1.8.3 Biological evolution, Darwinism and Neo-Darwinism

Biological evolution is the theory that all existing species of plant and animal have developed from common ancestors. It has to do with the survival and adaptation of existing biological forms of life, and is thus distinct from other varieties of evolution, such as stellar or chemical evolution. It is also the one which receives the most popular attention and controversy.

Charles Darwin’s book On the Origin of Species is most commonly credited with the development of the “theory of evolution,” based on his observations of geology and the variety of species, but there were others around the same time proposing similar theories (such as Alfred Russel Wallace). Previous to Darwin’s time, a common view was that all of nature was specially designed for specific purposes, and biological species were thought to remain unchanged as originally created. Darwin suggested that organisms change over time, branching out from a common ancestor (“descent with modification”), and that competitive pressures will lead to the survival of organisms that can pass on traits which make their continued survival more likely (“natural selection”). Thus, biological evolution is sometimes referred to as “Darwinism”.
However, at the time Darwin wrote, neither he nor anyone else had knowledge of genetics (later discovered by Mendel and others), DNA, and a variety of other mechanisms which have since been discovered in biological organisms. Darwin himself proposed that parent species acquired new observable traits during their lifetimes which were passed on to their descendents (later termed “Lamarckism”, which has since fallen out of favor in the scientific community). The modern scientific theory of evolution is sometimes referred to as “neo-Darwinism”, because it retains the original ideas of Charles Darwin, but has been modified and synthesized with other theories.

Darwin’s theories of natural selection and common descent are central to current biological theory, but in many ways the modern synthesis of evolutionary theory is different from Charles Darwin’s original writings. Most scientific publications don’t generally use the term “Darwinism.” The term seems mostly to be used by creationist organizations in their rhetoric against “the godless, atheistic alternative to the Biblical creation account.” They are describing a philosophy rather than a strictly scientific account of nature. For these reasons, the term “Darwinism” is fairly useless today for describing the current scientific theory of biological evolution, because it means vastly different things to different people.

It should also be noted that even though some people credit Charles Darwin with striking a fatal blow against religious belief and promoting merely blind chance in place of divine providence, Darwin’s theory did not exclude the influence of a divine Creator. Even though he personally went through periods of theism, deism, and ended up an agnostic, he was never an atheist. His view of nature always acknowledged some sort of belief in intelligent design, as he could not bring himself to think of the wonderful complexities of nature occurring completely on their own (http://www.ualberta.ca/~dlamoure/3Darwin.htm). In the sixth edition of On the Origin of Species, the phrase “by the Creator” was added to the final paragraph: “There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

1.8.2 Chemical Evolution

Chemical evolution has to do abiogenesis (“origin of life”). It involves scientific hypotheses for how the first living things might have been able to form from the right combination of chemicals and other factors. Experiments, such as one conducted by Stanley Miller and Harold Ulrey in 1952, show that organic compounds, including amino acids, can form spontaneously from the right combination of chemicals and energy. It is speculated that this might have been one means of forming the precursors to the first living things on earth.

There are a number of problems with the scientific data on this, including the fact that such molecules found in nature are either all “left handed” or “right handed,” but those formed spontaneously in the experiments contain an equal number of both, which is not suitable for life as we know it. It is also unknown what combination of chemicals were present in the earth’s early atmosphere, and whether the precise environmental conditions were present to allow them to form spontaneously. Many scientific theories abound, which attempt to explain these questions, but so far there is no definitive model which can explain the pathway from inorganic chemicals to self-replicating molecules, not to mention complex living cells, etc.