origin of life, etc.

David Campbell (bivalve@isis.unc.edu)
Tue, 15 Dec 1998 15:15:19 -0400

>a) Looking for some opinions on the claim that life cannot have arisen by
>chance.
>I see the argument in many christian books using outrageous odds but
>something is
>not sitting right with me. I see Hoyle and others quoted on this often.What
>do you think?

We do not know enough to make accurate estimates of this probability. Some
of the assumptions that often appear in such calculations are not correct
(e.g., that the exact sequence of bases found in a particular modern genome
must be generated to produce essentially the same organism). A more basic
problem is that evolutionary theory claims that a strong non-random
component exists, namely natural selection.

>b) Is the human evo. tree really as confused as some say? Does anyone have
>a order of the known species that stands up? I saw a art. in Discover today
>that seemed to even concede that the Australopithecine A.Afarensis sequence
>is doubtful.The data on this subject is arranged to support or deny evol.
>depending on the source. Either someone is misleading or the data is super
>ambiguous.

Exactly how the different species connect up is debated (even if one
disregards people who do not know what they are talking about). However,
this does not take away from the fact that there are fossils that reflect a
series of improvements in upright walking (and concurrently getting worse
at climbing trees), increases in brain size, and decreasing sexual
dimorphism. These changes correspond with the age of the fossils. How
many groups were experiencing similar changes at the same time is still
uncertain. Among paleontologists, the debate is essentially whether a
particular fossil is a direct ancestor or a side branch. This confusion
reflects a high level of similarity between more derived and earlier
hominids, not a lack of similarity.

David C.