Quizzes & Puzzles1 min ago
Origin of the species
Answers
No best answer has yet been selected by druiaghtagh. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.A theory, however, can only stand until someone can disprove beyond doubt. And no one has yet disproved Darwin nor the theories put forward by the church. However, since various people seem to have further proved the theory of evolution, and since the church are reluctant to undertake any exercise that may prove their theories, I suppose it's all down to what the individual believes.
The "alternative" most readily put forward, namely intelligent design was rejected last year in an American court as basically religion in drag (my terminology )
"We have concluded that it is not [science], and moreover that ID cannot uncouple itself from its creationist, and thus religious, antecedents," (District Judge John Jones' terminology)
You might say that leaves Darwin with the force of Law.
http://www.cnn.com/2005/LAW/12/20/intelligent.design/index.html
Darwin's theory never set out to explain the initial creation of life. So it can hardly be seen as a hole.
That particular nut is still one of the toughest nuts in science.
Hybrid fossils are unlikely to be found due to the time spans involved we have only a handful of complete T. Rex fossils despite their being around for millions of years. Even when against the odds a good candidate like archaeopteryx appears its dismissed because no fossil would get these people to accept evolution.
The simple fact of the matter is there is no competing scientific theory if one does arrive I'll treat it with respect but don't ask me to respect people who expect people to believe that some vast intelligence created all life and have no rational explanation of where the designer came from.
It's just another case of "turtles all the way down"
Darwin claimed that living things changed slowly over time and he postulated that the reason for this was that some off spring were born slightly different from their parents. If this difference benefited the individual in competition for survival or mating then it had a good chance to survive and be passed on to off spring and so become a typical characteristic of a species. However, Darwin had no idea how this process actually happened.
Mended experimented with garden peas and found he could map the variations produced through hybridisation. Mendel's work laid the foundations for understanding the means of heredity which is now called genetics. This work was refined by scientists such as Miescher, Avery, Rosalind Franklin, Watson and Crick and countless other less famous biologists and has given us an understanding of RNA/DNA.
Through DNA analysis, scientists are able to determine the extent of inter-relatedness between distinct species and provide a compelling history of life on earth. But most importantly, an understanding of evolution has enabled scientists to understand and combat serious threats to public health such as HIV/Aids through our knowledge of mutations and enables advances in understanding hereditary conditions such as sickle cell .
So, no, Darwin is not the only show in town. His work was just part of a collective effort to understand how life works so we can take better care of it.
D
Secondly, experiments on bacteria do indicate adaptaion... but no speciation. At the end of the day they are still bacteria. An extensive test of radiation on fruit flies produced no genetic changes or speciation, only deformed fruit flies. Why are these two facts important? Because it is shown, repeatedly, that even adaptive changes occur only in creatures with high population numbers and rapid repoductive cycles, not in advanced life forms... Darwin clearly stated that he expected an examination of the geologic strata to produce incaluable numbers of transitional forms, yet today scientists estimate the strata to be 90 to 95 percent complete and yet with not one indisputable transitional form in evidence.
Jake would like one to believe that it's only the wild-eyed, Bible thumping creationists that disbelieve examples like archaeoptryx when certainly he must know it's deep within the scientific community that the controversey and disbelief exists...
Clanad
The Cambrian Explosion is a controversial area of evolutionary biology and much debate between competing theories around the 'explosion' occurs within the science community. This type of debate occurs across all of science manifesting itself most notably in the peer review system. If the theory is robust enough, it stays. You say: "Darwin was wrong..." over "slow change over time" and cite the arguments for punctuated equilibrium as a cause. If you do not recognise the effects of evolution how can you use an alternative evolutionary argument to discredit Darwin? Both Punctuated Equilibrium and Phyletic Gradualism support adaptation and speciation they simply differ in the minutiae on how they occur. In fact, Darwin discusses a form of punctuated equilibrium in "the origin" in terms of the relative time where speciation occurs being short in relation to stasis so he agreed with PE.
There are many recorded events of speciation. You may want to start here for the fruit fly: Speciation via disruptive selection on habitat preference: experimental evidence," in The American Naturalist, vol. 131 (1988) pp. 911-917
Then there is your statement "it is shown, repeatedly, that even adaptive changes occur only in creatures with high population numbers and rapid reproductive cycles, not in advanced life forms..." I don't know where you are getting your information from but this is completely untrue. lets think of a really simple human adaptation: Skin pigmentation giving protection from the sun. All living things are the results of adaptations.
cont...
D
Problem is, dawkin, whether on purpose or simply misunderstanding, you misrepresent my position. As you rightly declare, the Cambrian Explosion is a hotly debated event, the meaning of which is disputed, but not the fact of the event. Your misrepresentation occurs when you suggest that by citing the Cambrian Explosion in which nearly all higher phyla appeared suddenly, that I support and use as an argument Punctuated Equilibirium... could not be farther from the truth. Stephen Jay Gould, et al, developed this sub set of theories when he recognized that the evidence for speciation over long periods of time, ala Darwin, simply was not supported by the evidence. It has been, as have many other belief systems, cast on the ash heap of failed hypothesis.
Your position is weakened when you infer my reliance on Gould's faulty reasoning to support a reasoned unbelief in that religion.
Your comments on fruit fly experimentation do not fully state the outcome(s). There have been many well-known experiments using fruit flies, attempting to show that mutation and natural selection can turn primitive species into new, more highly developed species. These experiments have shown just the opposite.
Contd.
Contd.
When fruit flies are subject to x-rays or toxic chemicals, they do mutate. But in the mutation process they lose genetic information. For example, the genes that control the development of eyes or wings might be damaged, resulting in blind fruit flies, or wingless fruit flies but fruit flies, nevertheless. They are merely degenerate variants of an existing species.
Finally, how does the development of a light skin shade lead to speciation? What proof exists that the skin shades of various races has not always been what it is today? As you must know, the 'out of Africa' theory is highly in question now. One example is this from the Japan Times, 2004: "Australian and Chinese scientists have dated China's Nanjing Man as 580,000 to 620,000 years old, further supporting a multiregional theory of human evolution that argues Asians evolved locally and not out of Africa.
The scientists said Nanjing Man (Homo erectus), a male and female skull discovered in 1993 in Tangshan Cave near Shanghai, shows that humans lived in isolation in China and much earlier than previously thought. "
Finally, I apologize for my inability to decipher what you mean by your statement, "...If someone could find just one fossil out of place..." Please explain your phrase "out of place". By the way, all geologists and palenontologists I know or read readily concede the fossil record to be all but complete. Complete enough to be chagrined at the total lack of transitional forms, which Darwin predicted to be overwhelming in numbers...
Clanad
The Cambrian explosion generally means the geologically abrupt appearance of shelled and other hard part fossils most famously found in the Burgess Shale BC. I can discuss the whole issue of the Cambrian explosion and the fossil record together:
The Cambrian "explosion" is a period of 10 million years, give or take, where many hard bodied fossils appear in the fossil record. Since very few living things get to become fossils (it is an extremely unlikely event) then we are lucky to have the fossils we do have but the development of hard body parts was particularly significant in allowing fossils to form under ideal conditions. This leads us to a situation where we have very good fossil evidence for many species and very poor fossil evidence for other species.. The Burgess Shale is just one example where conditions were good for fossil formation. This does not mean that these animals were not related to fauna that went before it just means they were harder.
While 10 million years is an explosion geologically speaking it is not a short time span in evolutionary terms and indeed allows ample time for gradual evolution. Stebbins calculated that a mammal the size of a mouse could evolve into an animal the size of an elephant in 20000 generations, which as you will agree is significantly less than 10 million years. Fossils tell us a lot about evolution and provide evidence through transitional forms. They also provide a simple way to disprove evolution. All that needs to happen is for someone to discover a fossil out of place in the fossil record. As Haldane put it: "A fossilised Rabbit in the pre-cambrian should do it."
Cont...
Anyway, I'm going to leave the fossil world behind because you're going to keep on using that word "uncontested" which really is a circular argument because anyone can contest anything.
Molecular evidence: Molecular evidence enhances what we know from the fossils and from comparative studies of modern animals. Again, if evolution was to be falsified then surely the molecular evidence would not agree with the other evidence we have gathered. What it does in fact show is that closely related animals such as rats and mice are more closely related than say rats and donkeys. It also shows that species in specific geographical areas are more closely related than their more geographically remote cousins.
Y chromosome and mitochondria analysis proves we all descend from Africa. Do you not believe in Adam and Eve?
Loads of evidence on skin pigmentation, like this:
Fruit flies separated after selection for different traits put back together did not mate with different type = speciation. If you want to see something a bit grander you will need to stay alive for a few thousand years or more. But animal husbandry has changed a wolf into a Yorkshire terrier in just a few hundred years, or do you not believe in that kind of adaptation either?
Anyway. Interesting points
D
I'm truly surprised, dawkin! I've even complemented you on your presentations elsewhere. But, your insistence on mischaractization is puzzling.
You must certainly know that your description of what you infer to be a minor incident labeled 'Cambrian Explosion' , was, in fact the singular paleontogically related event in the history of the Earth! "... According to Valentine, Jablonski and Erwin, "...extensive new data do not muffle the explosion, which continues to stand out as the major feature in early metazoan history"
(Excerpt E, p. 851).
(D) Samuel A. Bowring et al., "Calibrating Rates of Early Cambrian
Evolution," Science 261 (1993): 1293-1298.
In an effort to not re-cover already plowed ground, I simply appeal to almost all paleontologists and geologists and my own training in Geology that clearly attribute the spectacular rise of all almost all phyla to inhabit the Earth as occurring in this blink of geologic time. "...Valentine and his
colleagues found that "it has not proven possible to trace transitions" between the phyla, and the evidence points to a Cambrian "explosion" that "was even more abrupt and
extensive than previously envisioned" (ibid., Excerpt B, pp. 281, 294).
Further, I appreciated the article you quote as "brilliant" since it contains all of the "buzz" words that seem to imply scientific sincerity but in reality are used to infer rather than to prove ones position. Here's probably, my favorite quote from your presented article"...
Contd.