Ecology exam

• Ecology Notes


  • carbon cycle
  • nitrogen cycle
  • water cycle

  
• how these processes are also affected by human disturbances
• photosynthesis


  process where plants use water, sunlight, and carbon dioxide to create oxygen and glucose
• invasive species


  species that are not native to an ecosystem and can cause harm
• analyzing food webs and roles of organisms within

  1. how energy flows within

  2. bio amplification

  3. calculating it
• 01:: 02:: 03:: Food Chains, Food Webs & Energy Pyramids

  • Pyramids
  • Pyramid of Biomass
  • Pyramid of Numbers
• Energy Cycling in Ecosystems

  1. Photosynthesis

  2. Cellular respiration

  3. Carbon, nitrogen, phosphorus & water cycle
• Carbon Cycle


  how it is affected by human disturbances

  
• Nitrogen Cycle


  1. Production

  2. Fixation

  3. Nitrification

  4. Assimilation

  5. Ammonification

  6. Denitrification

  
• Eutrophication


  too much nitrogen enters an aquatic ecosystem, causing rapid growth of algae and loss of food, habitat and oxygen production

  
• Pesticides and bioaccumulation


  • Bioaccumulation
  • Bioamplification
  • Bioamplification VS bioaccumulation
• Invasive species


  Control of Invasive Species
• energy pyramids (constructing your own) based on food web


  1. calculating energy passed on

  2. role of a keystone species (remembers octonauts! otters/kelp)

  3. transfers of energy and inorganic nutrients in ecosystems (difference)
• Energy flow/ availability


  • calculating the amount of energy available at each tropic level
  • calculating amount of energy in pyramid
• Autotrophs / producers


  organisms that make their own food either using sun's energy for photosynthesis/ chemical energy for chemosynthesis
• Heterotrophs / consumers


  • Primary consumers - they eat producers/ autotrophs
  • Secondary consumers - they eat primary consumers
  • Tertiary consumers - they eat secondary consumers
  • Quaternary consumers - they eat tertiary consumers
• Decomposers


  break down dead organisms and organic matter to obtain chemical energy, in the process, they recycle materials
• Energy Flow


  • there are different levels called tropic levels in an energy pyramid (represent a food chain)
  • most limited to 4-5 levels, because the flow of the energy between levels is inefficient
  • 10% Energy Transfer Rule - around only 10% of energy stored as biomass in one tropic level ends up biomass in the next tropic level
• Chemical equation for photosynthesis: 6CO2 Carbon dioxide + 6H2O Water → (light)→ C6H12O6 Glucose + 6O2 Oxygen
• Chemical equation for cellular respiration: Glucose + oxygen → (energy released) → carbon dioxide + water
• Breakdown of dead organisms and animals waste (from plants and animals) by decomposers
• Fossilization of dead animals and plants under certain conditions can produce fossil fuels → combustion by humans
• Human Impact


  • Deforestation
  • Burning Fossil Fuels
  • Climate Change causes melting permafrost in North
• Nitrogen cycle


  1. N2 gas released to atmosphere

  2. Bacteria convert NO3 to N2 gas

  3. Bacteria convert atmosphere N2 gas to usable NO3
• Nitrogen fixation


  The process of converting atmospheric nitrogen (N2) into forms that plants can use

  
• Ways nitrogen can be fixed so plants can use it

  • Natural - Lightning, Nitrogen Fixing Bacteria, Nitrifying Bacteria
  • Manmade - Fertilizers made from N2 gas

  
• Eutrophication


  1. Nitrogen and Phosphorous cause plants and algae to grow rapidly

  2. Algae covers surface blocking sunlight

  3. Plants die due to lack of sunlight

  4. Bacteria break down dead matter, consume oxygen and release CO2

  5. Loss of oxygen leads to hypoxia and dead zones
• Causes of eutrophication


  • Fertilizer runoff or leaching
  • Algae bloom due to presence of nutrients
  • Bacteria use oxygen to break down the algae
  • Fish suffocate due to lack of oxygen
• Phosphorus cycle


  1. Weathering releases phosphate ions

  2. Phosphate ions dissolve in water and transported

  3. Marine plants and algae absorb phosphate ions

  4. Phosphate enters soil and food chain

  5. Decomposers recycle phosphates

  6. Sedimentary rock formation and uplift

  
• Water cycle


  1. Evaporation

  2. Transpiration

  3. Condensation

  4. Percolation

  5. Runoff

  
• Human impacts on water cycle include deforestation, diverting runoff, and climate change melting ice
• Pests


  Organisms that compete with or damage crop species
• Pesticides


  Substances used to kill pests
• Types of pesticides


  • Broad spectrum - toxic to many species
  • Narrow spectrum - toxic to limited number of species
• Bioaccumulation


  The process by which toxins accumulate in the bodies of animals
• Bioamplification


  The increase in concentration of a substance such as a pesticide as we move up trophic levels within a food web
• Differences between bioaccumulation and bioamplification

  • Bioaccumulation - Accumulation of toxins within the bodies of organisms at the same trophic level
  • Bioamplification - Accumulation of toxins as you move up trophic levels
• Types of species


  • Endemic - native to a defined geographic region
  • Alien - transferred from natural habitat to new environment
  • Invasive - alien species with detrimental effect on pre-existing food chains
• Methods of controlling invasive species

  • Biological control - manipulation of natural enemies
  • Mechanical control - physically removing invasive species
  • Chemical control - use of herbicides and poisons
• Abiotic limiting factors


  Non-living factors that living things depend on to survive