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KS4 Habitats & Sampling
Learning Objectives

7.1.1 Communities

Students should:

• Know that an ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
• Know that to survive and reproduce, organisms require a supply of materials from their surroundings and from the other living organisms there.
• Know that plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil.
• Know that animals often compete with each other for food, mates and territory.
• Know that within a community each species depends on other species for food, shelter, pollination, seed dispersal etc.
• Know that if one species is removed it can affect the whole community and that this is called interdependence.
• Know that a stable community is one where all the species and environmental factors are in balance so that population sizes remain fairly constant. Examples include tropical rainforests and ancient oak woodlands.
• Be able to record first-hand observations of organisms.

7.1.2 Abiotic factors

Students should:

• Be able to explain how a change in an abiotic factor would affect a given community given appropriate data or context.
• Know that Abiotic (non-living) factors which can affect a community include:
  - light intensity
  - temperature
  - moisture levels
  - soil pH and mineral content
  - wind intensity and direction
  - carbon dioxide levels for plants
  - oxygen levels for aquatic animals.
• Be able to extract and interpret information from charts, graphs and tables relating to the effect of abiotic factors on organisms within a community.

7.1.3 Biotic factors

Students should:

• Be able to explain how a change in a biotic factor might affect a given community given appropriate data or context.
• Know that Biotic (living) factors which can affect a community include:
  - availability of food
  - new predators arriving
  - new pathogens
  - one species outcompeting another so the numbers are no longer sufficient to breed, such as the introduction of grey squirrels into southern Britain outcompeted the native red squirrels.
• Be able to extract and interpret information from charts, graphs and tables relating to the effect of biotic factors on organisms within a community.

7.1.4 Adaptations

Students should:

• Be able to explain how organisms are adapted to live in their natural environment, given appropriate information.
• Know that organisms have features (adaptations) that enable them to survive in the conditions in which they normally live and that these adaptations may be structural, behavioural or functional.
• Know that organisms that live in environments that are very extreme, such as at high temperature, pressure, or salt concentration are called extremophiles.
• Know that bacteria living in deep sea vents is an example of an extremophile.

7.2 Organisation of an ecosystem

7.2.1 Levels of organisation

Students should:

• Know that photosynthetic organisms are the producers of biomass for life on Earth.
• Know that feeding relationships within a community can be represented by food chains.
• Know that all food chains begin with a producer which synthesises molecules and that this is usually a green plant or alga which makes glucose by photosynthesis.
• Know a range of experimental methods using transects and quadrats are used by ecologists to determine the distribution and abundance of species in an ecosystem.
• In relation to abundance of organisms students should be able to:
  - understand the terms mean, mode and median
  - calculate arithmetic means
  - plot and draw appropriate graphs selecting appropriate scales for the axes.
• Know that producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.
• Know that consumers that kills and eat other animals are predators, and those eaten are prey.
• Know that in a stable community the numbers of predators and prey rise and fall in cycles.
• Be able to interpret predator-prey graphs.

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