Essential idea: The continued survival of living organisms including humans depends on sustainable communities.
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Honey bees are in decline in many parts of the world, the phenomena is known as Colony Collapse Disorder (CCD). Though many factors, including parasites are involved it is likely that a major factor is in CCD is modern farming practices, particularly pesticide use. This is ironic given that approximately a third of all crops rely on bees for pollination. Food production is reliant on healthy, sustainable communities of animals surrounding the agricultural land.
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Understandings, applications and skills
| 4.1.U1 | Species are groups of organisms that can potentially interbreed to produce fertile offspring. |
| 4.1.U2 | Members of a species may be reproductively isolated in separate populations. |
| 4.1.U3 | Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods). |
| 4.1.U4 | Consumers are heterotrophs that feed on living organisms by ingestion. |
| 4.1.U5 | Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion. |
| 4.1.U6 | Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion. |
| 4.1.U7 | A community is formed by populations of different species living together and interacting with each other. |
| 4.1.U8 | A community forms an ecosystem by its interactions with the abiotic environment. |
| 4.1.U9 | Autotrophs obtain inorganic nutrients from the abiotic environment. |
| 4.1.U10 | The supply of inorganic nutrients is maintained by nutrient cycling. |
| 4.1.U11 | Ecosystems have the potential to be sustainable over long periods of time. |
| 4.1.S1 | Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition. |
| 4.1.S2 | Setting up sealed mesocosms to try to establish sustainability. (Practical 5) [Mesocosms can be set up in open tanks, but sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones.] |
| 4.1.S3 | Testing for association between two species using the chi-squared test with data obtained by quadrat sampling. [To obtain data for the chi-squared test, an ecosystem should be chosen in which one or more factors affecting the distribution of the chosen species varies. Sampling should be based on random numbers. In each quadrat the presence or absence of the chosen species should be recorded.] |
| 4.1.S4 | Recognizing and interpreting statistical significance. |
[Text in square brackets indicates guidance notes]
Presentation and notes
The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
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Use the Cornell style template to collate your own notes for Topic 4.1 Species, communities and ecosystems.
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Nature of science
Looking for patterns, trends and discrepancies—plants and algae are mostly autotrophic but some are not. (3.1)
International-mindedness:
The need for sustainability in human activities could be discussed and the methods needed to promote this.
