Box 3A: Evidence for Evolution (pp 50-51).
From comparative data amassed by systematics we can identify several patterns that confirm the historical reality of evolution:
  1. The hierachical organisation of life. Only a historical process of branching and divergence will yield objects that can be hierarchically ordered.
  2. Homology. Similarity of structure despite differences in function follows from the hypothesis that the characteristics of organisms have been modified from the characteristics if their ancestors. Claiming intelligent design makes little sense. (E.g. hands of primates, digging forelimbs of moles, wings of bats, wings of brids).
  3. Embryological similarities. Some features that appear during development are unnecessary and can only be understood as modifications of its ancestors' ontogeny.
  4. Vestigial characters. Features that served a function in the species' ancestor, but do so no longer.
  5. Convergence. Functionally similar features that differ profoundly in structure. (E.g. eyes of vertebrates, molluscs, insects). Incompatible with an omnipotent creator.
  6. Suboptimal design. Features that no intelligent engineer would design. E.g. food and air cross in the pharynx of terrestrial vertebrates, with the risk of choking on food. Or the 'blind spot' in the eye.
  7. Geographic distributions. The distributions of many taxa make no sense unless they have arisen from common ancestors. E.g. marsupials.
  8. Intermediate forms. Innumurable cases exist in which characteristics vary by degrees among species and higher taxa. E.g. gradations in beaks of birds.

Together these arguments substantiate the theory of evolution by consilience.

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