History of evolutionary thought Flashcards
- Organisms of one species do not interbreed with members of another.
- Used species as the basic unit of taxonomy.
- Grappled with the contradictions between the biblical account of creation and the evidence of change and extinction.
- Rejected any possibility of an old and changing Earth
17th Century: John Ray: The “species” concept
- Use the name “systematically” in his classification system.
- Believed that all species were created together.
18th Century: Carl Linnaeus and the Modern Taxonomic System
- set out the current knowledge of the whole of natural history in the 44-volume “Natural History”.
- Suggest that our planet had formed in a molten state and that its gradual cooling must have taken far longer than 6000 years.
- Gave consideration to the concept of evolution.
Buffon on Evolution and the Age of the Earth (George Louis Leclerc, Comte de Buffon)
- Book: The Loves of the Plants
- Another book: Erasmus
- Aware that modern species were different to fossil types.
- Saw how plant and animal breeders use artificial selection.
- Life on Earth could be descended from a common ancestor.
Erasmus Darwin’s Thoughts on Evolution
- His work was extremely useful in interpreting the remains of fossil, animals and relating them to living species.
- Classified animals according to their body plan (as vertebrates, those with jointed exoskeletons.
- His extensive studies of fossils gave rise to the science of paleontology.
- Recognized that particular groups of fossil organisms were associated with certain rock strata.
George Cuvier’s Contribution to Paleontology
- A series of catastrophes.
- Areas were then repopulated by migration from unaffected areas.
- There was no room in this model for the evolution of new species.
- Life has existed unchanged on Earth for hundreds of thousands of years, ever since the Creation.
The Catastrophism Model of Earth’s History
- His model of evolution proposed that individuals were able to pass to their offspring characteristics acquired during their own lifetimes.
- States that evolution produced more complex organisms from simple ancestors.
- Etienne Geoffroy Saint-Hillaire also felt that the environment could produce changes in living things.
- If changes were harmful, then the organisms would die.
Jean Baptiste Lamarck’s Concepts of Evolution and Inheritance
- Recognized that the Earth was extremely old.
- There was no need for global catastrophes to shape the surface of the Earth.
- Sedimentation, erosion could produce the geological features.
- Darwin specifically applied Hutton’s concept of gradual change.
James Hutton and the Principle of Uniformitarianism
- Support evidence for principle of uniformitarianism
- Building on the idea of gradual long-term natural changes, he considered the origin of plants and animals.
- He also recognized that many species had become extinct and been replaced by others.
18th Century: Charles Lyell
- Charles once more ignored his official studies and took classes reflecting his interest in the natural world, including botany and geology.
- Expectation from his friends and university tutors: Charles was to collect scientific specimens.
- Darwin’s took Lyell’s “Principle of Geology, ” led him to accept the uniformitarianism approach to Earth’s history.
- He made extensive fossil collections and noticed that these fossils were found in regions now occupied by their slightly different descendants.
Charles Darwin and the Theory of Evolution by Natural Selection
- He had always had an interest in natural history but not the funds to indulge it.
- Like Darwin, he was influenced by the ideas or limits to population size.
Came up with the idea that the best-adapted organisms in a population would survive to breed, passing on their adaptations to their offsprings.
Alfred Russel Wallace Arrives Independently at a Theory of Evolution
All major chemical and anatomical similarities between living things can be explained by assuming that species were originated from the same ancestor.
Anatomical Similarities of Living Organisms
- Seven elements to build the body of living organisms: oxygen, hydrogen, carbon, iron, silicon, calcium and nitrogen.
- Abiogenesis- formation of living forms into from non-organic matter.
Chemical Similarities of Related Life Forms
The environment plays a very important role in the process of biological evolution.
Geographic Distribution of Related Species
Biologists who examined questions of ancestry
Systematics
