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Learn about Darwin's travels on the HMS Beagle, exploration of the Galapagos Islands, and his groundbreaking ideas on evolution. Discover how he observed and theorized about natural selection, descent with modification, and survival of the fittest.
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Charles Darwin • Born in England • Traveled around on HMS Beagle - Set Sail in 1831 • Collected many specimens • Father of the idea of Evolution
Darwin & The Galapagos • Galapagos Islands are a small group of islands 1000km west of South America • Studied Tortoises and Finches on the islands. • Used geography of islands and differentiation of species to figure out evolution
Galapagos Islands • Although they were closetogether, the islands had very different climates. • The smallest,lowest islands were hot, dry, and nearly barren. • Hood Island - sparse vegetation. • The higher islands had greaterrainfall and a different assortment of plants and animals. • Isabela Island - rich vegetation • Allowed for different species of the same animal --> formed through evolution!
Galapagos Blue-Footed Booby • Male dances and shows its feet to the female to attract her • Female chooses male with brightest feet and best dance • Sexual selection! • Sexual selection is a trait or behavior that acts on an organism's ability to obtain a mate
Darwin’s Thoughts • On his travel home, he began to think of his observations. • He found…characteristics of many animals and plants varied noticeably among thedifferent islands of the Galapagos • According to this hypothesis, these separatespecies would have evolved from an original SouthAmerican ancestor species after becoming isolated fromone another
Inherited Variation and Natural Selection • Darwin noted that plant andanimal breeders used heritable variation, whatwe now call genetic variation, to improve cropsand livestock. • Artificialselection: nature provided the variation, andhumans selected those variations that theyfound useful. • A.K.A Selective Breeding
Natural Selection • Each organism has different advantages and disadvantages • Individual best suited for environment survive and REPRODUCE • Pass these traits onto offspring, and they are more able to survive and reproduce • Occurs only when a few survive • Remember: differences (genes) in offspring occur at random!
Darwin’s Concept of Evolution • Biggest contribution is his idea of the mechanism behind Evolution • The Struggle for Existence • Survival of the Fittest • Descent with Modification
Struggle For Existence • Struggle for existence:means that members of each speciescompete regularly to obtain food, living space, and other necessities of life. • Predators that are faster win • Prey that are better camouflaged or protected win
Survival of the Fittest • Fitness: ability of an individualto survive and reproduce in its specific environment. • Result of adaptations • Adaptation: any inherited characteristic that increases anorganisms chance of survival
Survival of the Fittest • Survival of the Fittest: the idea that individuals that arebetter suited to their environment survive and reproduce more successfully • A.K.A. Natural selection
Descent with Modification • Natural selection produces organisms that havedifferent structures • Descent with modification: each living species has descended, with changes,from other species over time
