g perlemoen fishing game farming problems with over fishing and poaching

G perlemoen fishing game farming problems with over

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discuss the sustainable use of animals in South Africa, e.g. perlemoen / fishing/ game farming; problems with over-fishing and poaching; economic and employment opportunities ; discuss why toxic animals from a variety of phyla are often of great interest to especially researchers in pharmacology. Give examples of South African animals that are researched because of the toxins that they produce. Sources Prescribed sources: Mader and Windelspecht pp. 519-548 Appendix 1 - 3 Introductory remarks In this module, a large number of organisms within nine phyla (there are more) will be investigated. Despite the variety of shapes and forms, animals are built fundamentally the same (outside tube, inside tube, stuff in the middle). However, because these characters are so fundamental you don't think about them typically. In this module we examine what these characters are and which animal groups share them. This type of study are called comparative anatomy. T he study of comparative anatomy predates the modern study of evolution. Early evolutionary scientists used comparative anatomy to determine relationships between species. Organisms with similar structures, they argued, must have acquired these traits from a common ancestor. Today, comparative anatomy can serve as the first line of reasoning in determining the relatedness of species. However, there are many hidden dangers that make it necessary to support evidence from comparative anatomy with evidence from other fields of study. A major problem in determining evolutionary relationships based on comparative anatomy can be seen when we look at a commonly found structure: the wing (Figure 1).
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Study unit 3 15 Figure 1: Comparative wing structure of insects, dinosaurs, birds and bats Down loaded on 23 August 2012 Wings are present in a number of very different groups of organisms. Birds, bats and insects all have wings, but what does this say about how closely related the three groups are? It is tempting to say that the three groups must have had a common winged ancestor. However, were you actually to take the bait and say it, you would be wrong. Dead wrong. The wings of bats and birds are both derived from the forelimb of a common, probably wingless, ancestor. Both have wings with bone structures similar to the forelimbs of ancestral and current tetrapod, or four-legged, animals. Such traits that are derived from a trait found in a common ancestor are called homologous traits. Another classic example of HOMOLOGY is seen in the skeletal components of vertebrates (Figure 2). Structurally speaking, though, the wings of bats and birds have little in common with those of insects. Bird wings and insect wings are an analogous trait, or a trait that has developed independently in two groups of organisms from unrelated ancestral traits.
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  • Spring '16
  • Ambani Mudau
  • Phylum, Windelspecht

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