A-Level Biology. Phillips, W. D., and T. J. Chilton. 1994. Oxford University Press, Oxford.
This textbook overstates the case for evolution, failing to present the limitations of the evidence.Evolution is controversial not so much because the scientific evidence is in any doubt, but because some people do not like or refuse to accept its implications in a religious or philosophical context.
Evidence for evolution
The direct evidence for evolution comes mainly from the study of fossils.
When fossils are arranged in chronological order, clear patterns of evolutionary descent normally emerge. Changes in structure can be interpreted as adaptations to new environments.
This
makes it appear as if gradual incremental change was the norm in the
fossil record, when in fact it is rarely found. The idea of accelerated development or jumps in evolution is introduced, then gaps in the fossil record are cited as evidence for such jumps occurring.
But the text moves rapidly on from these unfilled gaps:
The book fails to mention that many missing "missing links" provide evidence against evolution. For a summary of this evidence see The Fossil Record.
This textbook also uses similarities between Embryos as evidence for evolution:
The Peppered Moth is given as an example of natural selection.
Sickle cell anaemia is used an an example of a balanced polymorphism.
Darwin's Finches are used as an example of an adaptive radiation of species (without reference to the experiment on beak size by the Grants).
Homology is used as an evidence for evolution, as are vestigial organs, and artificial selection
Although the textbook states that:
It does not mention that some scientists believe that such structures have been found (this may be because the textbook is over 10 years old). Instead, it denies that there is a scientific controversy over Darwinism.
Thus, though different views of origins are mentioned, any controversy is presented as religion versus science. There is a clear assumption that any theory of origins must be a theory of evolution, as this extract shows:
The only alternative presented to evolutionary theories is special creation with fixity of species, and no micro-evolution, a view which was common in the early nineteenth century, but is not held today by any creationist group. This is presented as a religious belief which has no scientific support.
It does not mention that some aspects of evolution are very hard to test empirically.
The occurrence of rapid transitions helps to explain why intermediate forms are sometimes 'missing' from the fossil record.
But the text moves rapidly on from these unfilled gaps:
the suspected evolutionary link between birds and reptiles was positively established with the discovery of Archaeopteryx, a fossil form showing both avian and reptilian characteristics. The existence of such ‘missing links’ is strong direct evidence for evolution.
The book fails to mention that many missing "missing links" provide evidence against evolution. For a summary of this evidence see The Fossil Record.
This textbook also uses similarities between Embryos as evidence for evolution:
The embryonic development of vertebrates is extremely uniform. For example, all early embryos have brachial grooves and internal gill pouches.
The Peppered Moth is given as an example of natural selection.
Sickle cell anaemia is used an an example of a balanced polymorphism.
Darwin's Finches are used as an example of an adaptive radiation of species (without reference to the experiment on beak size by the Grants).
Homology is used as an evidence for evolution, as are vestigial organs, and artificial selection
Teaching the controversy?
Although the textbook states that:
If modern organisms were to possess any features which failed to conform with evolutionary principles, or could not be explained by processes of mutation and natural selection, then the theory would be definitely rejected.”
It does not mention that some scientists believe that such structures have been found (this may be because the textbook is over 10 years old). Instead, it denies that there is a scientific controversy over Darwinism.
Evolution is controversial not so much because the scientific evidence is in any doubt, but because some people do not like or refuse to accept its implications in a religious or philosophical context.
Thus, though different views of origins are mentioned, any controversy is presented as religion versus science. There is a clear assumption that any theory of origins must be a theory of evolution, as this extract shows:
Theories of evolution
1 Special Creation. Many religions teach that species were created by God and have existed on the Earth unaltered from generation to generation. According to this view, an organism’s adaptive features are inherited from its ancestors and were present fully formed at the moment of creation. The essential elements of the theory are not open to scientific investigation and cannot be tested. Other evolutionary theories accept that species characteristics do change and that all present day species are derived from a few very simple types of organism which first arose from non-living material more than 300 million years ago.
2. Inheritance of acquired characteristics…In some respect this theory is an attractive one but there is no experimental evidence to support it…
3. Neo-Darwinian theory. A coherent and plausible theory of evolutionary change was first described in detail by Charles Darwin...
The only alternative presented to evolutionary theories is special creation with fixity of species, and no micro-evolution, a view which was common in the early nineteenth century, but is not held today by any creationist group. This is presented as a religious belief which has no scientific support.
It does not mention that some aspects of evolution are very hard to test empirically.
This
textbook is clearly one-sided in its presentation of origins, and fails
to mention significant scientific debate over evolution.