weird animal relatives

[jess]

I have been interested in watching survival story's about animal attacks so I started researching them out of boredom then I found out that Crocodiles are related to birds and hippos are related to whale.

 

I was wondering if there was any other relatives to animals you would never expect??

Edited July 2, 2010 by jess

[ajb]

This should be moved to the Biology section.

[jess]

This should be moved to the Biology section.

oops sorry I'm new how do i do that

[swansont]

No worries. You can't, but mods can.

 

Done.

[cypress]

I have been interested in watching survival story's about animal attacks so I started researching them out of boredom then I found out that Crocodiles are related to birds and hippos are related to whale.

 

I was wondering if there was any other relatives to animals you would never expect??

 

Relatedness at a these levels is proving to be much more tricky than earlier classification might indicate. This is because the process is based on groupings and categories populated by noting various similarities in both modern historical specimens and now gene sequencing as well. The assumtion is that closely related species will share more developmental and genetic similarities than distantly related species.

 

With modern genetic techniques available, we see that the tree of life is not so much a tree as it is a tangled bush or even an brier patch. It is proving much more difficult to establish actual relatedness than once presumed.

 

To answer your question, there are numerous examples of what are thought to be very distant species with genetic similarities that are astonishing. It makes it difficult to know if these species are related in the sense you mean or if the assumptions about relatedness are not correct. It gets back to the point that based on current data, the tree of life looks more like a tangle of bramble. It is likely going to take a long while to untangle it, it it seems certain that many of the assumptions that went into the original model of a tree of life were incorrect.

[jess]

Relatedness at a these levels is proving to be much more tricky than earlier classification might indicate. This is because the process is based on groupings and categories populated by noting various similarities in both modern historical specimens and now gene sequencing as well. The assumtion is that closely related species will share more developmental and genetic similarities than distantly related species.

 

With modern genetic techniques available, we see that the tree of life is not so much a tree as it is a tangled bush or even an brier patch. It is proving much more difficult to establish actual relatedness than once presumed.

 

To answer your question, there are numerous examples of what are thought to be very distant species with genetic similarities that are astonishing. It makes it difficult to know if these species are related in the sense you mean or if the assumptions about relatedness are not correct. It gets back to the point that based on current data, the tree of life looks more like a tangle of bramble. It is likely going to take a long while to untangle it, it it seems certain that many of the assumptions that went into the original model of a tree of life were incorrect.

 

I guess I never really thought of it that way thanks mate

[Moontanman]

A human and a Dimetrodon...

 

 

[jess]

A human and a Dimetrodon...

 

 

 

WHAT REALLY!!!!!!

that's so weird thanks mate

[skyhook]

one example is hyrax related to elephant. The rodent is hairy while the elephant looked like it doesn't have much hair.

[Sisyphus]

Since all known life almost certainly shares a common ancestor, you could actually say any combination. You and a potato: family. (Quite distant though!)

[cypress]

Since all known life almost certainly shares a common ancestor, you could actually say any combination. You and a potato: family. (Quite distant though!)

 

 

You could, but it would be a circular argument since common ancestry is based on presupposition as opposed to established scientific fact. Common ancestry is an attractive narrative, but it is not established by the traditional rules of scientific discovery. If true, it would be a codependent series of historical singularities. Such things seem intractable to scientific discovery except perhaps by comparison to alternatives. Common ancestry is arrived at by noting similarities between organisms and ignoring or explaining away differences that don't fit the model. Humans are quite good at placing things in categories whether they fit or not. It can be a form of conformational bias.

 

The idea of common ancestry does not seem to be falsifiable either. How would one go about falsifying the speculation? To be falsifiable there must be an alternative, either one that is still in play or ones that have been tested and falsified. If no alternatives have seriously been considered then the speculation is more likely a metaphysical belief as opposed to a scientific proposition. Is there any good reason why alternatives should not be considered?

 

I think it is far better to acknowledge that we don't know and are still looking. To say it is almost certain implies knowledge we don't have.

[Sisyphus]

The idea of common ancestry is not based on merely "noting similarities between organism." Multiple methods independently predict and verify. It could have been falsified at any point. That is science. It is indeed "almost certain."

[Anura]

man and fish

[CharonY]

Common ancestry is about as certain as it gets.

[cypress]

Common ancestry is about as certain as it gets.

 

No, sorry it is far from certain. It is an inductive argument based primarily on noting some degrees of similarity. Trouble is the argument fails to account for most of the unexpected differences except for by appeal to unknown processes. Common ancestry may well be correct, but "certain" is about as poor a word choice as one could make.

 

Near certainties don't have a host of unaddressed or unresolved issues. Here are a few of the more serious issues with this idea.

 

DNA replication appears to have occurred more than once. Many of the primary proteins involved in DNA replication are not similar between species to be related via common descent.

 

Different DNA replication processes exist, used to replicate viral and plasmid DNA. It is surprising that the protein sequences of key components of the DNA replication machinery, above all the principal replicative polymerases, show very little or no sequence similarity between bacteria and archaea/eukaryotes.

 

The core enzymes of the replication systems of bacteria and archaea (as well as eukaryotes) are unrelated or extremely distantly related. Viruses and plasmids, in addition, possess at least two unique DNA replication systems, namely, the protein-primed and rolling circle modalities of replication.

 

the data regarding eukarya, archaea, and bacteria do not reveal any particular evolutionary pathway. We could interpret the data according to evolution, but there are no precursor structures and no intermediate cell types.

 

Numerous cases of functionally-unconstrained similar stretches of DNA have been discovered in distant species. Histones are a good example, they are proteins that help organize DNA. The gene that codes for histone IV is highly conserved among a range of species leading to speculation that they are highly conserved due to strong functional constraints. Despite this experiments showed only minor functional constraints. Even more incredible are the ultra-conserved elements (UCEs). Many thousands of these DNA segments, hundreds of base pairs long, have been found across a range of species including mouse, rat, dog, chicken, humans and fish and experiments have revealed no phenotype effects of these sequences.

 

Biological variation does not arise spontaneously. The idea of common descent relies on the preexistence of biological variation without understanding from where it came. We now know how variation occurs but not how the machine behind it arose. Now evolution proposes to tell us not only how variation is used but how all the species came about—and its answer is by unguided natural forces. But when we come to the Mendelian machine of variation we must ask how was it that evolution produced such a machine which is, in turn, supposed to be the engine for evolution itself? It is a tautology.

[alex sam]

A human and a Dimetrodon...

 

 

 

 

Wonderful

 

I have been interested in watching survival story's about animal attacks so I started researching them out of boredom then I found out that Crocodiles are related to birds and hippos are related to whale.

 

I was wondering if there was any other relatives to animals you would never expect??

 

Angora Rabbit

 

I guess I never really thought of it that way thanks mate