Preparing for the future

At all levels, living systems are in constant activity much of which is in preparation for the future. The reproductive system of a sexually mature woman goes through changes in preparation for the pregnancy that might come about. Multicellular life could not have come about without the prior colonization of the earth by single celled organisms.

The activity and behaviour of groups of organisms have a large influence on the subsequent forms they adopt. Likewise the behaviour of cells and how they manipulate their internal structures including genomes, determine the roles they play within their environment.

Ancestral relationships:

The evolving whole:

The tree of life
So 150 years after the publication of Darwin’s revolutionary book, modern genetics has confirmed its fundamental truth – all life is related. And it enables us to construct with confidence the complex tree that represents the history of life.

The individual person:

All cells in a person’s body are descendants of two cells, the mother’s egg and the father’s sperm. After the egg and sperm join together (fertilization), the fertilized egg is just a single cell. This cell, the zygote, divides many times, and as it divides, the descendant cells develop different characteristics and functions.</blockquote>

 

Growth and differentiation:

The evolving whole:

It began in the sea, some 3,000 million years ago. Complex chemical molecules began to clump together to form microscopic blobs: cells. These were the seeds from which the tree of life developed. They were able to split, replicating themselves as bacteria do and as time passed they diversified into different groups. Some remained attached to one another so that they formed chains – we know them today as algae. Others formed hollow balls which collapsed upon themselves creating a body with an internal cavity. They were the first multi-celled organisms – sponges are their direct descendents.

The individual person:

In mammals, the blastula forms the blastocyst in the next stage of development. Here the cells in the blastula arrange themselves in two layers, the inner cell mass, and an outer layer called the trophoblast. The inner cell mass is also known as the embryoblast and this mass of cells will go on to form the embryo. At this stage of development, the inner cell mass consists of embryonic stem cells that will differentiate into the different cell types needed by the organism.

 

Aquatic life:

The evolving whole:

As more variations appeared, the tree of life grew and became more diverse. Some organisms became more mobile and developed a mouth that opened into a gut. Others had bodies stiffened by an internal rod. They understandably developed sense organs around their front end.
A related group had bodies that were divided into segments with little projections on either side that helped them to move around on the sea floor. Some of these segmented creatures developed hard protective skins which gave their bodies some rigidity. So now the seas were filled with a great variety of animals.

The individual person:

Amniotic fluid surrounds the embryo and fetus during development and has a myriad of functions

 

Terrestrial life:

The evolving Whole:

And then around 450 million years ago, some of these armoured creatures crawled up, out of the water and ventured on to land.</a> And here, the tree of life branched into a multitude of different species that exploited this new environment in all kinds of ways

One group of them developed elongated flaps on their backs which over many generations eventually developed into wings. The insects had arrived. Life moved into the air and diversified into myriad forms. Meanwhile, back in the seas, those creatures with the stiffening rod in their bodies had strengthened it by encasing it in bone. They increased in size and grew skulls. They grew fins, equipped with muscles that enabled them to swim with speed and power. So fish now dominated the waters of the world.
One group of them developed the ability to gulp air from the water surface.</a>

The individual person:

When a baby is birthed down, Valeriana sees the baby stretch out its arms, which in turn expands its lungs for those first few breaths. “The Moro reflex makes such sense!” she adds, referring to the “startle reflex” where an infant throws open its arms (V. Pasqua-Masback, personal communication, January 19, 2010). Additionally, this pause is an important time for the placental transfusion, the return of the volume of blood that has backed up into the cord and placenta with the squeeze through the birth canal, a function that also aids in the transition to lung breathing.

 

Life’s transitions have been prepared well in advance. Tetrapods could only colonize the land if the atmosphere was suitable for breathing, they possessed a suitable respiratory system, and their bodies were able to cope with the additional gravitational forces. Functioning on land involves a different set of challenges from those brought about by a purely aquatic existence.

Evolutionary trajectories are constrained by their history. The tetrapod body form is constrained by the form taken in its primal beginnings. Notwithstanding these limitations in the paths available, this has subsequently given rise to a multitude of forms, many of them being extremely specialized. Due to the early limitations we never see directions taken that might has seemed possible. Such directions as tetrapods growing extra limbs, lung breathing animals reverting to breathing under water, or precocious primates with the ability to fend for themselves immediately after birth.

Another feature that the evolutionary trajectory allows for is the extremely complex central nervous system.. The actions of of organisms leading to the production of substances used to build up nervous systems have very deep origins.

Rational thought, organs necessary to communicate through spoken language, manual dexterity, inventiveness; our creative abilities, both physical and mental are what they are because early earthly life prepared the way. Evolutionary paths could have taken many different directions, which while being very successful at surviving and reproducing, would have precluded the above abilities.

57 thoughts on “Preparing for the future

  1. Corneel: I appreciate that the seduction of SIWOTI can be very powerful, but you do realize that Charlie is not actually listening to you but merely using your comments as an excuse to endlessly repeat Steiner-nonsense at you, right?

    Thank you for saving me from myself!

  2. Corneel to:
    Kantian Naturalist,

    I appreciate that the seduction of SIWOTI can be very powerful, but you do realize that Charlie is not actually listening to you but merely using your comments as an excuse to endlessly repeat Steiner-nonsense at you, right?
    The stuff about birds losing the potential to use their forelimbs by giving in to their “desire to fly” must have come up at least half a dozen times before at TSZ and I do not see the slightest indication that Charlie remembers *any* of those exchanges.

    I do listen to replies and quite often they inspire me to dig deeper into what they are saying. This is the case with Kantian Naturalist’s reply below:

    Kantian Naturalist: Teaching tool-use has been demonstrated in chimpanzees and in dolphins.

    There’s extensive documentation of crows and other birds using their beaks to invent tools to solve problems that they’ve never encountered before.

    Tool use by various species has been studied for quite a while and it’s not controversial. And the beauty of the internet is that it gives me access to the latest info available.

    So if I am mistaken in believing that the creativity of any animal kind is extremely basic compared to human creativity, then all you need to do is give me the link to any research which would counter my belief. If you agree with what I am saying then can you give us an explanation as to why this is so. What contributes to our very advanced creative abilities?

    I remember a few of those exchanges but I’ll need to be reminded of any substantial arguments against my position. Feel free to link to any replies you believe have contradicted anything I’ve said. I’m more than happy to go over them again.

  3. Kantian Naturalist: Thank you for saving me from myself!

    My pleasure!

    CharlieM: I remember a few of those exchanges but I’ll need to be reminded of any substantial arguments against my position.

    You listen to replies and they inspire you to dig deeper, but nevertheless you don’t seem to be able to recall any substantial arguments against your position. Isn’t that odd? 😉
    I am sorry, Charlie. But it is not the task of your interlocutors to remind you of past exchanges. This you have to do yourself, lest you never learn something.

    ETA: removed stuff

  4. Corneel: You listen to replies and they inspire you to dig deeper, but nevertheless you don’t seem to be able to recall any substantial arguments against your position. Isn’t that odd? 😉
    I am sorry, Charlie. But it is not the task of your interlocutors to remind you of past exchanges. This you have to do yourself, lest you never learn something.

    You are the one who has made vague claims about previous arguments against my posts. So I could be justified in ignoring this criticism. However I’ll probably spend some time in looking back to see what I can find.

  5. Corneel: You listen to replies and they inspire you to dig deeper, but nevertheless you don’t seem to be able to recall any substantial arguments against your position. Isn’t that odd? 😉
    I am sorry, Charlie. But it is not the task of your interlocutors to remind you of past exchanges. This you have to do yourself, lest you never learn something.

    As you have given no actual references I’ve begun to look back at some of the earlier exchanges.

    Here is one exchange about the pentadactyl limb which can be found in this thread

    Here, Kantian Naturalist writes:

    By what criterion is the hominid forelimb less specialized than that of any other tetrapod?
    You need a non-anthropocentric criterion of “specialization” in order to make your case here. Sure, humans can do lots of things with our arms — we can grasp, throw, carry, punch, pinch, lift — but we can’t fly, or burrow, or rend.

    I wouldn’t dream of telling a pilot he can’t use his hands to fly an aircraft, or a minor that he can’t use his hands to wield a spade. I’m not sure of the context of “rend”. Rend what? Hands play a major role in designing, building, maintaining, and flying aircaft.

    He went on to link to an article: “Freed hands or enslaved feet? A note on the behavioural implications of ground-dwelling bipedalism”. Unfortunately I can only access the abstract which I’ve copied here:

    It is argued that the routine portrayal of ground-dwelling bipedalism as involving an immediate and dramatic “freeing of the hands” obscures the more plausible scenario of a continuation into the new environment of the previous behavioural repertoire, including branch holding. Both the degrees of prior “enslavement” and of subsequent liberation are customarily exaggerated. It is suggested that the precise behavioural meanings of the terms “tool-usage” and “tool-making” are far from clear. It is not the complexity of particular behavioural schema which changes initially following the shift to ground-dwelling, but the variety of their outcomes as they are applied to novel objects. Feedback loops linking hand-usage and encephalization did not immediately ensue either, although neurological re-organization probably did, but this is more reasonably ascribed to the “enslavement” of the foot than to the “freeing” of the hand as such.

    What do they mean by, ‘the “enslavement” of the foot ‘? Possibly because the foot is now restricted to its main function of support and locomotion. It is precisely because the foot has stopped short at this ancetral stage that the hands have been able to advance towards the possession of a higher creative function. Bipedalism has allowed for this division of labour.

    If we speculate that both bird and human forelimbs have evolved from some common reptile-like ancestor with pentadactyl limbs, it isn’t difficult to figure out which path has resulted in the greatest specialization. There is nothing anthropocentric about this. It is an obvious observation and the same reasoning can be applied to cetaceans.

    I was involved in further discussions with others on this topic in that thread but I haven’t had a chance to have a closer look at them yet. Meanwhile if anyone who is interested would like to point us to any substantial arguments therein, I don’t mind discussing them further.

  6. When I asked for examples of limbs that match or exceed the human forelimb by not taking an increasing specialized route but have become more versatile, I don’t recall anyone mentioning octopuses. To me octopus arms would be a contender.

    From here

    The arms of an octopus are versatile and can perform a wide range of tasks. They are used for manipulating objects, capturing prey, and even communicating with other octopuses. On the other hand, the tentacles are primarily used for sensing the environment and detecting prey. They are equipped with chemoreceptors that allow the octopus to taste and smell its surroundings.

    And this site describes their arms and tentacles as “multi-purpose tools”.

    In my opinion octopuses are at the pinnacle of invertebrate evolution when it comes to intelligence and dexterity, as humans are regarding vertebrate evolution.

  7. CharlieM: I could be justified in ignoring this criticism.

    Don’t think of it as criticism. It’s more like sage advice 🙂

    CharlieM: Here, Kantian Naturalist writes

    See? All the stuff you brought up has been discussed before. You even wrote an OP with a very similar thrust a few years ago. Now all you need to learn is to keep track of the discussion. For example, KN asked:

    By what criterion is the hominid forelimb less specialized than that of any other tetrapod? You need a non-anthropocentric criterion of “specialization” in order to make your case here.

    And you not-replied:

    If we speculate that both bird and human forelimbs have evolved from some common reptile-like ancestor with pentadactyl limbs, it isn’t difficult to figure out which path has resulted in the greatest specialization. There is nothing anthropocentric about this. It is an obvious observation and the same reasoning can be applied to cetaceans.

    But KN didn’t say birds, he said “any other tetrapod” (similar to you in the preceding comment: “any other vertebrate”) and so you failed to provide the criterion he asked for. You just bluntly claimed it is “an obvious observation” which is, I am sorry to say, just you being anthropocentric again. So in the future, you may want to re-read the comment your were responding to and verify that you have actually written an answer to it.

    And now I am really off. Don’t forget to enjoy the lovely summer weather coming up.

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