Brain Makeover #17: Evolution

Lesson #17 of 18 in the Brain Makeover collaboration with Professor James Trefil/George Mason University, the 76ers Cheerleaders and the Science Cheerleader. See Brain Makeover Series.
17. All forms of life evolved by natural selection.

Scientists divide the development of life on Earth into two segments: chemical evolution, which involves the development of life from inorganic materials, and evolution by natural selection, which describes the process by which that early life form produced the diversity of modern life. The latter is what people associate with Charles Darwin and usually mean by the term ‘evolution’.

Evolution by natural selection depends on two things: first, that there are variations within populations (so that, for example, some rabbits can run faster than others) and, second, competition between individuals (so that fast rabbits are more likely to survive and reproduce). Over time, this selection process produces new species.

Evidence for evolution by natural selection comes from the fossil record and from the examination of genes in the DNA of modern life forms.

  • Great! A controversial one (as if it should be at all!) at that! Can’t wait to see what rounds the list off!

  • Great! A controversial one (as if it should be at all!) at that! Can’t wait to see what rounds the list off!

  • Christy

    Ummmm…. this isn’t true. We have genetically altered and selectively bred both plants and animals. My toy fox terrier is definitely not a result of natural selection.

  • Christy

    By “this” I mean the statement in the list – “All forms of life evolved by natural selection.” Unless you say that evolution by definition involves natural selection, but then the statement is just a tautology anyway, you know? Of course I believe in natural selection, but I hold sciencecheerleader.com to a high standard and expect the copy here to be more precise! 🙂

  • Christy

    By “this” I mean the statement in the list – “All forms of life evolved by natural selection.” Unless you say that evolution by definition involves natural selection, but then the statement is just a tautology anyway, you know? Of course I believe in natural selection, but I hold sciencecheerleader.com to a high standard and expect the copy here to be more precise! 🙂

  • Christy:
    That’s a great point. Let me see if Dr. Trefil can weigh in here. Thanks for addressing this (and for holding us to high standards!).
    -Darlene

  • Christy:
    That’s a great point. Let me see if Dr. Trefil can weigh in here. Thanks for addressing this (and for holding us to high standards!).
    -Darlene