R M Cullen MD MSc MFM BA DipStats DipProfEthics

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alternatives to darwin

This lecture will consider three alternatives to Darwin. They are

• creationism
• intelligent design
• Lamarck

There is a fourth alternative, a belief in evolution by descent where natural selection is but one mechanism. That alternative will be developed in later lectures.

Creationism, or creation science, receives the briefest of mentions. Although it is the most widely believed answer to the question "Why are there humans?" it provides no clues (beyond prayer) as to how humans might determine their own evolutionary future.

creationism

Creationists affirm that the various forms of life on Earth appeared suddenly with their distinctive features already intact: Fish with fins and scales, birds with feathers and wings, trees with trunks and leaves.

For many people who believe in God or gods this is exactly how they interpret their holy book(s). There was nothing and then, by the will of God, there was everything.

Creation science claims support through application of the scientific method. Young Earth creation scientists go further and claim that the physical evidence overwhelmingly supports their position that the Earth is only 6,000 years old, give or take.

intelligent design

Science fiction authors realized that Darwin’s theory was not the only possible non-theological explanation as to why there are humans. The meme that humans exist because an alien designer intended them to is well established in science fiction where the idea that life on this planet was seeded or directed by aliens recurs frequently. For example, in the 1968 film “2001: a space odyssey”, aliens influence human evolution by introducing early humans to the idea of weapons.

Intelligent design is the name for the concept that at one or more points, life on Earth in general, and/or the evolution of humans in particular, has been given a push in the right direction by a (benevolent) super being.

This solves two real problems with Darwin’s theory of evolution by natural selection.

Three billion years is not such a long time, and evolution went along very slowly until the “Cambrian explosion” around 530 million years ago when fossils that resemble modern animals appeared over the short period of 50-70 million years. That is, evolution seems to occur in bursts rather than by the slow accumulation of small beneficial changes.

The second problem that the theory of intelligent design solves is that Darwin’s theory seems to require extremely unlikely events to happen again and again over a short time period in small populations. These are miracles. Scientists don’t like the idea of miracles. They much prefer cause and effect.

Lamarck

Lamarck believed that characteristics acquired through use could be passed onto future generations. Similarly he believed that unused characteristics would become smaller.

Whales have a vestigial pelvis and legs. Lamarck explains this easily. When whales returned to the sea from the land, their legs were no longer used and got smaller as a direct result of this disuse

Lamarck contended that the children of humans who developed big muscles through use would have bigger muscles than would otherwise have been the case.

Lamarck's use/disuse explanation of small changes across generations was supplanted by Darwin's concept of natural selection. For many years, Lamarck was treated as a sideshow, a bit of a nutter. However, and unwillingly, it is accepted today that acquired characteristics can be inherited. This is the essence of the field of epigenetics. In this course, epigenetics means the study of how chemical products of parental acquired characteristics influence the phenotype of offspring.

readings

Further information, some more reliable than others, is availble on all three alternatives to Darwin through the internet or at most any municipal library.

There will be, I hope, time for a fair bit of discussion in this lecture. It is an opportune time to reflect on Darwin, on scientific method, and on what this has to do with human evolution, particularly our ability to determine our own future.