Chapter 22 Darwinism Flashcards
(19 cards)
What book did Charles Darwin publish in 1859 that began the Modern Era of Biology?
The Origin of Species
What inspired Darwin’s theory of evolution?
His 5-year voyage on the HMS Beagle, observing animals on the Galapagos Islands.
What did most people in the 19th century believe about species?
That species were immutable and created suddenly, remaining unchanged.
What did Darwin propose instead of fixity of species?
That species changed over time through descent with modification.
What is Natural Selection?
A mechanism where organisms with favorable traits survive and reproduce more, guiding evolutionary change.
How did Darwin’s evidence from fossils support evolution?
He found extinct fossils like Glyptodon and Megatherium resembling modern armadillos and sloths, suggesting common ancestry.
What did the similarities in bones among different species suggest to Darwin?
That they shared a common ancestor and diverged with modifications.
What did Darwin observe about finches on the Galapagos Islands?
Each island had distinct finches with different beaks and feeding behaviors, descended from a common ancestor.
What is Artificial Selection?
Selective breeding by humans that led to radical changes in domesticated species like dogs and corn.
What are the two key facts behind Natural Selection?
1) Variations exist and are inherited. 2) More offspring are produced than can survive.
What is the conclusion of these facts for Natural Selection?
Favorable variations accumulate in populations as they help survival and reproduction.
Who was Jean Baptiste de Lamarck?
An early evolution theorist who proposed use & disuse and inheritance of acquired characteristics.
What is the principle of use and disuse?
Body parts grow with use and weaken without use.
What is inheritance of acquired characteristics?
Traits acquired during an organism’s lifetime are passed to offspring (now disproven).
What is an example Lamarck used to explain long-legged birds?
Herons descended from short-legged birds that stretched their legs, passing on the trait.
Who disproved Lamarck’s theory?
August Weismann
What was Weismann’s contribution?
Germ Plasm Theory: inheritance only through germ cells (eggs and sperm), not body cells.
What experiment did Weismann conduct to disprove Lamarck?
Cut tails off 1500 rats over 20 generations; all offspring were still born with tails.
Mnemonic for Darwin’s Evidence (FRA): Fossils, Resemblances, Artificial selection – what do they stand for?
Fossils (extinct vs modern forms), Resemblances (homologous structures), Artificial Selection (dog breeds, crops).
