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There is a thread regarding this in General Discussion.
Feel free to ask questions about evolution.
- Thread starter Nesslig20
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Mr_Wilford
Member
Awesomesauce!
Well, here's my question.
In your opinion, what is the finest example of a transitional fossil, and what makes it such a good example? If not a single fossil, what lineage (i.e. land animals to whales)?
Well, here's my question.
In your opinion, what is the finest example of a transitional fossil, and what makes it such a good example? If not a single fossil, what lineage (i.e. land animals to whales)?
Grumpy Santa
Member
Nesslig20 said:
I have to admit to being partial to Tiktaalik as well. The traits that have been passed down to all tetrapods since, it's an amazing animal in our history.
he_who_is_nobody
Well-Known Member
What are your thoughts on punctuated equilibrium?
Nesslig20
Active Member
he_who_is_nobody said:
My thoughts on PE is that it is very poorly understood, well at least by people who complain about it like it reveals just how desperate the "evolutionists" are to safe their theory. Although I suspect that there are quite a few people who do believe that evolution is a thing, yet don't understand what PE is.
So (correctly if I am wrong on this) how I understand PE is that it is a hypothesis on how evolution, specifically speciation, occurs throughout time. It is opposed to gradualism or better put "phyletic gradualism" (which is also often misunderstood).
Phyletic gradualism proposes that speciation happens because species "gradually" change into a new species at a more or less constant rate of change over the evolutionary history. This means that speciation is a continues smooth process and that the boundary between the daughter species and the ancestral one is not determinable, like a transition between black to white and within it different shades of grey and then ask, when does it turn into white?
Punctuated equilibrium proposes that speciation happens in relative quick jumps of changes, relatively quick compared to the average rate of change over a longer period of time. These quick speciation events are often followed by longer periods of stasis, when the morphology, physiology and the gene pool of the species are more stable and the rate of change is slow.
To illustrate this:
Left phyletic gradualism and right Punctuated equilibrium.
Now to blow some misconceptions out of the way. PE doesn't necessarily mean that it isn't "gradual" in the sense that it happens so fast in "macro mutations" or "saltations" otherwise known as the "hopeful monster". PE is a form of gradualism where there is still small unnoticeable changes from generation to generation, the main difference between PE and phyletic gradualism is that the rate of gradual change isn't constant in PE. Even when PE is at its fastest, it still requires hundreds or thousands of generations to occur, so even PE is still gradual.
Look on the picture above and see the point where both lines start and end. The line representing PE at the end of it shows that "less" evolution has occurred compared to the evolution with phyletic gradualism. Of course this is a illustration to represent the main difference between the two.
On a large scale like between hundreds of million of years, the average rate of change of both PE and phyletic gradualism might as well be the same or it can also be that PE is slower.
This is why transitional species between larger taxonomic groups are abundant while species to species transitions are rare, because speciation happens due to PE rapidly (relative to geology) thus intermediates during a speciation event, are rarely fossilized. This is the point Gould tried to make, but his point "species to species transitional fossils are rare" turned into "transitional fossils are absent" thanks to creationists quote miners.
Another main difference is that PE speciation involves cladogenesis, where one daughter species splits from an ancestral one, often by a small portion of the population moves to new circumstances and are genetically isolated form the main population. The ancestral population or species could exists along side the daughter species, without having to go extinct. This is one of the reasons why the question "if humans evolved from apes, why are there still apes" is redundant like asking why wolves are still around, if dogs evolved from wolves.
And phyletic gradualism speciation involves anagenesis, where the entire population of a species gradually changed over many generations into a new species and the ancestral species is thus considered extinct.
This might be difficult to understand for some, but what I really like to use as an analogy which is easy to understand is how languages evolve. Like how Latin evolved into French is an example of cladogenesis. When latin people migrated to a new area, their vernacular changed while the main latin population retained much of their language. Smaller populations tend to evolve much faster. Same with language. So when the first Proto-French language speaking people came about, there might still be Latin speaking people around in Italy that spoke more or less the same language as the ancestors of those speaking French did. The slow change in Latin in this analogy is the evolutionary "stasis" in PE and the change form latin to french in a short time (though it took many generations with each generation small subtle changes) is the short period of rapid change. However Latin also evolved directly int Italian gradually overtime, which is analogous to anagenesis. So anagenesis and cladogenesis can both occur, though cladogenesis is more common. Like when Italian also gave birth to Spanish, Portuguese and more.
he_who_is_nobody
Well-Known Member
What are your thoughts on epigenetics?
Nesslig20
Active Member
he_who_is_nobody said:
I have to admit that I don't understand epigenetics. I haven't studied it in college nor much on my own.
I got embarrassed after I said that epigenetics is about methylation of DNA, which is epigenetics, but only one form of epigenetics.
I also do know that epigenetics isn't the same as Lamarckism.
thenexttodie
Member
What is the best evidence for Darwinian evolution?
Steelmage99
Member
Rhed said:
The weakest argument for evolution i can think of would be something along the lines of; "Darwin said it was right, so it is right".
Another really weak argument for evolution would be; "God doesn't exist, therefore evolution is right".
I can't really think of any arguments weaker than those. It is a good thing nobody uses arguments like that, as that would be really dumb.
Steelmage99
Member
thenexttodie said:
The best evidence for Darwinian evolution was morphology.
The best evidence for modern evolutionary developmental biology........well, where do you want to start? Genetics, cytology, systematics, botany, embryology, morphology, ecology or paleontology?
Asking for evidence of Darwinian evolution is like asking a Christian for the best evidence of the Jewish faith.
Rumraket
Active Member
Rhed said:
thenexttodie said:
When you guys ask this question, what are you asking really? Do you mean, the best argument for the common descent of all known life? Or the best argument for the claim that evolution happens (organisms do in fact evolve)? Or the best argument for the claim that evolution happens in some particular way? There are several ways to understand your questions.
thenexttodie
Member
Rumraket said:
Morphology then?
Steelmage listed it as the best evidence for Darwinian evolution and evolutionary developmental biology. So it must be pretty solid..
Steelmage99
Member
thenexttodie said:
Then you have misunderstood me.
I listed morphology as the driving factor for Darwinian evolution because that was the state of the science at the time. it wasn't presented as the best knock-down argument. it was basically the only argument.
I made the distinction partly to make fun of you, thenexttodie.
The fact that morphology is still used to some extent does not make it the best evidence.
Modern evolutionary biology is confirmed by many branches of science, and that is part of the greatest evidence for evolution. Coupled with evolutionary theory's predictive power it is pretty much a waste of time to discuss.
Aside from all that you still didn't answer Rumraket's question.
What do you mean by evolution in the context of your question?
Nesslig20
Active Member
Rhed said:
Strongest arguments are those that use evidence.
For The theory of evolution, it is the systematic classification of life forms that at the same time concords with common descend and falsifies that there is such a thing as "created kinds". I have put the argument in greater detail here:
http://www.leagueofreason.org.uk/viewtopic.php?f=8&t=13163
Or in other words, if you are in some way arguing that we did not came from apes, then why are humans still apes right now. That ends the conversation right there and then.
The weakest? Those arguments that don't use evidence. Though if I have to pick the weakest form of evidence for evolution, I have to say fossils, since the fossil record is incomplete for obvious reasons. By calling it the weakest I don't mean the fossil record does not support evolution. Because it does. Despite being incomplete we have hundreds of transitional forms that should only exists if life evolved from common ancestors. The fossil record or rather paleontology is one line of evidence that cross confirms the systematic classification of life forms, but even without any fossils, the argument from common descend is already strong with the support of genetics. That is not to say that the fossil record is not important. The only way we know that birds are the last remaining lineage of dinosaurs is because of paleontology applied to systematic classification. That is pretty interesting.
thenexttodie said:
Darwinian evolution is the evolution that happens as it is driven by natural selection. The best evidence for that is that it happens. We have observed evolution driven natural selection in action both in the lab and in nature, the best lab occurrence is the long term evolution experiment on E. coli. Of course there are other mechanisms that Darwin didn't knew of like genetic drift, genetic draft, meiotic drive, bottle neck, founder effect, etc. Those mechanisms have also been demonstrated to drive the process of evolution.
Rhed said:
The best I have written above. Against? I know some arguments against common descent, but they all fail one way or another by being either unfalsifiable or unsupported by evidence. Picking the best argument among those, is rather like picking the least smelly piece of shit from a big pile of bullshit. Doesn't matter what you pick, it still smells bad.
Bango Skank
Member
Some humans have tails when they are born and sometimes even some muscles to control it in some degree. Is this tail a remnant from our ape side (apes have no tails though?) or from our fish side, or something else?
Nesslig20
Active Member
Bango Skank said:
The most recent ancestor of ours that did have tails were the probably early hominoids that as they themselves are derived from the old world monkey group "Catarrhines". Over the years all hominoids that still had a tail wen't extinct. Hominoids is a fancy name for apes. The tail that we lost evolved after the first chordates arose. One of the trait that defines chordata is a post-anal tail and we still develop one during embryonic development, even if you are born without one.
So humans being born with tails is an atavism of our ancestors that normally did have tails after birth. It is a remnant from the most recent to the most ancient ancestor that had them.
Bango Skank
Member
Nesslig20 said:
Ok, thanks for the answer. Having a tail would be neat though...think of it's use in bedroom...
