species diversity as it kills pests (insects) which indirectly kills the food source of other organisms

  INDIRECTLY KILLS OTHER SPECIES AND AFFECTS FOOD WEBS/CHAINS

  could causes harm to humans due to bio-accumulation of food webs
• HERBICIDES


  reduces species diversity by killing weeds and removing vital food sources
• MONOCULTURE


  has an enormous local effect by lowering biodiversity as only one plant species is present which supports only few animal species

  REDUCES GENETIC VARIATION

  • monoculture
  • clearing land
  • selective breeding/cloning
• greenhouse effect


  sun/heat hits the earth and some is reflected back with a longer wavelength, so some is reflected again into the atmosphere

  MADE WORSE BY

  • burning fossil fuels (release CO2)
  • deforestation (removing trees that use CO2 in photosynthesis)
  • cattle/rice fields (produce methane)
• climate change

  MELTING POLAR ICE CAPS - lead to extinction of few plant/animal species in these areas

  RISING SEA LEVELS

  • seawater flooding rivers, reducing number of freshwater plant/animal species
  • flooding of low-land areas, resulting in loss of terrestrial habitats

  HIGH TEMPS+LOW RAINFALL - some plant species failing to survive, drought-resistant plant species dominate leading to loss of some animal species

  INSECT LIFE-CYCLES + POPULATIONS CHANGE - insects are key pollinators so if the range of an insect changes, it could lead to extinction of the plants it leaves behind
• effect of climate change on biodiversity on spread of disease

  DISEASE OF DOMESTIC ANIMALS INCREASES - blue-tongue in cattle will spread due to midge carrying the disease surviving in winter

  INSECT PESTS/PLANT DISEASES usually killed in frost will survive the milder winter conditions

  FEMALE ANOPHELES VECTOR MOSQUITO will spread plasmodium parasite to humans on feeding (cannot function under 10 degrees + need high humidity)
• other effects of climate change

  MANGROVE SWAMPS

  • mangroves rely on their roots being out of water to obtain oxygen
  • rising sea levels reduces their ability to survive so WILL BE LOST

  FISH

  • some fish species stop growing once a certain temp is reached
  • could stop growing before reproductive age or not a sufficient weight to survive in winter

  RAINFALL CHANGES

  • increase in rainfall in some areas and decrease in others
  • SELECTIVE BREEDING means low genetic variation so cannot adapt to changes in rainfall
• reasons for maintaining biodiversity


  • aesthetic
  • economic
  • ecological
  • ORGANISMS HAVE THE RIGHT TO EXIST
  • SPECIFIC RELIGIOUS REASONS
• AESTHETIC REASONS

  • ENRICHMENT OF LIVES
  • inspiration for people (musicians/authors)
  • people recover more rapidly from stress/injury when supported by plants/nature
• ECONOMIC REASONS


  desertification/soil erosion as a result of deforestation reduces ability to grow own crops - IMPORT

  non-sustainable removal of resources leads to collapse in industry in that area

  species with potential economic/medical/chemical value go extinct before discovered

  ECOTOURISM - attractive/pleasing places promote tourism to provide jobs for locals

  CONTINUOUS MONOCULTURE leads to soil depletion of mineral ions which increases vulnerability to insect/plant competition
• more economical

  PLANT VARIETIES needed for cross breeding which can lead to better characteristics - DISEASE RESISTANCE, INCREASED YIELD

  HIGH BIODIVERSITY PROVIDES PROTECTION AGAINST ABIOTIC STRESSES (disease/natural disaster) to prevent a change in conditions destroying crops + wasting money

  GREATER DIVERSITY

  • greater potential to manufacture different products in the future
  • greater potential to provide jobs and money
• ECOLOGICAL


  organisms are part of a food chain and are interdependent on each other for survival (food source/habitat)

  KEYSTONE SPECIES - species that play a key role in maintaining the structure of an ecological community - HAVE A DISPROPORTIONALLY LARGE EFFECT ON THEIR HABITAT, SO IF REMOVED, THE HABITAT DRASTICALLY CHANGES
• keystone species examples


  PRAIRE DOGS

  • food source
  • burrowing creates habitats for other animals - SNAKES
  • burrowing aerates soil and poo adds nutrients to soil

  SEA STARS

  • predator - maintain balanced ecosystem by eating sea urchins/mussels which have no other natural predators

  IF REMOVED

  • HUGE increase in mussels reduces the number of other species in the area
  • growing populations of sea urchins CROWD coral reefs, preventing other species occupying the same areas
• more ecological

  GENETIC VARIATION leads to evolution by natural selection, which is needed to allow organisms to adapt to changes in their environment:

  • change in climate
  • emergence of a new disease
  • arrival of a new pest
  • pollution levels increasing
• In-situ defintion, adv and disadv


  conservation of a species in its natural habitat

  ADV

  • conservation of a habitat and all organisms within the habitat
  • biodiversity of whole area is maintained
  • cheaper as only needs managing
  • allows evolution to continue

  DIS

  • large amounts of land needed which may be hard to manage
  • animals may leave reserve, causing problems for locals
  • locals may still hunt animals/harvest plants/timber from env
  • harder to control fires, floods, disease
  • nowhere for animals to go if there was climate change
• in situ in the UK


  national parks

  sites of special scientific interest

  local nature reserves

  NATIONAL NATURE RESERVES
• what do in situ charities do


  • purchase land
  • set up and manage nature reserves
  • education/public awareness
  • lobbying governments
  • national campaigns
  • wildlife surveys
  • magazines/giving lectures
• WILDLIFE RESERVES


  • CONTROLLED GRAZING - to maintain habitat/allow species to recover
  • restrict human access - completely or via footpaths
  • feeding animals
  • stop poaching
  • reintroduction of species
  • halting succession via controlled grazing
  • culling invasive species
• MARINE CONSERVATION ZONE


  PRESERVE species-rich areas - CORAL REEF which is being devastated by unsustainable fishing methods

  HOWEVER, THIS DOES NOT PREVENT FISHERMEN VISITING THE ENTIRE AREA

  create areas of refuge to help build up population and allow areas near areas of refuge to also REPOPULATE
• ex situ


  conservation of a species by removal of an organism from its natural habitat

  USUALLY A LAST RESORT

  • botanic gardens
  • seed banks
  • relocating
  • captive breeding

  RELOCATING - moving an organism to a safer area
• BOTANIC GARDENS


  • controlled environments used to grow a variety of rare plants with the purpose of DISPLAY, EDUCATION, RESEARCH, CONSERVATION
  • plants are actively managed and given the best resources to grow: SOIL MINERAL IONS, WATERING, REMOVAL OF PESTS
  • wild relatives of selectively bred species could be a potential source of genes conferring resistance to parasites, pests, disease
  • endangered species/species extinct in the wild can be reintroduced to safer/more suitable habitats
• what are seed banks and their aims


  • gene bank - storage of genetic material (STORE TEMPERATE/TROPICAL SEEDS)
  • expected that frozen and stored seeds will remain viable/fertile for centuries
  • provide a back up against the extinction of wild plants
  • useful source of seeds if natural reserves are destroyed (natural disaster/disease)

  MAIN AIMS

  • seeds are stored and GERMINATED
  • plant NUMBERS significantly increase and can be reintroduced into the wild
• VIABILITY


  • keeping the seeds healthy
  • GENETIC VARIATION MAINTAINED
  • STORAGE - (humidity less than 5% and -20 degrees)
  • seeds need to be regularly germinated to renew stock or less seeds could eventually lose viability
• variability


  seeds are collected from many locations and lots of them
• advantages and disadvantages of seed banks


  ADV

  • seeds can be produced in excess and stored in large amounts
  • don't take too much space
  • can be used in medicine
  • seeds can remain viable for a long time
  • can be researched on site

  DIS

  • collection of sample may cause disturbance to habitat
  • sample not representative of entire genetic diversity
  • asexual reproduction forms clones
  • seeds stored may not evolve/grow over time
• why seeds collected from many different sites

  • increases genetic and geographical VARIATION
  • reduces chance of INBREEDING
  • reduces chance of a change in env factor affecting the entire/wider population
• CAPTIVE BREEDING


  • run and managed by zoos and aquatic centres
  • AIMS TO PRODUCE A HEALTHY, STABLE POPULATION OF A SPECIES AND GRADUALLY REINTRODUCE THEM BACK INTO THE WILD

  DO THIS BY:

  • providing shelter
  • abundant supply of food (reduced competition)
  • absence of predators/vets

  SMALL NUMBER OF BREEDING PARTNERS CAN LEAD TO INBREEDING

  MATING CAN BE ARRANGED BY INTERNATIONAL CATALOGUES
• why captive breeding


  • Last resort for endangered species
  • only done when their population has reached a point where it can no longer survive in the wild

  GOOD FOR SPECIES THAT ARE EASILY BRED IN CAPTIVITY

  MORE SPECIALISED SPECIES ARE MORE DIFFICULT TO KEEP

  BEING ISOLATED IN CAPTIVITY MEANS SOME SPECIES DO NOT EVOLVE WITH CHANGES IN THEIR ENVIRONMENT
• how does captive breeding work


  individuals are selected on the basis that they are

  • healthy, not related, of reproductive age, opposite sex (greater proportion of females to males)
  • selected from several different areas to increase genetic variation as there will be a variety of different alleles
  • housed in different centres to reduce the risk of inbreeding and reduce chance of losing all individuals to a natural disaster/disease
• BEFORE REPOPULATION:

  • promotion of ecotourism
  • healthy and quarantined before release
  • adequate food supply
  • method of monitoring population (TAGS)
  • method of preparing animals for release (teaching to hunt)
  • PROTECTED RESERVES (no habitat destruction/hunting)
• why may some captive animals not be suitable for the wild


  • may have lost resistance to local disease
  • some behaviour has to be learned by copying/experiencing - some animals die as they don't realise they have to search for food
  • genetic makeup of captive animals may be so different to the original population that they can no longer interbreed
  • introduction of new individuals puts stress on a habitat - particularly if it's small - FIGHT FOR TERRITORY
• advantages of captive breeding


  • increases numbers of endangered species
  • bred plant/animal species can be reintroduced back into the wild
  • preserves diversity and prevents species going extinct
  • creates public awareness and raises funds
• disadvantages of captive breeding


  • small gene pool
  • reintroduced species may not be able to survive in the wild
  • isolated in captivity means they cannot evolve and adapt to changes in environment
  • capturing for conservation can affect wide population size
  • need to raise funding
  • INBREEDING (artificial insemination/IVF has been tried)
• exsitu over insitu


  • protection from hunting/predators
  • breeding can be manipulated via hormones/artificial insemination
  • reduced competition
  • species can be treated for disease
  • reduced mortality of young