Bat Evolution and Intelligent Design

The Honduran Whit Bat chews the central support of a large leaf, causing it to collapse to form a 'tent' in which the bats roost in the rain forrest (they make their own roost).

hi Farmerman,

An example I think you have referred to is the coelecanth.

Supposedly extinct for millions of years and then found alive in the past century.

Absence of fossilized coelecanths was not evidence that they didn't exist.

RL, who said that there were no fossil coelecanths? There were but the "gap" in their fossil record (Jurassic though tertiary) was more probably do to the fact that the earth was undergoing major fracturing of continents.

Your "absence of evidence" seems to have a better explanation for why we dont have fossil mammoths in the Devonian (or any time until the Pleistocene)

All the BILLIONS of species that were unique to a fixed stratigraphic sequence need to be explained wrt Creationist thinking. Thats your area , not mine. (eg no kore trilobites after the Permian, no birds UNTIL the Jurassic, No mammals until the Triassic, no trees till the Devonian) etc etc

bat evolution
Here's a quote from a recent BBC article on bat evolution:

"Ancestors linking bats to other mammal groups lived during the Palaeocene period which followed the extinction of the dinosaurs. However, none of their fossils have ever been discovered."

How can anyone write this type of fairy tale with a straight face??? But it was good for a laugh. Bio-evolutionary theory is hilarious.

Re: bat evolution


So are you.

Welcome to A2K.

Re: bat evolution

Understandable that might be so for the uneducated, the credulous, the superstitious, and the easily amused. Welcome to the fray.

what they said

fm wrote-



Rather amusing old boy. Loved it actually.Though incorrect. Obviously.

Im glad that the manifestations of my little handicap give you amusement spendi, thats what Im here for.

RL, I forgot to get back to the coelecanth fossils and the differentiation of the "absence of evidence". As I said , there were plenty of coelecanth fossils from the Devonian through the Creataceous, all in the shadow of the Southern PAngean sea. The coelecanth fossils are quite abundant throughought this period. They then disappear at the mid Cretaceous as the Laurasian terrane splits along the Tethyan sea and widens. The sediments of this period, in that area of the wrold are not "trailing edge " tectonics since India and Madagascar are floating around and the entire suboceanic sediments were being smooshed. Pelagic fossils were not common except for vertain neritic near shore deposits and for molluscs which could stand sediment laden waters. After the Cretaceous the fossils are not evident until the discovery of the "Lazarus fossil" Coelecanth. So your argument about absence of evidence is quite incorrect. Not leaving afossil just means that, without special tectonic circumstances, the animal probably didnt exist yet. My example of minus elephanyts in the Devonian is an example, or the entire class of mammals didnt appear until the Traiassic anbd then only in minor deposits until the mid Creataceous when a bloom of genera appeared.

Your attempted argument is not a valid one and Id go back to Sarfati and see whether the AIG guys cant come up with something a little more compelling(or at least more logical)

Can someone expand on this?

Thanks,

. This is just a personal drive through your question ros, Im not willing to defend anything herein cause Im slowly slipping into the social implications after I try my hand at deciphering.

This is what Gould nicely stated with the fact that "genes are merely the bookkeepers of evolution, not its driver"
The fact that certain genes align themselves on the chromosomes in a pattern unique to the individual species is merely the way that this organism uses the same series of protein syntheses and catalysis that a different organism uses in a totally different way. Since the codons act in multiples of groups of three base pairs, insertion and deletion of new codons and then entire new genes is a coded "response"that occurs gradually through time and ultimately makes the differences that evolution has wrought in the different organisms. This is, IMHO mostly as a consequential alignment of genomic order in response to an initial adaptation. Remember the three rules of Darwins natural selection? He amassed his evdience even without knowing about genes..

Biochemical evolution research right now, is more about discovering what these genetic switches do in different organisms. So far , I dont believe that were into a big time "custom genetics" world, although, this cant be far away when "artificial selection" will rule the science.

Considering the social implications, Im sorta glad that I wont be around , cause its going to be a strange world that's possible with boutique organisms and even people. Just as everything else, we create a technology , then we spend the rest of the time keeping everyone from applying it. IMHO

Ok. Here's what I'm trying to figure out. Maybe someone can help me understand this...

We know what bats look like today: [keeping it simple] They have long fingers with skin stretched between them to form a wing.

Let's propose the probable ancestor of a bat as a small mouse-like creature which lives in trees and has front paws which serve it for climbing, but also has skin between the fingers which help it to glide when jumping between branches to catch insects or to escape predators.

What I'm trying to understand is how a sequence of specific, but random genetic changes occur to change a gliding hand into a flying wing.

Let's say a genetic change occurs which makes the finges of the gliding mouse slightly longer. The mouse is now probably a better glider, but a worse climber. If the advantage of gliding exceeds the disadvantage of hindered climbing, then the path is clear for additional change. This part I understand.

However, doesn't it take another completely random genetic change to cause the fingers to lengthen once again (how many random genetic changes does it take to get from a short finger to a long finger in stages?). Or, is there something about the original genetic change which causes the fingers to get increasingly longer in each successive generation?

Thanks,

ros, you have a number of questions embedded in there. The area for you to look at regarding morphology and evolution can be broken down into a simpler question "How much actual genetic difference can account for morphological differences in polymorphic species". Bats have many species, like mice, so lets look at a selection process that has genereated different morphologies of same species. Lets look at DOGS. MIT had published a rather exhaustive yet readable analysis of the genomes of the different sub species and varieties of dogs. While they found many differences among the various morphologies, they found that a small subset of crucial genes account for the variations. These are called SNP's or singular nucleotide polymorphisms. As youd suspect it means that single genetic differences can account for large polymorphic variation. The MIT crew found that, along with the various morphological traits are also some associated health risks that are clustered within individual breeds. So the accounting of the SNPs and then , greater genomic variation as the clade (many bats species) begin to diverge are presumably a manifestation of SNP within the Hox gene and other extra nuclear DNA.

In other words, simply stated, it doesnt take a lot of genetic jiggering to manifest major morphological differences.
As fer bats. Ive always been handed the old line that the two major clades (micro and mega bats) each evolved seaparately from two different genuses that underwent parallel evolution.
The microbats were these little guys who,
1 first became nocturnal insectivores(so they wouldnt compete with their cousins the" paleo mega" shrews. The story is one of "best evidence" Since the Chiroptera and the insectivora share common morphological and genetic structures, it was felt that the Insectivora served as the foundation taxa and the divergence of the paleo chiropterans was as a species of nocturnal insectivores that developed echolocation and the ability to jump, then were selected for gliding , then active flight.
Theres only very limited evidence about bats and its quite indirect. We know that bats were around in the very early Tertiary and, because theyve found fossils of noctuid moths (which are moths that have sensetivity to echolocation and have an escape mode built around echolocation detection) It was felt that bats(very early jumping or gliding proto bats with echolocation were exploiting the niche as a night flying (gliding) , bug eating critter.
When you try to understand a creatures evolutionary path, dont try to bite off more than a few million years at a time. Its a talent for making yourself think multidimensionally with time as a control.
Also, remembre the Darwinian postulates

1constant relationship among founder and daughter species through generations (today we look at genetics and say "of course how else?')

2Small incremental changes through multiple generations


3Fecundity outstrips the ability of the environment to support all descendants( He nails us with Malthus)

4Mayr adds one more "NO SALTATION" or "NO PUNCTUATED EQUILIBRIUM" (Of this I have no yeomans opinion, Im a mere consumer of fossiliferous information, not a producer)

Thanks for the info FM. I'm still having trouble understanding it though.

How can single genetic differences give rise to multiple polymorphic variations?

(Also, what does PolyMorphic mean exactly?).



I'm still hung up on the sequence of events genetically which account for large change.

Let me see if I can give you another example, and maybe someone can identify where I'm going wrong...

Let's say you've got a population of short-toed, web-fingered gliding mice.

Within that population there is lots of variation. Some have short fingers and others have long fingers, but NONE have fingers long enough for flight.

If two long-fingered variants reproduce, they don't necessarily get fingers twice as long, do they? All you get is another long fingered baby, right?

So doesn't it take ANOTHER genetic change to make the fingers yet longer?

Or are you saying that the propensity for really long (flight) fingers already exists within the gene pool, but simply isn't expressed because the population must go through successive stages of gradual expression in order to have the final results survive?

Ros, lemme find the site on SNPs and maybe thatll help. Basically one nucleotide can have a multiple phenotypic effect. Like those selected for smallness (dogs) have a gene that may vary from a big dog by one nucleotide, not a whole string of multiple base pairs (codons). Remember, the genetic variability that describes a species and even a variety is best expressed as a statistical spread of options. So the built in variability is merely intensified and any new mutations that occur , and most of thesel happen after the breed is first established. Part of the polymorphic burden from SNPs is that the same SNP that makes a dalmation a dalmation, also can confer its breeds propensity for deafness.

Polymorphism is merely "multiple expression of an organism's phenotype"
For example, black widow spiders are sexually dimorphic, in that the males are waaay smaller than the females. Thats all. Male birds are usually more colrful than females, thats dimorphism. Polymorphism is just three or more expressions of color , shape, size, beak type , etc etc within the same species.

Border collies are polymorphic, they exp[ress themselves as,long haired, short haired, black and white, or liver and white.

The story I gave you about how bats became, was the story begun by Romer in the 20's and weve not improved on it, other than finding evidences of insects (assuming they were prey) with echolocation detection systems. These were found in the mid Cretaceous, so that would assume that (if this were true) that bats were at least echolocating in the days of the dinosaurs.

The story isnt the most convincing and it lacks a smoking gun, but it doesnt default back to RL's favorite explanation, because its one example of the "imperfection of the fossil record" and not a proof of "poof".

Im going surf fishing for Thanksgiving Dinner

More interesting critters...

Another thread which explores variation and genetics

bump

you starting this up again, ros? don't remember seeing it the first time. in the interim, I remember reading something about someone discovering a regulatory gene in the bat genome that, when switched on, made one or more of their "fingers" grow extremely long, which they thought made the expression of a wing-like structure possible in essentially one go, rather than a series of gradual lengthenings having to occur sequentially. That was maybe two years ago, don't have the article to hand anymore. It was in the Boston Globe, their archive may have it (probably they got it from some journal, so googling would probably turn it up).