the case against evolution

[madscientist]

It's possible that mortality was selected for its advantages to local biological communities as a method of balancing population and resources, or that any immortal animals were sterile or were wiped out by externally caused extinction events.

BTW why was the debate with evol/creat focused on mortality? didnt read all of i but i dont get how these 2 should be interconnected.
And it could be true - that to establish a balance in environment, God made it so - if you are a believer, if no then by evolution but it was for this i think. But still tehre were many animals extinct, and immortal animals - what is taht?/ There was death even before first sin, wasnt there?

And does Bible support that some animlas were wiped before first man was on Earth? No evolution but does it support at least this? e.g. dinosaurs and so on. (Bible doesnt speaks of dinosaurs, has been mentioned earlier somewhere...)

[Fortigurn]

It's possible that mortality was selected for its advantages to local biological communities as a method of balancing population and resources, or that any immortal animals were sterile or were wiped out by externally caused extinction events.

BTW why was the debate with evol/creat focused on mortality? didnt read all of i but i dont get how these 2 should be interconnected.

I think the argument was made that evolution would not have selected mortality, since it kills the organism.

[BGoodForGoodSake]

The chemical processes involed in life require energy to sustain them.
Once the energy, and resource supply run out, the process ceases.
Death is a result of this.
Thus death is an expected outcome, given the physical laws of our universe.

In order for these processes to continue the system needs to be replicated.
Replication of physical systems will undoubtedly introduce error.
The study of the modifications caused by imperfect replication have resulted in the theory of evolution.

Thus evolution studies how chemical reactions, necessary for life, have managed to outlive their normal "lifespan"; through duplication/relocation of the chemical engines.

[madscientist]

I think the argument was made that evolution would not have selected mortality, since it kills the organism.

Ok but that doesnt make sense since death is caused by the laws of nature and is unavoidable - so it did not choose it. Or were you refering to death of e.g. octopuses wjere 1% survives only? Or to death in general?
Thats a hard question, but same are favored ovee others, and ageing is a process whoch cant be stopped.
Or it may have "chosen" death since it was so random that not all was good, and one of the things it did which worked was death. Just 1 random step in it.

The chemical processes involed in life require energy to sustain them.
Once the energy, and resource supply run out, the process ceases.
Death is a result of this.
Thus death is an expected outcome, given the physical laws of our universe.

In order for these processes to continue the system needs to be replicated.
Replication of physical systems will undoubtedly introduce error.
The study of the modifications caused by imperfect replication have resulted in the theory of evolution.

Thus evolution studies how chemical reactions, necessary for life, have managed to outlive their normal "lifespan"; through duplication/relocation of the chemical engines.

Exactly what i thouhght...
but just reproduction cant cause that much "error" that from a virus, human being is formed. some changes are applicable, some mutations beneficial but not all. And why it always get more complex - from simpelst to human? what would be in a few million yrs? superhumans??? this is 1 thing forcing me go creationsism is crazy: human from a virus or whatever was thre first? cud get there, but not porobably if God wouldnt be tehre and control the system.

[BGoodForGoodSake]

There is not a general trend towards complexity per say.

However as a system develops it may come across a modulated solution. And future developments may then come to depend on the underlying system.

For example take language. We can imagine the development of words first, which symbolized perhaps discrete concrete objects. Only once words have been developed could complex phrases have been built from them. Once this relationship is in place it is now imposible to remove the words on which these phrases are dependant. Thus complexity has built up.

A more concrete example is a multistory highrise apartment. It's design has been developed over the course of human history, starting with the humble mud and stone contructions of prehistoric times.
But let's forget for now the actual evolution of the engineering techniques of homes. And let us focus on complexities which are the result of building one of these structures.
We begin with the foundation and at this point we have some freedom in terms of dimentions and such of this building. As more stories and subsystems such and plumbing and electrical systems are added in the older structures are now restricted in terms of modification. In the final building the various parts and systems are so interdependent that modification to the building would now be a costly undertaking.

In biology a similar sort of development is thought to have occurred. At first single celled structures were restricted to come sort of substrate. Their environment formerly consisting of non-living material now included other living cells. Communication between cells must have developed at this point. And thus eventually allowed the single celled organisms to form simple multicellular structures. Once communication developed further specialization dependent on position within the colony could be possible. This specialization and cooperation of cells may well have allowed this organism to take advantage of new, previously inaccessible environments/ecological niches. Once in the new environment/ecological role the new organization of cells has become pivitol to survival. Communication between cells once a nifty improvement is now a vital aspect of life for this organism. Complexity has thus built up.

[zoegirl]

In my graduate seminar on evolution, the theory about evolution and death revolved around the idea that selection acts upon phenotypes that were present during the organisims most fertile time of life. For instance, if genes were inactive during the reproductive times of the organism then they were not under selective pressure, thus they were/are not eliminated from the population, even if they were ultimately detrimental to the organism. Thus, genes that were invovled in aging or that were active during the aging process could be kept within the population.

Any thoughts?

[BGoodForGoodSake]

In order to exist now the previous generation needs to replicate successfully.

There are of course multiple strategies to this end.

One of course is to create a large quantity of offspring.

However in some cases resources may be low and this strategy will be impossible for larger organisms which require more resources. In this case fewer offspring and more investment into protecting young may be more optimal.

However more investment of time could possibly open the door to longer gestation periods.

These species may have offspring who are more and more dependent on adult protection over time.

In this case lifespans should tend to increase as a longer life would mean more offspring make it to maturity.

In social species, relatives can help contribute to the successful maturation of offspring. Thus even infertile and post fertile individuals can contribute to the fitness of thier related offspring.

So there can be indirect contributions in which case, phenotypes expressed, even after breeding is no longer possible, will contribute to the gene pools fitness.
However these organisms may become dependent on this social structure. Social structure for these organisms is a real part of the environment in which they have evolved. Just as real as the local climate, food resources, predators etc.

However faster breeding populations tend to be more adaptive both in the short term and long term evolutionarily speaking. Variables such as dramatic climate change may favor more adaptive species.

Another factor which may work against longer lifespans may be that within a population the younger individuals may be more fit to breed thus, as you said in your post favoring earlier breeding and thus eliminating any advantage to a longer life. Think rats.

It might be a good idea to select a few species for case studies, and see how each strategy is effective and which traits are beneficial to successful reproduction in each case.
Galapagos tortoise(Geochelone nigra), southern blue ringed octopus(Hapalochlaena maculosa), gadflies(Tabanidae), african elephant (Loxodonta africana), american white oak (Quercus stellata), common rat(Rattus norvegicus) or mouse (Mus musculus).

[zoegirl]

those are good models ...the question seemed to be more along the lines of why evolution doesn't eliminate death/aging....I remember my professor using this idea to support why death exists

[madscientist]

In my graduate seminar on evolution, the theory about evolution and death revolved around the idea that selection acts upon phenotypes that were present during the organisims most fertile time of life. For instance, if genes were inactive during the reproductive times of the organism then they were not under selective pressure, thus they were/are not eliminated from the population, even if they were ultimately detrimental to the organism. Thus, genes that were invovled in aging or that were active during the aging process could be kept within the population.

What you mean - "acted upon phenotypes" - does it mean that genetic information could change from generation to generation? If yes, then that could explain the possible changes over humans, even, for example, why there is so much vatiation between different ethnic groups, in character, skin color, height, etc. Maybe i misunderstood it; very possible. But how do they act upon phenotypes? - no genotypes? - or did change in phenotypes then lead to change in genotypes in later generations?
For example, how do species adapt to new environement?

those are good models ...the question seemed to be more along the lines of why evolution doesn't eliminate death/aging....I remember my professor using this idea to support why death exists

Well probably it doesnt because it is unable to - or, because it doesnt happen as macrevolution... for those belieivng it doesnt happen. It either is impossible, or God selected it as a means of making sure species dont live forever.

Adam and Eve were to live eternally till they sinned. How would that only have happened? They lived about 900 yrs, then lifespan of humans started to decrease rapidly. Why? Who knows. May be that there was radiation, more mutations, etc causing it to happen (duno, its up to you and BGFGS as you are biologists )
or mabye death was a means of making sure new generations become fitter and better adapted to environment - the more genertaions, the faster it occurs (in my opinion at least...).

[zoegirl]

Acted upon phentotypes, meaning that those organisms with phenotypes that provide for the most reproduciton and survival will pass on more genes than those organisms with phenotypes that decrease reproduction and surival.

Although genes are what are passed on from generation to generation, it it those genes that are expressed during the reproductive years that are the most crucial. FOr instance, there are many genes that are turned off while the organism is at its highest reproductive activity, these are not being expressed, thus are not "seen" or, more accurately, not influencing the reproduction or survival of the organism.

Then suppose that those genes are turned on later in life. WHile they are expressed now and we can observe them, these phenotypes are not contributing to the reproductive succes of the organism if the organism is now reproducing less or not at all. Thus the idea is that those genes that are detrimental to us are never selected against because they are not active during our reproductive years.

The above is the model that was presented to me during my seminar class. As for a Biblical explanation for Adam and Eve, I have heard that it was the cumulative effects of sin that affected populations of humans. I have not really studied this to my heart's content and so cannot offer proper ideas.

[BGoodForGoodSake]

Phenotype means the actual trait.
Genotype is the particular gene varient.

For example blue eyes is a phenotype.
There is more than one combination of genes which lead to blue eyes.

Each combination of genes is a genotype.

[zoegirl]

oops, sorry!! forgot to provide definitions!!

[madscientist]

Phenotype means the actual trait.
Genotype is the particular gene varient.

For example blue eyes is a phenotype.
There is more than one combination of genes which lead to blue eyes.

Each combination of genes is a genotype.

Ya done that in bio some yrs ago... know some of it. Ok ya ohenotype is what is expressed; genotype is what is coded as gene. But when referring to the fact that phenotypes can change in reprodictive activity in some previous post, what u meant?

oops, sorry!! forgot to provide definitions!!

No prob, its just me koz im quite young here so dont know as much stuff as you other people...

[zoegirl]

Some of our phenotypes change as we develop and grow. FOr instance, when we are young, some people are born with blond hair and yet as they get older their hair color changes to brown. This is a result of gene interactions that change the amount of melanin produced in the hair. So our phenotype changes from blond hair to brown hair. Another example are the genes that seem to be responsible for turning cells cancerous. These genes are not, on average, turned on in younger people. But because of their silence, they are not under selection because they are not being expressed. Some models hold that this is why selection does not get rid of cancer. In our most reproductive state, the cancerous genes are not expressed and thus our phenotype (no cancer, but keep in mind our genotype still has cancerous genes, they are simply shut off) means that we are still passing down those genes to our children.

[madscientist]

Hm interesting zoegirl about the changing in phenotypes. OK, but how does it happen? only phenotype changes, but no genotype? or does genotype change as a result? how can ph change just like that? and doesnt this get passed to next generations? somehow...
cos what causes this change in our genes to produce different hair color for example?
nurture having an effect on nature??

BTW noithing wrong so far with all this; isnt it looking kinda pro-evolutionist??