ARCHIVE - Evolution 2

More about evolution . . .

Two features common to last week's ordering of the natural world:

Types

Variation is noise, not of interest

Plato (ca 427 - 347 BC) world of ideas, truth inaccessible, ideal forms.

Aristotle (384 - 322 BC) 'natural philosopher' could obtain knowledge of the natural world.

Escala naturae - "Chain of being"

God - demons - humans - quadrupeds - birds - fish - reptiles - insects - sea urchins - plants - fungi - talc, gypsum - stones - metals - earth - water - air - fire - "more subtle material"

Things are the way they should be

Reintroduced to western thought in the early middle ages from the Islamic world (upcoming talk); thinking stagnant for centuries.

Newton - gravity, calculus and cause and effect

Linnaeus (early 1700s). (Linné - Swedish) Hierarchical classification by morphological similarity. Typological. Impetus for collection (cf. Darwin, Wallace, etc.).

Buffon - interbreeding and relatedness of taxa.

Erasmus Darwin (grandfather of Charles). Simplistic idea of evolution, but no concept of mechanism.

Jean Baptiste Lamarck (1744-1829) theory of evolution by inheritance of acquired characters. Continual change - didn't accept idea of extinction. "The scala naturae in motion"

Hutton and Lyell (late 1700s - early 1800s) - geological processes. Uniformitarianism.

Cuvier (1812) comparative anatomy - Platonic: vertebrates, molluscs, articulates, radiates. Strong believer in extinction, catastrophes. Marginalized Lamarck.

Some background: why did these ideas come out of this place at this time? (upcoming talk by visiting speaker)

Adam Smith. Economist. "Invisible hand."

Thomas Malthus. The tendency of populations to increase geometrically - struggle for life.

Charles Darwin (1809-82) Voyage of the Beagle, and Alfred Russell Wallace (1823-1913) biogeography. Travelled and collected extensively in tropical America and SE Asia.

Proposed natural selection as a mechanism for evolutionary change. (No clear idea of mechanism of inheritance)

The revolutionary breakthrough: variation is important, it's the stuff of evolution, it's the key to the whole story, it's not noise or imperfection or deviation from the "type"

Both were inspired by observations of different distributions of related species, especially in the tropics.

Wallace - tendency of varieties to depart indefinitely from the original type.

Darwin - origin of species, or the evolution of favored races in the struggle for life. (Herbert Spencer "survival of the fittest" used later by Darwin)