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
The branch of biology that is concerned with naming and classifying organisms.
Taxonomy
Three domains of life
- Domain bacteria (eubacteria)
- Domain archaea (archaebacteria)
- Domain eukarya (eukaryota)
- Also known as Kingdom Prokaryotes
- Reproduction is mainly by binary fission.
- Three ways of genetic recombination: transformation,
conjugation, transduction.
Kingdom monera
a bacterium takes up a piece of DNA floating in its environment.
Transformation
DNA is accidentally moved from one bacterium to another by a virus.
Transduction
DNA is transferred between bacteria through a tube between cells.
Conjugation
- Autotrophic or heterotrophic in nature.
- unicellular, colonial and multicellular organisms.
Kingdom Protista
- Eukaryotic, heterotrophic, sessile organisms
- Few are unicellular, but most are multicellular and multinucleated.
- Hyphae-threadlike filaments
- Cell walls are made up of chitin.
- Reproduction is sexual and asexual.
- Can be free living, parasitic, or symbiotic.
Kingdom fungi
Two broad categories of plants: Vascular plants & non-vascular plants
Kingdom plantae
