Opuntia galapageia

| 31 Comments
IMG_3672_P_Pear_Tree_600.jpg

Opuntia galapageia – cactus tree, Galápagos Islands.

31 Comments

Are we to just admire the view, which is pretty, but not spectacular. Or is there some subtle Darwinian allusion here?

Or is there some subtle Darwinian allusion here?

Yes.

Looks like a prickly pear trying to be a tree.

A higher resolution picture of the same two plants is at http://www.arkive.org/media/68/685F[…]hflowers.jpg

I wonder if it would be feasible to block posters that have the phrase “quality-papers” in their URL?

A higher resolution picture of the same two plants is at …

Yep - that’s the same pic I linked the photograph to. Surprised no one has noticed.

Who has been to the Galapagos Islands?

Bilbo said:

Are we to just admire the view, which is pretty, but not spectacular. Or is there some subtle Darwinian allusion here?

Yes - many organism undergo gigantism on oceanic islands because of release from competition. If I recall correctly this is termed “adaptive release”.

Klaus Hellnick said:

Looks like a prickly pear trying to be a tree.

But they are still tree kind. Oh, wait, they are still cacti kind. no? Still Crocoduck could not eat it. Also now there are two gaps, one between cactus and this cactree and another between cactree and tree. You Darwinists are lying. You probably cobbled it together with glue and chanel sticks. Show me how it evolved. Show me every intermediary is a biotic reality. Just put up the evidence and let three year olds listen to both sides and decide for themselves. Why are you so scared? Shows your theory is crumbling. I’m out of here.

So it’s the platypus of the plant kingdom?

ravilyn sanders Wrote:

But they are still tree kind. Oh, wait, they are still cacti kind. no?

Inside joke to Talk.Origins regulars: Is that a contiguous breeding population? Or a multiplex one?

Yes - many organism undergo gigantism on oceanic islands because of release from competition.

That is true, but I do not know whether this cactus is an example of gigantism – I thought it evolved a tree-like structure in order to keep the leaves out of reach of the giant tortoises. Perhaps some reader can clarify the point.

Perhaps the tortoises evolved longer necks by straining to reach the cactus pads!

Bilbo said:

Are we to just admire the view, which is pretty, but not spectacular. Or is there some subtle Darwinian allusion here?

Think big turtles, and adaptations of cactus to get their edible branches out of harms way. The turtles may be gone (I guess they were easy meat for sailors), but their legacy lives on.

Ron Okimoto said:

Bilbo said:

Are we to just admire the view, which is pretty, but not spectacular. Or is there some subtle Darwinian allusion here?

Think big turtles, and adaptations of cactus to get their edible branches out of harms way. The turtles may be gone (I guess they were easy meat for sailors), but their legacy lives on.

Right. See the cactus plant has a brain & it knew the turtles were munching on the branches. Right. Therefore it simply grew them longer.

Right. To get out of “ harms way.” Right.

Yet another perfect example of evos idiots logic on parade. It never ends. Same stupidity, different day.

JT Alden said:

Ron Okimoto said:

Bilbo said:

Are we to just admire the view, which is pretty, but not spectacular. Or is there some subtle Darwinian allusion here?

Think big turtles, and adaptations of cactus to get their edible branches out of harms way. The turtles may be gone (I guess they were easy meat for sailors), but their legacy lives on.

Right. See the cactus plant has a brain & it knew the turtles were munching on the branches. Right. Therefore it simply grew them longer.

Right. To get out of “ harms way.” Right.

Yet another perfect example of evos idiots logic on parade. It never ends. Same stupidity, different day.

Poor guy, to be demonstrate that you are this lost and have such an abject ignorance of the subject that you are commenting on takes what kind of person?

Why don’t you demonstrate that you know what “adaptation” means. What would be the scientific scenario for how the cactus adapted to the island tortoises eating them.

Go for it.

What would be the scientific scenario for how the cactus adapted to the island tortoises eating them.

I am afraid that both Mr. Okimoto and I may have confused the issue by using teleological language. I said “in order to,” and Mr. Okimoto similarly implied that the cactuses developed as they did “to get their edible branches out of harm[‘]s way,” as if it had been purposeful. Reminds me of a time when a philosopher caught me saying that a particle obeyed a certain equation – which is a shorthand way of saying that the equation accurately describes the motion of the particle.

Teleological language is similarly no more and no less than a metaphorical shorthand. Mr. Alden’s inane response notwithstanding, what really happened was that the tallest cactuses were more likely to survive predation by the giant tortoises. Eventually, by a process that can be easily visualized, after many generations, the cactuses developed a tree-like structure. The tortoises, meanwhile, developed long necks and a specialized carapace that allowed them to reach higher than their ancestors.

harm[‘]s way

Bloody markup languages! That was supposed to have been an apostrophe.

Yeah, if it had been teleological, the tortoises would have become mutant ninja turtles, and just kicked the plants down!

Henry J

Matt Young said:

What would be the scientific scenario for how the cactus adapted to the island tortoises eating them.

I am afraid that both Mr. Okimoto and I may have confused the issue by using teleological language. I said “in order to,” and Mr. Okimoto similarly implied that the cactuses developed as they did “to get their edible branches out of harm[‘]s way,” as if it had been purposeful. Reminds me of a time when a philosopher caught me saying that a particle obeyed a certain equation – which is a shorthand way of saying that the equation accurately describes the motion of the particle.

Teleological language is similarly no more and no less than a metaphorical shorthand. Mr. Alden’s inane response notwithstanding, what really happened was that the tallest cactuses were more likely to survive predation by the giant tortoises. Eventually, by a process that can be easily visualized, after many generations, the cactuses developed a tree-like structure. The tortoises, meanwhile, developed long necks and a specialized carapace that allowed them to reach higher than their ancestors.

You shouldn’t do his homework for him. He had to show that his statement wasn’t as inane as it was.

Yeah, if it had been teleological, the tortoises would have become mutant ninja turtles, and just kicked the plants down!

Doesn’t that depend on whether the designer was a turtle or a cactus?

Doesn’t that depend on whether the designer was a turtle or a cactus?

Huh. I didn’t think of that.

YEC here. While its not a big deal to see a fast result from these plants being selected because of prey it could rather be a example of something else. I find always that diversity is not from selection but rather a natural reaction in nature. so it might be a better idea that upon landing n these isles this plant immediately got powerful in variety and it was just a later immigration of creatures that eliminated the ground varieties. Not selection making bigger plants because of predation but simply the bigger ones survived. So this need not be a case of evolution at work but a case of errors in biological history. Diversity is the norm and a instant result from colonization. Later comes extinctions. There is just data and then interpretation.

(Please, please, no, noboby feed this troll. Please.)

Um, isn’t there island dwarfism, too? Or was I just really high in class that day?

fnxtr said:

Um, isn’t there island dwarfism, too? Or was I just really high in class that day?

Of course there’s island dwarfism, though the only examples I can think of right now are dwarf elephants and pygmy giant elk of the Mediterranean.

Robert Byers said:

YECMoron here. While its not a big deal to see a fast result from these plants being selected because of prey it could rather be a example of something else. I find always that diversity is not from selection but rather a natural reaction in nature. so it might be a better idea that upon landing n these isles this plant immediately got powerful in variety and it was just a later immigration of creatures that eliminated the ground varieties. Not selection making bigger plants because of predation but simply the bigger ones survived. So this need not be a case of evolution at work but a case of errors in biological history. Diversity is the norm and a instant result from colonization. Later comes extinctions. There is just data and then interpretation.

There, I fixed that first sentence for you, Byers. Now everything you say makes sense in the context of stupid.

Stanton said:

fnxtr said:

Um, isn’t there island dwarfism, too? Or was I just really high in class that day?

Of course there’s island dwarfism, though the only examples I can think of right now are dwarf elephants and pygmy giant elk of the Mediterranean.

Also Homo floresiensis.

Hmmm. I’m wondering if there’s a tendency during the lifetime(?) of island species to gigantism at some point and dwarfism at some other point. Gigantism during the florescence of adaptive release and dwarfism later as resources are maxed out? Anyone read/written anything about this?

(Please don’t acknowledge the wacko, you’ll just get more and more idiocy. He’s proven to be unteachable.)

It makes sense to me (IANAS) that on an island where one or more elements, that would be present in a mainland environment, are missing, an island species may no longer be under the same predation pressure, or may be entirely free of it. Or they may face different competition, or maybe none. So if enlarged size serves them by enabling them to reach higher, or retain body heat longer, or beat the lizards to the goodies–and there’s no penalty to gigantism, like being seen easily by predators, then the bigger ones will have an advantage. And that’s all it takes.

Same for dwarfism: a different balance of competition and defense techniques could make smallness more advantageous.

Hey, I’ll bet that the SAME island environment could drive one species in both directions at the same time: there could be an advantageous niche for bigger critters, and one for smaller ones, but a DISadvantage for the original size. Thus the original species might be split into one giant and one diminutive species on the same island. Of course interbreeding would tend towards evening things out. Does anyone know of an example of one original species splitting like that into one giant and one dwarf in an isolated environment?

…or maybe two similar and related species, like, say, two chicken-sized species, one of which rapidly evolves to gigantism (swan-sized or larger), while the other goes the opposite direction (baby-duck-sized maybe). That might prevent the interbreeding that would tend to level out the extremes.

Are there any examples of anything like that in nature, or is my fevered imagination running away with me?

If there aren’t cases like that, then there should be, you know? Maybe on another planet, where earthlings are trying to colonize. They could be intelligent species! Hey, what an idea for a 3-D movie!

Just Bob said:

…or maybe two similar and related species, like, say, two chicken-sized species, one of which rapidly evolves to gigantism (swan-sized or larger), while the other goes the opposite direction (baby-duck-sized maybe). That might prevent the interbreeding that would tend to level out the extremes.

Are there any examples of anything like that in nature, or is my fevered imagination running away with me?

If there aren’t cases like that, then there should be, you know? Maybe on another planet, where earthlings are trying to colonize. They could be intelligent species! Hey, what an idea for a 3-D movie!

Northern White-tailed deer compared to Key deer.

http://floridakeystreasures.com/cre[…]res/keydeer/

http://en.wikipedia.org/wiki/White-tailed_deer

There is also the case of island dwarfism of large animals such as mammoths, elephants and hippos. They think that it is an adaptation to maintaining a viable sized population on limited resources of an island.

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This page contains a single entry by Matt Young published on February 15, 2010 12:00 PM.

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