(25 hours)
2.1 Species and populations
2.2 Communities and ecosystems
2.3 Flows of energy and matter
2.4 Biomes, zonation and succession
2.5 Investigating ecosystems
At the end of this Subtopic 2.1 - Species and populations, you should be able to:
- Define the following terms biotic, abiotic, species, population, carrying capacity, limiting factors and habitat.
- Explain what a niche and the difference between a fundamental and realised niche.
- Explain how selected non-living factors influence organisms and ecosystems.
- Sketch and interpret S- and J-shaped population curves.
- Identify and explain S- and J-shaped population curves.
- Discuss how populations change and interact with the physical environment.
- Describe the following species interactions: predation, herbivory, parasitism, mutualism, disease and competition.
- Explain how the species interactions impact population dynamics and carrying capacity.
At the end of this Subtopic 2.2 - Communities and ecosystems, you should be able to:
- Define ecosystem and community.
- Explain the concept of trophic levels.
- Describe and explain the different groups of organisms – producers, consumers and decomposers.
- Describe the feeding relationships between these groups of organism using food chains, food webs and ecological pyramids.
- Construct diagrams of food chains, food webs and ecological pyramids from given data.
- Describe and explain respiration and photosynthesis as a system of inputs, processes and outputs.
- Represent respiration and photosynthesis as word equations.
- Construct diagrams of respiration and photosynthesis.
- Explain the process of respiration and how it relates to the laws of thermodynamics.
- Explain the process of photosynthesis and how it produces the raw materials for producing biomass.
- Describe and explain the different type of ecological pyramid.
- Explain why most ecological pyramids are pyramid shaped with a wide base narrowing towards the top.
- Explain why some pyramids are not pyramid shaped.
- Explain how food chains, food webs and ecological pyramids exemplify the laws of thermodynamics (the transfers and transformations of energy through the system).
- Analyse the efficiency of energy transfers from given data.
- Explain the impacts of energy transfers on the top trophic levels in terms of toxin build up and bioaccumulation and biomagnification.
What you should know
At the end of this Subtopic 2.3 - Flows of energy and matter, you should be able to:
- Explain the pathways of solar radiation as it passes though the atmosphere.
- Explain the pathways of energy through the ecosystem – conversions, transfers, transformations, efficiencies and losses.
- Define and explain productivity – gross and net.
- Calculate net primary productivity, gross primary productivity, net secondary productivity and gross secondary productivity from given data and diagrams.
- Explain the link between net primary and net secondary productivity of a system and maximum sustainable yield.
- Describe the differences between energy flow and nutrient cycling.
- Explain how energy and matter may transfer and transform in ecosystems.
- Demonstrate how the carbon and nitrogen cycles illustrate stores and flows of matter.
- Outline the different stores and flows in the carbon and nitrogen cycles.
- Discuss the impacts of human activity on energy flows and the carbon and nitrogen cycles.
- Construct and analyse quantitative models of energy and matter flows from given graphs or data.
What you should know
At the end of this Subtopic 2.4 - Biomes, zonation and succession, you should be able to:
- Define the terms biome, succession and zonation.
- List the five major classes of biomes.
- Explain how insolation, precipitation and temperature determine the distribution of the biomes.
- Use the tri-cellular model to explain the distribution, structure and productivity of the biomes.
- Use case studies to explain the distribution, structure, limiting factors, productivity and biodiversity of contrasting biomes.
- Analyse data from various biomes.
- Discuss how climate change is impacting biomes and causing them to shift.
- Explain how energy flows, GPP and NPP, diversity and mineral cycling change during succession.
- Demonstrate how reproductive strategies change between pioneer and climax communities.
- Distinguish the roles of r and k strategists in succession.
- Use a case study to describe the pattern of change in the plant communities during succession.
- Explain how succession links to habitat, species and genetic diversity.
- Explain how complex ecosystems contribute to stability by having a variety of nutrient and energy pathways.
- Explain how climax communities will vary depending on climate, soil and a range of other local factors.
- Discuss the range of factors that can divert the progression of succession.
- Explain how the diversion may end in a permanent or temporary alternative stable state.
- Explain how the resilience of the ecosystem can impact its response to change.
- Interpret models and graphs of succession and zonation.
- Discuss how human activity impacts ecosystem stability, succession and diversity.
What you should know
At the end of this Subtopic 2.5 - Investigating ecosystems, you should be able to:
- Demonstrate sound knowledge of named and located ecosystems.
- Explain how to identify organisms using keys, technology and scientific expertise.
- Construct and use simple keys to identify eight organisms.
- Explain and evaluate sampling strategies and how they are applied to measuring changes in abiotic and biotic factors over time and space.
- Evaluate methods for investigating at least three abiotic factors.
- Explain why measurements need to be repeated.
- Explain and evaluate methods for estimating biomass and energy in different trophic levels.
- Explain how biomass and energy measurements can be used to construct ecological pyramids.
- Explain and evaluate the use of quadrats for estimating the abundance of non-motile organisms through making actual counts, measuring population density, percentage cover and percentage frequency.
- Evaluate the use of use of quadrats as tools for measuring abundance of non-motile organisms.
- Apply and evaluate the use of the Lincoln index and the Simpsons diversity index.
- Interpret species richness data.
- Construct graphs to show spatial or temporal changes in species richness.
- Discuss the use of species richness to compare ecosystems.
- Design, conduct and evaluate ecological investigations using appropriate techniques.
- Design and evaluate ecological investigations that look at changes in an ecosystem along an environmental gradient and after human impact.