Self-Defence Mechanisms in Nature.


#1

If there is no goal-direction in nature, then how do Naturalists explain the existence of self-defence mechanisms in biological organisms?

I don't know how to look at this fact as being anything but evidence of goal direction in the evolution of organisms.

On a side note, I am not an advocate of the idea that there can be "empirical evidence" of goal direction in nature, since the empirical method cannot measure goal direction; but I am saying that we do observe goal direction in biological processes.


#2

[quote="ReapReason, post:1, topic:289809"]
If there is no goal-direction in nature, then how do Naturalists explain the existence of self-defence mechanisms in biological organisms?

[/quote]

Natural selection. Organisms with a better self-defence mechanism tend, on average, to have more descendants that those without. If the self defence mechanism is genetic, then those offspring will carry extra copies to pass on to their descendants in turn.

For example, in malarial areas of West Africa, people with the HbC mutation (beta6Glu --> Lys) are better defended against malaria, so that mutation is spreading. See Haemoglobin C protects against clinical Plasmodium falciparum malaria.

I don't know how to look at this fact as being anything but evidence of goal direction in the evolution of organisms.

It is merely, "survival of the better self-defended", to coin a phrase. Evolutionary mechanisms can give the appearance of design. Random mutations try out all sorts of possible variants. Natural selection differentially amplifies those variants which are successful, such as HbC in the presence of malaria.

On a side note, I am not an advocate of the idea that there can be "empirical evidence" of goal direction in nature, since the empirical method cannot measure goal direction; but I am saying that we do observe goal direction in biological processes.

The general goal direction in evolution is "have lots of grandchildren", in effect have lots of children that are themselves successful reproducers.

rossum


#3

[quote="rossum, post:2, topic:289809"]
Natural selection. Organisms with a better self-defence mechanism tend, on average, to have more descendants that those without. If the self defence mechanism is genetic, then those offspring will carry extra copies to pass on to their descendants in turn.

For example, in malarial areas of West Africa, people with the HbC mutation (beta6Glu --> Lys) are better defended against malaria, so that mutation is spreading. See Haemoglobin C protects against clinical Plasmodium falciparum malaria.

It is merely, "survival of the better self-defended", to coin a phrase. Evolutionary mechanisms can give the appearance of design. Random mutations try out all sorts of possible variants. Natural selection differentially amplifies those variants which are successful, such as HbC in the presence of malaria.

The general goal direction in evolution is "have lots of grandchildren", in effect have lots of children that are themselves successful reproducers.

rossum

[/quote]

Natural selection is about genetic preservation. It explains only that a feature is preserved due to its effectiveness. It doesn't in and of itself explain the existence of self-defence mechanisms in nature. The point is, something exists in nature that acts specifically for the preservation of an organism. That is goal-direction.


#4

[quote="ReapReason, post:3, topic:289809"]
It doesn't in and of itself **explain **the existence of self-defence mechanisms in nature.

[/quote]

Pure accident - that gave it an advantage and allowed it to survive/compete/defend.

Sarah x :)


#5

[quote="atheistgirl, post:4, topic:289809"]
Pure accident - that gave it an advantage and allowed it to survive/compete/defend.

Sarah x :)

[/quote]

There have been aproximately 1000000+ pure accidents.


#6

[quote="atheistgirl, post:4, topic:289809"]
Pure accident - that gave it an advantage and allowed it to survive/compete/defend.

Sarah x :)

[/quote]

What does that mean in the context of biological organisms? How does that work?


#7

[quote="ReapReason, post:6, topic:289809"]
What does that mean in the context of biological organisms? How does that work?

[/quote]

There is no such thing as pure accident at molecular genetic level or polypeptide level. Despite the infinite degree of freedom or permutation the base pairs are arranged or protein folding, certain alleles or configuration do arise quite counter-intuitive of our observation and understanding of thermodynamics. Even so, certain mutations do not change the expression of protein nor change the phenotype at all. If pure accident is so powerful a force in creating new alleles, protein engineers would not be having such a hard time designing and producing new antibodies to cure cancer.

I can't commend on larger animals though. I do not study much about animal behavior with respect to their habitat. :o

But to say things happen by pure accident is as uninformed as saying God created the universe in seven solar days. But I recognize that it is a creed that a population of people have faith in it so I respect that.


#8

Most organisms have innate DNA repair mechanisms, some repair mechanisms are fascinatingly complex. When DNA repair mechanisms fail, people have cancer.

Our immune response is also an interesting type of somatic hypermutation that produces a large variants of antibody which have very targeted defense against specific type of invasion of bacteria or virus.

I supposed that can be considered a kind of evolution at cellular level. Too bad this type of evolved defense mechanism does not get pass down to the progeny. If not, we will see super breed of human beings who never get sick because its immune system has evolved to such an extent that nothing can harm him.

We have yet to see nature produces super human breed like that after years of evolution. In fact, human seems to get weaker, which explains why the healthcare budget swells.

:)


#9

[quote="johnnyjones, post:5, topic:289809"]
There have been aproximately 1000000+ pure accidents.

[/quote]

Oh at least.

[quote="ReapReason, post:6, topic:289809"]
What does that mean in the context of biological organisms? How does that work?

[/quote]

In copying and reproducing itself, genetic information gets messed about, new bit of information is accidently acquired, which just happens, purely by accident, to now convey some kind of purely accidental advantage, and from this point on, it's now positively selected for, as those with this little bit of messed up genetic variation, which in this case allows the organism to defend itself against some threat or other, survive better.

Just my ''uniformed'' opinion and understanding of course.

Sarah x :)


#10

Did you read my example? There was single amino acid change in the beta haemoglobin chain. A single change. Are you trying to tell me that a single random mutation cannot happen?

There are seven billion people on this planet. Every one of them has about 150 mutations when compared to their parents’ DNA. That is 1,050,000,000,000 mutations every generation. With about 3 billion base pairs in the human genome, that is an average of 350 mutations at each base pair in the human genome every generation. The HbC mutation is going to pop up all over the place every generation. In non-malarial areas it has not advantage and will probably just disappear. In malarial areas it has a distinct advantage and will spread.

Remember that we are talking about populations, so we can get a lot of trials in each generation. Only one trial has to succeed for a new mutation to start spreading through the population.

Defence mechanisms are no different to other mechanisms. Things that give an advantage, whether defensively or offensively will tend to spread through the population over the generations…

rossum


#11

[quote="johnnyjones, post:5, topic:289809"]
There have been aproximately 1000000+ pure accidents.

[/quote]

Every human being has about 150 "pure accidents" in their genome. Every human being is the descendant of billions of generations of ancestors, every one of whom succeeded in reproducing. Not one of you ancestors for all those billions of generations failed to reproduce. Any one of those ancestors with a lucky accident reproduced. Any one with an unlucky accident very probably didn't and so was removed from your ancestry.

Once you spread those accidents out over the number of generations and the size of the populations involved then it is not as unlikely as it seems at first.

rossum


#12

[quote="rossum, post:11, topic:289809"]
Every human being has about 150 "pure accidents" in their genome. Every human being is the descendant of billions of generations of ancestors, every one of whom succeeded in reproducing. Not one of you ancestors for all those billions of generations failed to reproduce. Any one of those ancestors with a lucky accident reproduced. Any one with an unlucky accident very probably didn't and so was removed from your ancestry.

Once you spread those accidents out over the number of generations and the size of the populations involved then it is not as unlikely as it seems at first.

rossum

[/quote]

Are you saying pregnancy occurs by accident? All the people before us exist due to an accident? There is no purpose behind the creation of a human?


#13

[quote="atheistgirl, post:9, topic:289809"]
Oh at least.

Sarah x :)

[/quote]

Kind of a tough way to justify existence, one big accident. I suscribe to purpose.


#14

[quote="rossum, post:2, topic:289809"]
Natural selection. Organisms with a better self-defence mechanism tend, on average, to have more descendants that those without. If the self defence mechanism is genetic, then those offspring will carry extra copies to pass on to their descendants in turn.

For example, in malarial areas of West Africa, people with the HbC mutation (beta6Glu --> Lys) are better defended against malaria, so that mutation is spreading. See Haemoglobin C protects against clinical Plasmodium falciparum malaria.

It is merely, "survival of the better self-defended", to coin a phrase. Evolutionary mechanisms can give the appearance of design. Random mutations try out all sorts of possible variants. Natural selection differentially amplifies those variants which are successful, such as HbC in the presence of malaria.

The general goal direction in evolution is "have lots of grandchildren", in effect have lots of children that are themselves successful reproducers.

[/quote]

  1. To believe in purposeful spiritual development yet at the same time attribute all physical development to purposeless events is incoherent.

  2. The "two-disparate-worlds" hypothesis is comical as well as uneconomical.

  3. The materialist's world is comical in its purposeful rejection of purpose but it is **relatively **economical in its reduction of everything to purposeless events!


#15

I am talking about random mutations. And also our ancestry goes back a long way before pregnancy evolved. Bacteria do not get pregnant.

rossum


#16

You say a random mutation is the physical medium through which emergent properties are formed. These properties are then selected. I am not arguing against this fact. However, this does not change the fact that there are emergent properties in existence that act and function specifically for the end goal of biological survival. Self defence is one demonstration of that fact. In other-words while its emergence is random, the natural end of its activity is not. We are dealing with information that is intrinsically teleological, regardless of the fact that a random mutation is at the root of its activity. Something may occur randomly, but this fact has no relevance to whether or not its activity serves an objective purpose. We are not just dealing with meaningless interactions of particles. It is evident that there is objectively meaningful information involved in biological processes which only makes sense in terms of goal-driven activity.

Randomness is not a refutation of purpose.


#17

I have a big problem with “purpose”. What is the purpose of a hammer? Is it to drive in nails? Is it to keep my paperwork from blowing away? Is it to kill someone? Is it to use as a plumb-bob?

I can use the same hammer for many different purposes. The purpose of the hammer is not fixed. I can assign different purposes to the same hammer at different times. Other people can assign yet more purposes to the same hammer.

Purpose is not intrinsic, it is extrinsic, and is assigned by something external. Is the purpose of humans to open tins of cat-food? A pet cat might see us that way. Does that purpose justify belief in the existence of Her Theofelinity?

Purpose is temporary, changeable and dependent on external conditions. To reify it into some over-arching, capitalised, “Purpose”, it to make a mistake. It is certainly not the kind of thing to hang a justification for God on – it cannot bear the weight.

rossum


#18

This is a flawed comparison.

A hammer is very different from a mechanism or a piece of information that functions to a particular end or produces a particular result that is specific to the survival of biological organisms. The fact is, biological organisms over time, whether random or otherwise, produce qualities or features that conveniently express its instinct to survive and procreate. Randomness and selection does nothing to help us understand why so much of what an organism is can only be understood and described in reference to its natural end which is biological survival; for example the heart can only be understood as that which pumps blood around the organism in-order to sustain the organisms functionality. These things cannot be understood purely in reference to themselves, but rather we understand them in terms of their activity, and their activity is clearly goal directed toward the survival of organisms. The development of organism, despite trial and error, is clearly teleological in nature.

The parts of an organism can only be understood in-respect of what an organism is holistically; and in that respect we see the purpose of its parts.


#19

The survival of biological organisms is not a “purpose”, it is a cause. Biological organisms that failed to survive are no longer around, Trilobites for example. Biological organisms that have succeeded in surviving are still with us, sharks for example.

Survival is not a “purpose”, it is a cause. It is the reason those organisms still survive today.

The fact is, biological organisms over time, whether random or otherwise, produce qualities or features that conveniently express its instinct to survive and procreate.

Any random that increases the number of offspring will increase in the population. The process is a bit like compound interest. As an example, take a stable population; on average each organism has one descendant in the next generation. Now let a beneficial mutation appear with a 1% advantage, so the mutated organism will have on average 1.01 descendants in the next generation. See what happens if we let the population reproduce for one thousand generations:



Generation  Normal   Mutant
----------  ------   --------
     0       1.00        1.00
     1       1.00        1.01
    10       1.00        1.10
   100       1.00        2.70
   500       1.00      144.77
   700       1.00     1059.16
  1000       1.00    20959.16

You can see how the small 1% advantage is amplified over the generations as the mutant variant spreads through the population.

This is a very simple model, but it is enough to show the advantage a beneficial mutation has and how it can spread through a population. This is simple mathematics spreading an advantageous mutation. There is no more complex mechanism needed. If you have more offspring, on average, then, on average, you will have more copies of your genes in the next generation.

rossum


#20

[quote="johnnyjones, post:13, topic:289809"]
Kind of a tough way to justify existence, one big accident. I suscribe to purpose.

[/quote]

I don't find it tough at all.

Life is just one big accident from my point of view.

That's what makes it so precious and special and valuable, when you think there is no good reason at all why we should be here.

Gould said it very well, when he said if we rewound the tape of life and let it play again, there is absolutely no reason what so ever to think we would be an outcome the second time around.

The fact we're here is just one big accident to me, and I relish and treasure and savor every minute of life, for that very reason.

It so easily could have been a very different story.

Sarah x :)


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