Ecology

• Ecology

  all organisms have relationship
• Habitat

  where an organism lives
• Population

  all the organisms of one species that live in a habitat
• Community

  all the populations of a different species that live together in habitat
• Biotic factors

  living factors that effect another organism or helps shape the ecosystem
• Abiotic factors

  non-living parts of the environment that can effect organisms
• Ecosystem

  the interaction of a community of living organisms with non-living parts of their environment
• Competition

  when organisms have to compete for different resources - resources are limited
• Animal competition

  food

  water

  territory

  mates
• plant competition

  light

  space

  water

  mineral ions
• Interdependence

  species depend on other species in some way in order to survive

  If something happens to one species it will effect the others in that community
• food web

  show feeding relationships within a community
• Biotic factor - examples

  • predation - predators eat prey, living process, can effect the population of another species
  • competition for resources
  • amount of disease
  • availability of food
• Abiotic factors - examples

  • chemical/physical part of the environment
  • light intensity
  • wind strength/direction
  • carbon dioxide concentration
  • moisture levels
  • pH / mineral content in soil
  • temperature - animals (less energy spent staying warm, more on growth), plants (increase rate of photosynthesis - enzymes work faster - increase overall rate of plant growth)
• Adaptations

  in order to survive, organisms need to be adapted to their environments in some way;

  • structural
  • behavioural
  • functional
• structural adaptations

  • physical features that we see
  • shape
  • colour

  eg - Seal, live in cold environment - round = store fate and low surface area : volume (conserve heat), brown (camouflage)
• behavioural adaptations

  • the way an organism behaves or acts, eg eating

  elephants - live in hot environments - flap ears +spray themselves with water = cool themselves

  swallows - migrate to warmer conditions in the winter = avoid cold and lack of food
• Functional adaptations

  • processes inside an organism
  • metabolism
  • reproductive system

  desert animals - produce little sweat and small amounts of concentrated urine - conserve water
• Extremophiles

  Microorganisms (bacteria or archaea) that can live in extreme conditions

  • high temperature - hot springs
  • high salt concentrations - salt lakes
  • high pressure - deep sea vents
• Food chain

  how energy is passed through an ecosystem

  what gets eaten by what in an ecosystem

  simplified version of a food web
• Producer

  photosynthetic (glucose via photosynthesis)

  eg - Plant and algae
• Primary consumer

  eats a producer

  can be multiple animals
• secondary consumer

  eats a primary consumer

  some kind of predator
• Tertiary consumer

  eats a secondary consumer
• Producer -> Primary consumer -> Secondary consumer -> Tertiary consumer

  -> = eaten by

  as things get eaten energy is passed on - most gets loss
• biomass

  biological molecules made from the sun incorporated into the plant
• Predator - prey cycles

  shows the relationship between a predator and prey

  predator population is always slightly behind the prey

  the difference in peak = lag = out of phase

  
• abundance

  how many organisms there are
• distribution

  where the organisms are
• sampling

  ideally it would be great to know the abundance and distribution of organisms

  but

  in real life that would be time consuming or impossible

  so

  biologists use sampling - measure a small section and use this to estimate the population
• sampling - Quadrats (distribution)

  1. Grid the sampling area
  2. Randomly pick out coordinates using a random number generator
  3. Place the quadrat in these coordinates
  4. calculate how many of a particular organism there is
  5. Repeat at 2-4 for 4 more coordinates
  6. calculate the mean
  7. estimate for the whole area - $\frac{total\ area}{sample\ area}\times number\ of\ organisms$
• sampling - transects

  1. lay a transect line (with a tape measure) on the sampling area
  2. put the quadrat on the line (so one corner is at 0cm)
  3. Count the number of organisms in the quadrat (write it down)
  4. Use a light meter to record the light intensity (write it down)
  5. move up 5m
  6. Repeat step 2-5
  7. Repeat whole experiment 3 more times and work out a mean
• quadrat

  1 metre by 1 metre frame that has been divided into 10cm x 10cm squares
• Carbon and water cycle

  life has existed for billions of years because it recycles everything -

  atoms can be used over and over again

  makes loads of organisms over millions and millions of years
• Water cycle

  1. Energy from the sun comes down and causes the water to evaporate into water vapour or water vapour travels upwards from transpiration
  2. the water vapour collects in the sky, it condenses into clouds
  3. at some point, the water vapour will fall back fown to earth - precipitation

  then it repeats itself

  
• carbon cycle

  carbon is found in the air, plant, soil, fossil fuels (oil, coal and natural gases), animals

  photosynthesis (plants take in $CO_2$ converts into glucose)

  carbon gets released again by;

  • respiration
  • animals eat the plant - respiration
  • plant/animal die - decay
  • decay - aerobic conditions - breaks down until Carbon is released as $CO_2$ - microbial respiration
  • decayed in anaerobic conditions - fossil fuels - burnt - releases $CO_2$
• decomposition

  dead organic matter being broke down in to inorganic matter

  what carry it out -

  detritus feeders - small animals, worms, that feed on dead organic matter

  decomposers - microorganisms - bacteria or fungi
• factors that effect decomposition

  1. Oxygen availability - high oxygen levels = high aerobic respiration = more energy available = faster growth and decomposition
  2. Temperature - high temperature = more kinetic energy in particles and enzymes are closer to optimum temperature = higher rate of reaction = more decomposition (temperature = too high - enzymes denature - decrease rate of reaction - decrease rate of decomposition
  3. Water content - decomposers need water to survive - moist conditions = increased rate of decomposition (soil = water logged - oxygen levels fall - decreases decomposition rate)
• Compost

  a mixture of decayed organic material that is used to fertilise and improve soil

  leave and plants in ideal conditions
• biogas generators

  some decomposing microorganisms can decompose without oxygen - anaerobic conditions - releases a mixture of gases - methane - methane is combusted and releases a lot of energy - used for cooking, heating or electricity

  Biogas generators - large containers which animals/plants are left to decompose anaerobically - no oxygen !!!!!

  Once biogas is removed from tank - sludge is left over - sludge = high density of useful minerals = fertilisers