7-Ecology

• habitat is where an organism lives
• population is all the organisms of a particular species that live in a habitat
• community is all the population of different species that live together in a habitat
• • biotic factors are living factors of the environment
  • abiotic factors are non-living factors of the environment
• ecosystem is the interaction of a community of living organisms with the non-living parts of their environment
• competition in animals and plants

  • animals compete for - food, water, mates, territory
  • plants compete for - mineral ions, water, space, light
  • organisms compete within the same and different species
• interdependence

  • interdependence is that all species depend on other species in some way
  • if anything happens to one of the species the others will be affected
• biotic and abiotic factors

  • biotic factors are how living organisms affect one another such as predation, competition, food availability, disease
  • abiotic factors are the non-living parts of an environment that affect organisms such as light, moisture, wind intensity
• types of adaptations

  • structural
  • behavioural
  • functional
• structural adaptations

  • the physical features of an organism
  • this includes the colour and shape
• behavioural adaptations

  • the way an organism behaves or acts
• functional adaptations

  • the processes inside an organism
  • this includes metabolism and reproductive system
• extremophiles

  • they are organisms that have adapted to survive in extreme environments
  • they are bacteria or archaea
  • they can survive in very high temperatures (hot springs), high salt concentration (salt lakes), high pressures (deep sea vents)
• food chains present how energy is passed through an ecosystem by what gets eaten by what
• food chain order

  1. producers are photosynthetic organisms like plant or algae
  2. primary consumers are organisms that eat the producers
  3. secondary consumers are organisms that eat primary consumers
  4. tertiary consumers are organisms that eat secondary consumers
• food chains

  • food chains present how energy is passed through an ecosystem by what gets eaten by what
  • as you go along the food chain levels, most of the energy gets lost
• • predator is an animal that hunts and kills other animals for food
  • prey is an organism that is killed and eaten by a predator
• predator-prey graphs

  • these graphs fluctuate in cycles

  1. as preys increase, predators increase
  2. once there are too many predators, prey decreases
  3. once there are too little prey, predators decrease which allows prey to increase again

  • they are usually out of phase because it takes a long amount of time for entire populations to increase or decrease

  
• • abundance refers to how many organisms there are
  • distribution refers to where the organisms are
• sampling

  • finding the abundance and distribution of organisms would be extremely time consuming or impossible so sampling is used
  • sampling is a method where a subset of organisms are measured and subset is used to make predictions about the whole population
  • two types - quadrats or transects
• • quadrats - square frames used to measure abundance
  • transects - to measure how distribution changes
• using quadrats to sample

  1. use tape measures on a field and turn it into a grid (each is 1 metre squared) and number the different areas
  2. use a random number generator 10 times
  3. place the quadrats at those numbered areas on the field
  4. calculate the mean number of dandelions per metre squared
  5. estimate the total population size with the mean of dandelions and the area of the field
• the water cycle

  1. water evaporates from lakes, oceans, rivers, puddles, soil or from leaves of plants (transpiration), into water vapour
  2. water vapour starts condensing into clouds which are blown into different areas
  3. the clouds precipitate and release the water back down as rain
  4. the water can seep into the soil, flow into rivers or get taken up by plants
  5. the cycle repeats
• the carbon cycle

  1. green plants and algae take in carbon dioxide for photosynthesis to convert it into glucose
  2. carbon that's locked up in plants can be let back out through respiration or be passed on to animals that eat them who also respire to release carbon dioxide
  3. when plants and animals die they either decay and release carbon dioxide during microbial respiration or can be decayed in anaerobic conditions which are slowly converted into fossil fuels
  4. fossil fuels are burned (combustion) and release carbon dioxide back into the air
  5. the cycle repeats
• biodiversity

  • biodiversity is the variety of different species on earth or within an ecosystem
  • it is important to have biodiversity :

  1. to increase the stability of an ecosystem so changes have less affect
  2. different species provide different services such as pollination
  3. many of our medicinal drugs come from wild species
• biodiversity is negatively impacted by the rapid growth in human population

  • more resources are being used
  • more waste is being produced
• reducing biodiversity - using resources

  • resources such as raw materials are being used up faster than they can be replaced
  • getting resources often requires clearing out a natural ecosystem like deforestation
• reducing biodiversity - waste

  • water pollution - sewage, chemicals from industry and farming running into lakes, rivers, oceans
  • land pollution - landfill, nuclear waste chemicals can seep into the surrounding ecosystem
  • air pollution - industrial processes like burning fossil fuels can release sulphur dioxide

  pollution can harm ecosystems directly or indirectly
• maintaining biodiversity

  • breeding programmes - build up numbers of endangered species. cons - if their natural habitat is not safe they will decrease
  • protected areas - regenerating rare habitats to ensure the living organisms are safe
  • reducing impact - government can pass laws or encourage things like hedgerows or field margins
  • government - set quotas or pass laws prohibiting, limiting or paying businesses for certain practices e.g. on deforestation, release of carbon dioxide
• problems of maintaining biodiversity

  • it is expensive so individuals, companies and governments overlook how they benefit from high biodiversity
  • maintaining our current high standard of living must damage the environment as fertilisers and pesticides have to be used to grow enough food, huge mines have to be dug for rare metals
• atmosphere

  • the atmosphere is a layer of gases surrounding the earth that is held in place by gravity

  1. solar radiation from the sun passes through the atmosphere and hits the earth
  2. some of this energy is reflected straight back towards space, some is absorbed and then reemitted back to space and much of it is absorbed by greenhouse gases
  3. greenhouse gases reemit the energy randomly
  4. trapped energy keeps the atmosphere warmer and more stable
• • global warming is the overall increase in the earth's temperature
  • climate change is a consequence of global warming and the effects on climate
  • weather is short term atmospheric conditions
  • climate is typical weather conditions in an entire region for a very long time
• effects and consequences of global warming - climate change

  • rare weather events like droughts, hurricanes, floods will become more common and severe
  • sea level rise as high temperatures will cause ice caps to melt and as water in the oceans warms up it will expand - this can lead to seasonal flooding and submersion of land
  • species won't be adapted to their environment anymore so won't be able to survive
• deforestation

  • it is a large scale clearance of trees from an area
  • is done to clear land for farming, grow biofuels, logging
  • causes more carbon dioxide to be left in the atmosphere as less photosynthesis happens, burning forests to take them down releases carbon dioxide and smoke, habitat with high biodiversity has been destroyed
• peat bogs

  • areas of land where soil is acidic and waterlogged and carbon is stored
  • they are drained to be used as farm land, the microorganisms can decay the plants
  • the peat is removed to be burned as a fuel or used as compost
  • it destroys habitats and reduces biodiversity
• • human population has increased dramatically, 1 billion to 8 billion
  • average person eats much more than what they did in the past and is more resource intensive

  these factors meant that global food production had to increase

  • clearing natural lands for agriculture
  • application of fertilisers, pesticides and other chemicals
  • selective breeding
  • genetic modification
• • genetically modified organisms have had their genomes changed to make them inherit a useful gene
  • pest resistance - produce toxins that kill insects like Bt toxin produced naturally by bacteria
  • increased nutrients - such as golden rice which has a chemical that is converted into vitamin a
• mycoprotein is a protein made by fungi used to make high protein meat substitutes - fungi fusarium