Evolution and Darwin

• Evolution is defined as gradual change over time
• The word evolution comes from the Latin words "e-", meaning "out of", and "volvere", meaning "to roll"

Types of evolution:

• Geologic evolution
• Biological or organic evolution
• Charles Darwin described the basis of modern evolutionary thought

Evolution Before Darwin

• Greek philosophers, like Plato, had the concept of idealism
• Aristotle created "scala naturae" (scale of nature)
• Idea of special creation of each species
• Idea that organisms were created in their current forms
• The Earth was only a few thousand years old

Carl Von Linne

• Carl Von Linne was a Swedish botanist
• He worked on plant classification
• He published "Species Plantarum" (~7,300 plants)
• Carl Von Linne ordered plant classification based on similarities
• Showed the natural relationships among plants

Thomas Malthus

• Thomas Malthus was an economist and clergyman
• Thomas Malthus published "An Essay on the Principle of Population"
• Populations tend to increase geometrically
• Resources needed to support population growth increase slowly or not at all
• Growth will be limited since continued growth of a species will outstrip needed resources

Jean-Baptiste de Lamarck

• Jean-Baptiste de Lamarck was a French biologist
• He purposed modern species descended from other species
• Lamarckism is based on two theories:
  • Inheritance of Acquired Characteristics: Traits acquired by an individual during its life are passed to its offspring
  • Use and Disuse: Organs of the body used extensively to cope with the environment become larger and stronger, while organs that were not used deteriorated
• Giraffes obtained their long necks from previous giraffes who stretched to eat the leaves of high tree branches
• Stretching increased length of necks, and this acquired characteristic was passed to the next generation
• First to present a unified theory that attempted to explain the changes in organisms from one generation to the next
• But the mechanisms proposed for change was wrong, since acquired inheritance is not heritable
• Origin of species from preexisting species
• Ability of organisms to adapt

Darwin's Time (1800s)

• Georges Cuvier was a French anatomist, naturalist, and writer
• Georges Cuvier was a paleontologist
• Georges Cuvier strongly opposed the concept of evolution
• The history of living organisms are recorded in layers of rock
• Layers of rock contain a succession of fossil species in chronological order
• Fossils were organisms that had died in a series of catastrophes
• After the fossils died, extinct plats and animals were replaced by immigration of distant species to the devastated region (catastrophism)

James Hutton

• James Hutton was a Scottish geologist
• Also study law, medicine, and agriculture
• Published "Theory of the Earth"
• Geological change occurred slowly but continuously by gradualism
• Sedimentary rock encased fossils - formed by gradual accumulation of sediments in bodies of water

Charles Lyell

• Charles Lyell was a Scottish lawyer turned geologist
• He published "Principles of Geology"
• Lyell believed in Uniformitarianism: the processes that alter the Earth are uniform through time
• Believed Hutton's evidence for gradualism indicated the Earth was millions of years old
• Believed slow and subtle processes cause change over time
• The Earth is very old and constantly changing
• Life existed millions of years ago
• Geologists were convinced of an ancient Earth
• Geologists were at odds to explain the appearance and disappearance of species in the fossil record
• Believed in special creation

Gregor Mendel

• Gregor Mendel was an Austrian biologist
• He discovered the basic principles of heredity
• He is known as the father of classical genetics
• Individual characteristics are determined by inherited factors transmitted from parent to offspring

Charles Darwin

• Charles Darwin voyaged on the H.M.S Beagle in 1836
• He published The Origin of Species in 1859
• Charles Darwin was the first person to propose a mechanistic approach to evolutionary thought
• The father of synthetic evolution
• Species were not specially created in present forms
• Proposed a mechanism for evolution: Natural Selection
• A population of organisms can change over time
• This is a result of individual organisms having certain heritable characteristic and therefore leaving more offspring

Alfred Russell Wallace

• Alfred Russell Wallace was an English naturalist
• He studied the Malay archipelago and Amazon
• He proposed a theory of evolution similar to Darwin's

Neo-Darwinian/Contemporary Times

• Hugo de Vries, Carl Correns, and Erich Von Tschermak rediscovered Mendel's laws of heredity
• Started rediscovering evolution in terms of Mendel's ideas

James Watson and Francis Crick

• James Watson and Francis Crick: elucidated the structure of DNA (genetic material)
• DNA contains coded information which acts as a blueprint for the transfer of hereditary information from generation to generation
• Mutation serves as the raw material for evolution