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Subject:
Evolution
Category: Science > Biology Asked by: vaac-ga List Price: $10.00 |
Posted:
20 Jul 2006 20:20 PDT
Expires: 07 Aug 2006 14:14 PDT Question ID: 748178 |
Belief in evolution has recently become so strong that it became illegal to teach creationism in high-school even as an alternate hypothesis. However, even the greatest believer in evolution will have to admit that a chance of a species changing to another species within a given amount of time, is highly improbable. Any event, even the most improbable one, can, and will occur if you wait long enough. Thus the occurrence of an event with a probability of one in a million, will have a probability of 37 % of occurring once in a million trials. Thus, any change from species to species, as improbable as it is, will occur if given enough time. But for evolution to take place it must have occurred during the limited amount of time (4.5 billion years) that the earth existed. Does anybody know of a study in which the probability of a change of species to species within a given time has been calculated, or estimated , or assigned an order of magnitude? I believe that there is some speculation about a simian ancestor of man and when he lived | |
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There is no answer at this time. |
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Subject:
Re: Evolution
From: livioflores-ga on 20 Jul 2006 20:30 PDT |
I think that it is better to talk about specializationof species than change of species to species. For example only a fast gazelle can escape from the lions, this means that only the faster ones will survive in the time; this means also that the slow lions will no eat and therefore die by starvation; then the faster lions will survive in the time. This proccess makes the called natural selection work (lions with big and strong muscles instead weak ones, etc.). |
Subject:
Re: Evolution
From: denco-ga on 20 Jul 2006 22:10 PDT |
This might interest you, vaac-ga. http://abcnews.go.com/Technology/wireStory?id=2189240 "Finches on the Galapagos Islands that inspired Charles Darwin to develop the concept of evolution are now helping confirm it by evolving. A medium sized species of Darwin's finch has evolved a smaller beak to take advantage of different seeds just two decades after the arrival of a larger rival for its original food source." |
Subject:
Re: Evolution
From: myoarin-ga on 21 Jul 2006 03:02 PDT |
Also, somewhere in the calculation suggested, it needs to be considered that a specie includes many, many creatures. One specie mutating into a new specie is perhaps a one in a million event, but with millions of members of the specie, the time frame in which this can happen decreases significantly. I doubt if any new "specie" in taxonomic terminology can develop now. An existing one may be discovered in a remote region, but any evolutionary mutation, such as mentioned by Denco, will be identified as a new sub-variety, or at best as a new variety. |
Subject:
Re: Evolution
From: anonymous3141-ga on 21 Jul 2006 05:41 PDT |
Species can be defined as the group of population that can reproduce a fertile offspring. "Creation of a species" is not a one step process, it's gradual. To give an example, let's say a group of monkeys leaves the group living on an island and swims across to the mainland. Now the two groups will evolve differently as natural selection will work differently on the two groups. After a while the two groups may start looking different, but they can still interbreed producing mixed babies. After even longer time, they can still interbreed but they may produce a large number of deformed offspring. The offspring may or may not survive, or may or may not be sterile. After even longer time, the two groups will not be able to produce any offspring, or all offspring will be sterile. At this time process of species bifurcation is over. There are many other ways in which new species may arise, but in most cases it's a gradual multi-step process. Talking about probability, it's very improbably that a group of existing population does not evolve into another species over time. Most species we see today will not exist after a few million years. For example, if you freeze a human being now, and revive him/her after a few million years. Most probably he/she will not be able to produce a fertile offspring with any of the species existing at that time. Like most processes in biology, the time needed to create a species is highly variable and depends on genetic structure, environmental conditions, amount of interbreeding between groups etc. |
Subject:
Re: Evolution
From: elids-ga on 21 Jul 2006 08:00 PDT |
First, evolution is not something you ?believe? in, much like gravity, evolution is a fact. Something we can learn about even though we still can?t explain everything about it. Just like gravity, the fact that we don?t know how it works doesn?t mean it is not there or that it is something you can chose to ?believe? in or not. It has already been pointed out that the chances of a species evolving (not changing, if an individual animal were to become a member of another species it would have ?changed? into a member of this other species, but that never happens. If the descendants of a particular species have characteristics that are different from those of their ancestors, it is said that the species evolved as supposed to ?changed?. One applies to the individual, the other to the species.) are 100% it is practically impossible for a species not to evolve. That said, not all species evolve at the same rate, for instance cockroaches have not evolved at all over the last 400 million years, while during that time the ancestral species that led to humans number in the dozens over several genre namely : -The Gnathostomata, or gnathostomes, are the majority of the Middle Devonian (-380 million years ago) [Teleostomy-Ostheichthyes-Sarcopterygii the last one includes lobe-finned fishes and four legged vertebrates] to Recent vertebrates -The Tetrapoda, the reptiliomorpha, the amniota (the last one includes reptiles, mammals, birds, dinosaurs etc). -The Synapsida - Eupelycosauria - Sphenacodontia - Sphenacodontoidea - Therapsida (mammals and extinct relatives) - Eutheria (placental mammals, originate in the Southern Hemisphere 120 million years ago during the age of dinosaurs.) Primates - Catarrhini (humans, great apes, gibbons, Old world monkeys) - Hominidae - Homo From here on the line of descent is not entirely clear but it includes at least these species: -Homo Habilis - Homo Rudolfensis - Homo Ergaster - Homo Erectus - Homo Sapiens - Homo Sapiens Sapiens. So you see, while the cockroach and scorpions as well as other species like them have not changed in 400 million years, others like sponges for 1.2 billion years and other even more primitive life forms like the Eukaryotes haven?t changed in 2.1 billion years our line of ascent went through over a dozen genre and many, many more species. Smaller microscopic life forms can literally evolve right in front of our eyes, for instance a well known and extremely documented line of descent would be the several strains of the HIV virus. ?We think of evolution as requiring thousands, tens of thousands or millions of years to make significant changes - and often, it does. But evolution can also occur in a relative eyeblink. That's the case when the human immunodeficiency virus (HIV) becomes locked in a survival struggle in the body of a patient who's taking powerful anti-viral drugs. It's evolution in fast-forward mode. The virus, replicating billions of times a day, can acquire new mutations at lightning speed: eventually, some of the genetic changes enable the virus to resist even the most powerful drugs. These drug-resistant viruses come to dominate the population and threaten the patient's life.? to read more about it go to http://www.pbs.org/wgbh/evolution/library/10/4/l_104_10.html You should spend some time browsing through http://tolweb.org/tree/ and reading the links provided. For a more entertaining autodidactic site http://www.becominghuman.org/ As for the probability of a species evolving into another, it would by force have to be little more than guess work, as we don?t know the number of species that are alive today, much less the amount of species that ever existed! |
Subject:
Re: Evolution
From: gregaw-ga on 21 Jul 2006 09:43 PDT |
Here's a quick lesson in probability that is relevant to this subject. http://www.icr.org/article/155/ To call evolution a "fact" is to be very narrow-minded. To say: "we don?t know how it works", but we know it's true, takes "belief". We can know that there is a force pulling us toward the earth (gravity) because I jump up and I always come down. I (nor anyone else) has ever seen a species become another species. Evolution is a relatively new theory and while I don't see it going away any time soon, I think more people are starting to question its validity as a "fact". That scares people like elids-ga. |
Subject:
Re: Evolution
From: elids-ga on 21 Jul 2006 12:23 PDT |
Interesting comment Gregaw. If you take the time to analyze what you just said, you?ll see that it makes no sense. However, will not attempt to convince you of what is plain to see. You see, people engage in theological debates not so much with the intent of convincing the other party of his/her beliefs but to convince themselves of what they are saying. This is the main reason why all religions encourage their followers to ?spread the word?, the more the convert repeats the mantra to others the more they themselves will be convinced of what they are saying, and they may get a new convert. The same is true of new atheist people, they seek religious people with the intent of debating their religious beliefs because doing so re-enforces their own convictions, explaining it to others allows them to find better ways to explain it to themselves. It?s been a very long time since I stopped being an atheist, for me all superstitions fall in the same category, be that black cats, ladders, gods or witchcraft. A good way to describe me would be; no more religious than a cow, no more atheist than a horse. Wish you well, hope you find solace in your beliefs. |
Subject:
Re: Evolution
From: frde-ga on 24 Jul 2006 04:41 PDT |
I find your question rather specious. Deliberately using 'species' as the criterion for evolution, or more precisely 'selection' is a simple attempt to deny that, what we can observe in a short period of time, happens to a greater extent over a long period of time. Elephants in Africa that have (genetically) no tusks, have become significantly more common due to human predation. There are lions that are substantially different in size and behaviour in some obscure place due to a change in their environment. Inbreeding and interbreeding produces identifiable changes in humans, let alone domestic and farm animals. Resistance to pesticides turns up in plants without the intervention of a laboratory. Malaria has got resistant to a number of drugs in my memory. By attempting to redefine 'change' as 'radical change such that it is incapable of interbreeding' is like saying because a man cannot lift the Eiffel Tower he cannot lift a toothpick. Incidentally, very different plants can interbreed, there are also vague tales of mules not being sterile. Personally, I suspect that there is something called 'accelerated selection' whereby genes become dominant simply because they are needed. |
Subject:
Re: Evolution
From: dops-ga on 25 Jul 2006 13:58 PDT |
I just wanted to add a note that evolution (with the lowercase "e") is defined as a change in gene frequency over time. We can directly measure this in wild population using standard molecular biology techniques. As frde-ga points out the effects of these changes are often noted by changes in the frequency of characters in a population. These changes can occur very rapidly with high selection pressures. I'd also argue that, if you define species as an interbreeding populaiton with fertile offspring (which not everyone does) then new species of plants arise continually in the span of a generation. Plants are extremely tolerant of polyploidy and will often ungergo entire (or partial) genome duplication. This tetraploid plant is now unable to mate with the dipliod relative because of incompatible chromosome number. Hence by the above 'species concept" now constitutes a new species. I also suspect that depending upon the nature of the mutation (eg change in sperm morphology, etc) reproductive isolation could occur within the span of tens of years not millions. |
Subject:
Re: Evolution
From: zerosystem-ga on 31 Jul 2006 11:20 PDT |
"First, evolution is not something you ?believe? in, much like gravity, evolution is a fact. Something we can learn about even though we still can?t explain everything about it. Just like gravity, the fact that we don?t know how it works doesn?t mean it is not there or that it is something you can chose to ?believe? in or not." fyi anything that is not supported by facts or empirical mesurements/experiments is a belief. you can mesure gravity, you can test it, there are facts that can support it (if you drop something it falls) thus gravity is no more a theory or a belief but a fact. evolution on the other hand is a belief (religion if you like) you cannot mesure it, test it, there is no fact or evidence that supports it.Dont let yourselfe be fooled by the propaganda, anyone who claims having found proofs or facts supportion evolution (up untill now) has been proven wrong (of course these scientist cannot publish their stuff because the media and scientific community is controlled by evolutionists) |
Subject:
Re: Evolution
From: dops-ga on 31 Jul 2006 12:56 PDT |
Hi zerosystem-ga, Your assertion that we can not measure evolution (ie changes in gene frequency) is incorrect. Biologist can use either visible or molecular markers to detect changes in allele frequency in a population. These frequency of the changes can then be used to calculate whether the population is under selection. There is no belief involved. It is an objective measure. For example adult lactose intolerance is an ancestral trait. However due to selection, most caucasin populations have developed lactose tolerance. The ability to eat calorie rich dairy products has allowed a selective (and apparently fitness) advantage to lactose tolerant individuals. This change in prevailing genotype from lactose intolerance to tolerance does not constitute a speciation event. However changes in gene frequencies are the basis of "Evolution" or "The Origin of the Species." |
Subject:
Re: Evolution
From: zerosystem-ga on 01 Aug 2006 08:48 PDT |
dops-ga i did not say that we cannot mesure the micro ovolution of genes, i am very well aware of these as i am a biochemistry graduate. i meant that, given the time span that a specie is supposed to become another specie, it is impossible for us to witness it or mesure it. this is why Evolution will always remain a theory, even if it is true. to elids-ga quote This is the main reason why all religions encourage their followers to ?spread the word?, the more the convert repeats the mantra to others the more they themselves will be convinced of what they are saying, and they may get a new convert. end quote this is the absolute best description of evolutionists i have ever heard, i couldn't come up with a better one myselfe also quote You see, people engage in theological debates end quote this is also something that evolutionists do when engaged in a debate with someone qho does not believe in their theory, they accuse them of being religious and try to take the debate to a religious debate to discredit their opponent |
Subject:
Re: Evolution
From: dops-ga on 03 Aug 2006 18:52 PDT |
Zerosystems And I hold a Ph.D in biology. I don't care about your politics or religion. I agree with you that belief should not be considered as fact. This is why I avoid religion and bad science. However where you are wrong is in your statement that " i meant that, given the time span that a specie is supposed to become another specie, it is impossible for us to witness it or mesure it." Perhaps you might want to look at my earlier comment. Speciation occurs in real time. Plant species are arising as I type. |
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