Evolution Before Darwin

What is natural theology, and who is its key figure?

The idea that organisms look designed and their features show evidence of a creator’s purpose. Its major figure was William Paley (author of Natural Theology, 1802).

What did Cuvier think the fossil record showed, and why?

Saw abrupt changes in fossils and believed the intermediate forms were missing, so he concluded that life did not change gradually.

What is the plenitude principle?

The idea that all possible species already exist, creation was fully complete from the start, and no gaps in creation are possible.

How was natural selection misused in the late 19th and early 20th centuries?

It was used to justify social Darwinism, a harmful idea that applied “survival of the fittest” to human societies

Social Darwinism

A misuse of Darwin’s ideas to claim that some people or groups are naturally “better” or more “fit” than others in society.

What indicated evolutionary change before Darwin?

Classification, anatomy, fossils, variability, vestigial traits, adaptation, and long-term changes in Earth, planets, and languages.

What did Erasmus Darwin propose about evolution in Zoonomia (1796)?

Suggested that species change over time and pass on improvements acquired during life to their offspring (similar to Lamarck).

What did Charles Darwin conclude about the ancestry of warm-blooded animals?

He concluded that they descended from a single common ancestor, “one living filament” endowed with life by the First Cause

Why did Lamarck believe that life evolved?

• species are related (Linnaean hierarchies)

• environments change,

• extinct species must be replaced by new ones, so life evolves to survive.

What were Lamarck’s two proposed causes of evolution?

1. Innate tendency toward complexity: organisms naturally become more complex over time; new structures formed are inherited.

2. Use and disuse: organs grow stronger if used and shrink if not; these changes are passed to offspring (inheritance of acquired traits).

Who was Patrick Matthew (1790–1874)and what was his contribution to evolutionary thought?

proposed natural selection and common descent in an appendix to his 1831 book On Naval Timber and Arboriculture, 28 years before Darwin’s Origin of Species.

What is Vestiges of the Natural History of Creation and who wrote it?

Published in 1844 by Robert Chambers (anonymously), it argued that life evolves as part of a general Law of Development of the Universe.

What evidence and ideas did Robert Chambers present for evolution in Vestiges?

• fossil sequences

• comparative anatomy,

• embryology

• apparent progression from simple to complex as evidence.

• proposed new life arose via frequent spontaneous generation and species evolved through variable embryonic development.

Why was evolution significant in 19th-century biology?

Many fields of biology pointed to evolution as a unifying idea, and the public often accepted it before scientists.