B7 improved

• Ecosystem


  The interaction of a community of living organisms with the non-living parts of the environment

  
• Biotic and abiotic factors

  Biotic factors are a result of living things in an environment such as food availability, abiotic factors are a result of non-living things in an environment such as temperature

  
• Habitat


  The specific area or environment where an organism lives

  
• Organism


  An individual living thing that is part of a much larger ecosystem

  
• Population


  A group of individuals of the same species that live in the same area and time and are capable of reproducing to produce fertile offspring

  
• Community


  All of the individuals of the different species that live in the same area and time and interact with one another in an environment

  
• Interdependence


  Each species within a community depends on other species for food, shelter, pollination and seed dispersal

  
• Predator-prey relationship


  The interdependent interaction between an organism that eats another organism and the consequent effect one species has on the other

  
• Removing a species from an ecosystem

  If one species or population is removed from an ecosystem it can have a significant impact on the entire community
• Stable community


  One where all the species and environmental factors are in balance so the population sizes remains fairly constant
• Resources


  To survive and reproduce, organisms require a supply of materials from their surroundings and from the other living things there
• Competition


  Organisms need resources that are often scarce to survive and reproduce, so most organisms must compete with one another to obtain or claim these resources

  
• Competition between species


  Also known as interspecific competition, different species may compete for resources such as food or territory

  
• Competition within a species


  Also known as intraspecific competition, individuals within a species may compete for resources such as food, territory or mates

  
• Reasons for competition in animals

  Food, access to water, mates, shelter or territory

  
• Reasons for competition in plants

  Light for photosynthesis, space, water and mineral ions in the soil

  
• Adaptation


  Organisms have specific features that enable them to survive in the conditions in which they normally live

  
• Examples of adaptations


  Large surface area to volume ratio to keep cool in hot environments, thick fur in cold environments, camouflage to hide from other organisms, feet with large surface area to trek on sand or snow

  
• Surface area to volume ratio (SA:V ratio)

  The amount of surface area in relation to how large something is, for example organisms in a cold environment reduce heat loss by having a low SA:V ratio

  
• Structural adaptation


  Physical features that allow organisms to compete, such as sharp claws in animals to catch prey or broad leaves to optimise photosynthesis in plants

  
• Behavioural adaptation


  Behaviours that give organisms an advantage, such as nocturnal activity in desert animals to stay cool or plant shoots growing towards light in plants

  
• Functional adaptation


  Adaptive body functions in an organism such as concentrated urine in camels to prevent water loss or poison to prevent predation in plants

  
• Extremophiles


  Some organisms like the bacteria living in deep sea vents live in extreme environments such as at high temperature, pressure or salt concentration

  
• Ecosystem


  The interaction of a community of living organisms with the non-living parts of the environment

  
• Community


  All of the individuals of the different species that live in the same area and time and interact with one another in an environment

  
• Biotic


  Factors that result from living things in an ecosystem

  
• Abiotic


  Factors that result from non-living things in an ecosystem

  
• Light intensity


  An abiotic factor, plants require energy from sunlight to photosynthesise

  
• Temperature


  An abiotic factor, most organisms are sensitive to temperature as it can affect metabolic rates and enzyme activity

  
• Moisture levels


  An abiotic factor, moisture in soil is necessary for the survival of most plants and specific humidity levels or water sources are essential for most organisms

  
• Soil pH and mineral content


  An abiotic factor, plant cells and enzymes are sensitive to pH and also require minerals for sufficient plant development

  
• Wind intensity and direction

  An abiotic factor, wind can affect the rate of transpiration in plants, can damage organisms and can help some organisms to disperse

  
• Carbon dioxide levels


  An abiotic factor, plants require sufficient levels of this gas for photosynthesis

  
• Oxygen levels


  An abiotic factor, the levels of oxygen in water can affect animals in aquatic environments

  
• Food availability


  A biotic factor, animals depend on other animals or plants as sources of food

  
• Arrival of new predators

  A biotic factor, the arrival of new organisms capable of predation can affect the levels of animals or plants in an ecosystem

  
• New pathogens


  A biotic factor, organisms can be severely affected by the introduction of new diseases

  
• One species outcompeting another species

  A biotic factor, if one species is outcompeted the population of that species may decline as individual organisms may not be able to obtain the resources needed to survive and reproduce