Question Detail

Looking for engaging evolution lessons for resistant HS biology students.

Apr 4, 2017 1:51pm

  • Science
  • 10
  • Engagement

2

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    • Apr 8, 2017 8:19am

      Hi, I'm taking my teaching certification and have higher than average knowledge about evolution. I probably can't give you very solid lesson plans, but hopefully you can work off of my ideas.

      There's one thing you could do that would provide a breathtaking big picture while making the concept small and relevant.

      Show three siblings who lived a few hundred years ago. Anne has no children, Bob has three children, Cory has two children. Go down a few generations so that Cory's children end up with no offspring after a couple steps. Give a couple extra generations to Bob's lineage, the one lineage with surviving children. Say these are the children that are alive today. Show that all the living children are related to each other through one common ancestor, Bob. Bob had siblings and relatives, but none of their offspring are alive today.

      Then show a microorganism, the common ancestor to all living things. This microorganism had siblings at one point, but none of them survived long. This is the only organism that successfully passed on its genes to all the organisms we have fossils for and all the organisms that are alive today.

      From here, there are lots of routes you could go.

      You can briefly overview the evidence of common ancestry-- proteomic evidence, fossil records, embryonic development, genetic analysis, morphology and vestigial traits, etc. Keep it simple... ex. for proteomic evidence, there are certain structures in the cell that are identical in the cells of all living things.

      Or, you can can bring up a phylogenetic tree and show some related species and dying-off lineages and compare it to Ana, Bob, and Cory's families.

      The students are probably going to be resistant to the idea of a common ancestor. Another way to lead them to see the logic behind the theory of evolution is to start with an example of a species that has natural variation, such as finches. Some finches have wider and more powerful beaks, some have narrower and sharper beaks... there is variation maintained among them because with their diet, say fruit, it doesn't really matter too much what shape it is. Then they enter a new environment, and find hard seeds. Which finches do you think will be more successful at surviving, the ones that can eat the hard seeds easily or the ones that can't? The ones that are better at eating the hard seeds have better nutrition, better readiness to reproduce, and lower starvation rates. They have a higher survival rate. The ones with thin beaks have less offspring, and less of their offspring survive. So then there are less and less thin-beaked finches in the population. Meanwhile, the thick-beaked finches have more offspring. You need good illustrations for this to show the change in balance in population. This example leads students to Darwin's classic postulates, that there are more offspring than can survive, there are variations in a population, there is competition for survival that these variations can give advantages or disadvantages for, and traits are passed from parent to offspring. Students can do a group project where they think of a variation that can help or harm a species in a new environment, and then draw the offspring branching off of surviving parents.

      (I know the example of finches is usually used to show adaptive radiation and the success of both wide and narrow beaked finches in different niches, but that's too advanced at this stage.)

      Some students may accept this kind of "microevolution" but deny "macroevolution" takes place. This is a good situation to teach about the evolution of the eye. There are some engaging videos out there. Students can draw different eye shapes and draw and imagine what they can see. You might even be able to make some glasses that show what the eye could have seen... like wax paper so you can only see light/dark.

      Another point to make about "macroevolution"/speciation is to show how there is a living continuum right now between species of felines... some species can interbreed, some can't. Students can easily argue that the difference between a tiger and a lion is only microevolution, but what about the difference between a tiger and a civet? Contrast related families. Go back just a little bit to a recent common ancestor, say of weasels and cats. An advanced lesson could use a cladogram.

      I know I didn't convey any stellar lesson plans here, but I hope I was able to inspire something useful. This was an interesting question and I'll be back to see what other people suggested.

      • Apr 27, 2017 10:01am

        Have you looked at the Deep Dives on this site for NGSS? https://www.teachingchannel.org/ngss. There are high school biology teachers who are sharing out their favorite resources and some might be helpful.