Evolutionary Thought Flashcards
What is the prerequisite for evolution?
Variation in heritable traits. Without variation, evolution is impossible because there is nothing for selection to act on.
What were Aristotle’s ideas on species?
Species were not variable but fixed. Species are arranged on a ladder of increasing complexity called the great chain of being or scala naturae.
In the binomial nomenclature Canis lupus, what does each word mean?
Canis is the genus. Lupus is the specific name that refers to one species in the genus Canis.
What scientific ideas did Carlous Linnaeus have?
He accepted Aristotle’s idea that species are fixed and developed the binomial system of classification still in use today.
How was Linnaeus’ system of classification different from Aristotle’s?
In contrast to scala naturae, Linnaeus’ system was not linear but nested (species are nested within genera, genera are nested within families, etc).
Who was the first to propose a coherent theory of evolution?
Jean Baptiste de Lamarck.
What was Lamarck’s first law of evolution?
Use and disuse leads to acquired traits.
What was Lamarck’s second law of evolution?
Acquired traits can be inherited.
Describe Cuvier’s scientific ideas.
He is often credited as the founder of vertebrate paleontology and extinction. He opposed Lamarck’s view of “evolution” and believed that there were cyclical creations and destructions of life forms by global extinction: “deluges.”
How did Darwin explain large morphological gaps between related groups?
He explained this by branching and extinction events.
How are elephants an example of branching and extinction events?
Living elephant species are similar because they split from a recent common ancestor. The extinction of seven older species helps explain the dissimilarity between elephants and their nearest living relatives, hyraxes and manatees.
How does natural selection work?
Differential success in reproduction results in certain alleles being passed to the next generation in greater proportions.
What were the two major hypotheses of Darwin’s Origin of Species?
- Life’s history can be explained through the evolution of species by descent with modification from common ancestors.
- The cause of evolution is natural selection acting on hereditary variation.
What criticism did Fleeming Jenkin have of Darwin?
He questioned how variation is inherited.
How did Darwin respond to Jenkin’s critiques?
He proposed the pangenesis hypothesis, in which hereditary substances called gemules or pangenes are shed by all parts of the organism and carried in the bloodstream.
