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  Topic: Evolution paths, A technical question...< Next Oldest | Next Newest >  
wiwaxiathumb



Posts: 5
Joined: July 2006

(Permalink) Posted: July 13 2006,11:04   

Hello people
I'm not sure to be in the right place (though seems friendly enough...). I am a student in phi of bio looking for an answer, here it is :
Is there in evolutionary biology a term or concept fit to distinguish the phylogenetic developmental paths followed by  lineages? For example it would distinguish and describe a crocodile's resistance through evolution; a fruit fly's unchanging niche occupation; the famous cheetah's improvement race; finally homo's behavioral plasticity development. Does that ring any bells? I am using such a concept but I wonder - if it is useful for me, then maybe it has appeared elsewhere...

Any ideas? Other places to ask?

Florian

  
keiths



Posts: 2041
Joined: Jan. 2006

(Permalink) Posted: July 13 2006,11:36   

Quote (wiwaxiathumb @ July 13 2006,16:04)

Is there in evolutionary biology a term or concept fit to distinguish the phylogenetic developmental paths followed by  lineages?

Hi Florian,

Welcome to AtBC.

Perhaps I'm misunderstanding you, but doesn't the word "lineage" itself denote the concept you're asking about?  Isn't the path followed by a lineage the same as the lineage itself?  After all, if it had followed a different path, it would no longer be the same lineage.

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And the set of natural numbers is also the set that starts at 0 and goes to the largest number.  -- Joe G

Please stop putting words into my mouth that don't belong there and thoughts into my mind that don't belong there. -- KF

  
Chris Hyland



Posts: 705
Joined: Jan. 2006

(Permalink) Posted: July 13 2006,12:02   

I can't think of anything that describes all of those examples they seem to secribe different things. Are you talking about the lineage of specific traits of an organism or the evolution of adaption to an environment? By development do you mean change over the course of evolution or actual embryonic development?

  
wiwaxiathumb



Posts: 5
Joined: July 2006

(Permalink) Posted: July 14 2006,09:14   

Thanks for answering, I'll try to clarify:

First, I am refering to development in the course of evolution.
Second, it is clear that lineages indeed exhibit different ways of responding to evolutionary pressures and changes. Though each lineage is unique in its specific evolutionary history, I venture that these paths could be classified in a few categories. (This may be due to self-promoting or niche construction effects. )

For example, it seems that overall some lineages (or "evolutionary species") have followed the path of stability (i.e. withering environmental changes and conditions), other have pursued an ever tighter integration into a niche (e.g. the cheetah's predatory improvment ; and a great many species which exhibit what Nature show usually call "improvement") ; then some (read: us) have found themselves into the path of plasticity.

So, then, if there is a term in evo bio, it would sound as: crocodiles have followed the  schmoogle of resistance or such...

The reason I ask is I am using such a concept, and calling it an "Evolutionary path" (voie d'évolution in french).

  
stephenWells



Posts: 127
Joined: April 2006

(Permalink) Posted: July 14 2006,10:44   

Quote (wiwaxiathumb @ July 14 2006,14:14)
Thanks for answering, I'll try to clarify:

First, I am refering to development in the course of evolution.
Second, it is clear that lineages indeed exhibit different ways of responding to evolutionary pressures and changes. Though each lineage is unique in its specific evolutionary history, I venture that these paths could be classified in a few categories. (This may be due to self-promoting or niche construction effects. )

For example, it seems that overall some lineages (or "evolutionary species") have followed the path of stability (i.e. withering environmental changes and conditions), other have pursued an ever tighter integration into a niche (e.g. the cheetah's predatory improvment ; and a great many species which exhibit what Nature show usually call "improvement") ; then some (read: us) have found themselves into the path of plasticity.

So, then, if there is a term in evo bio, it would sound as: crocodiles have followed the  schmoogle of resistance or such...

The reason I ask is I am using such a concept, and calling it an "Evolutionary path" (voie d'évolution in french).

I think this is something you can only define post hoc. I think I see what you mean- e.g. sharks seem to have stayed very sharky for a long time while primates keep changing shape- but I don't think you can validly say that sharks have "pursued a strategy" or "followed a schmoogle" of remaining the same; it's just that they're well adapted to a niche and neither the niche nor the adaptation has changed much over very long periods of time. If the environment alters to change the niche, sharks will either adapt or die out.

BTW I think you mean "weathering" changes, not withering.

  
Henry J



Posts: 4565
Joined: Mar. 2005

(Permalink) Posted: July 14 2006,10:55   

Re "sharks seem to have stayed very sharky"

That might be largely the streamlining for fast swimming - i.e., a change of shape would slow them down.

Henry

  
ericmurphy



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Joined: Oct. 2005

(Permalink) Posted: July 14 2006,10:56   

I (in my humble capacity as a non-specialist) think this may be a bad avenue to pursue, because it positively reeks of teleology. And if there's one think virtually all research into evolutionary mechanisms demonstrates, it that there is no teleology to evolution. Organisms don't have a strategy when it comes to evolving. Everything is contingent, nothing is planned.

That sharks have essentially stayed the course in remaining very sharky, in Stephen's words, whereas other organisms have seen more variable "strategies" (even that word probably skirts the edge of permissibility) almost certainly has nothing to do any kind of "schmoogle."

My guess is that if an evolutionary lineage inhabits an ecosystem that changes relatively slowly (sharks are probably a good example of that), that lineage will remain more or less the same for long periods of time. By contrast, the habitats frequented by, e.g., primates are extremely variable over time. Hence, more variation over time within a lineage.

Comments?

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2006 MVD award for most dogged defense of scientific sanity

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wiwaxiathumb



Posts: 5
Joined: July 2006

(Permalink) Posted: July 17 2006,10:54   

Quote (stephenWells @ July 14 2006,15:44)
I don't think you can validly say that sharks have "pursued a strategy" or "followed a schmoogle" of remaining the same; it's just that they're well adapted to a niche and neither the niche nor the adaptation has changed much over very long periods of time. If the environment alters to change the niche, sharks will either adapt or die out.

I'll try to rephrase along those lines.

First, about teleology. Indeed, when I say the species or organism "pursue a strategy" this is a smelly shorthand... "can be described as pursuing a strategy, though by virtue of processes that are mechanistic or contingent" would a bit long!

About niches. We're zeroing on the point I try to examine. Let's reframe the idea: I claim that organisms have varying degrees of fit or latitude with regards to their niche, or to say it differently, their niche need be defined with varying levels of detail. Now the shark's niche is rather wide, as it is a rather resilient and super-predatory species. It takes serious modifications to push the species to change. Cheetahs would have a "tighter" niche - change the gazelle and it may lose its edge over e.g. hyenas. Now species which are more behaviourally plastic have a looser fit, but this time not by means of resistance.


So, the question would then be: what about the respective evolutionnary paths of such species? Would it sound right to describe one lineage as having gone through an history of resistance (looser fit to their environment) / increased adaptation (to fit into tighter vacant niches) / plasticity (evolving to fit into any available niche)?

  
Flint



Posts: 478
Joined: Jan. 2006

(Permalink) Posted: July 17 2006,10:58   

The usual term is "natural history".

  
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