[QUOTE=WhyNot]
Nah, it’s all hybrids and splicing onto rootstocks these days, innit? I’m sure the oranges we’re eating are all clones of the same two orange trees somewhere in South America. If you plant the seeds, you’ll get wildly different trees from them.
[/QUOTE]
Actually the most popular orange for direct consumption, the navel orange, is seedless and therefore sterile, and as WhyNot recalls, derived from two cuttings from a single tree. I think that you’ll find that most apple cultivars will only grow stunted trees if at all.
[QUOTE=Peter Morris]
Yeah, but orange farmers plant seeds from trees that produce the best oranges, and discard seeds from the less good ones, don’t they? A plant that produces the best oranges, (best from the human POV), gets its genes passed down to the next generation.
Isn’t that what evolution is all about?
[/QUOTE]
This is artificial selection, in which characteristics are consciously selected for human service or consumption rather than reproductive value. You can consider it part of the larger context of selection overall (especially if you subscribe to the notion of an extended phenotype) in the sense that in they’re now relying on humans to propagate the species. This is substantially different from natural selection, though.
[QUOTE=Peter Morris]
doesn’t it? Looking at the dictionary, it gives lots of definitions for design, most of them directly state some sort of intelligence
definitions include:
[ul]
[li]To plan and fashion artistically or skillfully.[/li]
[li]To form or conceive in the mind; [/li]
[li]To plan out in systematic, usually graphic form:[/li]
[li]To create or execute in an artistic or highly skilled manner.[/li][/ul]
and so on
[/QUOTE]
That dictionary definition missed the fairly common sense in which the word “design” is used in scientific and pop-scientific contexts. That sense does not imply intelligence, just as the corresponding sense of “selection” does not imply intelligence.
[QUOTE=Darwin’s Finch]
Not really. We breed them to eat, not to make seed-scattering more efficient (indeed, when was the last time you planted the seeds from an orange - or any other fruit - that you ate?). If anything, it’s a survival disadvantage (in the long term), as the juicier and more managable the fruit slices from a particular tree, the more likely that tree’s fruit is to be sold at market and consumed, and its seeds subsequently discarded. At least, until the seeds are bred out of the fruit entirely, at which point the plant’s survival becomes entirely dependent on humans.
Artificial selection has little to do with advantages to the organism, and everything to do with how that organism can be modified for our needs/wants.
[/QUOTE]
I would have said that, though these traits would be disadvantageous in many situations, still, in the particular environment these plants are in right now–the artificial environment designed to breed them for human use–these traits turn out to be advantageous. It’s nothing new that a trait can be advantageous in some environments and disadvantageous in others.
Here’s the WAG of someone who grew up with an orange tree in his yard. Some birds like to eat oranges. They land on the fruit, and punch through the skin with their beaks, drinking the juice and eating the meat of the fruit. So, I’ll suggest the possibility that the sections permit the greater part of the fruit to survive being penetrated by a bird beak: the membranes may operate to some degree to halt or slow down any subsequent rot or insects from getting to the rest of the segments, once the skin is breached in a particular spot.
[QUOTE=Grossbottom]
Here’s the WAG of someone who grew up with an orange tree in his yard. Some birds like to eat oranges. They land on the fruit, and punch through the skin with their beaks, drinking the juice and eating the meat of the fruit. So, I’ll suggest the possibility that the sections permit the greater part of the fruit to survive being penetrated by a bird beak: the membranes may operate to some degree to halt or slow down any subsequent rot or insects from getting to the rest of the segments, once the skin is breached in a particular spot.
[/QUOTE]
A *very *interesting theory! I know if my kid takes a bite out of an orange, rind and all (she’s not all that bright sometimes, but we love her anyway ), that segment will dry and harden, but the rest of the orange is unblemished, and edible the next day.
Do birds come back and re-attack an already breached orange in a new place?
[QUOTE=Peter Morris]
Relax, dude, I was just teasing you. Get a sense of humour, m’kay?
I’m sure you don’t *really *think that oranges were “designed.”
[/QUOTE]
This implies that your remark was, y’know, actually humorous. Given that it wasn’t exactly the height of wit, a winkie smilie, instead of a dubious one, would have been more effective in conveying your intention.
[QUOTE=Stranger on a Train]
Because you unconsciously used a metaphor which included the appearance of intentionality, even though it means no more than that anyone actually designed an orange to be conveniently segmented than that a photon ‘decides’ to go through one slot or another. . . In the case of speaking of the design of naturally evolved organisms, it should be understood that the design is the result of optimization for survival and reproduction between competing groups of organisms, not teleological organization.
[/QUOTE]
I wouldn’t say my use of the word “design” was unconscious. I meant it in the sense you define in your last sentence, which is routine enough among biologists to hardly be worth remarking on. But then, I’m in a working environment where that usage, rather than the telological one, pretty much goes without saying.
[QUOTE=yabob]
Especially considering that the banana as we know it is a cultivar, quite different from its wild ancestor. In particular, wild bananas have huge, inconvenient seeds in them, and are only marginally useful as a food item:
[/QUOTE]
Wow. That’s a wild banana? How did we get from tiny amounts of flesh to “ooh, maybe that’s good eatin’s?” Although now that I consider it, aren’t cultivated bananas kinda sterile and reproduced through cuttings these days? Or maybe I’m thinking about a different fruit.
Sometimes I seriously wonder about our precedessors – there are so many things that the average bear would consider icky when you spend more than five seconds thinking about it.
My wife–who generally knows about these kinds of things when she actually bothers to speak up about them–says that in an orange, each segment is actually a separate fruit. Like corn. Or a raspberry.
Doesn’t quite answer the question, but seems relevant, or at least interesting and related.
[QUOTE=Frylock]
My wife–who generally knows about these kinds of things when she actually bothers to speak up about them–says that in an orange, each segment is actually a separate fruit. Like corn. Or a raspberry.
Doesn’t quite answer the question, but seems relevant, or at least interesting and related.
-FrL-
[/QUOTE]
No, as I said before, this is quite definitely wrong. An orange is a single fruit, produced from a single fertilized flower. The segments represent the carpels of the original ovary;
[QUOTE=Colibri]
No, as I said before, this is quite definitely wrong. An orange is a single fruit, produced from a single fertilized flower. The segments represent the carpels of the original ovary;
[QUOTE=Mangetout]
He may still be nutty in plenty of ways, but it is worth noting that he has now conceded that the banana-fits-the-hand argument has no merit.
[/QUOTE]
[QUOTE=lizardling]
Wow. That’s a wild banana? How did we get from tiny amounts of flesh to “ooh, maybe that’s good eatin’s?” Although now that I consider it, aren’t cultivated bananas kinda sterile and reproduced through cuttings these days? Or maybe I’m thinking about a different fruit.
…
[/QUOTE]
You’re probably thinking about the right one. The seedless bananas you get in the grocery store are certainly sterile and reproduced through grafting. The wiki article on seedless fruit explains how seedless bananas come about:
You can imagine people finding the occasional seedless banana in the wild, and learning to maintain a supply of them by cultivating cuttings from it.
[QUOTE=Frylock]
I would have said that, though these traits would be disadvantageous in many situations, still, in the particular environment these plants are in right now–the artificial environment designed to breed them for human use–these traits turn out to be advantageous. It’s nothing new that a trait can be advantageous in some environments and disadvantageous in others.
But would I have been wrong to say this?
[/QUOTE]
Strictly speaking, yes. With respect to natural selection and the resulting adaptations, the idea is that individuals acting for their own benefit result in the the population’s geno-/phenotype shifting over time. Individuals who, in a given environment, have an “edge” over their conspecifics will get a bigger statistical piece of the genomic pie than their fellows not so endowed. The shifting of the population’s genome, then, is towards that of the advantage-possessing individuals.
On the other hand, one key thing to understand about about artificial selection is that it does not result in adaptations. The traits of a given individual are largely irrelevant in terms of how good or bad they are for that individual; humans are doing the selecting based on their own desires, and are actively guiding the species’ evolution. Humans decide which individuals reproduce and which do not.
Thus, we see that another key difference between the two methods of selection is that artifical selection is guided and directed by a conscious entity. “Intelligent design” does exist, to the extent that we humans perform it regularly. Natural selection, on the other hand, is unguided and undirected, driven by the myriad of environmental variables which exert their influence on an individual.
), that segment will dry and harden, but the rest of the orange is unblemished, and edible the next day.
