Ecosystems & material cycles

• What is the term for a group of individuals of the same species living in a specific habitat?

  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 (abiotic) parts of the environment.
• Why are organisms adapted to their environment?

  Organisms are adapted to live in the conditions of their environment.
• What is competition in ecological terms?

  Competition is when organisms need the same resources and compete for them.
• What are the types of competition that can occur in ecosystems?

  • Competition within a species
  • Competition between different species
• What resources do plants compete for?

  Plants may compete for light, space, water, and mineral ions.
• What resources do animals compete for?

  Animals may compete for space, food, water, and mating partners.
• What is an abiotic factor?

  An abiotic factor is a non-living factor that can affect a community.
• How does light intensity affect a community?

  Light is required for photosynthesis, which affects plant growth.
• What is the relationship between temperature and photosynthesis?

  Temperature affects the rate of photosynthesis.
• Why do both plants and animals need moisture levels?

  Both plants and animals need water to survive.
• How does soil pH affect a community?

  Soil pH affects the rate of decay and how fast mineral ions return to the soil.
• What is the effect of wind intensity on plants?

  Wind affects the rate of transpiration in plants.
• How do carbon dioxide levels affect plants?

  CO₂ affects the rate of photosynthesis in plants.
• Why are oxygen levels important for aquatic animals?

  Oxygen levels in water vary greatly, and most fish need a high concentration of oxygen to survive.
• What is a biotic factor?

  A biotic factor is a living factor that can affect a community.
• How does food availability affect a community?

  More food means organisms can breed more successfully, increasing the population.
• What happens when a new predator is introduced to a community?

  A new predator can affect the population dynamics of the community.
• How do new pathogens affect a population?

  A new pathogen can wipe out a population quickly if there is no resistance.
• What is the impact of competition on species in a community?

  If one species is better adapted, it will outcompete the other, reducing its numbers.
• What is interdependence in ecological terms?

  • Interdependence describes how organisms depend on each other for vital services.
  • These include food, shelter, and reproduction (e.g., pollination, seed dispersal).
• How does the removal or addition of a species affect a community?

  It can greatly affect the populations of others by changing prey or predator numbers.
• What characterizes a stable community?

  • All biotic and abiotic factors are in balance.
  • Population sizes remain roughly constant.
  • Difficult to replace lost factors.
  • Examples include tropical rainforests, oak woodlands, and coral reefs.
• What is parasitism?


  Parasitism is when a smaller species benefits at the expense of a larger species.
• What is a mutualistic relationship?

  A mutualistic relationship provides some benefit or resource to the other species.
• How does parasitism affect the host species?

  Parasitism involves taking nutrients from another species, which can lead to detriment for the host.
• What is an example of a parasite in humans?

  The tapeworm is a parasite that lives inside the gut.
• What is commensalism?


  Commensalism is when there is no damage caused to either species, often with mutual benefit.
• How do algae and fungi interact in lichens?

  Algae provide sugars for fungi, while fungi allow algae to live in extreme conditions.
• What are the methods for counting organisms in a given area?

  • Use fieldwork techniques and tools like quadrats and transects.
  • Estimate populations by sampling a small area.
• How can we estimate the number of 3-leaf clovers in a field?

  By taking a sample from a small area and using it to estimate the entire population.
• What is the process for estimating the number of clovers in a field using quadrats?

  1. Divide the field into 100 equal 1m x 1m squares.

  2. Randomly select a square using a random number generator.

  3. Place a 1m x 1m quadrat in the selected square.

  4. Count the number of clovers in the square.

  5. Repeat with a different square 4 times and average the results.

  6. Multiply the average by 100 to estimate the total number of clovers.
• What do pyramids of biomass show?

  Pyramids of biomass show the relative biomass at each trophic level.
• What happens to biomass as you move up the trophic levels?

  There is less biomass as you move up the trophic levels.
• Why is not all food consumed by an animal converted into biomass?

  Not all food consumed is converted into biomass due to waste and energy used in respiration.
• What is the formula for calculating the efficiency of biomass transfers?

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

  Because less biomass is transferred at each level.
• What are some positive human interactions with ecosystems?

  • Maintaining rainforests and habitats.
  • Raising public awareness about ecosystem protection.
  • Reducing water pollution and monitoring changes.
  • Preserving areas of scientific interest.
  • Replanting hedgerows and woodlands.
• What are some negative human interactions with ecosystems?

  • Production of greenhouse gases leading to global warming.
  • Introducing non-indigenous species that prey on natives.
  • Producing sulfur dioxide leading to acid rain.
  • Chemicals leaking into the environment causing eutrophication.
  • Clearing land for development, reducing habitats.