Evolution: A Timeline

Charles Darwin is born to a wealthy family in Shropshire, England.

Darwin begins a five-year voyage as a ship's naturalist on the HMS Beagle. His observations of scientific phenomena, particularly the wildlife on the Galapagos Islands, lead Darwin to form his theory on the origin and development of life.

Darwin publishes On the Origin of Species by Means of Natural Selection, the first detailed explanation of natural selection. The book becomes a sensation and sparks a contentious debate in Britain.

Darwin publishes The Descent of Man, which argues that humans are descended from apes.

American evangelists, including Dwight L. Moody, begin attacking evolution, arguing that Darwin's theory contradicts biblical truth. By the 1920s, many theologically conservative Christian ministers and pastors are publicly opposed to teaching evolution in public schools.

In State of Tennessee v. Scopes, public school teacher John Scopes is convicted of teaching evolution in violation of Tennessee's ban on the practice; Scopes' conviction is later overturned on the basis of a legal technicality.

Engineer Henry Morris and theologian John Whitcomb publish The Genesis Flood, which argues that there is scientific evidence to support a literal reading of the biblical creation story. The book becomes a major bestseller and helps spawn the "creation science" movement.

In Epperson v. Arkansas, the U.S. Supreme Court rules that an Arkansas law making it a crime to teach evolution in public schools and state universities violates the Establishment Clause in the First Amendment to the U.S. Constitution.

Henry Morris founds the Institute for Creation Research, a creation science think tank.

In Lemon v. Kurtzman, a case unrelated to the teaching of evolution, the Supreme Court establishes a set of legal criteria for determining whether a law violates the Establishment Clause. Under the "Lemon test," a law must have a secular purpose, not advance or inhibit religion and not excessively entangle the government with religion. The Lemon test will be applied to subsequent cases on the teaching of evolution.

The National Center for Science Education is founded to advocate the teaching of evolution in public schools.

In McLean v. Arkansas Board of Education, a federal court strikes down an Arkansas law requiring public schools to teach creation science alongside evolution.

In Edwards v. Aguillard, the Supreme Court rejects as unconstitutional a Louisiana law prohibiting the teaching of evolution in public schools if creation science is not taught alongside it. The court rules that the law had a religious purpose.

The Discovery Institute, a Seattle think tank, launches the Center for Science and Culture to promote the concept of intelligent design. Supporters of intelligent design contend that life is too complex to have evolved without the intervention of an outside, possibly divine, force.

The Kansas Board of Education rules that biology teachers can offer instruction in evolutionary theory but that the subject will not be included on statewide standardized science tests. The ruling sparks a number of subsequent battles over the state's science standards.

In Freiler v. Tangipahoa Parish (La.) Board of Education, a federal appeals court strikes down a Louisiana law requiring public school teachers to read a disclaimer urging students to question evolutionary theory.

In Selman v. Cobb County School District, a federal court rejects as unconstitutional the Cobb County, Ga., school board's requirement that a sticker be affixed to public school biology textbooks instructing students to think critically about evolutionary theory.

In Kitzmiller v. Dover Area School District, a federal district court strikes down the Dover, Pa., school board's requirement that the term "intelligent design" be mentioned in the public high school biology curriculum.

The South Carolina Board of Education adopts new science education standards that call on public school students to "investigate and critically analyze aspects of evolutionary theory."

A newly elected Kansas Board of Education overturns a 2005 directive allowing public school students in the state to hear criticisms of evolution.

This timeline was written by David Masci, a senior research fellow at the Pew Research Center's Forum on Religion & Public Life.