FACTBOX-Different theories to explain life's origins

(Reuters) - Former students of Pope Benedict published a book in Germany on Wednesday showing how Catholic theologians see no contradiction between their belief in divine creation and the scientific theory of evolution.

Here are details on some views of life's origins, which continue to be debated, notably in the United States.

* THE BIBLE: Genesis, the first book of the Bible, says God created the Earth, plants, animals and man all in six days. Christian fundamentalists read this as the literal explanation for life's origin and say scientific theories such as evolution cannot be true. This view is called creationism.

The main Christian denominations -- Roman Catholic, Orthodox and mainline Protestant -- interpret Genesis as an allegory on how God created life and accept the scientific theory of evolution as an explanation of how living species developed. This view is known as "theistic evolution."

* DARWIN: Charles Darwin (1809-1882) was a British naturalist whose theory of evolution founded modern evolutionary studies. His 1859 book "On the Origin of Species by Means of Natural Selection" argued that organisms with more favourable traits were more likely to survive and reproduce. His 1871 book "The Descent of Man and Selection in Relation to Sex" derived the human race from anthropoid ancestors related to the descendants of the orang-utan, chimpanzee and gorilla.

Religious critics accused Darwin of opening the door to moral breakdown, saying people who rejected God because of his theory would not follow what they saw as God-given moral laws.

* NEO-DARWINISM: This further development of Darwin's theory emerged in the 20th century as scientists added insights from new discoveries, especially Gregor Mendel's theory of genetics. Supporters say this updated version of evolution is one of the most solidly based theories in all of science.

* INTELLIGENT DESIGN: "Intelligent Design" (ID) emerged in the United States after a 1987 Supreme Court ruling that teaching creationism in public school violated the constitutional separation of church and state. ID argues that some aspects of nature are so complex that they must have been the work of an unnamed creator rather than the result of random natural selection. Supporters want ID taught in science classes as an alternative to the neo-Darwinist accounts presented there.

Critics say ID is a thinly disguised version of creationism. In late 2005 a U.S. judge ruled that ID was essentially religious and a Pennsylvania school teaching it had violated the constitutional ban on religion in public schools.