4.1 Species, Communities and Ecosystems
Nature of science:
- Looking for patterns, trends and discrepancies—plants and algae are mostly autotrophic but some are not. (3.1)
- The continued survival of living organisms including humans depends on sustainable communities.
U 4.1.1 Species are groups of organisms that can potentially interbreed to produce fertile offspring.
U 4.1.2 Members of a species may be reproductively isolated in separate populations.
U 4.1.3 Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).
U 4.1.4 Consumers are heterotrophs that feed on living organisms by ingestion.
U 4.1.5 Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
U 4.1.6 Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
U 4.1.7 A community is formed by populations of different species living together and interacting with each other.
U 4.1.8 A community forms an ecosystem by its interactions with the abiotic environment.
U 4.1.9 Autotrophs obtain inorganic nutrients from the abiotic environment.
U 4.1.10 The supply of inorganic nutrients is maintained by nutrient cycling.
U 4.1.11 Ecosystems have the potential to be sustainable over long periods of time.
S 4.1.1 Classifying species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition.
S 4.1.2 Setting up sealed mesocosms to try to establish sustainability. (Practical 5)
S 4.1.3 Testing for association between two species using the chi-squared test with data obtained by quadrat sampling.
S 4.1.4 Recognizing and interpreting statistical significance.
In The News
- The need for sustainability in human activities could be discussed and the methods needed to promote this.
Alex Lee on Topic 4.1
Here’s a neat time-lapse of flesh-eating beetles at London’s Natural History Museum doing some recycling of their own:
For more on how saprotrophs such as fungi can be harnessed to solve pollutant problems, check out Paul Stamet’s talk: 6 ways mushrooms can save the world.
Here’s a nice time lapse showing the breakdown of food by bacteria, fungi and other organisms (nutrients being recyled):