A worksheet targeted for High School students proving once and for all that Photosynthesis is not “Irreducibly Complex”

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Some present may remember an entertaining (not to mention illuminating (pun intended) ) blog by Professor Larry Moran:

http://sandwalk.blogspot.ca/2016/04/fun-and-games-with-otangelo-grasso.html

I am a high school Biology teacher and Professor Moran threw out some challenges which cut me to the quick.

Here is a very brief and incomplete summary:

The dual photosystems of Blue-Green Algae clearly evolved late from a combination of a type I reaction center in species like Heliobacter and green sulfur bacteria and a type II reaction center from species like purple bacteria and green filamentous bacteria. The oxygen evolving complex was a late addition.

Both photosystems employ Porphyrins and Carotenoids which are important in various metabolic processes (not just photosynthesis) meaning their evolutionary history may reflect many other functions only to be co-opted later for photosynthesis. Meanwhile both can be demonstrated to have abiogenic origins.

Meanwhile RuBisCO is found in non-photosynthetic species…

According to Professor Moran, many misconceptions are perpetuated when teaching according to textbook orthodoxy. Instead we should consider Photoreduction and Photophosphorylation as two stand-alone processes, and that the capture of light energy to produce carbohydrates is a highly specialized phenomenon; which, from an evolutionary point of view is not really (at least not originally) part of “photosynthesis” (i.e. carbohydrate anabolism).

Even Flowering Plants not only can, but in fact most of the time do, decouple ATP/NADPH production from Carbon fixation. Indeed, much of the ATP & NADPH generated by Photosystems II & I respectively are in fact redirected to immediate energy needs, even in flowering plants.

Meanwhile, I heartily agree with Larry Moran’s thesis that it is important (nay, let’s say instead imperative) to teach students that there’s more to life than just flowering plants and humans?

Larry Moran (in very unsubtle and less than gentle terms) “suggests” such strategies should apply to teaching of all biochemistry; i.e. from simple pathways to more complex pathways.

A recent “must-read” article inspired me to respond to Larry Moran’s challenge,

https://www.nature.com/articles/ncomms13924.pdf

… and I have cobbled together a worksheet, where I attempt to prove that photosynthesis is

1 – misunderstood (tis not really about Glucose and it’s not even about the Calvin Cycle) at least from a Biochemist’s evolutionary POV. Ecologists have justification to differ.
2 – NOT “irreducibly complex” but rather a hodge-podge cobbling by evolution over a long period of time. (cf https://embryo.asu.edu/pages/evolution-and-tinkering-1977-francois-jacob)

Larry Moran’s fingerprints are all over this work of mine, for which I really cannot claim any originality on my part.

I would be grateful for any constructive input and suggestions for improvement. Remember, the intended target audience remains high school students.

Thanks in advance and best regards,

Here it is:

https://drive.google.com/file/d/0By6ZKSkkTEG-QXFtWVhKOWNwREE/view

374 thoughts on “A worksheet targeted for High School students proving once and for all that Photosynthesis is not “Irreducibly Complex””

  1. Bill,

    Before you change the subject, do you finally accept that when Behe says “Common descent is true”, he means that common descent is true?

    Or are you going to come up with another Billsplanation, like “He doesn’t mean it’s true true — he’s just saying we can’t rule it out”, or some other hogwash?

  2. Rumraket,

    Yes I agree with him, the explanation is trivial. It’s just reproduction over many many generations.

    Do you think Mike believes that it is just reproduction over many generations? Do you think Mung believes that? How do you think these guys integrate ID into their belief that common descent is true?

  3. Mung: What on earth does common descent have to do with your worksheet?

    The notion of endosymbiosis

    As Larry Moran eloquently elucidated on frequent occasion: the distinction between host and symbionts remains rather arbitrary and capricious

    Review my OP

    The dual photosystems of Blue-Green Algae clearly evolved late from a combination of a type I reaction center in species like Heliobacter and green sulfur bacteria and a type II reaction center from species like purple bacteria and green filamentous bacteria. The oxygen evolving complex was a late addition.

    So I ask my students: how can the evolution of such cooperation even begin to happen?

    That is the thrust of my worksheet: intercellular syntrophy between two Litotrophs enabling each other’s independence from an inorganic substrate can eventually lead to intracellular endosymbiosis where one biological system acts as an electron donor and the other as an electron acceptor within one cell

    Yet again your challenges have proven useful! I will follow up on your recommendations and continue in similar vein with Cyanobacteria evolution. Thank you, yet again you are my Muse!

    Do we agree that even if a case for Irreducible Complexity can be suggested, any such IC is in fact “evolvable”, even in Cyanobacteria which is really a “Jonny-come-lately” in the history of evolution?

  5. Mung: It’s cartoonish in its simplicity. Therefore misleading in important ways.

    Have a look at this book if you don’t believe me:

    Bioenergetic Processes of Cyanobacteria: From Evolutionary Singularity to Ecological Diversity

    Cyanobacteria are way way later developments in this evolutionary story and as a result, inappropriate to consider as starting points in how far more ancient Lithotrophs mutually enabled each other’s independence from inorganic substrates for biological redox reactions’

  6. I must thank the agent provocateur who posted the following:

    Evolution as a Ralph’s Supermarket
    Uncommon Descent
    November 11, 2017 at 6:13 pm

    […] at the The Skeptical Zone there’s a reference to a post from Larry Moran’s blogsite. The question of irreducible […]

    Evolution as a Ralph’s Supermarket Store

    Where Mung opines:

    Mung
    Reminds me of how Walter ReMine refers to evolutionary theory as a smorgasbord.

    At last! Some unambiguous clarification exactly why Mung takes exception to my worksheet!

    He would prefer to dwell on how miraculously complex Cyanobacteria appear as irreducibly complex and unevolvable and not be distracted by simpler and easier scenarios to behold (syntophic Lithotrophs mutually assisting each others’ independence from inorganic substrates) which are occurring even as we speak

    NowI understand his chagrin

  7. Again, Bill:

    Before you change the subject, do you finally accept that when Behe says “Common descent is true”, he means that common descent is true?

  8. colewd: Do you think Mike believes that it is just reproduction over many generations?

    Yes, Mike believes there is common descent through reproduction over many generations.

    He also believes that along this process, God comes down from heaven in order to *POOF* things like the flagellum, and portions of the vertebrate immune systems, into existince in a puff of smoke.

    Do you think Mung believes that?

    I have no idea what Mung believes about common descent. But why don’t you just ask him instead of me?

  9. Rumraket: I have no idea what Mung believes about common descent. But why don’t you just ask him instead of me?

    God leaves out the puff of smoke unless someone is actually watching.

  10. Rumraket,

    Yes, Mike believes there is common descent through reproduction over many generations.

    He also believes that along this process, God comes down from heaven in order to *POOF* things like the flagellum, and portions of the vertebrate immune systems, into existince in a puff of smoke.

    Exactly, with the possible exception that the flagellum may be part of the original design of the bacteria. Also he believes that the causation may be front loaded into unfolding of the universe.

    Given this why is it so important to keiths that Behe concedes common descent given his version is so different from Darwins. Just a rhetorical question 🙂

  12. Bill,

    We’re laughing at you because of your panicked reaction to learning that Behe accepts common descent, and your lingering inability to come to grips with it. It’s fantastic entertainment!

    And yes, Behe accepts common descent — the belief that life on earth is related by common ancestry — just like Darwin himself did:

    Over the next few sections I’ll show some of the newest evidence from studies of DNA that convinces most scientists, including myself, that one leg of Darwin’s theory — common descent — is correct.

    Behe thinks that you’re wrong, and Darwin is correct, about common descent.

    He also thinks that you’re wrong, and Darwin is correct, that we share a common ancestor with chimpanzees.

    Put that in your pipe and smoke it.

    And please share your panicked reaction so we can laugh some more.

  13. Keiths

    I owe you a preemptive apology

    Only after hitting send did it occur to me that I again conflated IC with unevolvability

    I seem to make that slip frequently because those detractors who do not seem to understand Behe, make the same conflation

    This is a draft

    I see other corrections are needed

    I would appreciate any suggestions on your part

    Thanks in advance

  14. TomMueller: I would appreciate any suggestions on your part

    Instead of teaching biology to kids, maybe you could open up your own church?

    That seems to be more of your interest.

  15. phoodoo: Instead of teaching biology to kids, maybe you could open up your own church?

    That seems to be more of your interest.

    I do not understand. Church?

  17. phoodoo: Well, at least then when you are preaching its tax deductible.

    Preaching? Listing acumulated scientific observation is “preaching”?

    Out of curiosity: you think Galileo was treated fairly? Was he preaching?

  18. TomMueller,

    Then as now I doubted your earnestness when I realized your sophist ulterior motives

    The only reason I have lingered so long on this thread is due to the abundance of dissimultude you and your confreres are spewing in response to the cogent rebuttals of your detractors

    I remain grateful and will rewrite my worksheet in anticipation of the ID Taqiya prolgated by creationist jihadi outside my classroom

    Um, yea, right.

    Amen brother!

  19. Rumraket: phoodoo: What are the functioning “parts” of chloroquine resistance? What is their function?

    Mutations in a number of protein coding genes that make up a cellular membrane transport complex.

    I missed this gem from Rumraket. The functioning parts of chloroquine resistance are the mutations in the protein coding genes.

    Yippee, we no longer have to be stuck with using English in this thread, we can make up any meanings we want. What freedom!

  20. keiths: And yes, Behe accepts common descent — the belief that life on earth is related by common ancestry — just like Darwin himself did:

    I think Behe’s belief is even stronger than Darwin’s.

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