What is a trasitional fossil?

[ab1385]

Totally serious question here...

My understanding is that a species, as a whole, is constantly evolving, some individuals will have large mutations, others none, but overall a species will continue to evolve. Surely this means that any species, at any point in time is transitional between what has been past, and what is to come? What I mean is, is there such thing as a non-transitional fossil? Other than those of species which died out, obviously.

 

[Hnefi]

You've hit the nail on the head. Every fossil is, in a sense, transitional unless it's the last in its lineage.

What people usually mean by transitional fossils though, is a fossil that shows a clear transition between species. Archeopteryx, for example, has features of both reptiles and birds.

 

[drlao23]

Yes, you are correct. The fact that some fossils look especially transitional has to do with our own observational bias due to our current place in history. Archeopteryx looks especially transitional mostly because we live in a world where birds and reptiles are especially distinct. Many of the links between them have died out so we don't think of birds and reptiles as one big supergroup with a wide range of variablity, we think of them as two separate groups and any fossil containing a mosaic of bird and reptilian features as transitional.

 

[coyoteBR]

And, to add, if you want to find a transitional animal alive today... just look for a mirror.

Right, maybe not so, because we have plenty of ways to cheat natural selection. For instance, if someone has not the most desirable phisical characteristics on a comunity, this person can dye the hair, wear tinted contact lents, do cosmetic surgeries ... and buy a red Ferrari .

To live at the desert, we don't need to increase the melenine in our bodies, nor to shorten our height to make our bodies more efficients. Now, to live on desert, we build Vegas (actually, thinking about it, it's not all that of an improvement).

But every other living thing on the planet is an faster transational form than us, poor cheating humans.

 

[Aron-Ra]

Totally serious question here...

My understanding is that a species, as a whole, is constantly evolving, some individuals will have large mutations, others none, but overall a species will continue to evolve. Surely this means that any species, at any point in time is transitional between what has been past, and what is to come? What I mean is, is there such thing as a non-transitional fossil? Other than those of species which died out, obviously.

While any fossil could be said to be transitional in some respect, there are fossils that are 'distinctly' so, and these are the ones creationists keep claiming have never been found. These are defined thus:

“A transitional fossil is one that looks like it’s from an organism intermediate between two lineages, meaning it has some characteristics of lineage A, some characteristics of lineage B, and probably some characteristics part way between the two. Transitional fossils can occur between groups of any taxonomic level, such as between species, between orders, etc. Ideally, the transitional fossil should be found stratigraphically between the first occurrence of the ancestral lineage and the first occurrence of the descendent lineage...”
​

Not only is this the proper scientific definition, but I copied this text from a site dedicated to promoting young earth creationism, and they hold this as the proper definition as well.

 

[TeddyKGB]

What people usually mean by transitional fossils though, is a fossil that shows a clear transition between species.

Not exactly. Transitions between species are likely very subtle features, rarely discernible via observation alone.

Archeopteryx, for example, has features of both reptiles and birds.

Yeah, you need larger groups, with unique characteristics, in order to have observable transitional features.

 

[LadyLRae]

Totally serious question here...

My understanding is that a species, as a whole, is constantly evolving, some individuals will have large mutations, others none, but overall a species will continue to evolve.

Oxy-moron... Evolving is getting better, growing to achieve possibilities, growing more complex, and able, is it not? There has not been one beneficial mutation in all of history. If you know of one, please do tell. All mutations are harmful in some way. They do not 'help out' their host.

Surely this means that any species, at any point in time is transitional between what has been past, and what is to come? What I mean is, is there such thing as a non-transitional fossil? Other than those of species which died out, obviously.

All animals are in a set kind. There are no transitional species anywhere. Yes, there may be changes within the kind, but this never turns into macro-evolution. There are no credible fossils recorded that are transitional species.

 

[drlao23]

Oxy-moron... Evolving is getting better, growing to achieve possibilities, growing more complex, and able, is it not?

No, it is not.

There has not been one beneficial mutation in all of history.

You are mistaken

If you know of one, please do tell.

Bacteria resistance to antibiotics.

All animals are in a set kind. There are no transitional species anywhere. Yes, there may be changes within the kind, but this never turns into macro-evolution. There are no credible fossils recorded that are transitional species.

Again, you are mistaken.

 

[Aron-Ra]

Oxy-moron... Evolving is getting better, growing to achieve possibilities, growing more complex, and able, is it not?

Sometimes it is. Sometimes it is not.

There has not been one beneficial mutation in all of history. If you know of one, please do tell.

I know of many.

All mutations are harmful in some way. They do not 'help out' their host.

Wrong again. Some mutations can be harmful, but the vast majority are completely neutral, and a few are definitely beneficial.



For example, a group of kinfolk in in the village of Limone Sul Garda in northern Italy have a mutation which gives them better tolerance of HDL serum cholesterol. Consequently this family has no history of heart attacks dispite their high-risk dietary habits. This mutation was traced to a single common ancestor living in the 1700's, but has now spread to dozens of descendants. Genetic samples from this family are now being tested for potential treatment of patients of heart disease.

The Vadoma tribe, AKA the "Ostrich People", a family in Zimbabwe share a disctintive inherited mutation in their feet, (and sometimes in their hands also) which deprives them of all the bones for their three middle toes. These people claim the advantages of this include their ability to run faster and climb trees much better than normal-footed people.

Another example of new variance is the Glycophorin A somatic cell mutation (Jensen, R. H., S. Zhang, et al. (1997) which has been identified in some Tibetans, which allows them to endure prolongued periods at altitudes of 7,000 feet without succumbing to apoplexia, or “altitude sickness”. A different, but similar mutation was identified in high altitude natives in the Andes.

Another example of that is the CCR5-delta 32 mutation. About 10% of whites of European origin now carry it. But the incidence is only 2% in central Asia, and is completely absent among East Asians, Africans, and American Indians. It appears to have suddenly become relatively common among white Europeans about 700 years ago, evidently as a result of the Black Plague, indicating another example of natural selection allowing one gene dominance in a changing environment. It is harmless (or neutral) in every respect other than its one clearly beneficial feature; if one inherits this gene from both parents, they will be especially resistant (if not immune) to AIDS.
(source: Science-Frontiers.com / PBS.org)

Similarly, population genetics is being credited as one reason incidence of sickle-cell gene in African-Americans is apparently decreasing over time.

There’s also a family in Germany who are already unusually strong. But in one case, one of their children was born with a double copy of an anti-myostatin mutation carried by both parents. The result is a herculian kiddo who was examined at only a few days old for his unusually well-developed muscles. By four years old, he had twice the mucle mass of normal children, and half the fat. Pharmaceutical synthesis of this mutation is being examined for potential use against muscular dystrophy or sarcopenia.

There is also a family in Connecticut that has been identified as having hyperdense, virtually unbreakable bones:
“Members of this family carry a genetic mutation that causes high bone density. They have a deep and wide jaw and bony growth on the palate. Richard P. Lifton, M.D., Ph.D., chair of the Department of Genetics, along with Karl L. Insogna, M.D., professor of medicine and director of the Yale Bone Center, and colleagues, traced the mutation to a gene that was the subject of an earlier study. In that study researchers showed that low bone density could be caused by a mutation that disrupts the function of a gene called LRP5. In the recent study, the Yale team mapped the family’s genetic mutation to the same chromosome segment in LRP5. “It made us wonder if a different mutation increased LRP5 function, leading to an opposite phenotype, that is, high bone density,” Lifton said.
Family members, according to the investigators, have bones so strong they rival those of a character in the 2000 movie Unbreakable. “If there are living counterparts to the [hero] in Unbreakable, who is in a terrible train wreck and walks away without a single broken bone, they’re members of this family,” said Lifton. “They have extraordinarily dense bones and there is no history of fractures. These people have about the strongest bones on the entire planet.”
--Med.Yale.EDU

For another example apart from those I’ve already listed today, we’ve also identified an emerging population of tetrachromatic women who can see a bit of the normally invisible ultraviolet spectrum.

Now do you admit that there have been several mutations that were positively identified and definitely beneficial?

All animals are in a set kind.

Are they?

Is the short-tailed goanna related to the Perentie and all other Australian goannas?
Are all Australian goannas related to each other and to the other monitor lizards of Indonesia and Africa?
Are today's varanids related to the giant goannas of Australia's past?
Are terrestrial monitors related to the mosasaurs of the Cretaceous?
Are Varanoids related to any other Anguimorphs including snakes?
Are any Anguimorphs also related to scincomorphs and geckos?
Are all Scleroglossa also related to iguanids and other squamates?
Are all of squamata related to each other and all other lepidosaurs?
Are all lepidosaurs related to placodonts and plesiosaurs?
Are Lepidosauromorphs related to archosaurs and other diapsids?
Are all diapsids related to anapsids, or synapsid "reptiles" like dimetrodon?
Are all reptiles related to each other and all other amniotes?
Are all amniotes related to each other and to all other tetrapods?
Are all tetrapods related to each other and to all other vertebrates?
........and so on.

Which of these are related? Which of these are created? Which of these not-at-all set kiinds of kinds is a "kind"?

There are no transitional species anywhere.

Have you checked this list of many that were found everywhere?
http://www.talkorigins.org/faqs/faq-transitional.html

Yes, there may be changes within the kind, but this never turns into macro-evolution.

I have a list of directly-observed and documented cases of macroevolution which is too long to include in any single post to this forum. Do you doubt me?

There are no credible fossils recorded that are transitional species.

Can you explain to me how Acanthostega, Ambulocetus, Mixopterus, cynodonts, Homo habilis, Rahonavis, Confusiousornis, Mixosaurus, Merychippus, Microraptor, or any of the many other proposed transitional species do not really qualify as such according to the only definition possible, and which is used by both sides of this alleged contraversy?

 

[Dannager]

Oxy-moron... Evolving is getting better, growing to achieve possibilities, growing more complex, and able, is it not?

No, it's not.

There has not been one beneficial mutation in all of history. If you know of one, please do tell. All mutations are harmful in some way. They do not 'help out' their host.

Some examples of beneficial mutations: http://www.talkorigins.org/faqs/mutations.html#Q2

All animals are in a set kind.

No, they're not. There is no such taxonomic classification as a "kind" in cladistics.

There are no transitional species anywhere.

Some examples of transitional fossils: http://www.talkorigins.org/faqs/faq-transitional.html

Yes, there may be changes within the kind, but this never turns into macro-evolution.

Macro-evolution is speciation. Some observed instances of speciation: http://www.talkorigins.org/faqs/faq-speciation.html

There are no credible fossils recorded that are transitional species.

I'll repeat this link again: http://www.talkorigins.org/faqs/faq-transitional.html

Please take a look at these websites, LadyLRae. It seems as though you've kind of been living in the dark for a while when it comes to what evolution actually is about.

EDIT: In hindsight, Aron-Ra's post was so much more awesome than mine I shouldn't have even tried.

 

[metherion]

[Poe]
A transitional fossil is one with definite characteristics from 2 or more different species, e.g. fish gills, gorilla arms, and a St. Bernards' tail. Anything less is still within a kind and therefore unacceptable.

[/Poe]

Metherion

 

[Nooj]

A (stupid) question from me:

A transitional fossil or transitional form is the fossilized remains of a life form that illustrates an evolutionary transition. It can be identified by having certain primitive (plesiomorphic) traits in comparison with its more derived relatives, such as defined in the study of cladistics.

How do you determine who the relatives are in the first place?

 

[Aron-Ra]

A (stupid) question from me: How do you determine who the relatives are in the first place?

That's not an easy task. Systematic taxonomy is an extremely intricate and detailed process of in-depth character analysis and cross comparison charting morphological, physiological, and genetic synapomorphies to isolate a monophyletic phylogeny.

Does that help?

 

[Nooj]

Humour a 16 year old for a second. But isn't it circular logic?

To find where transitional fossils fit into evolutionary relationships: Use cladistic analyses.

To use cladistic analyses (based on character states): Use transitional fossils, leading back to the problem of where they fit in.

 

[Aron-Ra]

Humour a 16 year old for a second. But isn't it circular logic?

To find where transitional fossils fit into evolutionary relationships: Use cladistic analyses.

To use cladistic analyses (based on character states): Use transitional fossils, leading back to the problem of where they fit in.

I actually meant to sound facetious. It would seem circular except for the fact that the idea of evolution was never based on fossils -other than simply noticing forms that didn't still exist in the absense of fauna that does exist now. Taxonomy was the first clue to evolutionary relationships. But to support that we had to find transitions. We have, and now we're checking and re-testing them every way we can think of to make sure of the highest possible accuracy in our clade tree(s).

 

[CACTUSJACKmankin]

There has not been one beneficial mutation in all of history. If you know of one, please do tell.

Disease resistance isn't a beneficial mutation? There are multiple populations of people that developed resistance to HIV. That sounds beneficial to me.

All mutations are harmful in some way. They do not 'help out' their host.

Actually MOST mutations are benign. A mutation is a mistake in the process of copying a strand of DNA. That mistake will result in a new codon, but that will usually not result in a new amino acid since the amino acid code is redundant.

All animals are in a set kind.

Define a kind.

there may be changes within the kind, but this never turns into macro-evolution.

The only barrier between macro and microevolution is time, and there's plenty of that.

There are no credible fossils recorded that are transitional species.

tiktaalik, probainognathus, archaeopteryx, whale series, horse series, human series, and Yanoconodon.

 

[Nitron]

I get the feeling of another drive-by creationist. Yet another one who's not gonna learn anything.

 

[Aron-Ra]

I get the feeling of another drive-by creationist. Yet another one who's not gonna learn anything.

A fifteen year-old girl duped into believing the propaganda of paranoid fools. Such a trajedy.