Ecology

• organisms compete for resources to survive

  plants need light and space as well as water and mineral ions

  animals need space, food, water, and mates

  organisms compete with other species for the same resources
• any change in an environment can have knock-on effects


  species depend on one another for food, shelter, seed dispersal- this is called interdependence

  the interdependence of all living things in an ecosystem mean any major change can have huge effects

  in some communities all the species and environmental factors are in balance so the population sized are roughly constant
• abiotic factors


  moisture level

  light intensity

  temperature

  carbon dioxide level

  wind intensity and directions

  oxygen levels

  soil pH and mineral content
• changes in abiotic factors can affect populations

  a change in the environment could be an increase or decrease

  they can affect the population sizes of other organisms that depend on them

  a decrease in light intensity can affect photosynthesis levels with can affect growth levels
• biotic factors


  new predators

  competition

  new pathogens

  availability of food
• changes in biotic factors can have knock-on effects


  these changes can affect the sizes of populations in a community which can have knock on effects because of interdependence

  a new predator could decrease numbers in the prey population
• adaptations allow organisms to survive

  structural

  behavioural

  functional
• structural


  the features of an organism's body structure- shape or colour

  arctic animals have white fur so they are camouflaged against the snow
• behavioural


  these are ways an organism behave-many species migrate to warmer climates during the winter to avoid the problems of living in cold conditions
• functional


  these are things that happen inside an organisms body that can be related to processes like reproduction and metabolism

  desert animals conserve water by producing little sweat and small amounts of concentrated urine
• microorganisms have a huge variety of adaptations


  some microorganisms are known as EXTREMEOPHILES because they are adapted to extreme environments (high temperatures-volcano)
• food chains show what is eaten by what in an ecosystem

  they start with a producer- make their own energy- algae

  energy is transferred through living organisms in an ecosystem where organisms eat other organisms

  producer-primary consumer-secondary consumer
• populations of prey and predators go in cycles

  if the population of prey increases, so will the population of predators, which will decrease the number of prey, decreasing the population of predators, increasing the population of prey

  continuous cycle of fluctuating population levels
• environmental changes affect the distribution of organisms

  temperature

  availability of water

  composition of atmospheric gases
• temperature


  the distribution of bird species in germany is changing because of a rise in average temperature
• availability of water


  the distribution of some plant species in the tropics changes between the wet and dry seasons- the time of year
• composition of atmospheric gases


  the distribution of some species changes in areas where there is more air pollution
• the water cycle


  energy from the sun makes water evaporate from the land and sea turning it into water vapour, the warm water is carried upwards and when it gets higher its gets cooler and condenses into clouds, water falls from clouds as precipitation where it provides fresh water for plants and animals where it drains into the sea repeating the process
• materials are cycled by decay


  living things are made up of materials they take from the world around them, these materials are returned to the environments in waste products or where the organisms die and decay, material decay because they are broken down by microorganisms. this happens faster in warm climates decay puts the stuff that plants need back into the soil
• the carbon cycle


  co2 is removed from the atmosphere during photosynthesis, the carbon is used to make glucose which can be turned into carbohydrates, fats, and proteins. when plants and algae respire some carbon is returned to the atmosphere as co2, when they are eaten by animals, some carbon is passes up the food chain, those animals then respire. when they die, other animals and microorganisms feed on their remains. these organisms respire animals also produce waste

  carbon is constantly being cycled throughout the environment
• decomposition can produce compose


  compost is decomposed organic matter that is used as a natural fertiliser for crops and garden plants

  farmers and gardeners try to provide the ideal conditions for quick decay to make compost
• the rate of decay is affected by factors

  temperature

  water availability

  oxygen availability

  number of decay organisms
• temperature affects the rate of decay

  warmer temperatures speed up decay because they increase the rate that the enzymes involved in decomposition work at. however if it is too hot decomposition slows down because the enzymes are destroyed

  really cold temperatures slow the rate of decomposition
• water availability affects the rate of decay

  decay takes place faster is moist environments because the organisms involved in decay need water to carry out biological processes
• oxygen availability affects the rate of decay

  many organisms need oxygen to respire which they need to do to survive. the microorganisms involved in anaerobic decay do not need oxygen
• number of decay organisms affect the rate of decay

  the more microorganisms and detritus feeders there are, the faster decomposition happens
• biogas is mainly made of methane which can be burned as a fuel


  lots of different microorganisms are used to produce biogas. they decay plant and animal waste anaerobically which produces methane gas sludge waste from sewage works or sugar factories is used to make biogas on a large scale biogas is made in a simple fermenter called a digester or generator need to be kept at a constant temperature to keep the microorganisms respiring- biogas cannot be stored as a liquid so has to be used straight away
• biogas generators


  batch generators

  continuous generators
• batch generators


  make biogas in small batches. they are manually loaded up with waste, which is left to digest and by-products are cleared away at the end
• continuous generators 


  make biogas all the time. waste is continuously fed in, and biogas is produced at a steady rate. more suited to large-scale biogas projects
• a biogas generator needs

  an inlet for waste to be put in

  an outlet for the digested material to be removed

  an outlet so the biogas material can be piped where it is needed
• decay practical


  measure 5cm3 of lipase solution into test tube, measure out 5cm3 of milk and add it to a different test tube, add drops of phenolphthalein indicator to the milk tube, measure 7cm3 of sodium carbonate solution and add it to the tube containing milk it should turn pink, place both tubes into a water bath set to 30C and leave them in- add thermometer add 1 lipase solution to milk tube, start stopwatch, stir the contents, as it loses pink colour record how long took place, repeat at different temperatures and calculate rate of decay
• biodiversity


  the variety of different species of organisms on earth or within an ecosystem
• high biodiversity is important


  ensures ecosystems are stable because different species depend on each other for thing like shelter and food, different species can help maintain the right physical environment
• humans have an increasing effect on the environment

  increasing population puts pressure on the environment as the resources needed to survive are taken

  people around the world are demanding a higher standard of living so more raw materials and more energy is used- more resources

  raw materials are being used quicker than they are being replaced
• humans are producing more waste- pollution

  water

  land

  air
• water pollution


  sewage and toxic chemicals from industry can pollute lakes, rivers, and ocean, affecting the plants and animals that live there

  chemicals used on land can be washed into water
• land pollution


  toxic chemicals are used for farming

  nuclear waste is buried underground and household waste is dumped in landfill sites
• air pollution


  smoke and acidic gases released into the atmosphere can pollute the air- acid rain is caused by sulphur dioxide
• carbon dioxide and methane in the atmosphere trap energy from the sun


  gases in the atmosphere act as an insulating layer, they absorb most of the energy that would normally be radiated back into space greenhouse gases in the atmosphere keep energy in- the earth is heating up due to the increase in the amount of greenhouse gases