Tags
Biology, Central nervous system, evolution, Human, Human evolution, Organism, Peripheral nervous system
Two questions for those who believe in human evolution.
1a] Peripheral nerves can regenerate but nerves of the central nervous system can not regenerate themselves.
1b] We descended from single-cell organisms that have only central nervous systems.
1c] How can the central nervous system of a single-cell organism evolve into the central nervous system of a homo-sapien if the nerves of the central nervous system can not regenerate?
2] If the bones of the homo-sapien have grown from the size of a single cell organism into a five to six foot tall organism, wouldn’t the homo-sapien continue to still be evolving into something bigger and taller? Why has the homo-sapien apparently stopped growing eight million years ago, at five to six feet tall?
.
.
.
robin claire
.
.
.
We wouldn’t grow into something bigger and taller unless there was a need. Evolution is about paring down useless traits and genes in favor of the ones more suitable to adapting to our environment and obtaining resources. If the majority of our species has access to the resources we need without impediment, we don’t need to evolve in that sense. We may need to evolve to adapt to our changing climate and environment, and perhaps we will not do it quickly enough for our species to sustain ourselves. But evolution was never a random ball of clay rolling around in a field just collecting sediment to make it grow bigger and bigger. It’s about resources and climate.
So what you do you think about the central nervous system not being repairable? I’d be interested in finding our your thoughts on that.
I’m not a biologist or neurobiologist, so I don’t feel equipped to answer. It might not be a necessary part of evolution. We also don’t have eyes on the back of our heads, though that could be useful at times. I also don’t know for certain that point 1b is factually accurate. We also share what is it? 74% DNA with bananas, but we don’t have peels on us, and that’s ok. I just don’t think that an inability to understand something scientific, or a lack of education or knowledge about is means that religion is a viable replacement. Somebody knows, and it might not be you or I, but that doesn’t mean that information or knowledge isn’t out there.
ok
About 1b’
But if we “evolved” from something, where else would our origins come from if not a single cell organism. And wouldn’t that organism only have 1 nerve in it? You say; “I don’t know but that doesn’t mean the information or knowledge isn’t out there”. Isn’t that the same answer that those who believe there is a creator give? “We don’t know, but that doesn’t mean the information or knowledge isn’t out there.” ?
No, it means I know that this is something that is known but I don’t know how to explain it. Like, I know your understanding of evolution is way off and it’s spurring me to study up on it so I can help you with it, but this is already known and demonstrable. I don’t know how to do physics, but that doesn’t mean other people don’t, is what I’m saying. The knowledge and information are out there, known and existent, I just don’t have the particular skill set to engage effectively.
Dear Sara,
Are you suggesting I may have evolved from a banana?
What shall I tell the children? The bible says I was made from dirt.
Is it possible then to be dirty and fruity? 😉
I’m not sure that you highlight anything about the nervous system that could limit the variation between a parent and its offspring.
Ignoring the fact that humans have continued to get taller until about 80 years ago (and that is a diet and technology based change, not a genetic one), what evolutionary pressure (i.e. rates of survival or ability to have children) do you think should continue to make humans taller?
I think you’ve looked at patterns and trends within biology but skipped over the mechanism by which they occur.
If humans used to be the size of chimpanzees why would they keep getting taller than that? Of what value is our evolving into becoming taller than that serve?
Long legs aids running speed. Early primates grew taller to see over savannah grass. Being taller is useful is sexual selection (i.e. attraction). Longer limbs aid dexterity and tool use.
The genes code for a height taller than the height of the individual in order to compensate for environmental pressures (like diet or over exercise compounding joints).
To grow much taller than we currently are will put a lot of stress on our hearts and spines (e.g. people over 7 feet tall). So the benefit of being taller is out weighed by the costs.
okay dokey
From the Top!
1a] Peripheral nerves can regenerate but nerves of the central nervous system can not regenerate themselves.
True, kind of. The process of CNS (Central Nervous System) regeneration is simply a destruction of old nerves, and a replacement with new nerves. It’s a process called Neurogenesis.
1b] We descended from single-cell organisms that have only central nervous systems.
Single celled organisms are only one cell. A nerve is only one cell. The single celled organisms from which we evolved were not nerve cells, hence, Single Celled organisms did not have a CNS. They did, and still do, have a Nucleus, which is the closest parallel of a brain.
1c] How can the central nervous system of a single-cell organism evolve into the central nervous system of a homo-sapien if the nerves of the central nervous system can not regenerate?
As I explained in the last part, it didn’t. Nerves did not develop until our first animal (fish) ancestors. If you’re interested in the devlopment and the evolution of the Nervous System, I suggest going with this, http://en.wikipedia.org/wiki/Evolution_of_nervous_systems.
2] If the bones of the homo-sapien have grown from the size of a single cell organism into a five to six foot tall organism, wouldn’t the homo-sapien continue to still be evolving into something bigger and taller? Why has the homo-sapien apparently stopped growing eight million years ago, at five to six feet tall?
It shouldn’t necessarily keep getting taller. Evolution works through mistakes in the genetic code. Sometimes, the code makes the organism taller. Sometimes, it makes the organism shorter.
Bigger is not always better. A giant organism means a very large amount of food. That isn’t a good thing when food is scarce. It also isn’t so great when you live in a tree, like our ancestors did.
But yes, there were indeed humans who were really tall and big. They often fell out of trees when the branches broke under their feet. Because they were dead, they didn’t have children. Because they didn’t have children, they didn’t pass on their genetic code.
But why would the genetic code make you big and tall if it wasn’t a good thing in that environment? Because the genetic code doesn’t care. It isn’t a being, molding us into humans. It’s just mistakes in the genetic code that changes things about us.
Most of the time, the genetic change is doesn’t matter. For example: we will be born with a different eye color than our parents for example. That person has an average chance at passing on their genetic code.
Many times, the genetic change is harmful. For example: we will be born with only one leg. That person will have a really slim chance at surviving long enough to find a mate, and pass on their genetic code.
A few times, the genetic change is good. For example, It will give us stronger muscles. A person with stronger musles would have a much much greater chance at surviving long enough to find a mate, and pass on their genetic code to their child, who will also have the stronger muscles.
So, as time passes, we will get an average amount of people with a different eye color, very very few people who are born with one leg, and many many people who have stronger muscles.
This happens continuously. The better suited to the environment keeps passing on their benefits. Those benefits stack on top of one another. Over generations, we get better and better suited to the environment.
And that, is why we stopped growing. The tall people started dying off before they could reproduce.
Side note: It was about 10,000 years ago that we evolved into homo sapiens, not 8 million. And we never stopped evolving. That’s why a ton of people are being born without appendixes now.
As far as my own personal research has come up with – it was 8 million years. It seems that you do fully believe in human evolution as being “the fittest survive”. This makes sense. Now-a-days however, with so many of the more vulnerable people having so many babies, it doesn’t seem like “the fittest survive” any more. It looks like our “human evolution” is going backwards.
I don’t know where your research is coming from, but modern homo sapiens that we are certain that are part of our species (as in, we could have children with them), would have been alive about 10,000 years ago. The ones who we think are part of our species would have been alive about 50,000 years ago. Homo sapien is normally how I personally define “Human.”
However, many others define it as belonging to the “Homo” genus. The first members of the Homo genus (Homo habilius) lived roughly 2 million years ago.
What did happen 8 million years ago is a divergance from dryopithecines into two distinct groups. One group (I’ll only use animals still alive today for the sake of simplicity) gave birth to what would eventually become the gorillas, the other gave birth to what would become humans, chimpanzees, and bonobos.
Anyways, enough anthropology from me; I’m can feel the boredom oozing through the screen.
True, I do not believe that evolution is “the fittest survive.” It never has been. It has always been “The fit survive.”
If both you and I can outrun the bear, it doesn’t matter which of us is faster, at least, until the bear gets faster o.o
It is also true that culture and society slows down biological evolution. That is a good thing. I don’t want to live in a place where the weak are allowed to die. However, it doesn’t stop evolution; it can’t.
A child born with Cystic Fibrosis will probably not live long enough to pass it on to his child.
I’m not sure what you mean by “more vulnerable” people.
It is true that poor people do have more children than richer people. I’m not sure if that is what you mean, but I assume it is; please tell me if I have assumed too much.
And while it is the case that poor people are having more children, that has been the case since “poor” existed. Kings have always had less children than commoners (if for no other reason than there being 1 king for every few thousand people).
Even King Solomon, with his multiple wives and children, had far fewer children in total compared to his people’s children.
The fact that the poor reproduce more than the rich does not impede society all that much. Kingdoms have risen and fallen all too often for it to make a significant impact on the gene pool.
And it can’t “go backwards” unless the environment changed to make being stupider a desirable trait. I can’t think of an environment that requires being stupid. Hence, we can’t go backwards.
And it is true that we are still evolving, but most of our adaptions are cultural, not biological. Soap, for example, was a cultural adaption. Now, we don’t die of infection nearly as often.
You might find it useful to go back into the literature and try to get a sense of what “fittest” means in this context. It has a specific meaning separate from its normal or dictionary definition. That is a little misleading, I admit, but in animals that are under a lot of evolutionary pressures the difference between the dictionary definition and the evolution-specific definition is minuscule (so rarely needs to be mentioned).
However, when you talk about a species like humans it is worth pointing out that the evolution-specific definition of “fittest” is ‘suitability to survival and reproduction’. If we were in the wild, with a great number of natural pressures, the “more vulnerable” and their offspring would be under-fed and die off.
Hi Robin, a wonderful point you have made 😀 and very True, you are indeed spot on, 😀 sadly Christians who claim to believe in Evolution and try to gel it with the Scriptures are very deceived. God shows clearly in Genesis the foundation of the Scriptures, all of which He inspired and which can only be understood by The Holy Spirit’s empowering, that He Created the Universe including man and as you clearly showed they did not evolve as the unproven theory of Evolution claims, also no matter what they try to propergate as facts, there are none. Only God can create viable Life, Secular Scientists have tried for years but have failed, as mankind cannot create nothing from nothing.
God started with the infinite and it continues today, God is the Life giver not man or Evolution, besides we have distinct belly buttons, no animal life form has or ever had one and the claimed missing link has not been found, the last one was a distant cat, so they are still looking.
I will share with you Robin why Evolution as part of Genesis is impossible; to say one day of Creation, a morning and night could have been millions of years, just does not fit in.
As we look at those days and see what was created on each of them, we see that on Day 3 it was grass, flowers, tree bearing fruit etc what do these need to grow, three things water, sun and some need animals to multiply and propagate. We know that the Garden of Eden was watered from an underground river, Genesis 2 but the Sun was not created till day 4 and animals on day 5 so all that was created on day 3 would have perished without these if a day had been millions of years.
When Ministering to Atheists I was also presented with what was claimed to be evidence that supported Evolution but when investigated was shown to be invalid as it was not based on proven fact , there were also many contradictions from the different Links provided, in the end some even confessed to the Truth which was, there was no evidence to prove or support Evolution that was not consistent with Creation too but they then said that since I hadn’t died I couldn’t prove there was an after – life, strange but nor had they died and where did they come from then, Nothing!!
Thank you Robin dear friend, keep up the good work, I will be in touch when my Computer is working again, I have use of this one for a short time only each day.
Christian Love – Anne.
While this is an older post I would just put my two cents in. That being that evolutionists have never been able to re-create a human from what they say we began as…sludge….then….etc etc. Therefore this theory is not fact.
Whereas the creationist theory that God created a Man and a Woman to procreate and indeed we do and thus a human being with intricacies within a newborn baby to sustain life is fact.
Historically we learn of the first man and woman who God created from the Bible…and much of the bible has been historically proven to be correct. One only has to research to find this out…Diane
Robin, when you think of evolution, it helps to keep two central ideas in mind: generation and time.
Think of generation: Even in the case of multiple births, the offspring are not exact duplicates. Every individual in a new generation is unique from the previous generation. People who don’t understand evolution seem to me to ignore this central fact of life: Our offspring are different from us. If our offspring were virtually the same as us, like copies from a copying machine, then maybe no amount of time would be sufficient for later generations to evolve into different species. Each generation would look exactly alike.
But take a copy of an original and make a copy of the copy. Then make a copy of that copy, and then a copy of that third generation copy, and a copy of the fourth generation and on and on. You are bound to notice changes after time. Eventually all traces of the original will disappear.
Our reproductive system is even more inexact at making copies of us than a copying machine is of a page of text, mainly because we reproduce sexually–ie, by requiring two parents, each of whom has genes to pass on–so of course, time will have a distorting effect as each succeeding generation reproduces its own offspring. Nature–the elements of our environment–sculpts the species by enabling the individuals who can survive to pass on the genes they’ve inherited. Those that can’t survive tend not to pass on their genes, thus, whatever they inherited that made them unfit for the environment is lost to future generations.
If it suddenly benefited the species to be eight feet tall in the environment because of some radical change in it–especially if it was harmful to be less than eight feel tall–those of us less than eight feet wouldn’t live long enough to pass on our genes. Those eight feet or taller would. Eventually, only the eight-foot-or-taller gene would be copied.
You are free to look for science journals on the issue, but I thought this article might help answer the question about the evolution of the nervous system: http://www.huffingtonpost.com/2013/02/28/arthropod-fossils-limbs-fuxhianhuiid-sea-creature_n_2776045.html
This arthropod is the earliest known example of an animal with a nervous system spreading beyond the head, and to primitive limbs.