Darwin’s Five Observations

  • More young are produced than survive
  • Individuals vary in their characteristics
  • Some characteristics are better than others
  • These characteristics are inheritable
  • Long periods of time are available

Darwin’s Two Major Points

  • Many species of organisms presently inhabiting the earth are descendants of ancestral species that were different from modern species
  • The mechanism he proposed for this was natural selection

Results of Natural Selection

  • Evolutionary adaptation: an accumulation of inherited characteristics that enhance an organisms ability to survive and reproduce in its environment
  • Evolution: the change over time in the genetic composition of a population


  • Taxonomy: The branch of biology concerned with naming and classifying organisms
  • Classifying life: species > genus> family> order> class> phylum> kingdom> domain
  • Fossils: The remains or traces of organisms
  • Sedimentary rock: Formed from sand and mud that settles in seas, lakes, and marshes
  • Paleontology: The study of fossils
  • Catastrophism: Each boundary between strata represents a catastrophe. Opposes idea of gradual evolution
  • Gradualism: The idea that profound change can take place through the cumulative effect of a slow but continuous process
  • Uniformitarianism: The same geological processes are operating today as they did in the past
  • Population: The smallest unit that can evolve

The Origin of Species

Descent with modification: As descendants of ancestral organisms spilled into various habitats over millions of years, they accumulated diverse modification or adaptations that fit them into specific ways of life

Natural selection

  • Natural selection is the differential success in reproduction among individuals that vary in their heritable traits.
  • Over time, natural selection can increase the adaptation of organisms to their environment
  • If an environment changes, natural selection may result in adaptation to the new environment
  • Can amplify or diminish only heritable traits
  • Natural selection can distinguish between acquired traits and inherited traits
author avatar
William Anderson (Schoolworkhelper Editorial Team)
William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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