Some responses to my posts on the evolution of the eye, made use of the other senses to compensate for any short-comings found in vision during its evolutionary history. I would like to begin showing problems with this idea.
1. Physical sensations are the most underrated of the senses, and is perhaps the most important to our survival. There is an entire world of specialized receptors working in unison to provide us with essential information. There is no single sense for touch, instead we have specialized receptors for pain, for temperature, for stretching, for pressure, for vibrations, etc. The results of not having these sensations is harmful and lethal. There are many reasons why a person might lose these sensations, one of them is diabetes, which leads to neuropathy in the extremities. This makes the individual extremely prone to injury. They cannot tell when their circulation is cut-off. They cannot tell when they’ve cut or bruised themselves. They may ignore injuries that eventually lead to infections or ulcers. These infections can lead to rotting or death if the limb is not amputated.
Seeing how important these sensations are to survival. How did our ancestors avoid death and injury before these sensations evolved?
2. Without your sense of touch, you need vision to compensate. Bodily sensations don’t just inform you about what you’re bumping against in the external world, they tell you what your body is doing internally, how you’re oriented, and how you’re moving. Take Ian Waterman, a person that completely lost these sensations. He cannot do the simplest of actions. He cannot grab an egg without crushing it, he cannot stand and walk without looking, he couldn’t even sit up from his bed because he had no way of feeling his weight distributed. He had to learn to use visual cues to accomplish all these tasks.
If our ancestors relied on touch before the eye evolved properly. What did they rely on before these bodily sensations evolved?
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I don't get it, whats the point?
im just atheist
not knowing much on evolution doesn't make be believe in god
how does this make god more or less real for anyone?
Is the reason why you're atheist scientific in any way?
I don't even know what that is
why make stuff up about me?
im not a big science fan, little interest to me.
read bible, utter bolocks, the end.
less is more
more you type less you say
"Is the reason why you're atheist scientific in any way?"
Is science the reason you don't believe in fairies and unicorns, or Zeus or leprechauns? ?
I, ME, Mykcob4, understand why and what you are doing. I get it. I think that you are wrong of course, but I respect that you are making your point. I really like having you AND JoC on the forum.
I wonder if you have railed about evolution more or if I have railed for gun control. Who knows?
Have you looked into the Trichoplax?
Interesting little organism...
So to answer your question....
My opinion is that as single cells we didn't need to have a nervous system in order to float around and feed. Only as we evolved into multicellular organisms in the metazoa era did we evolve the nervous system
I suppose, but microorganisms aren't left without their own different sensory systems. Most can sense very dilute chemical changes in their environment, detecting whatever chemical it is they need. Other bacteria can sense light. You can even argue some sense temperature changes and dryness and base the production of endospores on that information.
True but as these organisms evolved more complex nervous systems would be needed to as limbs, brains, etc came to be.
For example the human stomach senses nutrition molecules which allows digestive enzymes to break down said molecules. So in our ancestors if we look back all the way till there were no nerves we would be looking at single celled organisms. ( not a scientists so I could be wrong on that) those organisms wouldn't need the sensory mechanisms you brought up in your OP, they could have a different form of sensory that is unlike anything we can see today. Maybe an innate trait to life is some form of sensory? I have heard many different hypotheses on how life arouse and one is that already formed single cell organisms crash landed from meteorites. I'm not sure which ones or how but I do know they have done studies that show some cells can withstand the vacuum of space.
Do you think organisms need these nervous systems first before they can evolve into multicellular organisms, or vice versa?
I think anything that moves and eats, including bacteria, requires some form of sensory system.
We know of organisms that can move around that do not have a nervous system as we know it.
If we blanket term sensory to not have to include a nervous system I will agree with you but I would then have to rethink your OP. As I read it you correlated sensory with nerves... if we didn't have nerves then how could we survive because sensory and a nervous system go hand in hand
Well yes, nerves are how we perceive sensations. But I'm interested in the sensation first, and the method by which it is perceived second. How bacteria sense things, and how we sense things are very different. So when you bring up bacteria, I have to adapt my post to the bacterial world.
Unless I'm mistaken the organism I gave you was not bacteria
"My opinion is that as single cells we didn't need...."
That's what my comment is based on. Whether you had bacteria, protists, or archeans in mind doesn't affect my response.
So I am saying that if you say what did our ancestors do without these nerves... I am responding that you are now traveling back to the metazoa era... please show how the lack of nerves would be bad for our pre metazoa ancestors.
What are pre-metazoan ancestor?
Ancestors that existed prior to the metazoan era.
There's no such thing as a metazoan era. He's asking about species from which animals evolved, which are presumably microscopic. I don't know what those species are, so I'm asking.
Sponges [Porifera] are the phylogenetically oldest metazoan phylum still extant today; they share the closest relationship with the hypothetical common metazoan ancestor...................
Ok, so we are entering hypothetical territory when going pre-metazoan?
"Ok, so we are entering hypothetical territory when going pre-metazoan?"
According to you it didn't exist? I've made no claims about it, though I did link some scientific research about life that existed in that period.
Sun, 11/12/2017 - 10:26 (Reply to #19)Permalink
John 6IX Breezy "There's no such thing as a metazoan era."
Sorry you claimed it never existed, now you seem to be acknowledging it did, which is it? You're not being very consistent here?
FROM MY EARLIER POST
"Sponges [Porifera] are the phylogenetically oldest metazoan phylum still extant today; they share the closest relationship with the hypothetical common metazoan ancestor."
Are you claiming the existence of sponges, for example, is only theoretical? I'd be prepared to go out on a limb in that case and say you're wrong. Or are you claiming no life existed prior to this era, and that all life sprang into existence ex nihilo? How do you claim this happened? Perhaps it's time for you to go scampering back behind the protectively dishonest veil of the thread OP?
There's no such thing as metazoan era. Eras are reserved for geological time, such as the Mesozoic Era. Metazoa is the animal kingdom. When BYB talks about pre-metazoan, he's talking about evolutionary time, before animals evolved.
Your quote says sponges are the oldest animals, and that the ancestor (which BYB is asking about) is hypothetical.
Breezy "There's no such thing as metazoan era."
Breezy "What are pre-metazoan ancestor?"
You understand there was a time when life did not exist on this planet? Is this another tiresome attempt to make the mendacious claim that evolution is not a scientific fact because it doesn't show us how that life originated?
Calculus doesn't show us how life started on this planet, nor does gravity or relativity, are they falsified then?
What are you talking about?
I don't understand the question?
You put two quotes up from me. Then post two links, one about the Cambrian explosion, another is an earth timeline. All without a single ounce of commentary or explanation, so I don't know what you want me to see or do with them.
Then you start rambling calculus and how life started.
Read what the links say, and how they relate to your previous claims.
In what way is the context in which I used my analogous comparison of calculus unclear to you?
You also missed both my questions yet again...
1. You understand there was a time when life did not exist on this planet?
2. Is this another tiresome attempt to make the mendacious claim that evolution is not a scientific fact because it doesn't show us how that life originated?
How do you jump from metazoan ancestors, to how life began? I just don't see the connection.
Do you understand what a question mark at the end of a sentence means?