ASSESSMENT TASK: Ecosystem report

Discussion:

Biotic components of the ecosystem

1. Comment on any differences in the number or types of primary producers that were present in your 2 ecosystems.

2. Provide at least 2 abiotic factors and 2 biotic factors that might be influencing these differences in primary producers between your two ecosystems. If you didn't find major differences, you should still comment on two abiotic and biotic factors that you think are having a significant influence on the primary producers in this system.

3. Think about any differences you have found and how these might influence the types of niches available for other plants and animals (e.g. how much structural complexity occurs in your 2 ecosystems and why might this be important

Interactions between biotic and abiotic components of the ecosystem

In addition to plant species, a range of different heterotrophs (animals, fungi and some bacteria) are typically found in an ecosystem. The dynamics and interactions between these plants and animals is also greatly influenced by the abiotic components of an ecosystem. This is where your list of heterotrophs will assist you with the following questions. Think about the kinds of animals you observed and where they were found. Now think about the abiotic components of your ecosystems, such as water, soil, rocks, air, light and other non-living components.

4. For each of your ecosystems, describe one example of how:
- the abiotic environment affects living things in each ecosystem;
- living things can change or modify the abiotic environment in each ecosystem over time.

5. Other than feeding, what types of biotic interaction did you observe or would you expect to observe at other times (i.e. just those interactions among heterotrophs)?

Energy flow in the ecosystem

All living organismsrequire energy for daily metabolism, growth, reproduction and movement (animals). Energy comes into most ecosystems from sunlight. Light energy from the sun is converted into chemical energy in plants by the process of photosynthesis. This chemical energy then flowsthrough the ecosystem in several ways. First, the ‘grazing pathway' involves the flow of energy from one organism to another as primary consumers eat plants, and secondary consumers eat primary consumers and so on. Second, the ‘detritus pathway' involves the flow of energy as degraders breakdown this detritus into small components and materials that are then recycled in the ecosystem. This often starts with larger detritivores (that typically eat leaf/woody material) and scavengers (that typically feed on carrion) and is finally broken down by the decomposers, which include fungi, bacteria and other microorganisms. The
degraders form part of the food chain because they are also consumed by higher trophic levels (e.g. the secondary and tertiary consumers).

Energy is transferred along these food chains, from one trophic level to the next, with large amounts being lost as heat along the way. Ultimately, all energy that enters the ecosystem is lost as heat: energy is NOT recycled.

Look carefully within your ecosystem to identify organisms that represent different trophic levels along the pathway of energy flow.

Primary producers (or autotrophs).

6. What were the two most common primary producers, based on percent cover, in each of your ecosystems?

7. From what you can recall, were these species also the most abundant within your ecosystem?? Remember, percentage cover and abundance are two very different measures of how ‘common' particular species might be.

8. Why do you think these species were more common than other primary producers in these ecosystems?

9. What other primary producers might be present in your ecosystem that you could not observe?

Primary consumers (heterotrophs)

10. What were the two most common primary consumers in each of your two ecosystems?

11. Were they consuming primary producers while you were observing them, and if so, what were they consuming?

12. If these primary consumers were not observed feeding, then how can you be sure that they are primary consumers?

Secondary consumers

13. What were the two most common secondary consumers that you observed in each of your two ecosystems?

14. If feeding, what were these secondary consumers eating during your observations?

15. If these secondary consumers were not observed feeding, then how do you be sure that they are secondary consumers?

Tertiary consumers

16. Can you identify any tertiary consumers in this ecosystem? Tertiary consumers are often harder to find. If not, describe at least one tertiary consumer that could potentially occur, even if you have not observed any? Hint: you may have observed evidence of tertiary consumers in your area, such as feathers, dropping, bones, etc.

17. Explain why tertiary consumers usually occur at a low density in ecosystems (hint: think in terms of availability of energy).

Food chain

18. Based on your observations, present a simple food chain for each of your two ecosystems (up to the level of tertiary consumer). Give the name of the organism at each trophic level and use arrows to indicate the direction of energy flow. You should provide references that support the trophic status of each level in your food chain.

Chemical cycling in the ecosystem

In contrast to energy, chemicals such as carbon (C), nitrogen (N), phosphorus (P), potassium (K), iron (Fe) and oxygen (O) are recycled within the ecosystem between the living community and the abiotic environment. For example, carbon occurs in living organic material of plants and animals in many kinds of molecules (carbohydrates, proteins etc.) and in the abiotic environment in the form of carbon dioxide (a gas), calcium carbonate or limestone (a rock) and other materials. It is also bound up in dead plants and animals, which would be locked away forever if it wasn't for the very important degraders that facilitate the breakdown and release of carbon and other nutrients contained within this material.

Look closely in this ecosystem for evidence of chemical cycling; for example where non-living organic material (detritus and carrion) is decomposing and being converted into inorganic material.

19. What kinds of detritus or carrion can you observe in this ecosystem? Is there any evidence that scavengers, detritivores or decomposers are utilising this decomposing organic matter? If yes, describe what you observed.

20. If you cannot directly see any decomposers, please describe the broad kinds of organism that are typically involved in the processing of detritus and carrion in an ecosystem?

Attachment:- Ecosystem report.rar