We are going to take a quick break from the recent multi-part segment “The Skeptical Samurai’s Guide to Comics Books: Iron Man Edition” to revisit an old blog post.
Specifically, a blog post titled “The Autotrophs Began to Drool” (https://theskepticalsamurai.wordpress.com/2011/04/27/the-autotrophs-began-to-drool/)
In that blog post we took a look at the theme song to the hit TV series “The Big Bang Theory”
Originally, we looked at the line “the autotrophs began to drool”, and the controversy regarding that particular passage. We then went on to investigate what exactly an autotroph is (an organism that produces its own food) and explain how exactly an autotroph would begin to drool (it would not actually begin to drool, instead it would pave the way for species that would someday begin to drool). As it turns out, things are not quite as simple as I made them out to be.
As is often the case within the scientific community, there are often several legit/reasonable trains of thought regarding a particular topic. There is often evidence both for and against each particular train of thought. This is especially true when it comes to the origin of life on earth.
As reader “Biogirl” pointed out, my assertion that autotrophs pre-dated heterotrophs (hence the line, the autotrophs began to drool) was not exactly correct. After doing some additional research, as best as I can tell, the general consensus within the scientific community is that heterotrophs pre-date the first autotrophs. Although there are some legitimate arguments to the contrary, our best evidence seems to indicate that heterotrophic organisms where the first (or 1st for my good friend Ernie) life form on the planet earth.
Let us explore this topic a little bit further shall we.
The current consensus is that prokaryotes where the first life form on the planet. Prokaryotes are defined by what they lack. Specifically, prokaryotes are typically single celled organisms (although there are a few varieties that are multi-cellular) that lack a cell nucleus, or any membrane bound organelles for that matter. It is worth noting that although this is the general consensus in the scientific community it is far from being considered fact. There is a reasonable amount of data to support the theory that eukaryotes where the first organisms on the planet, that the first prokaryotes (that we have fossil records of) evolved from them and then that the eukaryote ancestors that we have in our fossils records evolved from those prokaryotes (you still with me!?).
Let us work from the assumption that prokaryotes where in fact the first organism on the planet, when we consider the line “The autotrophs began to drool”, this leads us to the obvious question, did the autotrophs in fact begin to drool (or maybe put a little more scientifically, which came first the autotrophs or heterotrophs). My initial assertion was that the autotrophs came first which then paved the way for the development of heterotrophs (see the original blog post for a more detailed explanation of this process). Turns out this may not be the case. As we discussed above, the details regarding subjects such as the origin of life on earth are far from set in stone (get it!? Many of the details we have regarding organisms from the past are from fossils that are…wait for it…physically set in stone!).
The first life form on earth was the chemotroph. Chemotroph is just a fancy way to say that these organisms obtain energy by the oxidation of electron donors from the environment. This raises the obvious question, where the 1st chemotrophs autotrophic of heterotrophic? Although, the answer is still being debated amongst the scientific community, our best evidence tells us that the 1st chemotrophs where most likely heterotrophic. That is they consumed nutrient sources outside of their “body” in order to run internal processes (versus utilizing internal processes to produce nutrient sources).
So what does this mean for our now infamous line “the autotrophs began to drool”?
Well, according to our best evidence the autotrophs did not in fact begin to drool! Instead the heterotrophs began to self produce! Looks like we need to change the lyrics of the song! Or at least modify it to indicate something to the effect of “some within the scientific community believe that the evidence supports the notion that the autotrophs did not in fact began to drool, but instead the heterotrophs began to self produce”
Has a nice ring to it does it not!?
On a related note…
This blog series (The Autotrophs Began to Drool: Part 1 and 2) is an example what I love about skepticism. Contrary to what many have you believe, skepticism is not about heading out into the world and debunking everything that you come across, quite the contrary actually. Instead, skepticism is about the process of inquiry. Sometimes you are educating others and other times you are the one being educated. So I want to take a moment to officially thank “Biogirl” for her contribution to the blog!
This has been the Skeptical Samurai
Working to serve…
Through the process of inquiry…
The Skeptical Samurai 