Organisms and Evolution
This Unit explores the importance of parasites in evolution. The majority of living species on the planet are parasitic, and, naturally, the species that are not parasites are almost certainly parasitised by them. The evolutionary 'arms race' between parasites and their hosts requires the constant reshuffling of biological variation that can only be achieved through meiosis. On a macroevolutionary scale, parasites are often considered to be responsible for the maintenance of sexual reproduction. On a microevolutionary scale, mate choice behaviour is often correlated with parasite avoidance.
Biological variation is a central concept in this Unit. Variation is best observed in the natural environment, so this Unit begins with an outline of suitable techniques for ecological field study. Methods of sampling and the classification and identification of organisms are considered. In classification there is a focus on those groups that are commonly parasitic. Mark and recapture is included as one method of estimating population size. For animal behaviour studies, ethograms, time sampling and the avoidance of anthropomorphism are emphasised. The teaching of these techniques could be delivered in an integrated manner within the Unit.
The Organisms and Evolution unit is divided into 2 main areas of content viz: Field techniques for biologists, and Organisms. In the sections that follow you will find a series of links to resources and activities - some of these have been produced by SSERC whilst others are from sources which we are happy to endorse/recommend.