The book Darwin Devolves

[rogue06]

Yup - I once said to my daughter that evolution is pretty much proven on the level of species (cats for example developing into different kinds of cats), but at the family level (non cat becoming cat), nothing had been shown to demonstrate the possibility. Lo and behold, a few years later ...

If nothing else shows one family becoming a different family, whales certainly do. The developmental sequence is compelling - it's almost like watching a film of a developing foetus.

The evidence for the transition from reptile to mammal is so well attested to that there is heated debate on whether this or that extinct species should be called a mammal-like reptile or a reptile-like mammal.

[rogue06]

So? Is there a resource that someone with no background in the relevant sciences could understand?

An excellent resource for this sort of thing (although its a few years old and therefore missing the discoveries made in the past decade) is Prothero's book Evolution: What the Fossils Say and Why It Matters

[Roy]

I mean that evolution is expected to produce a sequence of small variation, accumulating to large variations. But we see large changes in the fossil record, that are not preceded by small incremental variation.

I don't think this is true, and see no reason to believe it.

Name three examples.

Don't neglect to show that their precursors did not show any incremental variation.

But the trend in evolution is large changes, followed by small ones, hence "punctuated equilibrium".

So you have no clue about punctuated equilibrium.

[TheLurch]

So? Is there a resource that someone with no background in the relevant sciences could understand?

Birds are actually a lousy example of the sort of "incremental change on one lineage" that had been the topic of discussion.

Their lung structure appears to have been widespread, and is present in some non-avian reptiles today.
Feathers evolved 10s of millions of years before birds, and were also widespread.
Digit reduction seems to have been a matter of drift, and occurred in other dinosaur lineages.
High metabolism seems to have been widespread in the lineage that led to birds.

So, rather than incremental change, the earliest birds seem to have been a matter of throwing together some spare parts that were all present in multiple dinosaur linages. They make for a great example, just not an example of this particular phenomenon.

[tabibito]

An excellent resource for this sort of thing (although its a few years old and therefore missing the discoveries made in the past decade) is Prothero's book Evolution: What the Fossils Say and Why It Matters

Birds are actually a lousy example of the sort of "incremental change on one lineage" that had been the topic of discussion.

Their lung structure appears to have been widespread, and is present in some non-avian reptiles today.
Feathers evolved 10s of millions of years before birds, and were also widespread.
Digit reduction seems to have been a matter of drift, and occurred in other dinosaur lineages.
High metabolism seems to have been widespread in the lineage that led to birds.

So, rather than incremental change, the earliest birds seem to have been a matter of throwing together some spare parts that were all present in multiple dinosaur linages. They make for a great example, just not an example of this particular phenomenon.

Thanks, both. Checked the book out - its on the back burner for now ... too many study books needed for an immediate purchase.
Also found what seems to be a good series of articles here

And a really informative but simple one here

[lee_merrill]

Only if the examples are relevant. Lots of examples that aren't relevant (like, say, these) won't tell us of a relevant trend.

Well, the bacteria mentioned previously show a trend, for example.

But the trend in evolution is large changes, followed by small ones, hence "punctuated equilibrium".

Really? How can you demonstrate this is a trend, and not just that there are examples of both?

NB: quoting a couple of guys as saying it is is not a demonstration.

Just the principle of punctuated equilibrium is a start, showing that gradual change is not the norm, though evolution might lead us to expect small, gradual change. Then there is the Cambrian explosion and later radiations:

Source: Wikipedia

The rate of diversification seen in the Cambrian phase of the explosion is unparalleled among marine animals: it affected all metazoan clades of which Cambrian fossils have been found. Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans.

Source

© Copyright Original Source

Source: Berkeley

Source

© Copyright Original Source

Source: Berkeley

By the the Middle Devonian, placoderms, the first jawed fish, appear. Many of these grew to large sizes and were fearsome predators. Of the greatest interest to us is the rise of the first sarcopterygians, the lobe-finned fish, which eventually produced the first tetrapods just before the end of the Devonian.

Source

© Copyright Original Source

Such appearances, with statis, would indicate that large changes are the norm in the fossil record, not small, incremental ones.

Blessings,
Lee

[shunyadragon]

Well, the bacteria mentioned previously show a trend, for example.


Just the principle of punctuated equilibrium is a start, showing that gradual change is not the norm, though evolution might lead us to expect small, gradual change. Then there is the Cambrian explosion and later radiations:

Source: Wikipedia

The rate of diversification seen in the Cambrian phase of the explosion is unparalleled among marine animals: it affected all metazoan clades of which Cambrian fossils have been found. Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans.

Source

© Copyright Original Source

Source: Berkeley

Source

© Copyright Original Source

Source: Berkeley

By the the Middle Devonian, placoderms, the first jawed fish, appear. Many of these grew to large sizes and were fearsome predators. Of the greatest interest to us is the rise of the first sarcopterygians, the lobe-finned fish, which eventually produced the first tetrapods just before the end of the Devonian.

Source

© Copyright Original Source

Such appearances, with statis, would indicate that large changes are the norm in the fossil record, not small, incremental ones.

Blessings,
Lee

Punctuated equilibrium DOES NOT remotely effect the question of what is the norm in the fossil record concerning the rate of change. Rates of change are driven by changes in the environment. If the environment remains constant and possibly isolated very little or no change may take place for some species for millions of years like the Coelacanth. If the evolution changes over time then evolution may show more changes in populations and species, but nonetheless evolution involves millions or maybe hundreds of thousands of years that changes to take place. Regardless changes are gradual in ALL cases.

[Seeker]

With all due respect, all you Christians on this thread who accept evolution, what do you think of Jonathan Sarfati's claim that Christians who promote evolution are 'useful idiots', paraphrasing Lenin?

[tabibito]

With all due respect, all you Christians on this thread who accept evolution, what do you think of Jonathan Sarfati's claim that Christians who promote evolution are 'useful idiots', paraphrasing Lenin?

It is amazing how often "with all due respect" prefaces an egregious insult.

With regard to Sarfati's claim (Citing a Wikipedia Article), he says far more than that ... Sarfati repeatedly and clearly implies non-Young Earth Creationists are barely saved, and are otherwise misguided, apostate, ineffective or tools of Satan for failing to take a literalist, presuppositionalist approach to scripture.

I will readily admit to not taking a presuppositionalist approach to scripture. Christians are expected to be dispassionate in their evaluation of scripture and any claims of fact. The YEC calendar itself is forced, a tacit admission that the Biblical time frame is wrong, but YECs won't acknowledge their (unstated) admission.

[rogue06]

With all due respect, all you Christians on this thread who accept evolution, what do you think of Jonathan Sarfati's claim that Christians who promote evolution are 'useful idiots', paraphrasing Lenin?

[TheLurch]

Well, the bacteria mentioned previously show a trend, for example.

A trend of what?

You seem to want to use them as evidence that a mutation that damages a gene will be adaptive to a wide variety of environments. But they don't show that. Saying "trend" over and over doesn't somehow turn them into support.


As for the rest, it's just you not paying attention to your own argument. Again.

Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans.

Wow, lots of gradual change there from the sound of it.

As mentioned earlier, this time period also marks the wide and rapid spread of jawless fish, along with the important appearances of both the first known freshwater fish and the appearance of jawed fish.

Let's see, we have a radiation well after an earlier origin (that's the jawless fish), and the appearance of more fish with an obvious evolutionary antecedent (freshwater and jawed). All that sounds remarkably gradual.

So, fragmentary indications that life might be partly capable of existing on land came millions of years before clear evidence of terrestrial adaptation. What's the word for something like that? Maybe gradual?

More generally, you're just being stupid with these quotes. To use yet another example:

Source: Berkeley

By the the Middle Devonian, placoderms, the first jawed fish, appear. Many of these grew to large sizes and were fearsome predators. Of the greatest interest to us is the rise of the first sarcopterygians, the lobe-finned fish, which eventually produced the first tetrapods just before the end of the Devonian.

© Copyright Original Source

There is absolutely nothing at all in that quote to indicate whether the pattern was gradual or an example of punctuated equilibrium. There has to be a first appearance in the record for everything. You can't just point to the term "first" and think it supports the idea that it means "sudden".

In other words, your inability to use a dictionary to see these terms are not the same does not magically turn sentences that include them into supporting evidence.


To be clear to anyone with actual reading comprehension: I'm not arguing that there are no lineages that display a pattern consistent with punctuated equilibrium. There are. But there are definitely a lot of lineages that don't, and its relative importance in earth's history is debatable (and being debated).

[Roy]

A trend of what?

I doubt he can remember.

[shunyadragon]

I doubt he can remember.

I believe he has a Discovery Institute hard drive for a brain.

[TheLurch]

To be clear to anyone with actual reading comprehension: I'm not arguing that there are no lineages that display a pattern consistent with punctuated equilibrium. There are. But there are definitely a lot of lineages that don't, and its relative importance in earth's history is debatable (and being debated).

I'm going to elaborate on this a little bit for people whose minds aren't completely walled off, using an example from some of the quotes above it: the origin of jawed fish.

We know where, in an embryo, the tissue that forms our jaws (and those of our fishy ancestors) comes from. If we look at that same tissue in jawless fish, we find that it forms a handful of distinct tissues, like facial muscles. In jawed fish, it forms those same tissues plus the jaw bone. And if we look into the processes underlying this change, we find that it's basically a change in gene regulation. There's what you might call a "cartilage formation program" that's active in places like limbs. In jawed fish, it gets activated in the precursors of the jaw. In jawless fish, it doesn't.

So, the origin of the jaw seems like a fairly incremental change in the grand scheme of things. Until you start looking at what it enables.

If you look at lampreys or hagfish, which are jawless, you'll see that they're not fantastic swimmers, and they have a rather limited body form. The jaw doesn't just alter the structure of the mouth; it allows a diverse set of body plans that are, to one degree or another, anchored to the jaw. But that's not to undersell the jaw itself, as it enables a large collection of new ways to eat.

So what happens after the jaw is fully evolved? You start to see a diverse set of body plans of jawed fishes, many of them more effective than the ancestors. So they displace their ancestors from a variety of niches. In addition, you see the jawed fish occupying new niches that weren't available to their ancestors, like grazing on corals or munching on crabs. So you get an explosive radiation of the group once the gradual evolution of the jaw is fairly complete.

Now, consider what this would look like if, instead of a cartilaginous tissue like the jaw, the enabling change was in a completely soft tissue. You wouldn't see the long setup, you'd just see a dramatic radiation of lots of species. It would probably look a lot like... punctuated equilibrium.

[rogue06]

Well, the bacteria mentioned previously show a trend, for example.


Just the principle of punctuated equilibrium is a start, showing that gradual change is not the norm, though evolution might lead us to expect small, gradual change. Then there is the Cambrian explosion and later radiations:

Source: Wikipedia

The rate of diversification seen in the Cambrian phase of the explosion is unparalleled among marine animals: it affected all metazoan clades of which Cambrian fossils have been found. Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans.

Source

© Copyright Original Source

Source: Berkeley

Source

© Copyright Original Source

Source: Berkeley

By the the Middle Devonian, placoderms, the first jawed fish, appear. Many of these grew to large sizes and were fearsome predators. Of the greatest interest to us is the rise of the first sarcopterygians, the lobe-finned fish, which eventually produced the first tetrapods just before the end of the Devonian.

Source

© Copyright Original Source

Such appearances, with statis, would indicate that large changes are the norm in the fossil record, not small, incremental ones.

Blessings,
Lee

As you noted there have been actually been several rapid diversifications of life during earth's history including at least one 30 million years before to the "Cambrian explosion" (the "Avalon explosion" of the Ediacaran biota in the Precambrian). The Cambrian "Explosion" is just one more meaning that there really is nothing unique about adaptive radiations like that.

For instance, there was the Ordovician radiation or biodiversity event (considered one of the most extensive diversifications of life seen), which saw the diversification of trilobites, echinoderms and brachiopods, as well as the rise of true corals, among other things.

There was a Devonian radiation, which saw another re-radiation of trilobite species, as well as the rise and diversification of large predatory fish such as sharks, ray-finned fish, lobe-finned fish, placoderms, and acanthodians.

The Devonian also experienced a one-time explosion in the evolution of terrestrial plants: after a cryptic history beginning about 450 mya, land plants underwent a uniquely rapid adaptive radiation. And speaking of terrestrial plants 100 mya (mid Cretaceous) witnessed a rapid radiation of angiosperms (flowering plants) as they diversified.

At the end of the Permian, when an estimated 90% of species and 50-60% of families appear to have become extinct and were replaced by a small number of genera which rapidly diversified to fill a wide number of ecological niches during the early Triassic. For instance Lystrosaurus, a small dicynodont therapsid, were by far the most common terrestrial vertebrates for millions of years and appear to have accounted for roughly 90% or more of early Triassic terrestrial vertebrates.

And the most recent was the Cenozoic radiation of mammals after the Cretaceous.