Evolution - Where are the Cracks?

[Tormod]

It's simpler to just say that "the theory of evolution is currently the best explanation we have for the structure of the tree of life". It is not the ultimate truth and there will always be things it can't explain - because no theory can explain everything.

 

There will be gaps that aren't gaps (because they are contested, so some people accept them while others don't), and holes where there are no current explanations.

 

You probably wouldn't be able to find two researchers with the exact same opinion as to what those gapes are, though. Just like in any other field of science.

[ughaibu]

Evolution is a fact, as much as anything is a fact. The theory of evolution is a collection of mooted mechanisms by which evolution occurs, there are some people who still dont seem to realise this. "Cracks" in the theory of evolution do not cast any doubt on the reality of evolution, any more than doubts about any theory of gravity would suggest that gravity is not a fact.

[CraigD]

What are the scientific ‘cracks’ in the theory of Evolution?

“Crack” implies a fracture in what was once smooth and continuous, something that scientific theories rarely if ever are. “Gap” implies a incomplete part of growing, changing object. It’s better, I think, phrase the question “where are the gaps in evolution.”

 

Simply put, the great gap in the theory of evolution is, IMHO, between the “big” analogies like adaptation, fitness, and natural selection, and the small, mechanical, chemical understanding of biochemistry. Ignoring some fringe theories to the contrary, the former are caused by the latter, but understanding how is a challenge likely to require man-millennia of scientific study and research.

 

I envision it as a gigantic jigsaw puzzle, where the final picture is vaguely known, but the details can only be seen as people painstakingly assemble the tiny pieces.

[HydrogenBond]

Evolution is obvious in the sense that life is moving in the direction of increasingly complex systems. But not all life does this. In other words, if we assume life started from single cells and evolve from there, one question would be is why aren't there many stages of evolution occurring side by side in our modern world There should be single cells just becoming multicellular. There should be simple multicellular blobs just becoming fish, etc., since single cells are very plentiful. There should be retiles ready to become mammals, livards ready to grow feathers or wings, some apes should be showing signs of becoming humans, etc.

 

What we see is a one shot deal as though evolution only happened down a main path with the past states of life stopped where they are or restricted to minor improvements. That is why I believe evolution was driven by earth potentials that no longer exist quite the same way, thereby resulting in one main evolutionary path.

 

If we look at existing evolutionary theory, mutations and selective advantage are still occurring. New life forms should be appearing almost as commonly as progression in existing life forms. Also major changes in the very nature of lower animals to form the precurosrs of higher animals should also be occurring. Isn't that what evolution is all about?

 

If one takes into consideration an evolving earth and environment setting the potential for the DNA to go down a main evolutionary street, than the DNA is not #1, but plays a support role to the various earth potentials in the evolving environment. These are mediated through the hydrogen bonding or hydrogen protons in the cell via the cellular water and the water of the earth.

[TheBigDog]

Some issues, there are many others I think.

 

(1) Statistically what are the chances of the components in the primordial soup combining to create the first cell?

(2) Is it possible that random mutations most often observed to have deleterious affects on organisms have really been responsible for building strength, adaptation and resilience in to populations?

(3) How can complex systems within the body have developed their component parts over time when in reality they only really make sense and only confer advantage when used simultaneously?

(4) Would adaptations like eyes, flight etc. really be sufficiently advantageous to an animal unless in their finished form?

(5) Some animals seem to have developed characteristics that are biologically costly rather than advantageous to them. For e.g. - Why did some dinosaurs get so big?

(6) If animals went through an evolutionary process why have we not found innumerable transitional forms in the fossil record?

I'll take a stroll down speculation lane with you Fiona. :eek_big:

 

1) 1 in x. x is finite, so given enough time it happened.

2) Random is as random does. We observe it having bad effects, but the nature of random means other times it would be good. See answer 1.

3) This is a tough one, but I would speculate that complexity is a function of specialization. The more times an organism is forced to specialize, the more complex it becomes. See answer 1.

4) Eyesight is on a sliding scale. There is light or no light. intensities of light. Depth of light. Focus. Colors. Eyesight was obviously needed for larger life forms to thrive as virtually every large organism in every environment has working eyes. Those without were supplanted by those with. Where better was an advantage those with better thrived. Where it was not needed, it is poor or missing.

5) What may seem to us as being a poor evolutionary model was in fact an advantage at some point. The fact that we cannot reason why does not change the reality of form/fit/function in nature.

6) This is actually the only one I was interested in anwering, but I figured I would give all six something. It is my belief that evolution is not a slow arduous process, but is in fact a rapid process. The reason we do not see the in between peices is because they happen in just a few of generations. It is my thought that when an isolated population gets so low that it is on the brink of extinction, at that point in time radical shifts in physical traints happen out of necessity, and because a smaller number of genes have a maximum impact on the gene pool. The closer an isolated population gets to zero the faster it will take on the traits of the survivors. In the circomstances of normal survival species reach an equilibrium that slows or stops the evolutionary process. Not all species evolve radically under such stress. Most simply die out. But when they adapt and evolve, they become something new very quickly indeed. IMVO.

 

Bill

[CraigD]

If we look at existing evolutionary theory, mutations and selective advantage are still occurring.

Agreed. Additionally, as an increasing number of organisms are fully and partially genetically sequenced, entered into bioinformatics databases, and subjected to numeric analysis, the continuous nature of genetic change is increasingly supported, and understood in greater detail.

New life forms should be appearing almost as commonly as progression in existing life forms. Also major changes in the very nature of lower animals to form the precurosrs of higher animals should also be occurring.

I believe this conclusion fails to take into account an important concept, that of the ecological niche, specifically the idea that, in a mature ecosystem, before a new organism can fill a niche, its old occupant must vacate it.

 

Consider this summary of how some believe complex multi-celled life evolved from single cells without nuclei (prokaryotes):

1. Prokaryotes evolve genes to excrete protective biofilm matrixes
   
2. Prokaryotes in the biofilm colony segregate/specialize
   
3. Some Prokaryotes evolve genes to express cell membranes, becoming eukaryotes
   
4. Other prokaryotes invade the eukaryotes, becoming mitochondria
   
5. The colony becomes motile
   
6. The colony is large (macroscopic)

Steps 1-2 are ubiquitous – nearly every microorganism either excretes a biofilm matrix, or genetically codes for specialized proteins to assist it in adhering to biofilm matrixes. Consider, however, the perils a colony reaching the final 2 steps encounters from existing, highly evolved animals contending for a given ecological niche. The likelihood of the transitional colony/animal prevailing in such struggles, allowing it to evolve increasingly complex animal traits, seems to me small. At the same time, its biofilm is still more an open ecosystem than a well-defended body, and the specialized organisms in it metabolically less efficient, on average, than random, unspecialized prokaryotes, so it is at risk of invasion and takeover resulting in the disruption and undoing of the colony’s evolutionary progress toward animalhood.

 

Now, consider a long ago time when these steps were happening for the first time. With the evolutionary niches vacant or occupied by unspecialized prokaryotes, transitional colony/animals would not have faced competition from existing animals, and would have had a greater likelihood of successfully filling the niches.

 

In short, it’s not that the process has ceased, but, like an endless succession of inventors filing patents for commonplace things, it could only succeed the first time in each niche.

 

I’ve hinted at a hypothesis, here, and not, I suspect, an original one. One should note that only a tiny fraction of the vast number of distinct biofilm colonies have been studied in detail, so despite lack of evidence (to the extent of my inexpert knowledge) of steps 3-6, such evidence may just be awaiting discovery.

[Boerseun]

There should be retiles ready to become mammals, livards ready to grow feathers or wings, some apes should be showing signs of becoming humans, etc.

Gotta agree with Craig on this one.

 

There were mammals for millions of years before the dinosaurs died out, but they were small, and lurking in the shadows. But once the dinos died out, whatever properties the mammals had that gave them the edge, let them survive what killed of 99% of the dinos and they entered a world of empty niches. And seeing as there were no competition left in these niches, they quickly evolved to all the varied mammalian forrms you see aound today. I think this also plugs into the idea of Punctuated Equilibrium that BigDog was talking about in his post above.

 

This is not to say that individual mutations weren't happening. They were, as they are happening today, but seeing as the niches are filled, a mutation must really be something that will make an animal fit into a niche which is currently empty or non-existent. For instance, if a lion were to experience a mutation of the front limbs which accidentally makes it an excellent tree-climber, it will find a niche in the treetops for a previously land-based hunter which would give it access to bird's nests, monkeys, etc. That will basically end up defining a *new* niche, because there are no animals doing that currently. It might impact negatively on its running capabilities, but so what - there's more than enough meat in the trees. And the longer this keeps up, the more specialized the tree-climbing lion would become, until eventually the poor sod's offspring can't walk properly on the ground anymore. Tree-climbing lions would end up mating exclusively with other tree-climbing lions, and hundreds of thousands of years later, would define a brand-spanking new species. The lions on the ground, however, will continue chasing after zebras and antelope, seeing as there's a lot of food in that niche still. Two niches, two distinct species - although they shared the same grandpappy.

[Zwirko]

Some issues, there are many others I think.

 

(1) Statistically what are the chances of the components in the primordial soup combining to create the first cell?

(2) Is it possible that random mutations most often observed to have deleterious affects on organisms have really been responsible for building strength, adaptation and resilience in to populations?

(3) How can complex systems within the body have developed their component parts over time when in reality they only really make sense and only confer advantage when used simultaneously?

(4) Would adaptations like eyes, flight etc. really be sufficiently advantageous to an animal unless in their finished form?

(5) Some animals seem to have developed characteristics that are biologically costly rather than advantageous to them. For e.g. - Why did some dinosaurs get so big?

(6) If animals went through an evolutionary process why have we not found innumerable transitional forms in the fossil record?

 

 

1) Looking backwards at the chances of something happening that has already happened is kind of illogical. Take a deck of cards as an example. Throw these into the air then pick 'em all up and look at the sequence of cards that results. There would be a 1 in ten to the 60th power chance of getting that particular sequence of cards. So how was it possible against such staggering odds to get the cards in that order? Yet you "beat" such huge odds every time you time shuffle a deck ...

 

Such claims of events being statistically impossible for past events such as these do not really "compute". It's a fallacy.

 

2) Mutations are NOT mostly deleterious. They are, as you point out, most often "OBSERVED" to be deleterious. This is only because such mutations are the ones that are most easily observed. How can you look at an organism and say "Oh, this critters hexokinase enzyme is 2.3% more efficient?". Neutral and most beneficial mutations would not be readily observable.

 

3,4,5 and 6) These are classic "creationist questions" that have been more than well answered many, many times. They simply reflect a misunderstanding of how evolution works. For example, transitional fossils exist in abundance (although not a "perfect" record, this is hardly surprising and would not even be expeced to be perfect).

[Michaelangelica]

Some issues, there are many others I think.

 

(1) Statistically what are the chances of the components in the primordial soup combining to create the first cell?

Quite good if you include symbiosis

(2) Is it possible that random mutations most often observed to have deleterious affects on organisms have really been responsible for building strength, adaptation and resilience in to populations?

Yes but evolution is about survival not strength and resilience. These can be two separate things

(3) How can complex systems within the body have developed their component parts over time when in reality they only really make sense and only confer advantage when used simultaneously?

A creationist furphy I think. primitive light sensing organs can still be useful. Plants have them

(4) Would adaptations like eyes, flight etc. really be sufficiently advantageous to an animal unless in their finished form?

Same as above

(5) Some animals seem to have developed characteristics that are biologically costly rather than advantageous to them. For e.g. - Why did some dinosaurs get so big?

Hard to know if your assumption is right. Certainly dinosaurs were far more successful than humans. They were on the planet a LOT longer than we have been

(6) If animals went through an evolutionary process why have we not found innumerable transitional forms in the fossil record?

We have; another creationist furphy

 

See the thread Darwin re-visited

[Edella]

A creationist furphy I think...

From Wiki:A furphy is Australian slang for a rumour, or an erroneous or improbable story. Having had a roommate from Port Macquarie years ago,I actually know this word.I'm so proud of myself!

[Michaelangelica]

From Wiki:A furphy is Australian slang for a rumour, or an erroneous or improbable story. Having had a roommate from Port Macquarie years ago,I actually know this word.I'm so proud of myself!

Thanks for translating

A tip

if you ever get to Australia never talk about Fanny bags as a visitor did on radio the other day. The anouncer could hardly talk. For us Fanny is the other side.

 

To the topic

If there are issues with evolution it is in the detail; the mechanisms. As everone has no doubt heard me before I don't think "Natural Selection" is enough to explain the process

[Paul H]

Dov Henis,

 

…containments in the cosmic space of ever diluting original singular energy, and life's initial "chemicals" just happened to be in a configuration/constellation able to support and sustain this proliferable containment via a cascade of favorable energy-effected steps…

 

A whole thread to itself I think?

[Paul H]

are the chances of the components in the primordial soup combining to create the first cell?

 

(2) Is it possible that random mutations most often observed to have deleterious affects on organisms have really been responsible for building strength, adaptation and resilience in to populations?

(3) How can complex systems within the body have developed their component parts over time when in reality they only really make sense and only confer advantage when used simultaneously?

(4) Would adaptations like eyes, flight etc. really be sufficiently advantageous to an animal unless in their finished form?

(5) Some animals seem to have developed characteristics that are biologically costly rather than advantageous to them. For e.g. - Why did some dinosaurs get so big?

(6) If animals went through an evolutionary process why have we not found innumerable transitional forms in the fossil record?

 

(There *are* inummerable 'transisitional forms'... the "transional forms" agrument is not one, for me)

 

While I accept all the above are issues for many people, and they can be argued at length. I think I'm familiar with those arguments. I could be ill-informed... maybe there's an anvenue there...

 

But they're not 'cracks' for me.

[Paul H]

I've been reading... you may not know (just for fun), that apparently:

 

One "Patrick Matthew", a Scottish gardener, came up with the theory of "Darwinian" Evolution 20 years before Darwin and Wallace did. First published in "Naval Timber and Arboriculture". How about that. Seriously.

[Paul H]

I mention this because it seems to me that the general Theory of Evolution (as expounded by Mathew) is about the only scientific theory that has no (scientific) competitors.

 

Isn’t that rare?

 

And interesting?

 

It’s very rare.

 

Unique?

[CraigD]

… it seems to me that the general Theory of Evolution (as expounded by Mathew) is about the only scientific theory that has no (scientific) competitors.

I don’t think “uncontested” scientific theories are exceptional when the knowledge domain (what Steven Jay Gould famously terms a “magisterium”) is sufficiently narrow. For example, classical Newtonian mechanics are not seriously contested when it comes to describing the short-term behavior of macroscopic bodies moving at small fractions of the speed of light, but is effectively superseded by theories such as Relativity for faster movement or long time periods, and quantum mechanics for bodies on an atomic scale.

 

Evolution is scientifically uncontested in the domain of molecular biology, but less so for describing “deep time” questions such as the very early origins and far future “destiny” of life. For example, evolutionary biology provides little in the way of useful techniques to evaluate competing scientific origin of life hypotheses such as abiogenesis and panspermia.

[HydrogenBond]

Monopoly control is resisting all competition. That makes it sort of a religious dogma. One of the points where evolutionary theory falls short is that major system wide changes in life occurred in a logical order. Single cells came first, then multicellular, then polarized multicellular to form things like simple plants (root-leave polarization/differentiation). Then simple animal polarizations/differentiations evolve. First cold blooded then warm blooded, etc.

 

One does not see an illogical evolution such as single cells direct to warm blooded animals back to cold blooded animals than to simple plants, etc. These logical system wide observations would indicate two layers of life progression, one that is logical orderred with another showing lateral variability along the main logical path.

 

Let me give an example. Picture a blob of cells gathered together in sort of multicellular contact, if the blob was vertically orientated with the top seeing sunlight and bottom in the murky muddy water, the blob would begin to polarize its cells into very simple analogs of leaves and roots. The circulation within the blob may begin to differentiate aspects that show both, such as pre-stems that can form buds or roots. Maybe selective advantage may cause certain cells in the blob to differentiated and proliferate faster but natural earth potential would be setting the logical stage of where life is heading, i.e, first plants.