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Author Topic:   Is this tree leaf evolution?
New Cat's Eye
Inactive Member


Message 5 of 20 (485221)
10-06-2008 12:26 PM
Reply to: Message 3 by straightree
10-06-2008 11:11 AM


Aceraceae species, in general, have lobed leaves. There are some exceptions, like Acer Negundo, that has composed leaves. The more I look to the pictures I have of these leaves, the more I think Acer Negundo is in the way of evolving versus lobed leaves.
It seems that you're trying to propse this leaf as comming from some transitional species. Right?
I have more pictures, and expect to put them in a place that can be reached by Internet.
Look up "Photobucket" or "ImageShack" for hosting sites that you can link too.
I'd like to see the pictures of what you think the leaves should look like.
We don't really ever get into plant evolution here.
Have you read up on Aceraceae and how they relate to Sapindaceae?
You should also read up on Acer negundo because according to that page it seems to be in the Sapindaceae family as opposed to the aceraceae one. But then, according to the page an acer:
quote:
Acer (maple) is a genus of trees or shrubs. They are variously classified in a family of their own, the Aceraceae, or (together with the Hippocastanaceae) included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group classification, favour inclusion in Sapindaceae.
So who really knows?

This message is a reply to:
 Message 3 by straightree, posted 10-06-2008 11:11 AM straightree has replied

Replies to this message:
 Message 7 by straightree, posted 10-06-2008 6:22 PM New Cat's Eye has replied

  
New Cat's Eye
Inactive Member


Message 8 of 20 (485318)
10-07-2008 10:27 AM
Reply to: Message 7 by straightree
10-06-2008 6:22 PM


The pictures have already been placed at Photobucked, at this address
http://s412.photobucket.com/...05/straightree/Acer%20Negundo.
Catholic Scientist, thank you for the information.
Welcome to EvC.
So... what is the problem with the leaves that makes you think of evolution?

This message is a reply to:
 Message 7 by straightree, posted 10-06-2008 6:22 PM straightree has replied

Replies to this message:
 Message 10 by straightree, posted 10-07-2008 3:11 PM New Cat's Eye has replied

  
New Cat's Eye
Inactive Member


Message 12 of 20 (485344)
10-07-2008 3:41 PM
Reply to: Message 10 by straightree
10-07-2008 3:11 PM


What do you think?
I think that some of the leaves don't look like maple leaves....
Like this one:
Did they all come from the same tree?
and this one:
...looks like it came from some kind of freak.
So, looking it up on wiki I see:
quote:
Unlike most other maples (which usually have simple, palmately lobed leaves), Acer negundo has pinnately compound leaves that usually have three to seven leaflets. Simple leaves are also occasionally present; technically, these are single-leaflet compound leaves. Although some other maples (such as A. griseum, Acer mandshuricum and the closely-related A. cissifolium) have trifoliate leaves, only A. negundo regularly displays more than three leaflets.
So yeah... might just be a normal tree.
Also, you will see that some of the leaflets in the pictures are lobed, some of them assimetrically. So it seems like Acer Negundo leaves are not at rest, not stabilized yet, in a transitional stage.
For something to not be evolving it is said that it is in stasis.
Technically, all species are in a constant flux, check out genetic drift, so they are always in a transitional stage. You seem to think that stasis is the default but its not.
Check out this that I found too:
Neat, huh?

This message is a reply to:
 Message 10 by straightree, posted 10-07-2008 3:11 PM straightree has replied

Replies to this message:
 Message 15 by straightree, posted 10-08-2008 4:11 PM New Cat's Eye has replied

  
New Cat's Eye
Inactive Member


Message 17 of 20 (485462)
10-08-2008 4:31 PM
Reply to: Message 15 by straightree
10-08-2008 4:11 PM


quote:
Technically, all species are in a constant flux, check out genetic drift, so they are always in a transitional stage. You seem to think that stasis is the default but its not.
This could be the solution to my question.
Right on!
I will document myself more extensively in the subject of genetic drift of species, and will look for some information on maples evolution.
Like I said upthread, we rarely talk about the evolution of plants.
I cannot seem to find much info on maple evolution....
I did find this though:
quote:
Evolution:
An angiosperm, the earliest known Acer (A. amboyense) was found in eastern North America from the fossil remains of the late Cretaceous period about 67 MYA. All maple fossils have been located exclusively in the Northern Hemisphere and the trees seem most abundant during the Miocene (Oterdoom 1994).
The closest fossil relative to A. macrophyllum appears to be A. merriamii Knowlton (or A. oregonianum Knowlton) from the Late Miocene around 5 MYA (Macginitie 1969; Oliver 1934). Macginitie (1969) notes the potential for a taxonomic problem with assigning the name of a fossil species to a living species, for although they may be morphologically similar it is difficult to determine if the species are genetically identical.
The flowering and sexual mating of Acer have ranged from wind-pollinated to insect-pollinated and monoecy to dioecy. A. macrophyllum is an insect-pollinated dicot in which female flowers occur before male flowers (Oterdoom 1994).
The form of the leaves in the Acer genus has changed over time. From the Late Oligocene to the Early Pliocene (from around 23 to 5 MYA, including the Miocene) the leaf form evolved from the originally more common 3-lobed maples to 5-lobed maples, as evidenced in the paleobotanical studies of the broadening of the A. tricuspidatum leaf base (Oterdoom 1994).
A. macrophyllum belongs to the deciduous maple Aceraceae family, which has 200 species distributed among 2 genera (van Gelderen et al. 1994). Acer species is believed to have originated in central and western China although no fossils have been located in this area (Oterdoom 1994).
Cladistic analysis has concluded that the Aceraceae family was formed by earlier members of the Sapindaceae like Bohlenia, which was characterized by loss of a stipule and a locule, as well as a change to opposite from alternate leaves. The Dipteronia line of the Aceraceae seems to be more closely related to the Sapindaceae ancestor Bohlenia, except for a change in the secondary venation of its pinnately compound leaves. The A. arcticum line resulted in an actinodromous maple leaf after the fusion of a minimum of three leaflets (Stewart & Rothwell 1993; van Gelderen et al. 1994).
Found HERE
Thank you for your help.
No problem, I'm happy that I could. Welcome to EvC.

Science fails to recognize the single most potent element of human existence.
Letting the reigns go to the unfolding is faith, faith, faith, faith.
Science has failed our world.
Science has failed our Mother Earth.
-System of a Down, "Science"
He who makes a beast out of himself, gets rid of the pain of being a man.
-Avenged Sevenfold, "Bat Country"

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