VCE Biology

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This chapter of work is about habitats and the factors that affect the survival of organisms in their environments. You will learn about biotic (living) factors – predators, competitors, pathogens, parasites - and abiotic (non-living) factors – temperature, wind speed, pH, atmospheric gases, turbidity, salinity, solar radiation etc. You will also learn about niches and resource use graphs. Match some Australian species to their habitats at DECC.

Living organisms survive in their environments due to structual, functional and behavioural adaptations. Evolution is the process by which living organisms have changed over thousands of years to become more suited to their environments. Google ‘evolution’ and you will find an enormous selection of contradictory articles confirming or condemning “The Theory of Evolution”, first proposed by Charles Darwin in 1859.

To summarise Darwin’s Theory of Evolution;
1. Variation: There is variation in every population.
2. Competition: Organisms compete for limited resources.
3. Offspring: Organisms produce more offspring than can survive.
4. Genetics: Organisms pass genetic traits on to their offspring.
5. Natural Selection: Those organisms with the most beneficial traits are more likely to survive and reproduce.

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Natural selection is the important process that results in changes in populations over time. All the structual, functional and behavioural adaptations we have discussed over the past few months have evolved as a result of natural selection. However, because the effects of natual selection can only be seen over many generations, it is difficult to visualise. There are a number of computer simulations that allow us to visualise natural selection. The Peppered Moth Simulation, from the Biology Corner, uses a well known example of a case study of natural selection. The Biology in Motion lab uses more stylized images for it’s Evolution Lab.