Module 4 (15-18)- Global biomes

• Define Biosphere, Ecosystem and Biome

  Biosphere: The worldwide sum of all ecosystems

  Ecosystem: A community of living organisms in conjunction with the non-living components of their environment, interacting as a system

  Biome: A community of plants and animals that have common characteristics for the environment they exist in
• Describe how variation in solar radiation affects global climates

  • Variation due to seasonality
  • Intense solar radiation near the equator initiates a global pattern of air circulation and precipitation
  • High temperatures in the tropics evaporate water from the earths surface and cause warm, wet air masses to rise and flow towards the poles
  • The curved shape of the earth means there will be latitudinal variation in the sunlight intensity, and the amount of heat per unit of surface area
  • Sunlight intensity is strongest in the tropics where solar radiation is most direct
• Latitudinal Variation in sunlight intensity

  
• Describe how bodies of water affect local climates

  • Ocean currents influence the climate of nearby terrestrial environments
  • Currents flowing toward the equator carry cold water from the poles
  • Currents flowing away from the equator carry warm water to the poles
  • Air is cooled or warmed by these currents before passing over land
• Describe how bodies of water affect local climates

  
• Give the names of the main terrestrial biomes of the world and their key characteristics

  • Major life zones are characterised by vegetation type (terrestrial) or physical environment
• Temperate Broadleaf Forest (as a terrestrial biome)

  
• Tropical forest (as a terrestrial biome)

  
• Temperate Grassland (as a terrestrial biome)

  
• Savanna (as a terrestrial biome)

  
• Tundra (as a terrestrial biome)

  
• Tropical Forest (as a terrestrial biome)

  
• Northern Coniferous forest (as a terrestrial biome)

  
• Desert (as a terrestrial biome)

  
• What are the Plant and Animal Adaptations to the Desert?


  Plant

  • Heat + Desiccation tolerance
  • Water storage
  • Reduced Leaf surface area

  Animals

  • Many nocturnal spieces
  • Water conservers
• Heathlands (as a terrestrial biome)

  
• What is an Aquatic biome?

  • Have salt concentrations of 3%, fresh water biomes have a salt concentration of less than 0.1%
• Lakes -Freshwater (as an aquatic biome)

  • Temperate: seasonal thermocline
  • Tropical: all year-round thermocline
  • Oligotrophic and eutrophic
• Wetlands (as an aquatic biome)

  • Support plants adapted to water-saturated soil
  • Periodic depletion of dissolved o2
  • Streams and rivers
  • Wetlands are one of the most productive biomes on earth
  • Wetlands purify water and reduce flooding
• Streams and rivers (as an aquatic biome)

  • Current is the most predominant characteristic of streams and rivers
  • Headwater: cold, clear, turbulent, O rich
  • Downstream: warm, thick, nutrient-rich
  • Headwater streams in grassland or desserts may be rich in phytoplanktons/rooted aquatic plants
  • Damming and flood control impair rivers and streams functioning
• Estuaries (as an aquatic biome)

  • The transition area between the river and sea and so it has both saltwater and fresh-water
  • Salinity varies with the rise and fall of tides
  • Nutrient rich and highly productive
  • Complex network of tidal channels, islands, natural levees, mudflats
  • Hightide: seawater flows into stream
  • Lowtide: seawater flows down from the stream
  • Surface: low density seawater
  • Bottom: High density seawater
• Intertidal zone (as an aquatic biome)

  • Periodically submerged and exposed by the tides
  • Upper more exposure to air and greater change in temperature and salt levels
  • Challenging for organisms living here
  • Both o2 and nutrient rich
• Oceans (as an aquatic biome)+ Recall the physical extent of aquatic biomes on planet earth

  • Largest (70%) of the earths surface

  > 50-85% of photosynthesis by phytoplankton

  • Temperate ocean: photic zone seasonal turnover
  • Tropic ocean: Low in nutrients
• Coral reef (as an aquatic biome)

  • Formed by CaCO2 of cnidarians
  • Creates coral atoll after underwater volcanic explosion
• Marine Benthic Zone (as an aquatic biome)

  • Sea floor
  • Organism adopted to cold and high blood pressure
• Describe the Characteristics of different depth zones in aquatic systems (marine zonation)

  • Many aquatic biomes are stratified into zones defined by light penetration, temperature and depth
  • The upper photic zone has sufficient light for photosynthesis
  • The lower aphotic zone receives little light
  • The photic and aphotic zones make up the pelagic zone
  • The abyssal zone is located in the aphotic zone with a depth of 2,000 to 6,000m

  
• Describe the Characteristics of different depth zones in aquatic systems (zonation in a lake)

  
• What is an Autotroph?

  • They convert inorganic substances (such as light) into organic substances (such as glucose)
  • They are self-sustaining and produce their own energy by photo or chemosynthesis
  • They generate organic compounds by using CO2 and H2O, converting sugars into carbohydrates
  • They can convert light energy into ATP via Photosynthesis or Chemosynthesis
  • They are primary producers at the bottom of the food chain, providing organic material for organisms higher up.

  
• What is a Heterotroph?

  • They are unable to produce their own energy and obtain energy by consuming organic matter
  • They rely on external food sources to meet their energy requirements for growth and development
  • They break down organic molecules for energy through cellular respiration
  • They sit at higher trophic levels than autotrophs in the food chain

  
• What is the first law of Thermodynamics?

  The energy in the universe is constant

  • Energy can be transferred and transformed, but it cannot be created or destroyed
  • This is also known as the 'Principle of Conservation of Mass'
  • Energy is the capacity to cause change

  
• What is the Second Law of Thermodynamics?

  During every energy transfer or transformation, some energy is unusable and is often lost as heat

  • ie every energy transfer or transformation increases the entropy of the universe
  • Entropy is a measure of molecular disorder or randomness

  
• What is Conservation of Mass?

  • Like energy, matter cannot be created or destroyed
  • Ecosystems are open systems, absorbing energy and mass and releasing heat and waste products
  • Chemical elements are continually recycled within an ecosystem

  * If a nutrient's output from a system, exceeds its inputs, that nutrient will limit production
• How is the law of conservation of mass relevant to the function of the ecosystem?

  • It ensures the total mass of elements remains constant with in an ecosystem
  • Elements like carbon, nitrogen, phosphorus and others ie in the carbon and nitrogen cycles
• What is 'Community Trophic Structure'?

  • The feeding relationships between organisms in a community

  • It is a key factor that affects the structure and dynamic of the community
• Describe what a 'Food Chain' is

  • Food chains link trophic levels from producers to top carnivores

  • The position an organism occupies in a food chain is called it's 'trophic level'
• What is GPP and NPP?

  • Total primary production is the net amount of energy converted into organic compounds, the gross primary production (GPP)

  • This is measured as the conversion of energy from light or chemicals to the chemical energy of organic molecules per unit of time

  • Net primary production (NPP) is the GPP minus the energy used by autotrophs for respiration

  •NPP is the amount of new biomass added in a given period, not the total biomass of autotrophs

  • Only NPP is available to consumers
• 
  

  • Tropical rainforests, estuaries, and coral reefs are among the most productive ecosystems per unit area

  • Marine ecosystems are relatively unproductive per unit area, due to light and nutrient limitations but contribute a lot to GPP because of their size
• What factors control Primary Production in ecosystems?

  1. Sunlight availability
  2. Nutrient availability
  3. Water availability
  4. Temperature
  5. Carbon dioxide
  6. Biotic interactions
  7. Disturbances
  8. Soil/ substrate conditions
• Recall the typical value for energy transfer efficiency between trophic levels

  • Energy transfer between trophic levels is only 10% efficient

  
• What is the ultimate source of energy for nearly all life on earth?

  The sun

  • Plants get the energy to prepare their food from the sun and that is transferred to the whole food chain.