I was reading through the Talk Origins feedback section for December 2000 (which BTW is an interesting one for those amused by the writings of Creationists) and one of the responses had this to say…
So the evolution of the Theory of Evolution went from…
Linne to
de Buffon to
Erasmus Darwin to
Lamarckism to
Darwinism to
neo-Darwinism
I’m no biologist, but I’m familiar with aspects of the modern theory of evolution. However, I’m not familiar with the older manifestations. What are the defining characteristics of each? How does neo-Darwinism differ from Darwinism (does the new version include mass extinctions, punctuated equilibria, etc.? from what I understand, Darwin did not accept the evidence for mass extinctions). I’ve heard “Lamarckism” tossed around (or kicked down) in the Great Debates forum…what was it?
I realize that we cannot fully explain each one here, but maybe we can outline some of the basic concepts.
Lamarck believed characteristics acquired during an individual’s life could be passed on. The cliched example is that giraffes’ reaching for leaves on higher branches stretched their necks and that their offspring’s necks were longer as a result. Contrast this to the idea that the experiences of the phenotype can have no impact on the genotype and that change happens through the differential survival of heritable characteristics. Nothing the individual does during its life can alter the genes it passes on to its offspring.
I might be confusing him w/others… but didn’t Lamarck also believe in the “Great Chain of Being,” where animals evolve into “higher” forms of life? (As opposed to Darwin’s non-directed, non-value-laden system.)
Well, Carl von Linne invented the classification system of taxonomy we use today. He was the first to group genera into a hierarchy. Beyond that, however, I don’t really know what role he played in evolutionary theory.
If I’m remembering correctly, I believe Erasmus Darwin’s (Charles Darwin’s grandfather) ideas were similar to Lamarck’s, except that he thought competition played some role (though he didn’t quite hit on the idea of natural selection). I could be mistaken, however.
toadspittle, yes. Lamarck believed evolution was directed, either consciously or unconsciously, towards greater differentiation and more complex beings.
To try to sum it up in an aphorism, Lamarck’s view of evolution was more like a ladder, while Charles Darwin’s view was more like a bush - generally growing upward but going off in all directions with shoots and twigs and branches etc.
IMHO the finds of such places like the Burgess Shale back up Darwin’s assertion more than Lamarck’s. Life is gonna fill up every niche it can find with whatever it can produce; the individuals whose genetic makeup aids their survival get to pass them on.
Aren’t there two systems of classification in use today? One is the kingdom-phylum-class-order-family-genus-species and the other is something-I-forget-at-the-moment.