Re: Rupture aortic aneurysm

Andrew B. Chung, MD/PhD schrieb: 
Thorsten Schier wrote:

Andrew B. Chung, MD/PhD schrieb:

Jeff wrote:


"Andrew B. Chung, MD/PhD" <andrew@xxxxxxxxxxxxxx> wrote in message
news:425EF094.8647BF66@xxxxxxxxxxxxxxxxx


Jeff wrote:


"Andrew B. Chung, MD/PhD" <andrew@xxxxxxxxxxxxxx> wrote in message
news:425EA876.68EF4951@xxxxxxxxxxxxxxxxx


[...]

Your arguement is like saying that jaguars couldn't have  developed
speed
through evolution because the slower jaguars would died because they
couldn't catch food or would have been killed by other animals.


No.  Natural selection (survival of the fittest) can explain how
jaguars
have become fast creatures.  Where natural selection fails is when it
tries to explain the existence of slow and seemingly stupid creatures.

Examples, please. 

(1) Slugs


1: Slugs don't hunt. So they don't have to be fast in order to get their
prey. They don't have to be very intelligent either, because it does not
require much brain to find the nearest eadible plant in comparison to
hunt other animals.

2: They don't taste very well


And how do you know this? 

This is common knowledge among biologists.

And how does its predators know this **before** killing it? 

Jeff has already answered this.


and therefore don't have many enemies,
meaning they don't have to be fast in order to escape them.



However, being fast would still confer a survival advantage.  Why has
this selection not taken place ?


As Jeff has already explained, being fast has a price. If there is no
significant advantage of being faster, the costs are easily higher than
the benefit and there is selection _against_ getting any faster.

In the case of slugs it should be noted that there are certain
constraints imposed by there morphology. To make them considerably
faster would require extensive rearrangement of their morphology. And
such massive changes don't happen very often.


3: They have a slow metabolism and therefore don't need much food. This
is an advantage of being slow. Their brain does not need much food
either. An advantage of lacking a large brain.



There really is no survival advantage to being either slow or "stupid."
Why has this not been selected against?


See above. Fastness and intelligence have their price.

Btw, different animals have different stategies of survival. Some are
fast to run away from their enemies, some hide from their enemies, some
don't taste good. The best stategy depends on what the animal is already
able to do (evolution is unlikely to massively transform animals if a
small change in a different direction will do as well) and the habitat
of the animal. For example it is easier to hide in the jungle than in
the savannah. So sloths can survive in the jungle by hiding from their
enemies while antelopes in the savannah have to run away from them.

(2) Sloths


1: They don't hunt.

2: They probably don't have many enemies that are able to follow them in
the height of the trees.


They are sometimes also on the ground.

That's why they shouldn't draw unnecessary attention to themselves by undue speed.


3: The slowness of their movements serves as camouflage, so such enemies
as might hunt them don't see them too often.



You are thinking of the chameleon.  The sloth's slow movements is not
camouflage.  Having speed would still confer a survival advantage.
Why has there not been selection for this speed ?


I'm not thinking of the chameleon, but camouflage is probably not the right word for what I meant. What I mean is that the slow speed helps the sloths to hide themselves. If they were a bit faster they would still be slower then their enemies but draw more attention to themselves. So there is probably a strong selection _against_ them getting any faster.


(3) Manatees 

1: They don't hunt.

2: They probably don't have many enemies due to their habitat and size,
except mankind, of course.



Speed would still confer a survival advantage.  Why has there not been
selected for this?


Like what survival advantage? How would this help the manatees?


3: Why do you think that manatees (and sloths) are stupid? They might be
more intelligent than you think. Of course not as intelligent as
chimpanzees or dolphins, but then again, there is no need for them to be
so intelligent.



Intelligence would still confer a survival advantage.  Why has there not
been selection for this?

Because a large brain is expensive. Usually animals are particularly intelligent if they are either carnivores or have a complicated social life like many primates. For a manatee being as intelligent as a dolphin would be a waist of resources.


Yes ?

And your explanation is ?

I'm not Jeff, but I hope you are satisfied with my explantion.


No. Nor should you be.

Well, I am. A specialist for these animals could probably give you even better or more elaborate explanations. So you see, if a non-specialist can come up with plausible explanations effortlessly, there does not seem to be any problem for the theory of natural selection at all.


[...]


Folks can witness the effect of gravity, firsthand.

No one has witnessed the evolution of a new species, firsthand. 

Many races of dogs are so different from each other that they would be
different species if they lived in free populations in the nature.


"Man selection" is not "natural selection."

It is really quite similar. In both cases the fittest survive. The only difference is that with "man selection", man is able to specify the conditions for survival and that is a lot faster, because man is able to put a greater selection pressure on the animal than is usually found in the nature.


You can say the same thing about gravity. 


Not really.



Where there is no life, there can be no "natural 

selection" which is the process by which living creatures are killed
off
to **select** those with traits that promote survival.


So what? where there is no life, there is no life.

Evolution requires life.

The theory of evolution actually requires death of the unfit. 

That is the theory of natural selection. Natural selection is one
mechanism
of evolution. There are more, of course.

Natural selection is at the heart of the theory of evolution. 

No it isn't. It is certainly a very important part of it.


Natural selection is at the heart of the current theory of how evolution
works (the synthetic theory).



Correct.


That does mean that other theories of this
are impossible and in fact many other theories have been proposed.


This underscores the problems with the **current** theory of evolution. 

No. Why should it?


You should not confuse obervable facts like evolution or the movements
of planets


In truth, the former has **not** been observed firsthand by anyone. 

Yes, it has. You only have to open your eyes.

with the theories with which scientists explain these facts
(the synthetic theorie with natural selection as most important part for
the evolution and gravity for the movements of planets).


Theories are neither facts nor observable phenomena.

Which is why evolution shouldn't be regarded as a theory, as it is an observable phenomenon.

Without natural selection, the theory of evolution would be dead. 

No it would not. Things can evolve without natural selection, like genetic
drift.



Genetic drift would not explain the creation of new species.


Not alone, but it is often a part in the creation of new species.


Only as passive substrate.


[...]


Truth is simple.

Only to the simple-minded. 


Actually, to the simple-minded without God's gift of truth discernment,
the truth does seem to be unfathomably complicated.


Reality _is_ complicated. But of course there are always those who prefer to avoid reality.

Regards,

Thorsten

--
"Nothing in biology makes sense, except in the light of evolution"

(Theodosius Dobzhansky)
.

Relevant Pages

  • Re: Rupture aortic aneurysm
    ... couldn't catch food or would have been killed by other animals. ... No. Natural selection can explain how ... "Slugs, when attacked, can contract their body, making themselves harder and more compact and thus more difficult for many animals to get a hold. ... direction that evolution will probably take. ...
    (sci.med.cardiology)
  • Re: Rupture aortic aneurysm
    ... Where natural selection fails is when it tries to explain the existence of slow and seemingly stupid creatures. ... They don't have to be very intelligent either, because it does not require much brain to find the nearest eadible plant in comparison to hunt other animals. ... for eating slugs. ... According to the theory of evolution, ...
    (sci.med.cardiology)
  • Re: Rupture aortic aneurysm
    ... speed through evolution because the slower jaguars would died because they couldn't catch food or would have been killed by other animals. ... Where natural selection fails is when it tries to explain the existence of slow and seemingly stupid creatures. ... They don't have to be very intelligent either, because it does not require much brain to find the nearest eadible plant in comparison to hunt other animals. ... "Many things eat slugs. ...
    (sci.med.cardiology)
  • Re: Rupture aortic aneurysm
    ... being fast would still confer a survival advantage. ... > the benefit and there is selection _against_ getting any faster. ... According to the theory of evolution, ... >>>different species if they lived in free populations in the nature. ...
    (sci.med.cardiology)
  • Re: Seanpit, ID and complexity
    ... random mutation and I assume natural selection. ... think (using empirical evidence to support your position) each of them ... I, in fact, did define evolution: ... Even Paley recognized variation within a species. ...
    (talk.origins)
Loading