1. ECOSYSTEMS

2. Learning objectives

3. Terms and definitions Define the term ecosystem and be aware of variations in ecosystem scale ranging from micro-scales to macro-scales (biomes). Be able to define ecosystems in terms of inputs, flows, stores and outputs.  

4. Biotic and abiotic components
Demonstrate an awareness of how the biotic (plants, animals, soil, bacteria, fungi)
and abiotic (water, air, minerals, nutrients, light) components interrelate to form a natural functioning system, taking into account other contributory factors of acidity, temperature, humidity and wind.

5. Links between the various components
Understand the relevant concepts of dynamic equilibrium, food webs and food chains.
Demonstrate an awareness of the complexity of links between biotic and abiotic components and how changes to one or more of the components can disturb the equilibrium of the system, especially as a result of human activity.
Understand how positive and negative feedback contribute to the stability of the system.

6. Fragility, vulnerability and resilience of the system
Understand that changes to ecosystems may be temporary (where recovery may occur leading to the re-establishment of the system) or permanent, leading to modification of the system.  

7. biosphere
The part of the Earth including air (atmosphere), water (hydrosphere) and minerals (lithosphere) where life can exist is called the biosphere.

8. One particular type of organism. Homo sapiens
species
One particular type of organism.
Homo sapiens

9. population
All the members of a species living in a particular area at the same time.

10. community
All of the different populations of organisms which live together for example the grasses, trees, insects, deer and birds which live in a part of a wood.

11. biota or the biotic factors
The living organisms in an ecosystem – the plants, animals, and micro-organisms.

12. The non-living chemical and physical parts of the environment.
abiotic factors
The non-living chemical and physical parts of the environment.

13. sun’s energy + = carbohydrates
producers
sun’s energy = carbohydrates

14. consumers

15. detritivores and decomposers
Detritivores digest the organic matter internally after ingesting it. They speed up decay by shredding the dead matter, thereby increasing the surface area for attack by the decomposers - bacteria and fungi (e.g., mushrooms).
Both bacteria and fungi have the capacity to release enzymes that break apart the organic molecules, thereby releasing the inorganic elements into the environment (e.g., soil or water). This process is called decomposition.

16. Some of these elements are then taken inside the bacteria or fungus to provide them with nutrients, as well as energy; those that are not taken in may be absorbed by plants and are eventually passed to herbivores and carnivores in the food chain. Nutrient cycling within an ecosystem is not a perfect process because some nutrients may be lost from the ecosystem as a result of soil erosion.

19. Detritus - Dead organic matter
Detritus - Dead organic matter. It includes the dead bodies of all organisms, as well as fecal matter and shed body parts (e.g., snake skin, outer shell of crayfish after it is molted). Detritivore - Organism that eats detritus. These are important in decomposition, but they are not decomposers. The term scavenger specifically refers to animals that feed on dead animals or their remains. Decomposer - Organism (bacteria or fungi) that is able to release enzymes outside of its body in order to digest organic matter into inorganic elements (saprophytes). Decomposition - gradual disintegration of dead organic matter resulting in the release of energy and inorganic elements from their organic state.

22. food web

23. feeding or trophic level

24. pyramid of energy

25. Energy (90%) is lost at each stage
Not all of the plant is eaten
Unable to digest or break down all of the material
consumed
Running
Respiration
Growing

26. Pyramid of numbers/ biomass
It takes a large number of primary producers to support a smaller number of primary consumers, which in turn provide food for an even smaller number of carnivores.
Pyramid of numbers/ biomass

27. symbiosis
Where two organisms live together in an intimate situation that is of benefit to them both.

28. The place where a particular organism or population lives.
habitat
The place where a particular organism or population lives.

29. niche
This refers to an animal’s role in a habitat – what it feeds on and when, where it finds shelter, etc.

30. Competition between two members of the same species.
intraspecific
Competition between two members of the same species.

31. Competition between members of two different species.
interspecific
Competition between members of two different species.

32. Gradual progression from one community to another.
natural succession
Gradual progression from one community to another.

33. primary succession
The introduction of species into an area that has never previously been colonised.

34. primary colonisers form a pioneer community
The first species to enter an area.

35. secondary succession
The re-establishment of species into an area that once contained populations of plants and animals, but which have been disturbed.

36. (climatic) climax community
Eventually a stable ecosystem develops which is in equilibrium with its environment and which normally undergoes little further change.

37. different soil types different climax community
edaphic climax
different soil types different climax community

38. plagioclimax A climax community produced by the action of humans.
Succession is then said to be deflected.

39. Environmental factors which produce zonation on rocky shores:
Ability to withstand drying (desiccation)
Ability to withstand wave pounding

40. Species diversity (D) can be calculated from the formula:
The most common formula for working out Species Diversity is the Simpson’s diversity index Simpson's diversity index,
which uses the following formula:
Where:
D = diversity index
N = Total number of organisms of all species found
n = number of individuals of a particular species
Usually used in studies of vegetation but can also be applied to animals.