|Advanced Biology - Nelson|
Advanced Biology. Roberts, M., M. Reiss, and G. Monger. 2000. Nelson
This book has replaced Biology: Principles and Processes. Roberts, M., M. Reiss, and G. Monger. 1993. Nelson
This textbook contains a detailed account of the theory of evolution, in three substantial chapters. The authors are honest about some of the shortcomings of the evidence for evolution. However, no other scientific theories of origins are presented, and the reader is left with the impression that despite its problems, the theory of evolution is the only possible explanation for how we came to be here.
Evidence for evolution
Most of the standard evidence for evolution is included in this textbook, and detailed at some length.
Darwin's Finches (p. 724) are described as an example of adaptive radiation. The pentadactyl limb (p. 726) is given as an example of Homology.
There is a section on Comparative Biochemistry, which has been used in recent years to identify and confirm evolutionary relationships (p. 729).
A short section on Embryology claims that:
the presence of branchial grooves (relics of gill slits) and segmental muscle blocks in the human embryo...are suggestive of a fish ancestry. (p.730)
This section does acknowledge flaws in Haeckl's drawings of insect larvae:
...there may have been some wishful thinking on Haeckl's part!
But there is no mention of Haeckl's fraudulent diagrams of animal embryos.
Heavy metal tolerance in plants, antibiotic restistance in bacteria, and DDT resistance in insects are cited as examples of natural selection (p. 752). For an analysis see: The Development of Biological Resistance.
The authors do highlight some areas of uncertainty. In the section on the origin of multicellular organisms, they write:
Like so many other aspects of early evolution, this is a controversial matter and we can do no more than touch on the possibilities (p. 764).
Evidence from fossils is covered in a manner which is baised towards the gradual evolution position.
Studying the fossil inhabitants of different [rock] strata...has made it possible to trace the evolution of successive groups of animals and plants during geological time…What kind of evolutionary sequences have been established from the fossil record? There are obviously far too many for us to look at all of them, so we shall choose one for detailed discussion: the evolution of horses" (p. 732-733).
This makes it appear that there are many sequences similar to that of horses, but a few sentences later it becomes clear that the apparent horse sequence is, in fact, very unusual:
...compared with most fossil sequences, the record for horses is pretty complete. (p. 733)
For an analysis of the story of horse evolution presented in detail by this book, see the article on Horse Evolution on this website.
The problems of the fossil record are mentioned, but these are used to introduce the alternative evolutionary theory of punctuated equilibrium, not to credit non-evolutionary theories.
Intermediate forms in the fossil record are surprisingly rare. The rarity of intermediate forms is seen by creationists, who believe in special creation rather than the in the evolution of species, as evidence that evolution has not occurred. However, two American palaeontologists, Niles Eldredge and Stephen Gould, put forward a different interpretation... (p. 755)
The Miller-Urey experiment is used to show how amino acids first formed. The book claims that:
Geochemical evidence suggests that at this time the Earth’s atmosphere was dominated by four simple gases: methane, ammonia, hydrogen and water vapour.
However, this is questioned a few paragraphs later:
...since Miller’s work, some earth scientists have questioned whether the Earth ever had a reducing atmosphere lacking oxygen. (p. 760)
Gene mutations are described as very important instigators of evolutionary change and are illustrated by changes of single letters in English sentences which change their meaning (p. 747). However, the book fails to mention that the probability of any of the changes it shows is less than 0.08%, and that the vast majority of possible changes in the sentences would result in nonsense.
A section on human evolution claims that:
a combination of the fossil record and evolutionary trees derived from DNA hybridisation studies and analysis of the amino acids in certain proteins suggests we shared a common ancestor with chimpanzees from which we split about five to eight million years ago.(p. 772-774)
The authors' position on the evidence for evolution is summed up at the end of the chapter Evolution in evidence:
The theory that all life today is descended through evolution from original inorganic precursors is testable, albeit only indirectly, and is therefore a scientific theory. However, the evidence in favour of it, although held by many to be convincing, is not absolutely conclusive" (p. 735).
A section on artificial selection by humans develops into a discussion of eugenics, something which the textbook appears to advocate:
There is nothing intrinsically evil about wanting to improve the quality of the human race…The theory and practice of improving the human species by means of selective breeding is known as eugenics, and despite its sinister undertones many people feel it is acceptable provided it is carried out on a voluntary basis (p. 757)
This section goes on to describe genetic screening of in vitro embryos, and their selective destruction.
Teaching the controversy?
The closest this textbook gets to teaching the controversy over origins is a box entitled Scientific arguments against evolution (p. 735). This describes several doubts which may be held about evolution, such as the origin of the first replicating molecules, and the evolution of the human brain. It admits that
...the fossil record is very incomplete and there are those who argue that it can be explained without assuming that evolution has occurred. (p. 735)
Interestingly, a phrase found in the 1993 edition of this book suggesting the need for an element of faith in evolution is omitted here. In the absence of good evidence, the book appeals to the great majority of scientists alive today who believe in evolution. No alternative theories are mentioned which pupils might want to consider.
Overall, school pupils using this book are left with little choice but to accept the theory which has been described to them.
Darwin's theory has stood the test of time and, with certain modifications, is accepted today by practically all biologists (p. 720).
It is remarkable to think that you, the person sitting reading this chapter, and we, the authors of it, are – if current scientific opinion is to be believed – the products of an evolutionary process that began some thirteen billion years ago with the birth of the Universe itself (p. 759).
Creationism is mentioned in an extension section about Darwin and Society where the conflict between Darwinism and nineteenth century creationist beliefs are outlined. There is no direct mention of modern creationism, nor of Intellligent Design.
Speculations on the chemical origins of life are almost universally covered in school curricula under ‘Evolution’, despite the questionable relevance of the topic for evolution, and its rather uncertain scientific basis.
Moore, A. (2008) Nature 453:31-32