Monday, January 4, 2010

Australopithecines: A Lesson in Evolution

Evolution is cladisitic, organisms change through various selections branching out in every which way based on many factors. The key is to remember that evolution is not linear and follows no terms of “more” or “less” evolved. In reality there is no such thing as an organism that is “more” evolved. There is no rule of hierarchy; if an animal happens to select a trait which is old in comparison to others… it doesn’t mean it is going backwards. It means it is doing it out of necessity, and in my opinion it is one of the corner stones of adaptation.

Creationists tend to think in terms that evolution as linear and in terms of hierarchy, this is false. The theory of evolution favors no traits over others in terms of what is more advanced or primitive, it only favors what is needed for proper adaptability and survival.

The reason the title of this blog is Australopithecines, is because it brings an interesting example of how evolution branches and is not linear or hierarchical. The term Australopithecines is used to refer to closely related branches of genera, and concerns with two individuals:

Australopithecus “Gracile Australopith”: 4 Million Years ago
Paranthropus “Robust Australopith”: 2.7 Million Years ago

For simplicity sake I will refer to them as Gracile and Robust for duration of this post.

The gracile is considered a Hominini which had very modern features. It is part of the human linage and shows features which are more attributed to modern humans than the ancestral ape linage. Of these anatomical features the most notable were smaller teeth, which lead to smaller jaws and a more shrunken in face. These are characteristic of an intermediate species in our evolutionary linage.

The gracile eventually parented another species, this was the robust. Due to vegetation the robust had adapted to eat (Think skinned fruit, nuts, and hard vegetation) its anatomical features were focused around chewing. The adaptations lead to larger teeth, a larger jaw, and a modified skull which would properly hold all the various large muscles needed for chewing hard vegetation.

In terms of evolutionary hierarchy the robust seems to be less evolved than the gracile, and this brings me to the misconception of linear evolution. It just doesn’t happen that way. Due to the diet the robust had adapted around, it developed those traits out of simple necessity. It was no more evolved than any creature, and just happened to carve out a niche in an ecosystem which required traits that seemed ancestral. Although the robust was an evolutionary dead end it is an excellent example of evolutionary branching.

When creationists mention this example to falsify evolution, it is merely showing their lack of understanding of the subject. I’ve had some interesting discussions with many creationists, where I had to stress this point to the extremes. It seems that even the most critical of creationists some times miss this point, and automatically make the mistake of hierarchical evolution which follows a linear pattern.

Although this post can be pushed deeper into heavy biological terms I decided to convey it in the simplest terms. I did this in hope that information would be not lost within a labyrinth of complex terminology and could be understood at least in the most general of senses. This is not to be condescending but to covey these thoughts to a wider audience.

Until my next post.

1 comment:

nothing profound said...

This is a fascinating post. I'm very interested in this concept of non-linear, non-hierarchical development. I would love to see it applied to human existence and human relations as well.