Evolution and The Origin of Species Flashcards
Exam 1
What were some early views on evolution?
Ancient philosophers primarily believed organisms remained unchanged overtime.
Ex) Plato and Aristotle
When did the views of evolution begin to change?
Age of Enlightenment (18th and 19th century)
Carl von Linne (Carolus Linnaeus)
18th century; orderly nested classification system; based on relatedness of common characteristics
Georges Cuvier
18th century; connected fossils to ancient ecosystems
Gradualism
James Hutton (18th century geologist); the evolutionary process in which species experience changes in characteristics slowly and incrementally
Charles Lyell
Fathers of Modern Geology; created “Principles of Geology (1830s)”; proposed the idea that the earth is old and processes continue; colleague of Darwin
Jean-Baptiste Lamarck
believed in heredity of acquired characteristics; connected evolution to adaptation; “use it or lose it” proposal; “Philosophie Zoologique (1809)”; “Lamarckism”
Lamarckism
the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime
Erasmus Darwin
Charles Darwin’s grandfather; philosophized on “minute forms” gaining complexity in late 1700s, or small changes over time lead to big differences over time
HMS Beagle
Charles Darwin (1831-1836)
-led inland expeditions for observations
-took samples and preserved them; made notes of species’ geographic locales
-noted adaptations of species
-believed he found evidence of Lyell’s geographical processes (1835)
-focused around the bottom of South America; went to bottom of Africa and Australia
-did not publish ideas upon return
Charles Darwin and Alfred Wallace
Both wrote scientific papers on natural selection that were presented together before the Linnean Society in 1858
Darwin published “On the Origin of Species by Means of Natural Selection” in 1859 (before Wallace published anything)
Darwin’s Theory Pt. 1
Descent with Modification:
-commons ancestor gave rise to present species through gradual modifications over time (evolution)
Darwin’s Theory Pt. 2
Natural Selection:
-most characteristics are heritable, passed from parent to offspring
-more offspring are produced than can survive; there is a competition for resources
-characteristics of offspring vary, and these variations are heritable
Darwin’s Observation
Darwin observed that beak shape varies among finch species. He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources
The mechanism for evolution
Natural Selection
Darwin’s Theory Postulate #1
Heritable variation exists in most species
Darwin’s Theory Postulate #2
All species produce more offspring than the environment can support. Many offspring die before maturity
Artificial Selection
Farmers can enhance heritable variations by artificial breeding. Humans have been doing this for thousands of years with crops and domesticated animals
Selective Breeding
Humans choose the phenotypes wanted and breed those individuals, as well as creating more idea hybrids and breeds
Natural Selection
There is an unequal reproductive success among individuals. Those with the “best” traits (help them survive and reproduce in their environment) leave more offspring than others
Those heritable, favorable traits accumulate over time, matching the species to its environment and ultimately leading to new species
Artificial vs. Natural Selection
Artificial:
-Different breeding goals
-Breeder’s choice
-Leads to different varieties
Natural:
-Different environments
-Nature’s choice
-Leads to different species
What does natural selection lead to?
Leads to different adaptations in different environments
