sorry, but I am not asking anything about the THEORIES of evolution.. I am asking the TREE of evolution..
2006-11-17 00:47:18 · 4 answers · asked by Lala 3 in Science & Mathematics ➔ Biology
I'm not sure, but I guess you could be referring to the graphic representation known as "tree of life".
This illustration pictures the living and extinct taxa (natural groups of living beings) according to their phylogenetic relationships (related groups are joined by shorter or less branched lines). Of course, these phylogenetic relationships are hypotheses advanced by the researchers about ancestor-descendant lines, and as new data arise, they might change, and thus the shape of the tree changes.
For instance, Darwin presented a "tree" that had one main trunk.
http://bioliteracy.net/Graphics/DarwinTree.jpg
Haeckel made another famous tree of life:
http://www.mun.ca/biology/scarr/Haeckel's_tree.gif
Nowadays, it has been proposed that the base of this tree comprises a series of combinations between different primitive "basal organisms" , and these different combinations produced the diversity of life as we know it. Check this modern representation:
http://www.panspermia.org/se2497604003.gif
In any case, note that the evolution of life is pictured as _branches_ of a tree, and not as a _scale_. There isn't any type of inherent "progress" in evolution, that is, humans are not "the best" of apes, and we're not any more "evolved" than a lobster. Each population alive today has a unique evolutionary history.
2006-11-17 01:27:22 · answer #1 · answered by Calimecita 7 · 3⤊ 0⤋
It's akin to a family tree. It is a branched diagram representiing how forms, fossil or living, relate to previous forms. There are several ways to represent it. I included two. The first is extensive and somewhat artistic. The second is a little more technical on the Canidae (dog-like creatures) showing the branches, and if they didn't make it to the line at the top, when they became extinct. I did not provide any links to genetic homolgy maps which look at the relatedness of genomic markers and extrapolte to estimate divergence. (Occasionally we get frozen extinct creatures that we can analyze.)
2006-11-17 03:50:58 · answer #2 · answered by novangelis 7 · 1⤊ 0⤋
I'm not really sure what you mean by tree of evolution. Are you referring to the order in which life and characteristics evolved?
In terms of animals, characteristics are thought to have evolved in the following order:
Notochord
Brain
Head
Vertebral column
Jaws/ossified skeletons
Lungs
Lobed fins
Legs (eg amphibians - tetrapods)
Amniotic egg (eg reptiles)
Milk and fur (mammals)
If you're talking about life in general, the earliest forms of life were thought to have been prokaryotes, about 3.8 billion years ago. These evolved into eukaryotic cells, sometime before 2.2 billion years ago. By 600 million years ago, small invertebrates and algae had evolved.
2006-11-17 01:23:04 · answer #3 · answered by birdbrained22 2 · 0⤊ 0⤋
http://en.wikipedia.org/wiki/Phylogenetic_tree ...I think this page will explain it pretty good.
2006-11-17 02:42:28 · answer #4 · answered by Saphira 3 · 0⤊ 0⤋