ecology

• habitat is the environment in which an organism lives
• population is the total number of organisms of the same species living in the same geographical area
• community is all populations of different species that live together in one place
• biotic means living

  abiotic is non living
• ecosystem is both the biotic and abiotic parts of the environment and how they interact
• describe the resources that organisms compete for

  • plants complete for light, space, mineral ions in the soil and water
  • animals compete for water, food, territory and mating partners
• interdependence 


  every animal depends on other living organisms for food

  eg. lions
• plants can also depend on animals like birds and bees
• animals which feed on food from plants would decrease if bees decrease
• biotic factors

  • arrival of a new predator
  • competition
  • new pathogens
• abiotic factors

  • light intensity (plants will grow more slowly, animals may not have enough food)
  • temperatures (animals could migrate, plant species may disappear)
  • water
  • pH and mineral content in soil (soil may be too acidic)
  • wind intensity and direction (plants loose water due to wind)
  • carbon dioxide (rate of photosynthesis may decrease)
  • oxygen (aerobic respiration, dissolved oxygen may drop, damaging aquatic species)
• describe how organisms are adapted to living in their natural environment (camels)

  • hump - store of fat, acts as a thermal insulator, reduces water loss through sweating, produce water from the fat
  • thick coat - insulates the top of the camel from the sun and reduces water loss
  • leathery mouth - chew desert plants with thorns which are a good source of water
  • wide feet - prevents it from sinking in the sand
  • produce concentrated urine and dry faeces - reduce water loss
  • tolerate large body temperature changes
• behavioural adaptations

  adaptations to the animal's lifestyle or behaviour
• structural adaptations

  adaptations of body shape or body structure
• functional adaptations

  adaptations to the body functions of an organism
• describe how an animal is adapted to living in their natural environment (arctic fox)

  • very thick fur - provides insulation and heat loss
  • very small ears - reduces surface area
  • white coat - camouflage, helps with preys
• describe how plants are adapted to living in their natural environment (cactus)

  • very small leaves - reduces water loss
  • spines - protects it from animals
  • extensive and shallow roots - catch as much water as possible
  • store water in their stems
• producer (tree) to primary consumer (caterpillar) to secondary consumer (small bird) to tertiary consumer (large bird)
• consumers that kill and eat other animals are called predators.
• animal that gets eaten is the prey
• the numbers of preys and predators rise and fall
• describe stages of the water cycle

  • energy from the sun causes the water to evaporate from the surface of the sea
  • water vapour travels into the air and cool
  • condenses to form clouds
  • falls to the ground as precipitation
  • evaporates back as water vapour, a lot of water forms into a river or streams which eventually drains back into the sea
• describe the processes that take place in the carbon cycle

  • carbon dioxide in the atmosphere is taken in my plants and algae through photosynthesis
  • some of the carbon is released back as carbon dioxide through respiration
  • plants and algae can be eaten by animals so the carbon in the plants becomes part of carbohydrates, fats and proteins in the cells of animals
  • when animals respire carbon is released again
  • all animals and plants die
  • waste products are decomposed by decomposers
  • when they carry out respiration the carbon is returned by dead remains and waste
• decomposers release mineral ions to the soil
• if decomposers cannot function effectively, the carbon in dead remains can slowly be converted to fossil fuels. burning fossil fuels releases a large amount of carbon dioxide back into the atmosphere
• biodiversity 


  the variety of the different species of organisms on earth. high level of biodiversity makes the ecosystem more stable
• deforestation

  large areas are being destroyed: grow crops or for rice fields
• describe how waste produced by humans can reduce biodiversity

  • water pollution = contains urine and faeces, untreated sewage can be released into rivers and streams
  • fertilizers from farms and untreated sewage cause dissolved oxygen levels to fall, killing aquatic organisms
  • toxic chemicals can kill animals in the river
  • burning releases smoke kills plants and animals
  • burning coal in power stations releases acidic gases causing acid rain
  • toxic chemicals can be dumped into land, killing living organisms
  • tons of waste are dumped into landfills
• describe how humans reduce the amount of land available for animals and plants

  • houses, factories, shops, landfills, airports, farms and quarries
• describe how the destruction of peat

  • contains large amounts of dead plant material
  • decay is very slow so contain a large amount of trapped carbon
  • peats can be burned to release energy such as electricity (carbon dioxide released) contributing to climate change
  • peats is used to produce cheap compost
  • their destructions destroys the habitats of animals, plants and microorganisms, reducing biodiversity
  • once peat is extracted it begins to decay and releases large amounts of carbon dioxide
• describe how we can reduce the loss of biodiversity

  • breeding programmes for endangered species - lending their endangered species to other zoos hoping they will breed.
  • wetlands are regenerated and protected so they can never be drained
  • field margins - wild animals can live
  • hedgerows help preserve biodiversity
  • governments - reduce deforestation, carbon dioxide emissions, increasing uses of renewable resources
  • recycling - less waste ends up in landfills so less habitats will be destroyed
• global warming

  • average temperature are increasing due to human activities and release of methane and carbon dioxide
• consequences of global warming

  • loss of habitat
  • animals may extend their range towards cooler regions
  • animals may migrate
  • too hot to grow crops they need