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Gradualism

Gradualism . One of the major components of the theory of evolution is that most changes happen slowly and that (thankfully) the earth has been around for a long time. Yet fully appreciating geological time is tricky.

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Gradualism

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  1. Gradualism One of the major components of the theory of evolution is that most changes happen slowly and that (thankfully) the earth has been around for a long time. Yet fully appreciating geological time is tricky. First, lots of crazy names for the periods and eras can make studying this a pain. Second, our comprehension of our lifespan and even that of human history distorts our mental understanding of the major changes in the history of life on earth. The toilet paper roll of evolution is meant to help students fully comprehend the immense periods of time that the earth has been present.

  2. How do you conceptualize big numbers? Tiger Woods is back as the most highly paid athlete in the world. He makes $78 million a year. How many years would he have to work to pay off the US national debt ($16.7 trillion)? Don't calculate it – just give me a number really quickly. Now calculate it.

  3. Problem with Evolutionary Time • Most textbooks shows evolutionary time at a bunch of different scales using breaks in the timeline. This can be misleading.

  4. Coyne's depiction of the history of major evolutionary events. This is from Chapter 2.

  5. Toilet Paper Roll of Evolution • This can be used in geology or biology. The task at hand is to roll out an entire roll of toilet paper with the first square as the beginning of the earth and the last as modern times. Then figure out which square the major evolutionary events occurred.

  6. Age of the earth is 4.5 billion ears (4.5X10^9). Count the number of squares and figure out how many years a square corresponds to. Some Major Evolutionary Events Prokaryotes beg about 3.8 billion years ago (or 0.7 * 10^9 years from time 0). Eukaryotes arose around 2.7 billion years ago. Oxygen becomes abundant 2.5 billion years ago. Jelly fishes, segmented worms, carol anemones, trilobties, etc. (Cambrian Explosion) around 600 million ears ago. Jawed fish appeared about 500 million years ago. Tetrapods and terrestrial plants appeared about 400 million years ago. Amphibians around 350 million years ago. Reptiles around 300 million years ago. Mammals appear around 250 million years ago. Birds appear around 200 million years ago. Humans appear around 7 million years ago. Feel free to look up some other stuff online. Mass extinction events? Plot your events on your roll of toilet paper.

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