Ecology

• What is a living organism?

  An individual capable of life.

  It could be a tiny bacterial cell, or a yeast cell, or it could be a tree, or elephant, or insect. All of these are individual organisms.
• What is a habitat?

  The place where an organism lives.

  Eg, a tadpole lives in a freshwater habitat, but a woodlouse lives in a woodland habitat.
• What is an abiotic factor?

  A non-living factor that affects where an organism can live.

  Eg. Temperature, pH, wind speed, carbon dioxide or oxygen availability are all abiotic factors.
• What is a biotic factor?

  A living factor that affects where an organism can live. Eg. Food availability, competition, new diseases (pathogens) and new predators are all biotic factors.
• What is a population?

  All the individuals of the same species in the same habitat.
• What is a community?

  All the individuals of different species in the same habitat.
• What is an ecosystem?

  The interaction of the community of living organisms and the abiotic factors that affect them.
• How do living organisms interact?

  To survive and reproduce, organisms need a supply of materials from their environment and from the other organisms living there.
• Why do plants compete with each other?

  Plants need light, water, mineral ions and space to grow. Some plants are better competitors for these factors.
• Why do animals compete with each other?

  Animals need oxygen, water, food, mates and territory. Some animals are better competitors than others.
• What is interdependence?

  Species in a community depend on each other for food, shelter, pollination, seed dispersal etc. If one species is removed, the community becomes unstable.
• What is a stable community?

  A community where all the species and all the environmental factors are in balance.
• How can we spot a stable community?

  In a stable community the population sizes remain fairly constant. This is a sign of stability.
• Why are adaptations of living organisms important?

  Adaptations can help individuals survive in their normal conditions. There are three types of adaptations; structural, functional and behavioural.
• What is a functional adaptation?

  An adaptation of how the organism functions. Eg. Desert rats produce almost no urine. This function helps it survive in low water conditions.
• What is a behavioural adaptation?

  An adaptation of how the organism behaves.

  Eg. Desert rats are nocturnal (they sleep in burrows during the heat of the day). This behaviour helps keep it away from heat and some predators.
• What is an extremophile?

  Any organism (but usually bacteria) that can survive in high temperatures, high pressures or high salt concentrations.

  Eg. Bacteria living in deep sea vents survive at very high pressure.
• What are producers?

  Any organisms that produce their own glucose supply by photosynthesis using light from the sun as their energy source. Producers are green plants or algae.
• What are consumers?

  Any organisms that have to eat to get food. Some consumers graze on producers, and other consumers hunt and kill to get their food.
• What is biomass?

  The mass of living tissue in an organism. It is usually calculated as "dry mass" by drying out the organism until no water remains inside it's cells.
• What are food chains?

  Flow charts that show feeding relationships. All food chains start with a producer, and the arrow means "is energy for" or "is eaten by".
• What is a food web?

  A series of interconnected food chains. Webs show more detailed information about all the different foods that an organism might consume.
• What is a primary consumer?

  A consumer that eats plants (producers).
• What is a secondary consumer?

  A consumer that eats primary consumers.
• What is a predator species?

  A consumer that hunts and kills other consumers.
• What is a prey species?

  A consumer that is hunted and killed for food.
• What is a predator-prey cycle?

  A graph that shows the rise and fall of predator and prey populations over time in a stable community.

  Well known eg. is the lynx and the snowshoe hare which live in Northern Canada.
• What do we mean by "distribution" of a species?

  The location in a habitat that a particular species is found.

  Eg. Bluebells are found distributed mainly in woodlands and under hedges.
• What do we mean by "abundance" of a species?

  The number of individuals of a particular species.

  Eg. There may be a higher abundance of bluebells near the edges of the woodland than at the centre.
• How do we measure distribution and abundance?

  Using quadrats and transects to find a sample of a species. The sample should be representative of the whole habitat.

  There are two main sampling techniques.
• What processing can we do with abundance data?

  Calculate the mode, mean or median and range.

  We can plot graphs to show how abundance of a species changes through a habitat / how abundance differs between two habitats.
• What is the required practical for this unit?

  Measuring the population size of a species in a habitat using sampling techniques.
• What is the carbon cycle?

  The interchanging of carbon between the atmosphere, plants and respiring organisms.
• Why is the carbon cycle important?

  Carbon dioxide is taken in by plants during photosynthesis and released back into the atmosphere during respiration. If there is an imbalance due to too much combustion it causes problems.
• What can go wrong with the carbon cycle?

  Too much combustion causes carbon dioxide levels in the atmosphere to rise. This can lead to global warming as carbon dioxide is a greenhouse gas.
• What do microorganisms do in the carbon cycle?

  Microorganisms digest the carbohydrates in waste material, producing glucose; and then respire the glucose. This also releases carbon dioxide into the atmosphere and minerals to the soil.
• What do we call microorganisms in the carbon cycle?

  Any microorganism that digests carbohydrates and then respires the glucose is called a decomposer. The process is called decomposition.
• What is the water cycle?

  The cycling of water between the atmosphere (as vapour and clouds) and the water stores (rivers, lakes, oceans).
• Why is the water cycle important?

  All living organisms need a supply of fresh water. For humans our drinking water needs to be potable (safe for drinking).
• What is precipitation?

  Any water falling out of the sky is precipitation. Rain, hail, snow, sleet.