Freethought & Rationalism Archive

Brian Lindsey · 10-25-2002, 01:17 PM

Looking for information about the origins of carnivorous activity, primarily in animal species.

I was having a discussion with the Youth Pastor at our church about a comment a Sunday school teahcer had made the previous week about how all animals were herbivores before "The Fall." I responded that this was ridiculous. But it spawned a series of questions and belied my ignorance about the subject. I was hoping some here could help me out.

What differentiates herbivores and carnivores (beyond the obvious, diet) and can we see these differences in the fossil record?

What proposed evolutionary pathway did/does the shift from herbivory to carnivory take? I'm thinking along digestive (biochemical?) lines and major organ adaptations.

Are there any documented cases of a species' shift from herbivory to carnivory?

My pastors comments were bewildering. He expressed that the faith our Sunday School teacher had that all animals shifted from herbivory to carnivory at the same time was the same "type" faith required of "evolutionists" to believe that a gradual shift happened in untold numbers of species over the eons.

Comments?

Thanks for any help you can proffer.

Brian

ps418 · 10-25-2002, 01:54 PM

Quote:

What differentiates herbivores and carnivores (beyond the obvious, diet) and can we see these differences in the fossil record?

Sure. dentition is where you want to look for the most direct evidence. Compare the teeth of a horse with the teeth of a dog, for example. The horse's teeth are flattish and blocky, while the dog's are pointed. The jaw morphology is often different also, with herbivores performing a side-to-side grinding chew rather than up and down.

I can just see T. rex with his conical teeth out there grazing on grass or chewing on leaves . . .

Some links:
<a href="http://www.life.umd.edu/classroom/bsci338m/Lectures/Teeth.html" target="_blank">Characteristics of mammals</a>

<a href="http://palaeo.gly.bris.ac.uk/Communication/Trickett/jaws.diet.html" target="_blank">Dinosaurs: how did they eat?</a>

[ October 25, 2002: Message edited by: ps418 ]</p>

Dr.GH · 10-25-2002, 01:56 PM

Opps, Patrick beat me to it.

[ October 25, 2002: Message edited by: Dr.GH ]</p>

Dr.GH · 10-25-2002, 02:14 PM

Creodonts are primitive carnivorous mammals, characterized by a particular configuration in their hind molars. Try your search on them.

lpetrich · 10-25-2002, 02:32 PM

There is an abundance of other evidence of what long-ago animals had eaten:

Stomach contents.

Coprolites (fossil excrement). These contain what had survived a trip through some gut.

Bite marks. Some of these are found as far back as the Cambrian, where some trilobites had Anomalocaris bite marks.

Direct evidence. There are some fossil fish that have other fish in their mouths, which suggest that the eating fish had choked on its would-be meal. This may be interpreted as evidence that there were sins being committed long before humanity had existed; those fish were clearly guilty of one of the Seven Deadly Sins: gluttony.

And even

Fossil vomit. There are deposits of belemnites that show evidence of having been etched by stomach acid. This suggests that some Mesozoic marine reptiles had swalled belemnites whole, digested the soft parts in their stomachs, and then vomited up their meals' shells.

lpetrich · 10-25-2002, 02:49 PM

And if one wishes to cover the entire animal kingdom, that's a very broad subject. There is an abundace of evidence for going both ways, as listed in <a href="http://www.cmnh.org/dinoarch/1995Oct/msg00290.html" target="_blank">responses to this message</a>.

Sometimes evolution can result in a species becoming unable to change. For example, cats are obligate carnivores, because unlike many species, they cannot make taurine for themselves, and thus must get it in their diet.

10-25-2002, 01:17 PM	#1
Brian Lindsey Junior Member Join Date: Apr 2002 Location: Washinton Posts: 7	Origin of Carnivory Looking for information about the origins of carnivorous activity, primarily in animal species. I was having a discussion with the Youth Pastor at our church about a comment a Sunday school teahcer had made the previous week about how all animals were herbivores before "The Fall." I responded that this was ridiculous. But it spawned a series of questions and belied my ignorance about the subject. I was hoping some here could help me out. What differentiates herbivores and carnivores (beyond the obvious, diet) and can we see these differences in the fossil record? What proposed evolutionary pathway did/does the shift from herbivory to carnivory take? I'm thinking along digestive (biochemical?) lines and major organ adaptations. Are there any documented cases of a species' shift from herbivory to carnivory? My pastors comments were bewildering. He expressed that the faith our Sunday School teacher had that all animals shifted from herbivory to carnivory at the same time was the same "type" faith required of "evolutionists" to believe that a gradual shift happened in untold numbers of species over the eons. Comments? Thanks for any help you can proffer. Brian

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10-25-2002, 01:56 PM	#3
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	Opps, Patrick beat me to it. [ October 25, 2002: Message edited by: Dr.GH ]</p>

10-25-2002, 02:14 PM	#4
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	Creodonts are primitive carnivorous mammals, characterized by a particular configuration in their hind molars. Try your search on them.

10-25-2002, 02:32 PM	#5
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	There is an abundance of other evidence of what long-ago animals had eaten: Stomach contents. Coprolites (fossil excrement). These contain what had survived a trip through some gut. Bite marks. Some of these are found as far back as the Cambrian, where some trilobites had Anomalocaris bite marks. Direct evidence. There are some fossil fish that have other fish in their mouths, which suggest that the eating fish had choked on its would-be meal. This may be interpreted as evidence that there were sins being committed long before humanity had existed; those fish were clearly guilty of one of the Seven Deadly Sins: gluttony. And even Fossil vomit. There are deposits of belemnites that show evidence of having been etched by stomach acid. This suggests that some Mesozoic marine reptiles had swalled belemnites whole, digested the soft parts in their stomachs, and then vomited up their meals' shells.

10-25-2002, 02:49 PM	#6
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	And if one wishes to cover the entire animal kingdom, that's a very broad subject. There is an abundace of evidence for going both ways, as listed in <a href="http://www.cmnh.org/dinoarch/1995Oct/msg00290.html" target="_blank">responses to this message</a>. Sometimes evolution can result in a species becoming unable to change. For example, cats are obligate carnivores, because unlike many species, they cannot make taurine for themselves, and thus must get it in their diet.

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