Natural Selection Lab

Archaeopteryx fossil Passenger pigeon, which became extinct in

the early 1900s due to human hunting

I’iwi, Hawaiian honeycreeper

By Jane Horlings

History

• Ideas about evolution originated before Darwin

• Aristotle

• Fossils

• Jean Baptiste de Lamarck– Inheritance of acquired

characteristics

Aristotle (UL), Ammonite fossil (UR), Lamarck (L)

History

• Lamarck – Characteristics which an organism

developed during its lifetime were inherited

– Now known to be invalid

History

• Charles Darwin

• H.M.S. Beagle

• South America & the Galapagos

Islands

H.M.S. Beagle (U), Galapagos turtle (LL), Darwin at early age (LR)

History

• Finches in the Galapagos

History

History

• Other scientists and research influenced Darwin’s theory

• Charles Lyell: Principles of Geology

Lyell

History

• Economist Thomas Malthus

History

• Alfred Russel Wallace

Wallace, early (R), and later in life (L)

History

• Darwin proposed that evolution occurs by natural selection

• On the Origin of Species by Means of Natural Selection published in 1859

• Darwin's theory had four parts:

1. Organisms produce more offspring than can survive to reproductive age

2. Members of a population vary and some of these variations are heritable

3. Resources available to a population are limited

4. Organisms with the most favorable traits have differential reproductive success, and those traits are passed to the next generation

History

History

• The synthetic theory of evolution or Neo-Darwinism

Darwin (R), Mendel (L)

Darwin in cartoon from 1800s

History

Darwin died in 1882

• Selection = when some individuals leave behind more offspring than others, and the rate at which they do so is affected by their inherited characteristics

• Selection can be artificial or natural

Selection

Peppered moth

• Artificial selection

Selection

• Biotechnology / Genetic engineering

Selection

• Natural selection

• Natural selection is the result of differential reproduction by members of a population

• “Reproduction of the fittest!”

Selection

See? The offspring in the last

generation now all have the gene

allowing them to be resistant to the

pesticide! This is a great example of

selection!

Selection

End