Monday 24 January 2011

They Don't Buy It

Today I discussed endosymbiosis with my AS Biology class. It's probably one of the most fascinating aspects of cell biology. There are three major similarities between mitochondria and bacteria: their membrane, their DNA and their method of reproduction. It is perhaps one of the most elegant theories in biology, and I find the evidence utterly compelling.

I drew this, so don't you dare copy it...

But the majority of students utterly rejected it. Now, I've been spoilt so far - my A2 students are mostly heathen and proud of it, last year's GCSEs barely had to look at anything more taxing than horse evolution, and the BTEC students don't have to learn a damn thing about evolution, natural selection or speciation.

So some of the gems I got today included:
"I accept it, I just don't believe it."

"You can prove collision theory. You can't prove evolution."

"Are gorillas going to evolve into humans?"

"This is rubbish!"
My responses, in order, were along the lines of "I don't want you to believe science, I want you to accept science, so that's fine by me.", "You can only prove mathematical theories - for all you know there are tiny elves living in chemicals who get really angry and throw atoms at each other when you heat up the solution.", "No." and "Tough, it's on the specification." These probably didn't convince anyone (although I am particularly proud of the collision theory elves).

So I'm starting to think of all the other topics I've taught them since the start of the year, and I'm wondering how much else in biology has as much/little supporting evidence as endosymbiosis, but is still entirely accepted by my students. As far as I am aware, the evidence for endosymbiosis is pretty good - it's been observed by Kwang Jeon in amboebae. Mitochondrial cristae seem to be homologous to prokaryote mesosomes. On the other hand, the last thing I heard is that the six-carbon immediate product of carbon dioxide and ribulose bisphosphate in the Calvin cycle is so unstable that it has not been identified yet. And the enzyme responsible for photolysis of water in the light-dependent reaction may or may not be one of the photosystems, according to a recent paper, but they absorb what I do teach them in this regard as gospel.

These students seem happy enough to accept a 4.6Ga old Earth. Most of them are satisfied with the Big Bang, and all of them are just fine with gravitational theory, collision theory and the kinetic theory of gases. It looks like I have an uphill battle, and I'm a little apprehensive about the prospect of teaching evolution and natural selection to them. I've also realised (naïve though I may have been) that there is very little chance of me convincing them of the evidence for any aspect of descent from a common single-celled ancestor, or any of the cool stuff in between that and the present day.



  1. Great article.
    It's increased my knowledge.
    I have vague memories of this theory, although I don't think it was taught back in the 80's when I did biology.

    You can add educating the over 40's to the list of your students.

  2. you should show them the endosymbiosis of algae in salamander- very good visuals in the paper


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