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Author Topic:   Why do apples taste good?
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 8 of 41 (402831)
05-30-2007 9:08 AM
Reply to: Message 3 by dwise1
05-30-2007 1:13 AM


Tazmanian Devil writes:
No, really, this is a joke, right? You seriously can't think of a reason why some plants have evolved to have edible fruits?
Obviously he can.
dwise1 writes:
Similarly, this food-evolution cropping up again tells me that it must be in some creationist's writings somewhere.
If you are the only evolutionist in the world who hasn't seen Kirk Cameron's piece on "Bananas: The Atheist's Worst Nightmare", I suggest you have a look. This has achieved cult status amongst fans of pseudoscience.
On the other hand, your belicose assumption that taylor31 is a creationist is unreasonable. It's a fair question. I think this is another guy like ogon who's trying to fill in gaps in his knowledge; and if this is a result of creationists' attempts to manufacture controversy, then creationists have inadvertently done science a favor.
There's no reason to suppose that everyone asking questions about evolution is a creationist. They might just be, y'know, interested in the answer.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 10 of 41 (402849)
05-30-2007 10:34 AM
Reply to: Message 1 by taylor_31
05-29-2007 11:24 PM


I was wondering why so many different species - including apples, oranges, pickles, and pears - taste so good. Why would they evolve that way?
What survival benefit would "tastiness" bestow? I can think of some hypothetical explanations:
1) The species somehow benefited from an organism that was eating it, or
2) The species was simply trying to protect its seeds, and accidently evolved tastiness, or
3) The tastiness is a product of artificial selection over human history.
I think we can rule out option 2 --- clearly having tasty fruit makes it more likely that the seeds will be eaten.
Option 1 is correct. Animals eat fruit seeds and all, and then seeds get dispersed --- each with its own little dollop of fertiliser. This is why you get so many tomato plants growning along railway lines --- humans eat tomatos seeds and all.
Option 3 is also correct --- we have bred fruit systematically for flavor.
However, you should also consider option 4, which you haven't mentioned. Consider the fact that meat taste good to us; or that we like salt on our food. In the case of meat, the animal gains no benefit from being eaten, and salt, of course, cannot evolve.
What you have to remember is that "tasting good" is not an intrinsic property of a foodstuff --- it's an interaction between the food and the organism eating it. We evolved so that things which are nutritious taste good to us.
---
In the case of fruit, the process seems to have gone like this.
* Early plants produced single-cell offspring (there are still some plants which do this).
* Natural selection favored plants which endowed their offspring with a store of nutrition for early growth --- seeds, in other words.
* This meant that natural selection favored animals which found seeds tasty and ate them thus availing themselves of the nutrients in them. (Of course, some browsing animals would just eat the seeds anyway along with the whole plant.)
* This meant that natural selection favored plants which produced tougher seeds which were more likely to survive the passage through the gut of an animal.
* Seeds which did survive this process were dispersed, each with their own supply of animal fertiliser.
* This meant that there was then a selective advantage to these plants having their seeds eaten. The plants which produced the best-flavored, the most brightly colored, and the most nutritious seed cases (fruit) were favored over other plants and naturaly selected for.
* Finally, humans used artificial selection to produce plants with bigger and tastier fruit. We also, by an ironic twist, prefer seedless fruit which has to be propagated by vegetative cloning (e.g. the banana).

This message is a reply to:
 Message 1 by taylor_31, posted 05-29-2007 11:24 PM taylor_31 has replied

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 20 of 41 (402935)
05-30-2007 7:33 PM
Reply to: Message 19 by Neutralmind
05-30-2007 5:54 PM


So, is it likely, that in later human evolution we will evolve to like vegetables and "healthy" products more?
Not necessarily: because alternatively our metabolisms can evolve to adapt to our diet. Indeed, this has already happened: look at how much more lethal a Western diet is to Polynesians than to Europeans. Or consider the geographical distribution of lactose tolerance, or alcohol tolerance. Or think of the fact that Britain has rodents which have adapted to live off discarded hamburgers.
Edited by Dr Adequate, : No reason given.

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 Message 23 by taylor_31, posted 05-31-2007 2:39 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 26 of 41 (402999)
05-31-2007 10:39 AM
Reply to: Message 23 by taylor_31
05-31-2007 2:39 AM


I'm not sure I understand. You're saying that our metabolisms can adapt to our diet, but I thought Western diets were actually worse for our bodies than other cultures (*cough* McDonalds *cough*). Have our metabolisms sped up or something to compensate for the unhealthiness? Have they adapted for survival benefits?
Sorry, I'm having a mental block right now.
Perhaps I wasn't sufficiently clear. When I said that "our" metabolisms can adapt to our diet, I wasn't talking about individuals adapting to the Western diet, but about the European lineage evolving.
When Europeans pursued an unnaturally fatty diet, this tended to kill off those Europeans who were genetically less able to cope with animal fats. This gave a selective advantage to Europeans who could cope with such a diet, and so by natural selection Europeans are better able to tolerate such a diet than, for example, Polynesians. Polynesians have not gone through this evolutionary process, so the result is that if you feed 'em on a Western diet, they get obese and then die of heart disease.
This is not to say that a diet of burgers and chips is healthy --- but people of European stock are much better adapted to such a diet.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 35 of 41 (404013)
06-06-2007 10:21 AM
Reply to: Message 32 by herrmann
06-04-2007 4:36 PM


Also, natural selection would allow for less tasty apples (mainly Granny Smith) to spread less far because they taste horrible.
Granny Smiths are the result of a chance hybridization in Australia in the 19th century, and they were cultivated because some of us like the taste, thank you so much.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 37 of 41 (406965)
06-23-2007 3:44 AM
Reply to: Message 36 by BattleAxeDime
06-23-2007 12:57 AM


Re: sloths a joke?
Giant ground sloths got about more than their arboreal cousins, and are only recently extinct --- within the last few thousand years. Being toxic to birds is presumably still useful, though being non-toxic to sloths isn't any more. So the hypothesis has some plausibility.

This message is a reply to:
 Message 36 by BattleAxeDime, posted 06-23-2007 12:57 AM BattleAxeDime has replied

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