Below is an image of the developmental path from human conception to adult in comparison with evolutionary path from prokaryote to human.
Unlike Haeckel’s biogenetic law with its focus on physical forms, the comparison above also concerns activity, lifestyle and behaviour. Comparative stages may be vastly different in detail, but the similarity of general lifestyles and consecutive stages are there to be observed.
Human life begins in an aquatic environment. Toddlers gradually learn to walk upright from a previous state of crawling and moving around on all fours. The brains of children develop through daily interactions and experiences. This brain development accompanies the child’s increasing ability to achieve complex manipulation skills using hands that have been released from the task of providing support and locomotion, and also the practice of producing sounds using the various muscles of the mouth. Well developed brains allow for rational thinking and the creative use of language.
Human minds have brought about technological advances which have allowed human activities to engulf the planet. Signs of intelligent human activity are evident a good distance beyond the earth spreading ever further out into space.
The various forms of extant animals and all other life forms have evolved as an integral component of the living earth and the whole forms a dynamic system.
The various animal forms should be studied in the context of the complete system in both time and space. Conditions would have been very different prior to the terrestrial colonization of earthly life In all probability none of the present aquatic animals would bear any resemblance to the aquatic ancestors of humans and other higher vertebrates save that at some stage they all require an aquatic environment for their continued existence.
From a point of view which regards physical organisms as the individual expressions of overarching general forms, the evolution of cetaceans need not have involved moving to the land only to return to the water at a later time. They may have reached the mammalian stage of evolution but in a way that was suitable for an aquatic lifestyle. They adopted the archetypal mammalian form in a way that suited an animal living in an aquatic environment and there would be no need to posit a terrestrial stage in their evolution.
It’s my belief that higher consciousness is ever present. Evolution is the process whereby higher forms of consciousness descend from the group level to the individual level. The most fully developed individual consciousness which I am aware of on earth can be found in humans but it is still rudimentary compared to the higher level group consciousness.
Plasticity is a fundamental feature of living systems at all levels from human brain development to the radiation of multicellular life. Paths are formed by branching out and becoming fixed along certain lines. It would be impossible to forecast specific paths but, nonetheless, there is a general overall direction.
Now that biological life has reached the stage where social organisms have become individually creative and rational, the all encompassing Word is reflected in single beings. This could not have come about without preparation and the evolution of earthly life is the evidence of this preparation. We, as individuals, are only able to use language and engage in rational thinking because our individual development has prepared us to do so. Likewise humanity could not arrive at the present state of culture without the evolutionary preparation in its entirety.
Focussing in at the lower level gives a picture of ruthless competition, of nature “red in tooth and claw”. But from a higher vantage point life benefits from this apparent brutality. For instance if a sparrowhawk makes regular hunting visits to a suitable habitat in your neighbourhood it signifies that this environment supports a healthy songbird population. In the case of the continued evolution of physical forms, survival of the breeding population is more important than any individual’s survival. In the evolution of consciousness the individual is the important unit.
I think it is a mistake to see biological evolution as a blind random groping towards an unknown and unknowable future.
Not the way I would have put it, but sure why not? Not sure why you restrict this to bacteria though. This applies to all living things. No variation, no evolution.
So here is the problem: HIV is a type of retrovirus, so do retroviruses make up a kind or is it a grouping of smaller kinds like HIV? Same goes for coronaviruses: Is it a kind in itself or a grouping of kinds like SARS-CoV-2?
I think these are arbitrary groupings and that you will be unable to identify “kinds” united by “group wisdom” in there. We humans drew some convenient lines in the sand but nothing indicates viruses care for them. Why would they? Take the flu: There are multiple subtypes of influenza. Why would the “wisdom” of influenza A include influenza B and influenza C viruses but not those of infectious salmon anemia virus or Quaranjavirus? Because we humans named the former influenza and the latter not?
mutationsDNA sequence changes resulting from inaccurate replication by DNA polymerase are not preferentially generated, right? These can be reasonably described as errors, don’t you agree?
You have backpedaled so far that we are in agreement again. I do like to point out that the speculation is all yours.
Populations do not respond to external influences such as this. But individuals within the population react in different ways. It is this individual variability within a population which will determine if it can survive environmental change. But this fluctuation within populations bears little resemblance to what is seen as the great diversification of life over evolutionary time.
The vast majority of mutations are just incidental “noise” which does not have any lasting affect one way or the other. But the fact that they add variety gives populations an adaptive advantage. Bacteria have remained as bacteria for millions of years by having this attribute.
I’m sure we all know that cell membranes are selective barriers in that they allow some, but not all molecules to pass through them by means of both passive and active transport.
If I was referring to a specific type of selection I would have said so.
Although now that you mention it I can see a resemblance to natural selection in which populations are regulated in a way that maintains their identity while the frequency of individual differences vary. 🙂
The word niche is commonly used to describe the environment and habits of a species. In my opinion the niche of, say, a giant panda would be equivalent to a niche of an individual human rather than us as a species. To say that the human species has a niche is meaningless in my opinion.
So why do I see all these headlines claiming that “the gene” for industrial melanism has been found?
I’d say they do – or rather, it’s a semantic nicety to say it’s not ‘the population’ that’s responding. An antibiotic kills a population by killing the individuals within it. Likewise, a mutagenic chemical agent, or a stress, changes the fidelity of replication of the individuals in the population, and hence the amount of variation in that population. Individuals don’t individually vary. Raising an “I think you’ll find…” finger when someone says that the mutagen changes the population is a bit pedantic. I realise I can talk about pedantry.
The arc of individual development bears little resemblance to the great diversification of life over evolutionary time, but that doesn’t stop you beating that drum! I’m certainly not trying to draw any parallels between within-population change and between-population diversification. They are related, but not by analogy.
Mutations are a part of stasis, now? Interesting …
Possibly. I was just checking.
Interesting that this is what you think natural selection does.
The word ‘niche’ suffers from similar problems to the word ‘gene’. It can be somewhat labile. Nonetheless, I have never seen anyone use it to refer to individuals.
No idea. You must be more widely read than I; this has escaped my notice.
No, they met their demise.
Ooh! Ooh! I let that one slide! This is flat-out wrong in its second part. The inheritance of mutation in a finite world prevents any population experiencing it from ‘standing still’. All classes of mutation beyond the substantially detrimental have the capacity to have a lasting effect: for the population at time t2 to differ irreversibly from that at t1. It’s something you can’t turn off.
Should I believe our hands are being selfish because their form is copied in our descendants?
Can you explain how natural selection could occur without death?
The death of mature mayflies leaves room for future populations. The apoptosis of cells during vertebrate limb development leave room for digits to form. Two levels in which the death of individuals benefits the higher entity to which they belong. (Cell death in one case and the death of individual organisms in the other.)
Apoptosis is a natural process within individual development. I don’t believe any embryo would reach full term without it, let alone reaching sexual maturity.
If the proteins within a cell are indiscriminately degraded how can you say that this does not lower the fitness of the cell?
I’d like to clarify that your view of my view is a false view of my view and so it is not my view which views viruses as being very diverse. See? 🙂
There is no mutual cooperation among viruses that I know of.
Silly billy. Corneel wrote
Thus ‘you should believe’ that your hands are merely tools that your DNA is using to express their (the DNA’s) selfishness. There’s a Dawkins bloke who wrote about this way of thinking a while back.
Differential reproduction. This, too, has been covered before.
‘Fitness’ is a technical term that does not apply to somatic cells, that’s how.
I am guessing that you haven’t looked very hard.
E4 kinder link
Giving specific examples does not mean I’m being restrictive. I’m just being selective in what I am focusing on. 🙂
I’m sure you’ve heard of nested hierarchies. As is usual in living systems, viruses (too) have been classed taxonomically.
I don’t know enough about the relationships between viruses to judge. I use the word “kinds” to describe groups of which individuals are members of. It is a broader category which may or may not align with a level of classification such as species or genera.
For example the species influenza A would include all influenza A individuals.
Yes they could be seen as copying errors.
To say that evolution has produced individual self-consciousness is not speculation, it is an observation.
To say that this has happened by chance or to say that it was destined to be are equally speculative for most of us.
Jock already fielded some stuff, I see. Starting on the remaining issues:
Yeah, that made me smile. Though the life span of mayflies may be ephemeral, their death is not programmed. Most species of mayflies do not have functional mouthparts or digestive system, so they simply waste away.
Nice try though.
Exactly, so somatic cells that appropriately execute apoptosis prevent the termination of the lineage they are part of by way of their close relationship to germline cells. That’s not exactly deleterious, is it?
If viruses do not give a rat’s arse about each other, then why would it be “wise” to “ensure the continued existence of its kind”? Looks like a big happy virus family to me.
I do not see how “group wisdom” stacks hierarchically.
The problem is the concept of “kind” in the mind of the average layperson. It has acquired a lot of baggage, you see?
I like this quote by KN. I believe it has some relevance here as well:
For me evolution is a well balanced journey. Natural selection maintains the balance but it does not control the route. For the living world to persist there must be a balance between life and death. And persistence of life at higher levels must include death at lower levels. A multicellular organism or a colony of single celled organisms maintains its life through death at the cellular level. A higher taxonomic group maintains it life through death of the individual organisms within it. A kingdom of nature maintains its life through the death of taxonomic groups within it. And as far as I’m aware earthly life as a whole has yet to reach the stage of total death even if death is a constant feature of lower levels.
So, arguing against myself, I could say that in one sense I am a population of cells responding to external stimuli.
They are related fractally as in the whole reflected in the parts.
Nothing is truly static. Analogy alert! Jupiter’s great red spot is a very dynamic system but it has been consistently present for at least hundreds of years. A fairly stable feature which at lower levels is a very energetic atmospheric storm.
Phoodoo will be pleased. 🙂
Typical and melanic peppered moths keep their identity as peppered moths while natural selection causes fluctuations in their relative densities. Similar processes can be seen in Galapagos finches. These examples are a favourite argument for natural selection in action.
Maybe not in the case of bacteria, but have you never heard it being said that someone has found their niche?
I didn’t find this by being widely read, I found it through focused searches on industrial melanism.
What? The eubacteria kingdom is no more? It is a dead kingdom? It is pushing up the daisies? Where do I send the flower to? 🙁
Nope, not that either. They are related because change in lineage (anagenesis) is the direct cause of divergence between two (cladogenesis), given a reproductive barrier.
Questionable relevance alert.
I’ve rarely known phoodoo be pleased by anything.
Ah, good old semantics, our constant companion. This is not the ecological use of the term.
I’ve just done a focused search and found that the difference is attributed to a transposable element. Is this reasonably called the gene ‘for’ melanism? Is that how the authors present it, or journalists? I’d be interested in a well-defended rationale either way.
Natural selection in action at any point is progressing towards the elimination of one form and fixation of the other, as a logical endpoint of the current trend. Of course that trend could change, leading to ‘fluctuation’, but you err in thinking that fluctuation is a component of selection.
I am given to understand that one does not send flowers, but potatoes.
I’ll happily go along with that. I went a bit far saying the noise has no effect.
Michael Behe argues that the vast majority of mutations that do have adaptive effects and alter organisms through Darwinian processes, do so by degrading genes that already exist. In this video he cites examples such as polar bears and dogs.
Considering your point that mutations can have irreversible effects. In the case of peppered moths, just think if the supremacy of the melanic form had gone as far as to annihilate the other forms. Through Darwinian processes at time t1 the species would have consisted of a wide range of patterns among individuals compared to time t2 at which point individuals would be restricted to the darkened form.
This is not a good argument for the power of Darwinian evolution.
I do see how there can be an orderly progression. And the lowest, most nascent form of wisdom is individual conscious human wisdom.
Yes I can see problems when people attach their own prejudices to the use of a word.
And so there is a polarity between the disruption of copying errors and error correction processes which tries to maintain order.
The wisdom lies not in eliminating errors completely but in using them constructively.
What does it mean for a trait to be advantageous? If by advantageous it means that they allow organisms the most reproductive success then bacteria and viruses by far outcompete us mere humans. There are no higher animals on the planet that can match bacteria and viruses if that is the measure of successful evolution.
Goethean science is not an activity which speculates about evolutionary origins. It is more concerned with observing the natural world and its processes as it is experienced.
If we look at the relationship between light and life, light plays a vital role in the growth of organic compounds. In the case of plants, light enables them to grow living substance from inorganic compounds. And this in turn leads to an advancement of the relationship between light and life.
As Goethe said:
It is obvious that without light eyes would not have evolved. And sense organs lead to, not only an awareness of the external world, but an awareness of self in relation to the world.
There is a progression in evolution which matches the progression we observe in the development of the individual human. From growth/expansion through the birth of sentience on to the arrival of self-awareness.
Self-awareness is a feature of life which does not give us outstandingly better reproductive rates over relatively more simple prokaryotes, yet here we are. We have been given access to an inner light that can say, “I see with my understanding”. Was this just an accident of blind evolution?
True, but let’s be honest: you haven’t been trying very hard, have you?
Whatever floats your boat!
That’s my take on it. As I said: you may disagree but there is no empirical evidence that evolution is steering to some specific goal.
Can go take a running jump. Who he? Where’s his rigorous analysis of relative adaptiveness been published?
If the melanic form does better than all rivals under the environmental conditions prevalent at the time, and ends up being the sole form at t2 as a consequence, I’m not seeing the problem. Melanic is best; lo! melanic it is! Good old Natural Selection.
‘Darwinian’ selection requires variation, but is not defeated by the observation that variation diminishes as selection progresses. It’s kind of expected.
Not surprisingly we see things from different angles.
What holds for one level of observed reality does not necessarily hold at all levels.
Do you know phoodoo well enough to judge?
Surely ecologists have borrowed this term from general use for a reason?
Some, but not all, of the differences are associated in some way with a specific gene. Is that gene specific to melanism?
But that is how they are related! Can you envisage uncorrelated change in 2 separate populations leading to anything other than divergence?
Rendering your too-frequent resort to analogy somewhat undermined!
I don’t need to in order to make the statement “I’ve rarely known phoodoo be pleased by anything”. It was, after all, a joke.
Of course – in order to permit endless equivocation! Scientists are always faced with 2 choices – generate an impenetrable neologism, or add a meaning to an existing word. The fun we have when they do the latter!
Don’t know. Would it be the gene ‘for’ melanism if it was?
Were the melanic forms not fixed in the population before selection due to tree discolouration caused by industrial pollution? Fluctuation in relative numbers of these previously fixed traits comes about due to selective pressures does it not?
Say natural selection brought about the elimination of all peppered moths except the melanic forms. Surely this is a restriction of variability which will tend to make the species less capable of adapting to future changing conditions?
You don’t happen to have the phone number for “Interpatata” do you? 🙂
You are lucky that I got that joke; that company goes by a very different name here.
Anyways, the point is that the bacteria from millions of years ago met their demise sensu Charlie, just like theropod dinosaurs did. Modern bacteria are as different from their mesozoic cousins as modern birds are from mesozoic theropod dinosaurs, contra your claim that “The vast majority of mutations are just incidental “noise” which does not have any lasting affect one way or the other.”.
Either that, or concede that eukaryotes have remained as eukaryotes for millions of years. Now you are just engaging in another round of “all those bacteria look the same to me”.
I’m no bacterium but I have had my reproductive successes. 🙂
Displacement floats my boat.
Below is the text which accompanies the attached figure.
According to that tree bacteria have only themselves as common ancestors whereas humans have an (a) to (g) of common ancestors. If evolution is defined as change over time then humans have evolved further than bacteria.
Even if evolution isn’t seen as progressing towards a specific goal it can been that up to this time there has been a progression towards creatures which possess a higher individual consciousness.
Here is a tree of life that better represents modern understanding of relative diversity within Bacteria, Archaea and Eukarya. For giggles, try to locate “ancestors (a) to (g)” from your figure. Hopefully, you’ll realize that a fair amount of navelgazing went into its production.
ETA: Also note how, in your figure, there is an implied progression from left to right. Phylogenetic trees can be rotated around their internal nodes without changing the topology, so why was it represented this way? Can you guess?
The environmental change caused a change in the direction of selection. This does not mean that fluctuation is a component of selection, simply that selection is responsive to it.
Sure. It happens. But it isn’t a universal. There is a constant flux of new mutations at one end, and a constant flux of fixation due to drift and selection at the other. So no biggie.
That’s one way of keeping fit. I’m using “fit” in its general, not necessarily evolutionary, sense. 🙂
I don’t know. But even if he had carried out and published his own experiments on this, it would not give enough data. In proposing that the vast majority of beneficial mutations are degrative he has examined and reviewed the literature to gather information from a much wider source than he alone could have produced.
Melanic might be best for the individual, but narrows the options available to the group. Having the option of various forms to cope with changing environments is best for the population.
I am not trying to defeat Darwinian selection, I am just pointing out its limitations.
And what protection do we mere mortals have from any suspicion he might have cherry-picked? He is, after all, an IDist. I realise that’s a reverse argument from authority, but that’s all you’re doing.
Isn’t it fortunate that variation is, indeed, the rule? Except where it isn’t. We get along just fine with everyone having a nose, for example.
But here’s the thing: what would you call the response to changing environments, given population variation with the capacity to so respond? Huh? It’s got a name, you know…
Thank goodness you came! Otherwise people might have run away with the idea that Natural Selection was all there was to evolution.
If the entire group does it, it’s group wisdom. Except where some are doing something different which is group wisdom as well.
If they wouldn’t be doing it, they wouldn’t be doing it. Things’d be different then and we can clearly observe they are not. Things are definitely like they are now.
There is also a creative circularity in deprecating Natural Selection for its reduction of the variation whose principal purpose is to provide a response to … Natural Selection.
Yeah like: “You shouldn’t drive your car because then all the fuel disappears”.
In the case of the peppered moth we can imagine two extreme forms diverging and remaining separate. But where will this lead? It is believed that moths existed on earth around 200 million years ago, so it is a fair assumption that these diverging peppered moths are descendants of lines of moths stretching back at least 200 million years. There is no evidence that, should they continue to exist, they will be anything but moths in the future. A creature whose form has been recognizable as a moth for such a long time has obviously made quite a specialistic, stable, evolutionary path for itself.
Not at all.
If we recognize what Goethe was saying about everything changing yet remaining the same, we can see essential unity observed diversity. The use of light made by the leaf of a plant cannot be likewise attributed to the petals of the flower, but Goethe points to the essential unity of leaf and petal.
Organs at different levels of development might serve very different purposes but still retain an essential unity.
And I was just making an off the cuff remark.
I think the concept of “niche” has been used to try to quantify relationships within ecosystems. But niches can have so many dimensions that to talk about an organisms niche in general becomes very abstract. Occupation of niches can be viewed with regard to temperature, salinity, relationships, feeding habits, and a host of other factors. Unlike humans, most species have a fairly common set of niche parameters between individuals. Niches for humans is often a matter of individual choice.
From what I can remember that gene is not specific to melanism, but I don’t have time to look just now.
Speciation is the word you’re looking for.
As my previous post demonstrates I’ve never disputed that eukaryotes have remained eukaryotes for millions of years.
To get a clue as to how different organisms have changed over their evolution we can look at individual development. Bacteria which reproduce by cell division are born mature with all the attributes of the parent cell. Now consider bird reproduction. The offspring begins life as a fertilized egg and from then on it matures adding differentiated cells, various organs, tissues and structures as it develops.
You might believe that individual bacteria have their own characteristics and personalities but it’s not a belief that I share.
So bacteria do have inter-individual variation that allows them to adapt but no individual characteristics?
Are you sure you thought this through?
Both the tree I posted and the one you linked to are useful for understanding evolution. And both emphasise different aspects of diversity. Like the figure below, reality can be distorted as an aid to understanding and both trees should be interpreted in this way.
The tree you linked to emphasises genomic diversity at the present time while downplaying the change over time that each branch undergoes. Although the length of the radiating to which we belong indicates that our lineage has had the greatest amount of evolutionary change over time. “Longer branches experienced more change”
The tree I posted gives a clear indication of when the various groups first appeared in evolutionary time. The appearance of a group does not mean that it had no predecessors, it just means that it has undergone a dramatic change in morphology over the course of evolution.
Both trees provide us with a lot of useful information.
The progression is not implied it is actual. Unless you believe that the advent of multicellularity is not a progression towards more organized complexity of individual organisms which leads to more autonomy from their milieu. For example endothermy allows for greater freedom of activity in environments where the temperature is constantly changing.
How did you conclude that from an unrooted tree? Where do the main branches connect to the common ancestor, you reckon?
Again, this is not something that follows from the figure you posted. For example, let’s consider node c (I believe this represents the branching off of bilaterians). Now, we are allowed to rotate the entire structure around this internal node like a crib mobile so let’s do that. Observe: humans are now cosying up side by side with corals and flatworms are top of the heap. Note that this tree is completely equivalent to the one that is depicted. So how did you conclude that there is a progression going from bacteria to humans based on that figure?
You see what you want to see, Charlie.
‘Moth’ is just what we call them. I’m willing to bet that in 200 million years both us and the word ‘moth’ will either have disappeared or changed beyond recognition. You play the same trick with ‘eukaryote’ in the subsequent comment to Corneel – imposing a static category simply by virtue of our nomenclature.
We humans like to name stuff. Things are sufficiently static over our lifetimes that the names appear to attach to something persistent. But they don’t. We could go back to dinosaur times and declare ‘there is no evidence they will be anything but dinosaurs in the future’. But that sodding blackbird nicking my raspberries illustrates the dubiousness of that declaration.
Yes, this another round of the naming game. No need to quantify stuff: As long as it bears the same name, it hasn’t really changed.
Yep. Something I should have said – it’s only just occurred to me – is that going back in time, we’d presumably reach the common ancestor of butterflies and moths. It would probably have some flavour of both, as well as some distinctions of its own. It’s a … um … mutterfloth. A Charlie of that period would confidently declare that no amount of divergence from an unassuming population of mutterfloths would ever be anything but mutterfloths. Yet, the very fact of bifurcation has demanded two categories instead of one.
If the butterfly lineage had failed to – ahem – take off, we’d just have modified mutterfloths, which we’d probably call primitive moths. But that’s not what happened. There are no mutterfloths any more. Except that there kind of are.
Haha. Do you want to hear something funny? Moths without butterflies is a paraphyletic group. Strict cladistically speaking, butterflies are a type of moth (Lepidoptera actually).
They all look the same to Charlie, I bet. Mutterfloths, the lot of ’em.
You talk about selection as if it were some overarching agent tweaking populations. Back in 2002 Craig Holdrege wrote about peppered moths and he had this to say:
If we are looking for the agents that have the greatest effect on relative percentages of the three moth varieties I would say predatory birds fit the bill. 🙂
But not all changes are equal in how easily they can be achieved. Fluctuating finch beaks and the plasticity of peppered moth populations are obvious observations. But the evolution of the simple proto feather to the Integumentary system of birds is a wondrous development that we can all see for ourselves if we are willing to learn as much as is possible by simply examining the feathers of birds.
Believing in the creative power of mutations, drift and natural selection takes a great deal of faith.
Noses are wonderful things. The animal kingdom has examples of all sorts of extreme forms from the trunks of elephants to the blowholes of cetaceans. Human noses come in a variety of shapes and sizes and it mystifies me why some people undergo plastic surgery in order to possess a nose which conforms to some perceived idea of beauty. All they are doing is sacrificing something which displays their individual personality in order to display the most popular prominence of the times. And Micael Jackson was the proof that it doesn’t always succeed no matter how much money is thrown at it.
So you have emphasized the point. Even if there is much variety in noses we can recognize a nose when we see one.
I would call it adaptive evolution. And I would class it as microevolution.
How can Natural Selection be something that can be deprecated? That would be like saying I disapprove of the process whereby stem cells give rise to specialist cells.
I hereby disapprove of the oil filter in my car’s engine because it is selective in what it let’s past. We should campaign against particulate prejudice wherever we find it 🙂
I’m not looking for one-word answers. I think we’re all aware of the ambiguity of the species concept