Creationism and evolution
Until the eighteenth century, religion shaped the dominant explanations for the origins of human life. In Europe, these came largely from Genesis, the first book of the Bible. This explanation, known as creationism, was based upon the idea that God had created all life in six days, and that the characteristics of plants and animals were fixed and unchangeable.
creationism The belief that all life was created by the actions of God
That is not to say there was no interest in the great diversity of animal and plant life. Early scientists showed a strong desire to organize different species and locate human beings within classification systems. For example, the Swedish botanist Carl Linnaeus (1707–78) was among the first to develop a scientific classification of animals and plants, or taxonomy. Linnaeus accepted the biblical explanation of creation, and his classification system is still influential today. This system is based on similarities and differences between species, which Linnaeus argued were part of God’s plan.
taxonomy The classification of organisms in an ordered system that indicates natural relationships
Creationist ideas are not limited to Christianity. Muslim creationists, for example, base their thinking on similar arguments and on passages such as this in the Qur’an: ‘God has created every animal from water. Of them there are some that creep on their bellies, some that walk on two legs and some that walk on four. God creates what he wills for verily God has power over all things’ (Sura 24:45). However, fossil discoveries during the eighteenth and nineteenth centuries challenged the ideas central to creationism by proving that different types of life had existed in the past. Creationists responded to these findings by arguing that various forms of catastrophe had occurred, which they claimed had destroyed other ancient species. This branch of creationists, known as catastrophists, argued that events such as the biblical flood involving Noah’s Ark destroyed ancient species, after which God created new species, leading to contemporary species.
fossil The preserved remains or traces of animals, plants and other organisms from the remote past
catastrophism The theory that the Earth has been affected in the past by sudden, short-lived, violent events, possibly worldwide in scope, which have led to the contemporary world with its current variety of animals and plants
There has recently been a resurgence of creationism. For example, the Discovery Institute, an American nonprofit public policy think-tank, developed a theory known as intelligent design (or neo-creationism). This is defined as a belief that the universe could not have been created by chance and that some higher power must have had a hand in it. The effects of this theory have been felt within both the public and the political sphere. For example, there has been a lot of debate over the teaching of the origins of human life in schools. Some creationists argue that teachers should explain the origins of human life through creationist ideas only.
intelligent design Also known as neo-creationism, the belief that the current state of life on Earth has come about through the actions of an intelligent designer; this designer need not be God, but most proponents of intelligent design seem to have God in mind
Scientific explanations of human origins
The Enlightenment and Victorian naturalism The eighteenth-century Enlightenment prompted a major revolution in the way Europeans thought of the world in which they lived. Whereas previously the Bible had been relied upon to explain the world, people began increasingly to seek explanations based on science and rational thought. The Enlightenment coincided with the expansion of Europeans across the world and the discovery of previously unknown peoples. This diversity of humanity needed explaining somehow, since there were clearly many more human populations in the world than were described in the Bible.
Enlightenment A period in Europe during the eighteenth century when there were many scientific discoveries that contradicted the accepted teachings of those in authority, notably the Church
Later, through the work of nineteenth-century British naturalists influenced by Enlightenment ideals, an alternative explanation to creationism emerged: the idea that new species arose from existing ones through a long and gradual process of transformation, known as evolution. Charles Darwin (1809–82) is best known for his theory of evolution by natural selection or, in other words, the view that competition for resources (the ‘struggle for survival’) is both unavoidable and ubiquitous in nature and is the driving force behind the continuous transformation of living forms.
evolution Any change across successive generations in the inherited characteristics of biological populations
Darwin’s theory of natural selection was one of many emerging ideas of the time that attempted to explain the diversity of animals and species found in the world. Alfred Russell Wallace (1823–1913), a naturalist working independently of Darwin at around the same time, developed a very similar theory. Both Darwin and Wallace presented their ideas to the public in 1858, which caused great controversy because they directly challenged prevailing religious explanations.
What is natural selection? Natural selection is a process whereby nature selects the forms most likely to survive and reproduce in a particular population. For natural selection to work, there needs to be inheritable (i.e., genetic) variation within populations – which there usually is – as well as competition for resources necessary for life, such as food and space. Those organisms that manage to get copies of their genes into future generations transmit characteristics that continue to evolve through the generations. Over time, the organisms that are less successful in passing on their genes, and are less suited to their surroundings, gradually die out, while the more successful organisms survive. This process changes according to the environment in which the species exist. Changes to the body that are acquired in the course of life, for example loss of a limb, do not get passed on.
natural selection The process in nature by which, according to Darwin’s theory of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations, while those less well adapted tend to be eliminated
Sexual selection In order to leave descendants, individuals must not only survive but also reproduce. As a supplement to the principle of natural selection, Charles Darwin developed the idea of sexual selection to attempt to explain the presence of characteristics of male animals, such as the elaborate tails of peacocks or men’s deep voices, claiming that these secondary sexual characteristics evolved not because they increase the survival prospects of individuals, but because females prefer to mate with individuals with those features. If this is the case, then those specific characteristics are more likely to be passed on to future generations.
In birds, for example, one form of sexual selection occurs when males compete for particular territories. A bird that manages to get the best location is more likely to be chosen as a mate. Geoffrey Miller (2000) develops Darwin’s ideas and argues that human culture arose through a process of sexual selection. He argues that there are many characteristics of human culture that are not necessary to survival yet play a strong role in sexual selection, for example humour. Miller believes that human culture arose through sexual selection for creative traits. In summary, since the main challenges faced by living beings are survival and reproduction, species are the outcome of both natural and sexual selection. Evolutionary anthropologists are still debating which features of humans were caused by natural selection and which were the result of sexual selection.