Ecology

• Water cycle


  1. Evaporation from oceans

  2. Water vapor travels into air

  3. Water vapor condenses to form clouds

  4. Precipitation (rain, snow, hail, sleet)

  5. Water hits ground

  6. Some evaporates back into atmosphere

  7. Some passes through rocks to form aquifers

  8. Some forms rivers/streams

  9. Rivers/streams drain back into sea

  10. Plants take up water in roots

  11. Water moves up plant in xylem

  12. Water passes out of leaf stomata as water vapor (transpiration)

  13. Animals take in water through drinking and food

  14. Animals release water in urine and feces, and when exhaling
• Almost all water on Earth is found in the oceans, which is salt water
• Energy from the Sun causes the water to evaporate from the surface of the sea
• Precipitation contains fresh water, not salt water
• Living organisms play a role in the water cycle
• Structural adaptations


  • Adaptations of body shape or body structure
• Functional adaptations


  • Adaptations to the body functions of an organism
• Behavioral adaptations


  • Adaptations to the animals lifestyle or behavior
• Extremophiles


  Organisms adapted to live in very extreme conditions
• Camel adaptations


  • Hump stores fat as thermal insulator
  • Thick coat insulates from heat
  • Leathery mouth to eat thorny plants
  • Long eyelashes keep out dust
  • Can close nostrils to keep out dust
  • Wide feet prevent sinking in sand
• Camel functional adaptations


  • Produce concentrated urine and dry feces to reduce water loss
  • Tolerate large changes in body temperature
• Kangaroo rat adaptations


  • Nocturnal to avoid daytime heat
  • Live in underground burrows to stay cool and avoid predators
• Arctic fox adaptations


  • Thick fur for insulation
  • Fur on soles of feet to reduce heat loss
  • Small ears to reduce surface area and heat loss
  • Camouflage coat for hunting
• Cactus adaptations


  • Small leaves or no leaves to reduce water loss
  • Spines to protect from animals
  • Extensive shallow roots to catch rainwater
  • Ability to store water in stem
• Extremophiles can live in very high temperatures, pressures and salt concentrations
• Conditions required for decomposition (decay)

  • Temperature
  • Amount of water
  • Amount of oxygen
• Decomposition takes place faster at warmer temperatures


  Decomposers use enzymes to break down plant materials, and these enzymes work faster in warm conditions
• Compost heaps tend to be quite warm because decomposers release energy when they carry out aerobic respiration
• It's important that the compost does not get too hot, as this can denature the enzymes and kill the decomposers
• Moist compost


  Decomposing microorganisms work faster
• Many chemical reactions in decay require water
• It's important that gardeners do not allow a compost heap to dry out
• Oxygen supply


  • Decomposers carry out aerobic respiration, which requires a good supply of oxygen
  • Compost bin has holes in the walls to allow oxygen to enter
  • Gardeners mix the compost regularly to increase oxygen supply
• Anaerobic decay


  Decomposing microorganisms carry out anaerobic respiration in the absence of oxygen
• Biogas


  Mixture of gases, including methane, produced by anaerobic decay
• Small-scale biogas generators use plant materials or animal manure to produce fuel for homes
• Biomass


  The mass of living organisms in a given area or ecosystem
• Measuring biomass


  1. Collect organisms

  2. Dry them

  3. Weigh them
• Dry biomass is more useful than wet biomass because the moisture content of organisms can vary widely and produce inaccurate results
• Pyramid of biomass


  A graphical representation of the biomass at each trophic level in an ecosystem
• Only around 1% of the light energy that falls on producers is actually absorbed and used for photosynthesis
• As you move up trophic levels

  The amount of biomass decreases
• Reasons for biomass decrease between trophic levels

  • Not all material ingested is absorbed
  • Some biomass is converted to waste products
  • Some biomass is used for respiration
• A more realistic pyramid of biomass reflects the fact that only around 10% of the biomass at one trophic level passes to the next level
• Calculating efficiency of biomass transfer

  1. Gain in biomass / Total biomass intake

  2. Convert to percentage by multiplying by 100