Evolutionary Theory FAQ: Introduction

In the interest of promoting a sound and solid understanding of evolutionary theory in all our visitors, we have provided this FAQ for quick and easy reference. In the answer to each question, we have provided links to other sources within this site or external to it; we strongly encourage you to visit these sections for more information. The general topics covered in this FAQ are as follows:

• General Questions
• Biological Evolution Questions
• Cultural Evolution Questions
• Language Questions
• Philosophy Questions
• History of Evolution Questions

Please see also Evolution, Religion, and Creationism, which answers a number of questions specifically relating to creationism or the relationship between religion and evolution.

General Questions

Who is the father of evolutionary theory?
Charles Darwin was the first man to think of natural selection as a mechanism for evolutionary change. However, the idea of evolution in the sense of change over time goes back to ancient Greece. Please see Natural Selection, Pre-Darwinian Ideas of Evolution.

Is evolution a theory or a fact?
Evolution is both a theory and a fact. It is an absolute scientific fact that genetic changes in species have occurred over time. However, evolution as a mechanism of change is a theory - but remember that, in science, a theory is not a baseless speculation; it is a hypothesis that has been repeatedly confirmed by numerous different lines of evidence. Please see Natural Selection, Talk.Origins FAQ, Talk.Origins - Evolution is a Fact and a Theory.

Is evolution based on randomness?
Yes and no. Random variation - that is, mutations caused by various external factors, as well as sexual recombination in some cases - forms the raw material on which natural selection acts. However, natural selection is a very precise process of differential survival and reproduction, such that the fittest individuals leave the most progeny on average. Because of natural selection, survival and reproduction is a very distinctly nonrandom process. Please see Natural Selection, Talk.Origins - Evolution and Chance, Talk.Origins - The Evolution of Improved Fitness.

Are all mutations harmful?
No, not all mutations are harmful. The majority of mutations are either harmful or neutral - that is, their effects are either problematic for the organism, or completely irrelevant to its survival. However, a small subset of possible mutations is at least potentially beneficial to the organism, and it is these mutations that are preserved by natural selection. Please see Natural Selection, Talk.Origins - Are Mutations Harmful?.

What is a good evolutionary definition of life?
From an evolutionary perspective, life is defined as a set of randomly varying, self-replicating entities that: temporarily reverse (but do not violate) the law of increasing entropy of a system, because they have continual energy input; are in both thermal and chemical disequilibrium; compete among themselves for finite resources; and survive and reproduce in a non-random way that is strongly correlated with their fitness relative to their environment. Please see What is a Replicator?, The Origin of Life on Earth.

Biological Evolution Questions

Are there any transitional fossils?
Absolutely. One major branch of scientific evidence for evolution rests on the existence of so-called "transitional" fossils - that is, fossils that are intermediate in one or more characteristics between two other groups. A few examples are: Archaeopteryx, a birdlike dinosaur; australopithecines, Homo habilis, Homo erectus in the line between apes and humans. For an extensive list see Talk.Origins - Transitional Vertebrate Fossils.

If there are transitional fossils, then why aren't they named that way?
Because of taxonomic naming conventions, species are classified in one taxon or another - if they are intermediate between two taxa, they must be placed in one or the other. Thus to cite a lack of transitional fossils between, say, australopithecines and Homo is merely to express the fact that all fossils that fall between these two groups are classified in either Australopithecus or Homo. Please see Talk.Origins - Transitional Vertebrate Fossils.

What's the difference between gradualism and punctuated equilibrium?
Gradualism is the theory of slowly accumulating change, mediated by natural selection, as the mechanism of evolution. Punctuated equilibrium was proposed by Stephen Jay Gould and Niles Eldredge as a "radical" alternative to gradualism, but in reality the two are the same process operating on different timescales. See Other Types of Selection, ch.9 of Richard Dawkins' The Blind Watchmaker, Talk.Origins - Punctuated Equilibria.

What is a replicator?
A replicator is anything that copies are made of. The best and most familiar example of a replicator is the gene, which forms the basis for the selfish gene theory and the gene-based view of natural selection. Organisms are not replicators because their characteristics are not transmitted to subsequent generations, except through the action of genes. Please see What is a Replicator?, Genes as Replicators, Replicators in Evolution.

How can natural selection be based on genes, if it can't even detect genes?
Natural selection cannot detect or distinguish between genes, so it uses phenotypic effects as proxy measures. This the reason why selection looks like it takes place at the level of the organism, and why most adaptations are to the benefit of the organism. However, the idea of gene-based selection is a powerful explanation for many otherwise baffling topics, such as kin selection and reciprocal altruism. Please see What is a Replicator?, Genes as Replicators, Replicators in Evolution, Other Types of Selection.

How can evolution account for irreducibly complex systems?
First, the term "irreducibly complex" is extremely difficult to apply to any one system, and it can never be absolutely proven that it applies to a system. However, these issues aside, evolution can produce such systems by working from precursor parts with slightly less functionality, adapting portions of its environment to replace missing parts, duplicating and slightly altering genes to produce a variety of different proteins, and reusing components of one system in the building of another. This is obviously a very brief explanation; see Talk.Origins - Darwin's Black Box, Behe's Empty Box. For the original presentation of the "irreducible complexity" view, see Darwin's Black Box by Michael Behe.

How could life have gotten started in the first place?
The origin of life from inorganic precursors is called abiogenesis, and it is the subject of a lot of research. It has been shown that some organic chemicals like amino acids and protein-like structures can spontaneously assemble under the right conditions; this is probably something like what happened on Earth. Another theory is that successive self-replicating molecules evolved until RNA arose, which started life down its familiar road. leading to DNA, organisms, and the rest. Yet another theory speculates that clay crystals were the first replicators, and they first assembled RNA and associated molecules. Please see The Origin of Life on Earth, Interesting Ideas in Evolution, Talk.Origins - The Probability of Abiogenesis, Talk.Origins - Probability of Abiogenesis Calculations.

Cultural Evolution Questions

What is a meme?
A meme is a unit of cultural inheritance - a thought, idea, belief, etc. that is a replicator and can transmit (or has transmitted) itself from the brain of one human being to another. The concept of the meme was first created by Richard Dawkins in his famous book The Selfish Gene, and since then it has taken off with enormous replicating power. Please see the entire Cultural Evolution section, but especially Memes as Replicators and How and Why Memes Spread. See also Principia Cybernetica Web, which contains excellent information about memes, especially Memetics Lexicon.

How close is the analogy between memes and genes?
Depending on how "meme" and "gene" are defined, answers range from not very to really close! Using the definitions adopted by this site, the answer lies in between these two responses. Both memes and genes are replicators and undergo natural selection due to differential reproduction and competition for finite resources - in the memes' case, adherents. However, mechanisms of inheritance differ between the two: memes can combine, fuse, and re-form in quasi-Lamarckian ways that genes cannot. Please see Memes and Genes.

What are some examples of memes?
Some examples of memes might be: ways of making pottery, storytelling techniques, writing styles, rumors and urban legends, chain letters, slogans, jingles, company or product logos, religious beliefs, and moral attitudes and values. More specific examples: The South should have won the American Civil War, Murder is morally wrong, Everyone has the right to free speech, Coke is better than Pepsi. For an overview, please see Memes as Replicators; for more analyses of examples, see Memes in History, Memes in Popular Culture, Memes on the Internet.

Do memes influence genes?
Memes influence genes, and vice versa. Genes, of course, provide the vehicles needed for memetic replication. Memes, in turn, compose part of genes' environment and therefore can affect genes and even evolution itself. For example, Susan Blackmore, author of The Meme Machine, believes that language may have evolved through memetic pressure. Please see Memes and Genes, and see Blackmore's book for more information on her theories.

How did memes come into existence?
Memes probably came into existence with the development of the capacity for imitation. Once people (or early hominids) could imitate one another, simple memes - such as those for basket weaving, hunting skills, etc. - could spread slowly from one adherent to the next. Language could then be a development mediated by the memes, or the genes, or both, for the benefit of both as replicators. See Memetics and Society, The Evolution of Language.

Language Questions

Is language an adaptation?
Language is generally considered to be an adaptation, but a few - such as Stephen Jay Gould and Noam Chomksy - dispute this interpretation. Still, the human language instinct is too well-developed for these disputes to carry much weight. However, what language is an adaptation for - memes or genes or both - is also under dispute. In sum, the evidence says: yes, language is an adaptation, but it isn't clear if it is for the benefit of memes or genes or both. See The Evolution of Language, The Grammar Module.

Are languages replicators?
No, in general languages are not considered replicators. Languages do not always (but may sometimes) spawn progeny in the form of dialects that compete with each other and with the parent language. The fact that language "reproduction" is sporadic at best, and not very fecund or high-fidelity, shows that languages are generally not replicators in the common sense of the word. They are, however, groups of replicators - that is, meme sets. They are also part of the larger memeplexes of cultures. Please see Language and Culture, Words and Languages, Languages and Memes.

Are words replicators?
Words can be memes, which means that they can be replicators. A good example of this is the competition between two rival coinages for the same meaning: meme and culturgen. Both were created at approximately the same time, in the late 70's, but today meme has thoroughly defeated culturgen, probably because of its close similarity to gene. An internet search now yields around 11,000 results for memetic (chosen to eliminate confusion with French meme) and 30 for culturgen. Please see Words and Languages.

Is it easier to learn a language when you're young?
The evidence suggests that this is true; there seems to be a crucial time period within which a first language must be learned in order for the language capability to develop properly. Similarly, it seems that attempting to learn a foreign language before puberty is relatively easy; during the teenage years, somewhat more difficult; and after maturity, quite difficult. Please see Language Acquisition.

Philosophy Questions

Is evolution a philosophy?
No, evolution is a scientific theory - it makes predictions and provides explanations about the world we live in, and it is both testable and falsifiable. However, science as a whole is built on certain philosophical principles: reality is both objective and consistent, and the human reasoning capacity is capable of explaining reality in factual terms. Please see Evolution and Philosophy.

What is the relationship between evolution and ethics?
The answer to this question can be debated. While the naturalistic fallacy (deriving an ought statement from an is statement) implies that ethics cannot be rationally derived from evolutionary theory, it can and does give us important insights into human nature. These insights may well be highly useful in the attempt to structure a rational ethical system and in the attempt to use such as system as a guide to behavior. These insights may also have profound implications for how our society is structured and why humans do or do not fit into certain molds. Please see Evolution and Ethics, Evolution and Human Nature, Talk.Origins - Evolution and Philosophy.

Does evolution imply determinism?
Most emphatically not. Biological determinism implies that people's thoughts, behaviors, and actions are absolutely dependent on genes, when in reality all evolutionary theorists recognize that environmental factors play an important role in the development of a human being. Moreover, evolution itself is not deterministic because it is contingent on historical events, and repeated trials, if they could be performed, would follow very different paths (though certain staple features might arise). Please see Biological Determinism.

Does evolution rule out religion?
No, evolution does not rule out religion or religious beliefs. Evolution does rule out certain religious claims - such as a literal interpretation of Genesis - but is not relevant to religion from a philosophical perspective. There are many people who are religious evolutionists, and they have reconciled the two positions in a number of different ways. Each person's religious convictions are entirely in their domain provided that they do not make claims that contradict evolutionary (or any other scientific) evidence. Please see Evolution, Religion, and Creationism, Religion and Evolution, Evolution vs. Creation, and Talk.Origins - God and Evolution. For an interesting combination of evolution and religion, see Finding Darwin's God by Kenneth Miller.

Does evolution promote social evils?
The direct answer to this question is: of course not, no more than any other scientific theory. To claim that evolution is responsible for social evils is to overlook a long and bloody part of human history that took place before evolutionary theory was even formulated. Moreover, even if you believe that social evils have increased since the formulation of evolutionary theory, correlation between the two things does not imply causation. Finally, even if evolution or any other theory did lead to social evils, that fact would have absolutely no bearing on its truth or falsehood. Please see Evolution vs. Creation, Talk.Origins - God and Evolution.

History of Evolution Questions

Did Darwin plagiarize from Wallace?
No, Darwin did not plagiarize the theory of natural selection from Wallace. Darwin actually developed the theory of natural selection many years before Wallace, but did not publish his ideas because he was busy with other work and because he wanted more time to perfect his presentation of the theory. Wallace, working entirely independently, developed the theory in the same way Darwin did - by reading Thomas Malthus' work on population growth. It is true that Wallace's discovery of the theory prompted Darwin to publish his work earlier than he planned, but both men shared the credit when they first brought their theory into scientific discourse. Please see Pre-Darwinian Theories of Evolution, Early Theorist Biographies, The Alfred Russel Wallace Page.

What is the modern synthesis?
The modern synthesis, also called the synthetic theory and the evolutionary synthesis, was the marriage of Mendelian genetics to Darwinian theories of evolution. It grew out of a long and drawn-out debate about the mechanism and relative importance of inheritance. Its basic conclusions now form the underpinnings of modern evolutionary theory. Please see The Modern Synthesis, Talk.Origins - The Modern Synthesis of Genetics and Evolution. For information on the people involved, see Modern Theorist Biographies.

What is Social Darwinism?
Social Darwinism is an overly simplistic ethical theory proposed by Herbert Spencer. The theory existed well before Darwin published The Origin of Species, but Spencer used a number of Darwin's ideas to modify and improve his ethical system. Essentially Social Darwinism argued that capitalism was consistent with evolution because it gave benefits to the strong, successful, and wealthy, and none to the weak, unsuccessful, and impoverished. Moreover, the theory stated that direct handouts to the poor were unhelpful or even evil because they encouraged the survival of the unfit. Social Darwinism in this form is generally not accepted today. Please see Evolution and Ethics, Social Darwinism.