Ecology and environment

• What is an individual part of a species living in its habitat called?

  Population
• How do different populations interact in the same habitat?


  They create a community.
• What is an ecosystem?


  An ecosystem is the interaction of a community with non-living parts of the environment.
• Why are organisms adapted to their environment?


  To survive in the conditions of their environment.
• What is the purpose of using quadrats in ecological studies?


  • To estimate distribution and abundance of organisms
  • To study a few smaller representative samples within a large area
• What is a transect?


  A defined area where samples will be taken to estimate the number of organisms.
• How are quadrats used along a transect?


  Quadrats are placed along the transect to count the amount of the chosen organism.
• Can quadrats be placed randomly across an area?


  Yes, quadrats can be randomly placed across the whole area.
• What is percentage cover in ecological studies?


  It is an estimate of how much area is covered by a particular organism.
• Why is estimating percentage cover considered less accurate?


  Because it is subjective compared to counting which gives a quantitative value.
• How can the accuracy of quadrat estimations be improved?


  By doing more samples, repeat testing, or completing sampling over larger transects.
• What does biodiversity measure?


  The range of species living within an ecosystem.
• How can biodiversity be measured using quadrats?


  • Count the populations of different species in each quadrat
  • Use the same size quadrats each time
  • Increase the number of samples taken in each area
• What are abiotic factors?


  Non-living components of the environment.
• What are biotic factors?


  Living components of the environment.
• How does light intensity affect plant growth?


  It is required for photosynthesis, which affects the rate of plant growth.
• Why is food availability important for organisms?


  More food means organisms can breed more successfully, increasing population numbers.
• How does temperature affect photosynthesis?


  Temperature affects the rate of photosynthesis.
• What happens when a new pathogen arises in a population?


  The population may have no resistance and can be wiped out quickly.
• How does soil pH affect plant growth?


  Soil pH affects the rate of decay and how fast mineral ions return to the soil.
• What is competition in ecosystems?


  If one species is better adapted, it will outcompete the lesser adapted species.
• What are trophic levels?


  The feeding levels in a food chain.
• What are producers?


  Organisms that make their own food by photosynthesis.
• What are primary consumers?


  Herbivores that only eat plants.
• What are secondary consumers?


  Carnivores that eat primary consumers.
• What are tertiary consumers?


  Carnivores that eat secondary consumers and have no predators.
• What are decomposers?


  Bacteria and fungi that break down dead matter for energy.
• What is the difference between food chains and food webs?


  • Food chains show feeding relationships organized by trophic levels.
  • Food webs are a collection of different food chains showing interdependence among organisms.
• What do pyramids of numbers show?


  The population of each organism at each trophic level of a food chain.
• How do pyramids of biomass differ from pyramids of numbers?


  Pyramids of biomass show the relative dry mass of material at each trophic level.
• Why is there less biomass as you move up trophic levels?


  Not all food consumed is converted into biomass.
• What percentage of incident energy do producers transfer for photosynthesis?


  About 1% of the incident energy from light.
• What percentage of biomass is transferred to the next trophic level?


  Approximately 10% of the biomass.
• Why can't all biomass be eaten by carnivores?


  Carnivores cannot generally eat bone, hooves, claws, and teeth.
• What happens to glucose used in respiration?


  It produces carbon dioxide as a waste product.
• What is urea?


  A waste substance released in urine.
• Why is not all biomass consumed converted into biomass of the animal eating it?


  Because lots of glucose is used in respiration and lost as waste.
• What is the formula for efficiency of biomass transfers?


  (Biomass transferred to the next level / Biomass available at the previous level) x 100
• Why are there fewer animals in higher trophic levels?


  Because less biomass is transferred at each level.
• What are the main processes in the carbon cycle?


  1. Respiration: CO2 is released by plants and animals.
  2. Photosynthesis: Plants remove CO2 from the air.
  3. Decomposition: Dead matter is broken down by decomposers.
  4. Combustion: Burning of plants and fossil fuels releases CO2.