I do not know what you mean by ‘biocycle’. Could you please explain what it means and how does it falsify my claim that the tree does not want to be eaten?
[‘does not want to be eaten’ is a figurative expression - a tree cannot think as humans but it is utilising the means it has to repell herbivores]
Your description about how the Lamarckian explanation differs from what you call ‘Darwinian’ is ok, as long as we are speaking about heritable traits. The responses that are not heritable are not transferred to the next generations.
Lamarckian explanation is not supported because there is no evidence to support it.
Maslows hierarchy of self needs has nothing to do with the comparison of the Lamarckian vs. ‘Darwinian’ explanations. The basic physiological and psychological needs are part of our life as created beings but do not reveal how did we get to this point.
A tree tries to get the water, nutrition and sunshine it needs, uses the available means to repell threats and invests in reproduction. These might be called ‘a hierarchy of needs’ for the tree but the tree cannot decide that it will develop a heritable trait as a response to the challenges it is facing.
@adamjedgar can we back the truck up a bit, please?
Let’s bring this closer to home. You have kids, right? Your bio parents certainly had at least one.
Think about how much control over the genetic material in their children your parents or your children’s parents had.
Things you can control: avoiding known environmental hazards to genetic material (radiation, x-ray, etc.), reproducing during the female’s optimal age range, choice of partner, and the like.
These strategies are all types of “safe handling” protocols for the material the parents have to provide to reproduction.
Beyond attempting to protect the genetic material, how much control did these parents have over the genetic material each contributed to reproduction during each separate event?
Understanding this is key to answering your own question.
Darwin proposed long term heredity. Traits were passed on unaltered for many generations.
Lamarck proposed short term heredity. The traits found in offspring could change generation to generation depending on the experiences of the previous generation.
Using the giraffe as our example, if we moved the giraffes into an environment where shorter necks were favored the two theories would propose two different outcomes. For Lamarckism, it would only be a few generations before all of the giraffes had short necks, and the trait would emerge in many different lineages in parallel. For Darwinism, you would need to wait for a short neck trait to emerge in a single lineage, and then wait for that trait to spread to the rest of the population over many generations.
Those are the big differences, at least how I understand them.
I don’t understand. How do termites eating trees falsify the claim that trees can’t outrun the species that eat them? Wouldn’t termites support the claim? Are there trees that are able to outrun termites?
If I understand rightly… Lamark’s idea was that need alone would somehow push or otherwise have some kind of influence on an organism toward developing a needed trait. Hence that common Lamarkian illustration of the giraffes needing to reach higher branches, so thus, their descendents gradually grew longer necks in direct response to said need… that is, the need directly influenced or somehow directly contributed to the organism developing longer necks.
Darwin’s view, or that at least of later developed Darwinism, recognizes that all the need in the world for said giraffes to reach higher branches wouldn’t in any way cause or contribute, or “push” an organism to develop a particular trait. The need, or benefit, for an organism to have said trait in no way pushes, coaxes, or influences said organism to develop said trait.
Rather, in basic Darwinism, basic variation (which modern science understands primarily as genetic mutation) means that some organisms will be born with longer necks, some with shorter… the ones with longer necks survive (due to being able to eat from the taller trees), the ones with shorter necks die… hence the one’s that randomly happen to have longer necks pass on their genes to their descendents. And then from within that population, there are some with longer necks due to natural variation and mutation, and then the longer necked ones pass on their genes, and so on, etc.
So briefly, Lamark’s idea if I understand rightly was that the need to reach longer branches in some way influenced, pushed, coaxed, or otherwise caused the giraffes to eventually have longer necks… Darwins view is that randomly, some of the animals had longer necks, and those that did survived to pass on their “long-neck” genes to their descendents, and so on, and so on, and thus the trait of long necks got solidified in the population. But not because the environment was putting any direct influence on what trait was desired.
Not in the least – the two rely on totally different causes and mechanisms. It would be more like a live chicken vs. LEGO chicken argument.
The biocycle of a tree involves leaves being naturally released, not them being eaten. While leaves being eaten may in some species stimulate growth, that growth comes at a cost that is generally greater than the benefit.
The tree isn’t forcing the giraffe to do anything, the giraffe is changing under impetus of mutations, and some of those mutations happen to make more of the tree accessible.
That is utterly different from the giraffe “trying to reach higher” – it’s a totally different mechanism.
There are no logical similarities – it’s the difference between cars driving where highways get built and highways appearing because cars drive somewhere.
And getting it wrong. Lamarck’s view boils down to organisms generating their own mutations, whereas standard ToE says mutations come randomly. There is no evidence that organisms generate beneficial mutations for their offspring.
No, because beneficial genetic information, including new genetic information (which we have observed happening), gets passed on more than detrimental information.
Totally irrelevant.
Sorry, but both of those are Lamarck because in both your examples an organism is “choosing” and generating new genetic information.
Wow – serious lack of information about astronomy! This is like saying that a soccer team should win every game because the team can sometimes make successful passes between players – but it isn’t about successful passes per se, it’s about passes that set up a successful goal. It isn’t about lots of asteroid impacts, it’s about impacts big enough to affect the entire ecosphere – and while there are plenty of asteroid impacts, most are the size of soccer balls, while the ones that matter are the size of soccer stadiums.
I doubt anyone is on the side of Lamarck since his system requires magic.
This shows a serious confusion about historical ecology that I’m not going to go into out of lack of expertise.
To me, it seems that a more easily seen example of how Lamarckism is wrong than giraffes is with something like the tail of some dog breeds like Australian Shepards. They are traditionally bobbed as pups, and have been for generations. Lamarck would predict that they would eventually be born with bobbed tails, and some are due to selective breeding, but the majority are born with normal length tails that are docked in many cases. Another example might be horned breeds of cattle that are dehorned vs. cattle that are genetically hornless or polled.
Darwin did propose mechanisms that were Lamarckish.
It was Weismann in the 1890’s that helped establish the barrier between somatic and germ line cells (i.e. the Weismann barrier). In the 1940’s and 50’s the work of the Lederbergs and the work of Luria and Delbruck demonstrated how mutations are random with respect to fitness which can be understood as a barrier between mutation and need.
As a humorous aside, my imagination keeps trying to come up with fictional theory/philosophy for Darinism. Being a child of the 70’s/80’s, can’t stop flashing back to the show “Bewitched”.
Yep. No inheritance of acquired characteristics. And when we discovered DNA we had a confirmation that Darwin was correct and Lamarck was wrong.
But perhaps this is hard for Adam to understand because there is a rather critical exception. That would be us. We do pass on acquired characteristics. Not with DNA to be sure, but via human language (and other human communications media). When we discover something we pass it right on to the next generation. And this is why we have surpassed biological evolution to change on a much faster time scale at an accelerating rate. And we even use this to overcome deficiencies in our genetic inheritance (take the use of eye glasses for example). And now that we understand our own genetic code this surpassing of our genetics by means of technology is only going to increase.
I’m not so sure about that. I could think of many ways Lamarckism could work through DNA.
I would argue the discovery of the Weismann barrier was much more of a blow to Lamarckism than the discovery of DNA. If there is no way for somatic cells to communicate environmental conditions to the germ line then there there can’t be transmission of acquired characteristics from one generation to the next.
Well, yes… but for me that is just details. When I learned how the whole inheritance thing worked, it was all of a piece and not so much an historical study of separate discoveries.
Though… thinking more about it… I am not sure I agree so much after all. Yes the separation of somatic and germ cells is significant, but it is not like we even add learned information to the DNA of our somatic cells either. The closest we would get to that, I can think of, is to say we don’t pass cancer on to the next generation. All the change from one generation to another all happens in the reproductive process by which we introduce variation into the combination of germ cells from both parents.
And what about single celled organisms? Are you claiming the discovery of the so called Weismann barrier applies there too?
I would agree that we need to look at inheritance as a whole which involves more than just the structure of DNA. If all we knew was the chemical structure of DNA and that it was the molecule responsible for inheritance we still couldn’t discount the possibility of Lamarckism.
This is where discussions on epigenetic inheritance comes in. Like Darwin’s gemmules, I would agree that epigenetics is Lamarckish (or Lamarck-lite if you like). For example, DNA methylation patterns do change in response to the environment and it does impact phenotype. In addition, there is a lack of a Weismann barrier in some plants and animals where somatic cells do give rise to germ line cells which allows them to pass on epigenetic modifications. However, these phenotypes are usually limited and they don’t stick around for many generations without the environmental pressures needed to produce them which means epigenetics can’t explain long term evolutionary patterns. The concepts get even messier with single celled haploid organisms.
Like almost everything in biology, it’s messy. There are seemingly no rules that are followed 100% of the time.
To answer my own question, sort of. There is no such barrier obviously, but single celled organisms sometimes do have a way of altering their own genetic code by means of transferring portions of their DNA to others. It is not Lamarkism. The changes are still a product of Darwinist mechanisms of variation and natural selection.
As for these epigenetic features, I would argue that these are an evolved flexibility and not an example of inheriting acquired characteristic.
But I acknowledge the messiness which causes us to expect/suspect most rules to have exceptions.
I’ve softened on transgenerational epigenetic inheritance over the years. It does absolutely happen, and I am not at all against claims that label it as being something like Lamarckism. In the end, science is about learning how nature works, not forcing nature into human defined boxes. If it turned out Lamarck was right then that would have been the theory we use in biology. If it is a 99%:1% mix of Darwin:Lamarck, then so be it.
I think that the main belief of Lamarckism is that acquired traits can be passed to descendents. There is some question over what constitute “acquired” traits. There is an article in Wikipedia (Lamarckism - Wikipedia) that contains a list of many of the experiments that attempted to demonstrate the inheritance of acquired traits. (The experiments failed to demonstrate such inheritance.)
When discussing quantum theory, Einstein argued against it by saying that God did not throw dice. It seems that many of the people that disagreed with Darwinism did not like a theory that said that human beings were the result of pure chance. However, one can argue that a theory that depends mainly on random chance is more likely to be correct that one which requires the development of some sort of biological machine learning which indeed would be much more complicated.
So what we have is a body of knowledge for building organisms that is mainly contained in the chromosones, but also partially in the mitochondria. Changes can occur due to the permutations of genetic combinations and chemical damage to the genes causing mutations. There may be other forms of inheritance, such as diseases being passed in the womb to the next generation, and in the same manner to following generations.
Although differences in which genes are attached to which chromosones can cause differences in what is passed on to the next generation, an essentially complete set of genetic information is passed on, including beneficial, detrimental, and neutral changes. There will also be some changes which cause both benefits and detriments. (Consider the body of knowledge on inherited medical conditions.) Furthermore, it would seem that the most likely result of detrimental information being passed on is that an embryo will not be formed or will be unable to survive after birth.
There is your answer, a tree being eaten is beneficial to the biocycle. I guess what i am saying is that this idea girafes get longer necks because trees grow taller (lamark) or the tree grwos taller because girafes have long necks…its a chicken and egg argument.
The logical problem may very well be that we cant actually see a giraf neck.grwoing long the higher it tries to reach…i get that, however i really dont see any difference between that and the darwinian view that a ramdon giraffe birth where said giraffe just happens to have a longer neck…thats is not a better explananation…especially given its actually beneficial.for the biocycle for trees to be eaten by giraffes. (Sorry for.spellimg…dont have glases on and this phone keyboard is hopeless)
Edit…
Oh.btw
See tree in image below…when our horses couldnt reach the leaves higher up, they instead just “ringbarked” the flaming tree!
You speak like ‘biocycle’ would be a conscious entity with its own goals. That kind of thinking resembles the ideas of ‘balance of Nature’ and the ‘Gaia hypothesis’ claiming that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating complex system that helps to maintain and perpetuate the conditions for life on the planet. [the description of the Gaia hypothesis was borrowed from Wikipedia]
The empirical study of nature and a critical theoretical analysis of the ‘Gaia hypothesis’ (and ‘the balance of Nature’) have concluded that it is a beautiful and seminal idea but not true. Reproducing entities do not sacrifice themselves for the ‘balance of Nature’. Individuals or units formed by close kin act in such selfish ways that often leads towards destabilation of the system.
Ecosystems with a high diversity are more resistant towards major changes because the crash or local extinction of a population of producers or consumers will be partially compensated by the other species that compete for the same space or food. Although this makes a diverse system more resistant or resilient than a simple system, even diverse systems can run towards destruction because of the acts of one or more populations(/species) within the ecosystem of selfish entities. So called ‘climax communities’ may last longer than the other stages of succession but eventually even the ‘climax communities’ are destroyed or change radically.
Evolution also involves natural selection. Selection is the opposite of random. In fact, one could say that the combination of random mutation and natural selection is very close to how we use machine learning. From my crude understanding, machine learning often involves random changes that are passed through a selection phase.
