Sunday, June 27, 2010

Why we shouldn't speak of "primitive" traits.

(While reading please keep in mind, that English is my second language so I might have different understandings of certain words.)

While reading Papers (and also in some Blogs) I very often come across the word “primitive” when people refer to a certain character state.

In an evolutionary context, a “primitive” trait is a trait that evolved quite early in the evolution of a certain group of animals. For example our Nails are “primitive” traits, because all primates got them. In our everyday Live we use the term “primitive” in rather different way. Something is “primitive” when it’s underdeveloped or antiquated.
Looking again at our Nails, you cannot say that these are underdeveloped or inefficient in some kind. In fact, without our Nails we are barely able grasp something. Also whether or not a trait is “primitive” differs from your caldistical perspective. Looking at primates alone, you would say that Nails represent the “primitive” condition of all primates while the claws of marmorsets are “derived”. If you look at all mammals you got a slight different view. Here the representation of claws is the “primitive” condition while the nails of primates represent a more “derived” state. By the way the claws of marmosets develop in different way than the “standard” mammal-claw.
You see there is a fundamental difference between the use of the word “primitive” in biology and the way it’s used in our everyday life.

In fact, the usage of the word primitive in evolutionary biology is somewhat “primitive” itself. Back at the beginning of the 20th century to its middle, many evolutionary biologists proclaimed a “scala naturae” like view on evolution. “Scala naturae” means that you have a direction in Evolution from simple (“primitive”) Forms to more complex forms; very often our own species sits at the top of that ladder.
But this assumption is wrong. Every living being on earth has undergone the same time of evolution since the origin of Life itself. From this follows that every living being is, in more or less the same amount adapted to its specifical niche. If one species is in some way “underdeveloped” or “inefficient” in the way it exploits its niche, then it would simply come extinct by time. You see, there’s literally no need to use the term “primitive” in this context, because there are words that describe the relationship of traits in much better way.
Also there is also the danger in producing misunderstandings in using words which meanings differ between the scientific communities and everybody else. And the last thing we should produce in evolutionary biology, are misunderstandings about the way evolutionary theory works.

I think we got rid of the scala naturae and now it’s time to get rid of its terms. Instead of speaking of “primitive” traits it is way more accurate if we use the word “ancestral” instead. You will avoid many misunderstandings and also describe our actual picture of how evolutionary theory works in a much better way.