Sciency Words: Orthogenesis

Hello, friends!  Welcome to Sciency Words, a special series here on Planet Pailly where we take a closer look at the definitions and etymologies of science or science related terms, in order to expand our scientific vocabularies together.  In today’s post, our Sciency Word is:

ORTHOGENESIS

Please be advised: orthogenesis is a discredited scientific hypothesis.  It has been for almost a century now.  That being said, the term has been coming up a lot in my research lately, and I do think there’s value in examining scientific hypotheses that didn’t make it, so to speak.  I think looking at a rejected scientific hypothesis, like orthogenesis, can give us a better appreciation for how the scientific method works.

Definition of Orthogenesis: In evolutionary biology, orthogenesis was the hypothesis that life evolves in a straight line progression, from simpler organisms to more complex forms.  Orthogenesis rather strongly implied that evolution is working toward some sort of predetermined end goal (i.e., intelligent life).

Etymology of Orthogenesis: The term was coined in 1893 by German zoologist Wilhelm Haacke, who was not convinced that natural selection alone adequately explained the evolution of complex life on Earth.  The word orthogenesis is derived from two Greek words meaning “straight” and “origin.”

When you think about the history of life on this planet, orthogenesis may seem to make sense.  Life started with just these simple microbes.  Then life “leveled up,” and we got more complex multicellular organisms.  And life kept “leveling up” after that to create fish and trees and dinosaurs and a surprising variety of crabs.  And then came humans, the most “leveled up” of all Earth’s creatures.

But as scientists learned more about genetics, and as they pieced together more of Earth’s fossil record, this straight line progression idea made less and less sense.  Evolution is a messy process.  It works in fits and starts.  It finds of-the-moment solutions without any regard for the future, leaving us with vestigial organs and other biologically inefficient stuff.  Increasing complexity is not necessarily advantageous; sometimes the simpler life forms survive while their more complex cousins go extinct.

By the mid-20th Century, orthogenesis had been soundly rejected by the scientific community.  Natural selection just made more sense in light of all the evidence scientists had accumulated since Wilhelm Haacke’s time.  However, while orthogenesis has not been considered good science for many decades now, certain orthogenetic ideas still linger in popular culture.  Whenever the mad scientist in a Sci-Fi movie starts ranting and raving about the “next phase of human evolution,” that’s orthogenetic talk.  Or when you hear dialogue about how one alien species is “more evolved” than another, that too is orthogenetic talk.

A lot of popular misconceptions about science seem to come from science fiction.  As a Sci-Fi writer myself, this is something I worry about.  “Evolutionary paths” and “evolutionary destiny” are such common tropes; it’s easy to write them into a story without realizing you’ve done it.  But I do not want to make these popular misconceptions about science worse, especially when it comes to a topic as controversial as evolution.

WANT TO LEARN MORE?

I’m going to recommend this article from tvtropes.org on “Goal-Oriented Evolution,” which does a good job summing up how Sci-Fi and other popular media keep getting evolution wrong.

I also highly recommend this research paper entitled “Fossil Horses, Orthogenesis, and Communicating Evolution in Museums,” because orthogenetic ideas don’t only linger on in Sci-Fi.  They’re an ongoing problem in museums, school textbooks, and other educational resources as well.

Does Evolution Want You to “Become Crab”?

Hello, friends!

So as far back as the mid-to-late 1800’s, scientists noticed that crab-like animals were oddly commonplace.  It seems that, for one reason or another, evolution favors crab-like body structures over other crustacean body types.  Well, maybe “favors” is the wrong word.  I wouldn’t want to imply that evolution plays favorites or that evolution has any sort of intended outcome.  That would be misleading.

When I read articles in the popular press about carcinization (the surprisingly common process of evolving a crab-like body), I feel like there’s a fundamental misunderstanding at work, not just about carcinization itself but about evolution in general.  Evolution doesn’t “prefer” this and it certainly doesn’t “intend” that.  There is no end-goal to the evolutionary process.

Evolution works by trial and error.  Organisms have problems, problems like “how do I find food?” or “how do I avoid becoming food?”  Some organisms manage to solve these sorts of problems; others do not.  The ones who solve their problems get to live, and they have the opportunity to pass their genes on to the next generation; the others?  They do not get to do that.

There are a surprising number of crab-like animals out there.  That must mean that being a crab helps you solve certain problems.  It does not mean that you’re evolution’s favorite, that evolution “wants” to create more crab-like creatures like you, or that being a crab is some sort of evolutionary end-goal.

All that being said, I have to admit it’s hard to avoid anthropomorphizing the concept of evolution just a little bit.  I mean, look at the stuff I do on this blog.  I anthropomorphize everything from atoms and molecules to planets and stars.  I imbue all sorts of things with wants and needs and strange personality quirks.  It’s only natural for me to say evolution “wants” this or “prefers” that, and I totally understand why so many other science writers fall into a similar trap.

So I guess what I’m saying is this: whenever you hear people talk about evolution’s “preferences” or “intentions,” bear in mind that those words are really just shorthand for something else.

Sciency Words: Carcinization

Hello, friends!  Welcome back to Sciency Words, a regular series here on Planet Pailly where we talk about the definitions and etymologies of scientific terms.  Today, we’re talking about:

CARCINIZATION

In time, we will all evolve into crabs.  Crabs are the ultimate life form, evolutionarily speaking.  At least that’s what certain Internet memes would have you believe.  But like most Internet memes, this whole “we will all become crabs” idea is an oversimplification of the truth.  Carcinization is a surprisingly common evolutionary process, but it doesn’t happen to all animals in all situations.

Definition of Carcinization: In evolutionary biology, carcinization is the process of evolving a crab-like body structure, especially a crab-like carapace (shell) with the pleon (tail) folded underneath the belly.  A surprising number of animals have evolved to have this body structure independently of one another.

Etymology of Carcinization: The term was coined in 1916 by English zoologist Lancelot Alexander Barradaile.  It uses a Greek root word meaning “crab.”  Although the term carcinization was coined in 1916, scientists had noticed the unusual prevalence of crab-like animals well before that.  Research on this phenomenon can be traced back to the mid-to-late 1800’s.

Carcinization seems to happen a lot in nature, but it does not happen to all animals equally.  It is far, far, far more likely to happen to an animal that already has a few crab-like characteristics.  For example, if you’re a lobster, a shrimp, or a prawn—in other words, if you’ve already got a bunch of legs and a pair of claws, and if you’re already living on the ocean floor—then there may be some real benefits to evolving even more crab-like characteristics.

It’s hypothesized that the compact body shape of a crab (compared to the more elongated shape of a lobster, for example) may make it easier to defend yourself against predators.  A lobster’s pleon (tail) is very exposed; crabs have their pleons neatly tucked beneath their bellies.  The compact body shape of a crab may also make it easier to scuttle about on the ocean floor, which could help crabs evade predators, and crabs may find it easier to fit into tight spaces as a way to hide from predators.

As a science fiction writer, I’ve long wanted to include some crab-like extraterrestrials in my Sci-Fi stories.  All those memes about crabs being the “ultimate life form” led me to believe this would be a good idea.  The actual science behind carcinization makes me think otherwise.  Carcinization certainly happens a lot with certain animals (i.e., crustaceans) living in certain environments (i.e., the ocean floor).  But it’s not a universal principle of evolution.

All that being said, I’m going to put some crab-like extraterrestrials in a story anyway, because I still think it’s still a fun idea.

WANT TO LEARN MORE?

Here are the research papers I have read or am in the process of reading on the topic of carcinization.  I will have more to say about carcinization later this week.