The Age of Things Using radiometric dating techniques, scientists have been able to estimate ages of various things.

But we finally did get to the party.

Who's Who in Evolutionary Theory: A History

Remember: The Origin of Life is not the same as The Evolution of Life.

We have a long history of trying to figure out both.

Plato and Aristotle

About 2500 years ago, these Greek philosophers were positing that the world had always been as they saw it, with everything having been put there by a divine creator.

Scala naturae

Aristotle created scala naturae, a representation of the hierarchy of life. He believed it was unchanging.

Creation Mythologies

Most of us are familiar with the story of a supreme being creating the universe from an empty void.

Ancient Norse creation mythology recounts the joining of primal ice and fire in the the great void--Ginnungagap--that created the oceans, the world, the gods, and how those gods created animals and humans.

There are as many creation stories as there are cultures.

Problem is...each of these stories is different from the others.
So they can't all be true.

Intellectual Stirrings in the Renaissance

As recently as the 1700's, biology was still studied in a framework of natural theology, the notion that science should be dedicated to studying nature in order to figure out the Grand Plan of the Creator.

Origin of Life: The Birth and Death of Some Popular Ideas

Ancient Romans thought that living organisms could spring, fully formed, from non-living matter by a process of spontaneous generation. This was inspired by common observations:

It took the work of more than one scientist to lay the idea of spontaneous generation to rest.

  • Francesco Redi

  • Anton van Leewenhoek

  • Georges Buffon

  • John Needham - Oops. Back to the Drawing Board.

  • Lazaro Spallanzani

  • Louis Pasteur - Let's end this.

    Taking Pasteur's Work Out of Context to Contest Evolution

    Unfortunately, some who are not fully educated about modern understanding of the Origin of Life have claimed that since Pasteur "disproved" spontaneous generation, that life cannot come from non-living matter, and hence, evolution cannot occur.

    This is, quite simply, WRONG.

    Miller-Urey: The Modern Understanding

    In the 1950s, Stanley Miller and Harold Urey duplicated the conditions of the primordial earth in this now-famous apparatus:

    (Click on the picture of Stanley Miller for more detailed information)

    The initial experiments, using water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2), yielded the amino acids glycine and alanine. Miller noted that over years of experiments, the apparatus produced eleven of the known amino acids.

    Later experimental runs using a Miller-Urey apparatus showed that the apparatus's original chemical components could react to produce hydrogen cyanide (HCN), formaldehyde (CH2O), acetylene and other biological molecules.

    Later it was shown that formaldehyde can react with water to produce various sugars, including ribose, the sugar component of RNA.

    In subsequent years, other researchers observed additional reactions in similar apparati that produced biological molecules.

    In 1961, Joan Oro demonstrated that the nitrogenous base adenine could be constructed from hydrogen cyanide and ammonia.

    In short, these important biological molecules were synthesized in Miller-Urey apparatus and in similar apparati used by other researchers:

    One critical feature of the Miller-Urey apparatus was the absence of oxygen, which was scarce in earth's earliest atmosphere. (Oxygen is highly reactive, and would have destroyed such large molecules if it had been present.)

    Still, no one knew how those molecules had come together to produce life.
    Recently, some researchers are getting a bit closer to witnessing the tiny steps to that amazing outcome.

    Abiogenesis: Recent Advances

    Today, research has revealed even more clearly how, at some point, Life must have originated from non-living matter.

    Which is not exactly what some people think.

    Organic Evolution

    Once life got here, how did it change into the vast variety of forms we see today?
    Many scientists have contributed pieces of the puzzle.

  • After life arose from non-living matter, how did it change into the vast variety of forms we see today?

    a testable idea of how organisms could change from one generation to the next was

  • Jean Baptiste Lamarck

    Lamarck: Use it or Lose it

  • Lamarck believed that evolution was driven by "use vs. disuse" We now know that--generally speaking--traits acquired during an organism's lifetime are NOT passed to its offspring. Mendel's and Darwin's work helped refute Lamarck's theory.

    Lamarck Rises from the Grave?

    The relatively recent discovery and understanding of epigenetic inheritance suggests that while Lamarck may not have quite hit the mark, not all inheritance is strictly Mendelian. Environment can play a role in how DNA is packaged and expressed, and some of those DNA re-arrangements are heritable.

  • Georges Cuvier

    Among these scientist creationists was a young student named...

  • Charles Darwin.

    One of the most influential scientists of all time, Darwin elucidated his theory of how evolution proceeds in his (then) controversial work, On the Origin of Species by Means of Natural Selection (1859). Origin of Species is arguably the most important biological work ever written, and most modern biology is framed in the context of evolution by natural selection.

  • Mootoo Kimura

    Not all evolution is strictly Darwinian.

    In 1968, Mootoo Kimura published his Neutral Theory of Molecular Evolution. In essence, his theory states that random, neutral changes in DNA at the molecular level can have profound evolutionary consequences over time. The rate at which these changes happen depends on population size. But Genetic Drift is now understood to play a major role in evolutionary change in living populations.

    Research in this area is ongoing.

    Here's a nice overview of some of what we know about the Facts of Evolution.