Lamark proposed that giraffes evolved longer necks by trying to reach leaves in the tops of trees
Darwin claimed survival of the fittest, there are more individuals of a species born than can survive, therefore, a struggle for existence ensues, so any variation in an individual that aids in its survival over another individual, under the principle of inheritance, is propagated.
I do not see that there really is any difference in the above two views…what is the difference there that im missing? Is it that Lamarks model is too simplistic or is he in the wrong location in a chicken v egg race in that Darwin is suggesting that the giraffe didnt know it could reach high branches until it first tried to reach them…some other giraffes who observed this, who were taller, they had a go and managed to reach the higher leaves…thus in a drought (for example) they survived and the shorter ones died.
I just dont see there any real difference in the two theories.
From my understanding, Lamarck believed that evolution works through passing on traits that are acquired during an organism’s lifetime through environmental or behavior factors, whereas Darwin argued that evolution works through passing on traits to offspring which the parents were originally born with. In the Darwinian version of the giraffe scenario, a giraffe is born with an unusually long neck, which allows him to gain access to more food higher in the canopy so he is more well nourished than the other giraffes with shorter necks and able to have more offspring that are well-nourished and able to survive to reproduce. This contrasts with the Lamarckian scenario where the long neck is something the giraffe acquires from behavioral factors (i.e., stretching of the neck). I should note that were Lamarck right, such traits would only be advantageous to the offspring if they were born after the traits were acquired, so we would observe a difference in the traits offspring born at different times of an organism’s lifetime. There is some evidence of this actually because of environmental influence on gene expression, but not the kind that would prove Lamarck right.
The problem for me is this…
If giraffes eat certain trees, then that harmony is beneficial to both the tree and the giraffe right…so
Why didnt the tree just evolve to grow shorter?
Lets look at my point another way…
If the tree grows taller and through natural selection therefore giraffes grew taller so they can reach higher leaves in taller trees, why did the dinosaurs die out? They were already taller and could reach the leaves in taller trees! (The oxygen environmental argument does not anser this dilemma btw… partially because taller trees photosynthesize a greater volume of CO2 producing more oxygen)
The giraffe example here is deleterious and not actually a positive gain.
Lamarck is saying that efforts made by living creatures can change the nature of their offspring. Darwin is saying that the nature of the offspring changes ordinarily, and that some of those changes may benefit the offspring that have them.
Huge difference!
First, how is getting its leaves eaten beneficial to the tree?
Second, almost regardless of how seeds are distributed, seeds from taller trees are likely to spread farther afield, which benefits the species.
Added height would only be deleterious if a giraffe grew too tall to reach most of the leaves.
Ah…because of a fundamental principle known as the BIOCyCLE!!!
You are hyper focusing on tall giraffe tall tree and not understanding the logical problem in the bigger picture here.
Now you are claiming gains outside of harmony claiming the tree is using natural selection to allow tree to suvive and kill the giraffe. So now the tree is forcing the giraffe to grow bigger…how is that even remotely different to the giraffe growing bigger by trying to reach higher…the tree choosing, that is crcular peter robbing paul nonsense argument. Surely logically you can see that?
Anyway, the.logical similarities here suggests quite strongly that fundamentally Lamark v Darwinian arent really any different.
You seem to have a whole forest of misunderstanding here - and you’re wanting to add in new misunderstandings and confusions of your own before even getting your first confusion sorted out. If it’s your own confusion that you want to hold onto and hide behind right now, rather than learn something, that’s understandable. But if you really do want to understand something, then @CSTR already gave the answer you need about the giraffes and their longer necks. Don’t immediately run away from that to introduce trees and leaves and whole webs of ecological interdependence without just first pausing to see where you already left the rails about evolutionary mechanism. Also - to get one more thing straight, Darwin didn’t know anything about the actual mechanisms in play. DNA, genetics, heredity - the actual mechanisms of all that came to light long after he was gone. So appealing to what Darwin thought about this doesn’t make any more sense than claiming that Sir Isaac Newton had a wrong understanding of electronic computers.
So - back to the giraffe. The giraffe’s genetics don’t change as a result of the giraffes efforts or exercises. But the genetics help determine its ability to produce offspring (or not!). And over many, many generations, the genetics that helped those generations come to be are the genetics that got passed on. And if ones that had slightly longer necks were helped to (on average) be more successful as reproducers, then those were the genetics that got passed on with a higher frequency. That is the understanding that makes the most sense of all the evidence, and the Lamarkian understanding hasn’t worked. Yes - there’s a lot more to be said about a lot of stuff. But can you stop right here and at least understand this? If you can’t then there’s nothing to be gained by running off into other stuff that you’ll understand even less.
I think Lamarck probably is right but not from the way he understood it. He would not have known about gene expression or cell memory correct? So the Darwinian version just looks at variation in offspring while Lamarckism is looking more at where the source of that variation comes from… from the parents and can include changes in behavior. The Bible talks about generational curses, where a bad behavior can be passed down to the next few generations.
I think that is correct. The influence of the environment on gene expression doesn’t mean that Lamarck was right about the source of variation. It does mean that something like what Lamarck was suggesting (transfer of traits to offspring acquired by a parent during its lifetime) is possible, but the mechanism is not the one that Lamarck thought it was. It is still more consistent with Darwin’s understanding of variation and inheritance.
Excuse me, this amateur, but my understanding about the giraffe’s neck:
Darwin, in the later editions of “On the Origin of Species”, allowed for some inherited of acquired characters, in particular, to explain the giraffe’s neck.
But there are some difficulty with that as a mechanism, in general, which Darwin didn’t know about - how inheritance works. So, there ought to be another mechanism, and evidence for that.
And, I recall - and, yes, I am not a scientist, so I may be wrong.
There is some evidence that the feeding behavior of giraffes may not take advantage of the long neck. Giraffes are seen feeding with their necks horizontal. There is some evidence that male giraffes engage in combat using their necks, and females have necks not as long. So maybe the mechanism of sexual selection is a better explanation.
Firstly, the genetics argument strikes trouble in that genetic information that is not passed on is lost. That means that eventually, the species will die out…because energy and matter are neither created nor destroyed. Trouble is, that facilitates the notion that we too will one day become extinct…which some secularists and also christians do believe as you know.
This isnt a YEC v evolution issue…its Lamark/Darwinian vs Nuetral theory of evolution
The logical problem is that whether you can appreciate it or not, THERE IS NO DIFFERENCE BETWEEN A TREE CHOOSING BY GROWING TALLER (darwin) AND A GIRAFFE CHOOSING BY GROWING A LONGER NECK (lamark)!
Dinosaurs dying out due to oxygen depletion (if you like) and larger trees therefore taller Giraffes, these notions are counter intuitive…larger trees photosynthesize a far greater volume of CO2 than small trees. So a giraffe growing a longer neck through selection given bigger creatures who could already reach higher tree leaves died out …those two are in the opposite direction.
Now for the Christian scientific dilemma that has to come up…(this isnt what i really want to focus on though)…in this thread im exploring Darwinian v Lamark and im not getting appropriate answers to the big picture here.
If a couple of isolated catastrophic events killed the dinosaurs, given the time.period in question, they shouldnt have even survived long enough to evolve into that size animal in the first ppace because pver a period of 165million years that the dinosaurs lived on this planet, the earth must have had dozens if not many hundreds (perhaps thousands) of catastrophic asteroid impacts!
Anyway, i dont want to get into YEC on this thread…that not my interest here. I simply want to research what this forums knowledge is on the Lamark v Darwin.
Surely there must be individuals here who are on one side or the other?
I agree with this csr, however the problem still isnt being answered…
Please discuss the differences between the two theories…im suggesting that a tree deciding (darwin) or a giraffe deciding (lamark) are not actually any different.
In the Darwinian model where the tree decides - giraffes with longer necks survive, those with shorter necks are at a significant disadvantage and die out. Survival of the fittest.
In Lamarks model, which i happen to agree is fundamentally flawed, tye tree has alreasy grown large and the biocylce is negatively impacted in that what it exists to provide a food source for…doesnt itself exist! There were once larger animals that ate bigger trees, so why when the larger animals.died out did we have bigger trees and not smaller ones?
I accept that parts of this become a chicken vs egg dilemma.
A tree does not decide and a giraffe does not decide. There is variation between trees and variation between giraffes and natural selection filters out of that variation who will get offspring.
The tree definitely does not want to be eaten but as it cannot hide or run away, it has only limited options available to stop the giraffe. Height does prevent most mammalian herbivores to reach the canopy but not the giraffes with the longest necks or the elephants that can break the trunk. The other options would be having thorns, producing chemicals that are poisonous or repelling, and having cooperation with the ‘enemy of the enemy’. The giraffes are not the only herbivores and the trees need to find ways to cope with them all, from caterpillars to elephants. The tree cannot specialize in defending against giraffes, at the cost of becoming vulnerable against the other herbivores. All that is available is to make the feeding as difficult and costly as possible and hope that the herbivore will leave it and search another tree that is less well defended.
Acacia trees use at least thorns and cooperation with aggressive ants as defence against herbivores. There is interesting research showing that the trees with the highest herbivore pressure seem to invest more in cooperation with the ants - they provide more swollen hollow thorns as nest sites and more sugarbased food droplets for the ants than the trees that grow in a herbivore-free environment.
For the giraffes, the long neck is both an advantage and a cost. Life would be easier with a shorter neck but if most of the good food is high up in the canopy, a long neck gives an advantage that outweights the costs. A giraffe cannot affect the length of its neck, it is what it is. The availability of food determines if the long neck becomes such an advantage that the individuals with the longest necks get more offspring.
I cannot fully follow the logic of this claim. Could you please describe this in more detail?
Mutations bring novel variation and natural selection filters away such mutations that affect negatively the success of the individuals. Neutral mutations will not be the target of strong filtering (natural selection) but some neutral mutations will anyway disappear because the individuals carrying these mutations will not pass these mutations to the next generation. These adding (mutations) and removing (natural selection, chance effects) mechanisms keep the number and quality of mutations within ‘tolerable’ limits.
About the extinction of humans: none of the biological species on Earth are everlasting, not even humans. Unless God does something to save the human species, we will go to extinction eventually, possibly because of the selfish and stupid decisions the humans make.
Luckily, I believe God has plans that will prevent a total extinction, although the selfish decisions made by humans are likely to cause much destruction and suffering.
Not even AiG or CMI would go along with what you are saying here. Start again at square one, this time with Khor’s response…
There is no point in framing Darwin vs Lamarck as current altenatives, because we now understand the general molecular basis of heredity, and putting aside epigenetics, characteristics acquired from behavior are not passed down to offspring. This applies to trees, giraffes, you, me, and all of life.
All of which options are used - the acacia trees giraffes browse on have long spines, produce tannin to deter browsing (and signal nearby trees to do the same), and attract ants that irritate browsers. But giraffes have long tongues, can detect the tannin (and don’t move to browse nearby trees), and have stiff hair and long eyelashes that obstruct the ants.
Sorry but that idea is falsified by the biocycle…thats a deeply flawed argument. Termites eat trees all the flaming time…you are hyperfocused on.giraffes and miss the point here.
Also theres this…
The crucial difference between “Darwinian” and “Lamarckian” mechanisms of evolution is that the former emphasizes random, undirected variation whereas the latter is based on variation directly caused by an environmental cue and resulting in a specific response to that cue (Figure 1).11 Nov 2009
If Darwin is right, and Lamark wrong how do we explain maslows hierarchy of self needs which aligns with tha latter?
