Reminder: I’m answering questions at 11am Central time today

Today I’m going to answer some patron/reader questions:

• Viruses replicate? Does that mean they mutate in infected people, too?
• Given the choice between a vaccine that stops spread but does nothing to reduce lethality and a vaccine that allows spread but eliminates lethality, what would be a better strategy for us?
• Hey, what about that old germ layer theory? It’s 205 years old, is mesoderm still a thing?

I’ll also try to answer any other questions that come up.

For a grand finale, today is the day I nuke my Facebook account. It won’t be too exciting: click, click, click, click, click, click (etc.), it’s gone. At least, it better not be exciting, I won’t be too happy if the Facebook police show up at my door.


  1. says

    I’m a bit puzzled why questions 1 and 3 are on the agenda. The answer to question 1 is obviously yes, and I certainly hadn’t heard that anybody was questioning the reality of gastrulation and the 3 germ layers. (Not the case with cnidarians, of course, but certainly with us.) What is the issue here?

    As for question 2, it would depend on the specific numbers. You could prevent more lethality with option 1 than with option 2 if it were sufficiently effective.

  2. says

    I should add that it’s not a real possibility that a vaccine that stops transmission won’t also prevent lethality. A fortiori, it must result in lower viral load. So this isn’t even a question that can be asked.

  3. says

    #1 because basic questions matter. If you haven’t got that point about viral replication yet, it’s going to interfere with learning other things. I’m fine with making sure everyone is on common ground.

    #3: Surprise! People are actively questioning the paradigm! Brian Hall makes the case that we ought to count neural crest as a fourth germ layer, for example. I sort of agree, but think we ought to be even more fluid and not restrict ourselves to just 4 (or any integer) number of layers.

  4. says

    I would also add that this is a lumping/splitting exercise. The neural crest arises from the ectoderm, so there are initially 3 layers. After all they all go on to differentiate further. This would be a semantic, not a factual argument. Also, the neural crest is unique to our phylum.