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Author Topic:   Genuine Puzzles In Biology?
Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 47 of 153 (585643)
10-08-2010 11:43 PM
Reply to: Message 1 by Dr Adequate
05-27-2010 12:05 PM


More Genuine Puzzles
Several issues in evolutionary biology have remained controversial for decades:

1) Why do most organisms grow old and die, while some (e.g., hydra) are immortal?

2) Why do so many organisms engage in sexual reproduction when asexual reproduction has the advantage of passing on ALL of one's genes to the next generation?

3) Is the individual the only important unit of selection, or does group selection play an important role in evolution?


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Replies to this message:
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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 49 of 153 (585669)
10-09-2010 5:16 AM
Reply to: Message 48 by crashfrog
10-09-2010 12:50 AM


Re: More Genuine Puzzles
Because asexual reproduction has the disadvantage of only passing on one's genes to the next generation.

Has the Amazon molly, a unisexual fish, found a way around this problem? See

http://www.biomedcentral.com/1471-2148/8/88

Perhaps we can learn something from this little fish. Because according to the article below, high mutation rates in asexually reproducing human mitochrondria could lead to our species' extinction.

http://archive.evolution.ws/...e-l/Loewe2006-MitoRatchet.pdf

Or perhaps our mitochrondria have already evolved a solution to the disadvantage of asexual reproduction.

Edited by Stephen Push, : Correct typo.

Edited by Stephen Push, : Replaced reference to abstract with reference to full article.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 51 of 153 (585927)
10-10-2010 3:30 PM
Reply to: Message 50 by Dr Adequate
10-10-2010 5:25 AM


Re: More Genuine Puzzles
So do these mutations even exist? No-one, to my knowledge, has actually shown this, or is in any position to do so. If they exist at all, there is the further question of how many of them there potentially are, which again has not been answered.

You do not believe that the accumulation of deleterious mutations is a disadvantage of asexual reproduction? What do you see as the advantages of sexual reproduction (other than the fact that it's fun :-) )?

Edited by Stephen Push, : Rephrased second question.

Edited by Stephen Push, : Added smiley.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 58 of 153 (586504)
10-13-2010 3:53 PM
Reply to: Message 56 by Dr Adequate
10-13-2010 1:40 PM


Free Will
Well, it's useful. In order to be able to plan ahead, we have to be able to say to ourselves: "What would happen if I do such-and-such a thing?"

Intuitively I agree with this account of the value of imagination. But as a scientific explanation it seems problematic because it presupposes the existence of free will, a property that appears to defy scientific analysis. Is there any way to establish that free will actually exists, not to mention how it could have evolved?

Edited by Stephen Push, : Corrected typo.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 60 of 153 (586525)
10-13-2010 5:38 PM
Reply to: Message 59 by Dr Adequate
10-13-2010 5:00 PM


Re: Free Will
Well, it's useful. In order to be able to plan ahead, we have to be able to say to ourselves: "What would happen if I do such-and-such a thing?"

By way of suggesting a practical value of imagination, you seem to be describing a conversation with yourself in which you choose from two or more options. That seems to suggest the exercise of free will. Unless this internal conversation is just an illusion without effect on the outcome. But if so, where is the practical value?
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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 63 of 153 (586563)
10-13-2010 9:09 PM
Reply to: Message 62 by Dr Adequate
10-13-2010 7:24 PM


Re: Free Will
And so, so long as I make superior non-choices with an imagination than without one, which I think is beyond doubt, then it is biologically advantageous to possess the faculty.

Well put. I see your point and agree. Thank you.
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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 64 of 153 (586564)
10-13-2010 9:09 PM
Reply to: Message 62 by Dr Adequate
10-13-2010 7:24 PM


Re: Free Will
And so, so long as I make superior non-choices with an imagination than without one, which I think is beyond doubt, then it is biologically advantageous to possess the faculty.

Well put. I see your point and agree. Thank you.
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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 69 of 153 (590175)
11-06-2010 2:00 PM
Reply to: Message 67 by Catholic Scientist
11-05-2010 5:09 PM


Animal Cognition & Consciousness
A study has shown that crows actually do not use autombiles as nutcrackers.

Nevertheless, this anecdote points to another set of Genuine Puzzles in Biology: animal cognition and consciousness.

Are animals conscious? What emotions do they feel? Do they have a theory of mind? Many interesting questions.

Edited by Stephen Push, : No reason given.

Edited by Stephen Push, : No reason given.


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Replies to this message:
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 Message 71 by nwr, posted 11-06-2010 3:09 PM Stephen Push has responded
 Message 73 by Dr Adequate, posted 11-07-2010 3:16 AM Stephen Push has responded
 Message 89 by Parasomnium, posted 11-18-2010 2:27 AM Stephen Push has responded

Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 72 of 153 (590244)
11-07-2010 2:12 AM
Reply to: Message 71 by nwr
11-06-2010 3:09 PM


Re: Animal Cognition & Consciousness
Thanks for the tip on links, nwr.
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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 74 of 153 (590248)
11-07-2010 3:24 AM
Reply to: Message 70 by Catholic Scientist
11-06-2010 2:54 PM


Re: Animal Cognition & Consciousness
Catholic Scientist writes:

How'd they show that?

Video shows that they do:

While we can't rule out the possibility that the particular crow in the video learned to use cars as nutcrackers, anecdotal evidence can be misleading. In the study, reasearchers did 231 paired observations of crows with and without cars approaching. The crows were no more likely to drop walnuts on the road if cars were approaching than if cars were not approaching.

Dude, crows are smart. Like way smart. Check out this one make a hook:

Yes, tool use in crows is well documented.

Well, they're not unconscious (unless they're sleeping).

A better word for what I think you're talking about would be sentient, no?

Definitions are part of the problem. Researchers in this field often have different definitions of what they mean by consciousness. We don't even understand consciousness in humans, so it's probably not possible at this stage to understand it in animals.

Even sentience is a problem. I can make a good case that mammals are sentient. But what about fish? Or crustaceans? There are serious researchers who claim all of these animals can feel pain. These claims seem plausible, but I don't see the objective tests.

When I was a kid, my friend's mom brought home their little white curly dog after it had just gotten totally shaved for the summer. I sware, that dog was embarrassed. I had never seen it hide and whine under the couch like, ever. Eventually it would come out, and then we'd point and laugh at it (it really was incredibly funny looking), and then it'd run and hide and whine some more.

Maybe your friend's dog was embarassed; or maybe it was reacting to your behavior. For example, many dog owners believe their dogs display a guilty look after misbehaving. But a study shows that the so-called "guilty look" is a reaction to the behavior of the owner when the owner believes the dog has misbehaved.

Animals? Only humans have theories.

"Theory of mind" refers to the ability to recognize that individuals other than oneself have beliefs and desires. Humans have this ability. Some researchers claim that some other species have this ability, too. But the interpretation of this research is ambiguous, since the observed behaviors may have other explanations, such as prior trial-and-error learning.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 75 of 153 (590249)
11-07-2010 3:37 AM
Reply to: Message 73 by Dr Adequate
11-07-2010 3:16 AM


Re: Animal Cognition & Consciousness
Dr Adequate writes:

These are all excellent questions which I shall answer the moment I figure out how to read the mind of a crow.

What about Gallup's mirror test? Don't you think that demonstrates self-awareness in chimpanzees, dolphins, and the other species that have passed the test?

Edited by Stephen Push, : No reason given.


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Replies to this message:
 Message 76 by Dr Adequate, posted 11-07-2010 4:45 AM Stephen Push has responded
 Message 77 by frako, posted 11-07-2010 5:07 AM Stephen Push has responded

Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 79 of 153 (590264)
11-07-2010 9:14 AM
Reply to: Message 76 by Dr Adequate
11-07-2010 4:45 AM


Re: Animal Cognition & Consciousness
Dr Adequate writes:

The same reason I suppose that you are conscious. I might be wrong.

Thanks. I'd hate to think I failed the Turing test.

Because of your answer, I conclude that you have a theory of mind. But I might be wrong, too.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 80 of 153 (590266)
11-07-2010 9:31 AM
Reply to: Message 77 by frako
11-07-2010 5:07 AM


Re: Animal Cognition & Consciousness
frako writes:

I think that test only demonstrates witch animals have the capacety to realise that the animal they see is only a reflection i doubt it has much to do whit self-awareness and more whit their cognitive functions that descypher their optical imput.

It demonstrates that the animal knows it is seeing a refection of itself. In chimpanzees, for instance, the chimp will touch its own forehead when it sees a dab of paint on the forehead in the reflection.


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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 81 of 153 (590267)
11-07-2010 9:45 AM
Reply to: Message 78 by ProtoTypical
11-07-2010 8:24 AM


Re: Ophiocordyceps
Dogmafood writes:

What is the prevailing theory about how this fungus evolved the characteristic of controlling it's hosts behaviour in such a specific manner?

From a blog called Neurophilosophy:

When the fungus is ready to sporulate, the mycelia grow into the antís brain. The fungus then produces chemicals which act on the hostís brain and alter its perception of pheromones. This causes the ant to climb a plant and, upon reaching the top, to clamp its mandibles around a leaf or leaf stem, thus securing it firmly to what will be its final resting place.

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Stephen Push
Member (Idle past 1271 days)
Posts: 140
From: Virginia, USA
Joined: 10-08-2010


Message 82 of 153 (590268)
11-07-2010 10:03 AM
Reply to: Message 78 by ProtoTypical
11-07-2010 8:24 AM


Amygdala & Fear
Dogmafood writes:

Another question is how does genetic memory or instinct occur? Why am I instinctively afraid of spiders and snakes and heights? I see how being afraid of dangerous things is helpful but how do my genes remember that from previous encounters in other generations?

Visual images of snakes and spiders stimulate a brain network centered on the amygdala, which in turn triggers the fear response. Conscious processing (e.g., you realize its a rubber snake, not a real snake) can halt this porcess.

Some fears are learned. But our brains appear to be hardwired to recognize images of snakes and spiders.


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