> cjcalleman Wrote:
> > I do not think this is a secondary point since
> > Darwin's theory can only
> > accommodate slow and gradual change and in his
> > view his theory
> > should be discarded if that is not how it
> > Since for a long time
> > paleontologists have found that species do not
> > emerge from slow an gradual
> > change, but in huge sudden bursts such as in
> > Cambrian explosion, the issue
> > is already settled, Unless, you do not want to
> > tear up the entire analysis of
> > the fossil record the case should be closed.
> There is no case to close. There are virtually no
> paleontologists who would agree with you.
> The "sudden' burst of the Cambrian explosion
> happened over millions of years - perhaps 50
> million years. Couple that with the fact that the
> Cambrian period started about 550 million years
> ago and all a sudden it doesn't seem that sudden
> unless you are trying to peddle nonsense does it?
> The Cambrian was preceded by a mass extinction
> event brought about by changes in global
> glaciation and an increase in oxygen in the oceans
> as temperatures rose and cyanobacteria began to be
> the dominant photosynthetic life form. This
> increase in oxygen and a rise in temperature
> allowed the radiative adaptation of creatures with
> increased metabolism and eventually more quickly
> moving predators which did not exist before.
> Before the Cambrian there were vast mats of
> anaerobic bacteria that coated the ocean floors
> and virtually no predation. All of a sudden the
> increase in oxygen and warming oceans allowed for
> increased metabolism and a host of radiative
> adaptation to fill all the opportunistic niches
> that the changing environment allowed for species
> to change and evolve. Most of the major body plans
> that we still see today arose at that time and we
> can trace the evolutionary changes that arose then
> to the present day from chordates to predatory
> The sudden burst of speciation which you are
> trying to invoke to deny evolution are nothing
> more that life evolving over millions of years to
> exploit opportunities that arise from changing
> environments and mass species extinctions. The
> "suddeness" in speciation you are trying to
> magically invoke is easy explained by the fact
> that mass die offs and changes in climate create
> increased opportunities for new life forms to
> adapt to and exploit compared to what exists when
> the environment is stable.
> Are you really a Ph.D?
> But I'll bite. You've never been able to explain
> your theory other than saying it is all in your
> book. Here is another chance.
> If not slow gradual changes through life adapting
> to changing environment, then what is the
> mechanism that creates new species? Some kind of
> creative intelligence? God? Quantum
> The floor is yours?? If you are going to make the
> kind of absurd claims your are trying to make, at
> least have the integrity to try and back them up.
> "The recent dispute between the legitimate
> scientific community and the Texas State Board of
> Education (TSBOE) has once again raised the
> specter of neo-creationism worming its way into
> public school biology classrooms. Although the
> ways in which the amended Texas science standards
> might be interpreted by both teachers and textbook
> publishers remain to be seen, the door for various
> creationist proponents to cast doubt on
> evolutionary theory is clearly now open. A
> significant component of the arguments used by
> creationists to question evolution has always
> focused on interpretations of the fossil record.
> One area specifically singled out as a target by
> the creationist majority on the TSBOE is the issue
> of “sudden appearance” in the fossil record
> (National Center for Science Education website
> 2009; Newton 2009). In this context, teachers
> should also note that the five to ten million year
> minimum time span generally allotted to this
> proliferation of animal “hard parts” is hardly
> “sudden.” Approximately the same time frame
> encompasses the entire hominin fossil record
> leading to modern humans.
> For teachers who would like a somewhat more
> comprehensive treatment of these issues, see the
> articles by Lieberman (2003) and Knoll and Carroll
> (1999). Originally published in Science, the Knoll
> and Carroll article can be accessed online at:
I am so glad I wasn't in this thread for this exchange. I have as much patience these days for creationists as I do anti-vaxxers. That is to say, none.
But to add to your wonderful post, it's possible that the various body plans already existed at the time of the Cambrian explosion. Oxygenation produced an increase in size, enough that we could actually see with the naked eye the fossils they left behind.