What is Natural Selection? by Caroline Daniel https://padlet.com/cgdaniel811/ueb00r42eot0 Cengage Biology 16.2 en-us 2018-03-28 21:50:39 UTC 2025-12-22 16:20:02 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Xmastree.png Georges Cuvier cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247097522
  • Expert in zoology and paleontology
  • Proposed idea startling for time: 
    • many species once existed, now extinct
  • Knew about evidence that Earth’s surface had changed
    • had seen fossilized seashells on mountainsides far from modern seas
    • assumed Earth’s age to be in the thousands, not billions, of years
  • Reasoned that geologic forces unlike any known at time would be necessary to raise sea floors to mountaintops in short time span
  • Catastrophic geological events would have caused extinctions, after which surviving species repopulated Earth
    • ]]>     2018-03-28 22:52:57 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247097522     Intro cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247097992 Around 1800, naturalists were trying to explain the mounting evidence that life on Earth, and even Earth itself, had changed over time. ]]> 2018-03-28 22:57:24 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247097992 Jean-Baptiste Lamarck cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098555
  • Thinking about processes that drive evolution
  • Thought that species gradually improved over generations because of inherent drive toward perfection, up the chain of being
    • environmental pressures cause internal need for change in body, resulting change inherited by offspring
    • (Lamarck was correct in thinking that environmental factors affect traits, but his understanding of how traits are passed to offspring was incomplete.)
    ]]>     2018-03-28 23:02:49 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098555     Evolution cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098655 Change in a line of descent.]]> 2018-03-28 23:04:03 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098655 Lineage cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098746 Line of descent.]]> 2018-03-28 23:04:48 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247098746 Charles Darwin cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247099253
  • Earned theology degree from Cambridge after attempt to study medicine
    • Through school, had spent most of time with faculty members and other students who embraced natural history
  • 1831 (age 22): joined 5-year survey expedition to South America on Beagle, quickly became enthusiastic naturalist
    • during voyage, found many unusual fossils, saw diverse species living in environments ranging from the sandy shores of remote islands to plains high in Andes
    • read the first volume of a new and popular book, Charles Lyell’s Principles of Geology
  • Exposure to Lyell’s ideas gave insight to history the regions encountered on journey
  • Among specimens collected during voyage were fossil glyptodons
    • extinct armored mammals are extinct
    • many unusual traits in common with modern armadillos 
    • Armadillos also live only in places where glyptodons once lived
    • ]]>     2018-03-28 23:09:10 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247099253     cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247099591 2018-03-28 23:12:31 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247099591 Charles Lyell cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247100014
  • Proponent of what became known as theory of uniformity: 
    • idea that gradual, everyday geological processes such as erosion could have sculpted Earth’s current landscape over great spans of time
    • challenged the prevailing belief that Earth was 6,000 years old
  • By Lyell’s calculations, it must have taken millions of years to sculpt Earth’s surface
    • ]]>     2018-03-28 23:16:22 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247100014     Thomas Malthus cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247938732
  • Economist 
  • Correlated size increases in humans 
    • famine
    • disease
    • war
  • Proposed: humans run out of food, living space, resources because they reproduce beyond environmental capacity 
  • Individuals of population must either compete with one another for the limited resources, or develop technology to increase productivity
    • ]]>     2018-04-02 21:08:16 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247938732     Fitness cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247954240 Degree of adaptation to an environment, as measured by an individual’s relative genetic contribution to future generations.]]> 2018-04-02 23:42:50 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247954240 Adaption, or Adaptive Trait cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247954310 A heritable trait that enhances an individual’s fitness in a particular environment.]]> 2018-04-02 23:44:25 UTC https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247954310 Summary cgdaniel811 https://padlet.com/cgdaniel811/ueb00r42eot0/wish/247954395 Evidence that Earth and the species on it had changed over very long spans of time led to the theory of evolution by natural selection. Natural selection is a process in which individuals of a population survive and reproduce with differing success depending on the details of their shared, heritable traits. Traits favored in a particular environment are adaptive.

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