Uncommon Descent Serving The Intelligent Design Community

Which came first – butterfly or caterpillar?

Share
Facebook
Twitter
LinkedIn
Flipboard
Print
Email

One of my favorite sources for “just so” stories in organic evolution is metamorphosis. Consider: when a caterpillar matures and forms a chrysalis, the caterpillar’s body almost completely dissolves into a yellow mush which then serves as a source for raw materials to reform into a butterfly. I wonder how that scenario came about through mutation and selection. How would destroying almost the entire body and reforming into something that, by morphology alone would be a very different species, come about by Darwinian gradualism? Where’s the selection value in a partially decomposed body? Surely the process could not have evolved in one fell swoop. What series of gradual transitions make sense in light of chance & necessity?

Comments
Here is one on the design-by-contract model : "In modelling on design-by-contract, evolution is seen as a continuously expanding system of functional modules which are separated by conserved interfaces. A scenario in which the larval stages were developed before the adult body plan, is relatively simple since it will keep existing developmental interfaces intact. It is therefore proposed that the larval stage of holometabolous insects reflect the reintroduction of an ancient, existing body plan and therefore represents an atavism." Origin of insect metamorphosis based on design-by-contract: larval stages as an atavism Enjoy!Mario A. Lopez
February 6, 2008
February
02
Feb
6
06
2008
11:50 AM
11
11
50
AM
PDT
Once the pupa or chrysalis stage is reached, the caterpillar starts emptying itself; its organs dissolve, and its outer covering is shed. Only certain groups of cells, called imaginal disks, remain vital. From these develop all the structures of the adult... Caterpillar and butterfly are widely differing forms, the one not derived from the other but both from totipotent embryo cells, some of which the caterpillar retains in its body so that they will in due course destroy it and replace it with another."--geneticist Giuseppe Sermonti pg 103 "Why is a Fly Not a Horse?"
Got that? The caterpillar does NOT develop into a buttterfly. It dissolves and becomes food for the next body.Joseph
February 6, 2008
February
02
Feb
6
06
2008
09:49 AM
9
09
49
AM
PDT
Gerry So how do you think the butterfly/caterpillar thing came to be, Dave? The same way humans design complex systems. Both the larva and the butterfly were preconceived in the mind of an intelligent agent who then turned abstract thought into physical reality. I think that's the best explanation at the current time although it may be proven incorrect in the future. That's just the nature of science. The best laid plans of mice and men often go astray. ~Robert Burns (misquoted for clarity in modern english) DaveScot
February 6, 2008
February
02
Feb
6
06
2008
07:11 AM
7
07
11
AM
PDT
Cloud of Unknowing Actually the development program appears to be outside the DNA. In experiments where an enucleated egg from one species has a nucleus from another species inserted into it development proceeds along the path of the egg's species not of the nucleus' species until incompatibilities between the egg and the nucleus cause a spontaneous abortion except in very closely related species. DNA appears to be a collection of building blocks where the majority of blocks are common to many species and few are unique to just one species. What is actually going to be built by the development process appears to be controlled by a program outside the nucleus. The following is a recent experiment where a carp nucleus was inserted into a goldfish egg (carp and goldfish are very closely related). Development proceeded along the lines of the goldfish, not the carp. http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1095%2Fbiolreprod.104.031302 As a systems design engineer I've consistently been of the opinion that the 1 gigabyte information carrying capacity of the human genome is grossly inadequate to contain the component specifications and assembly procedure required to build a human body. If a significant amount of that DNA is junk then it only exacerbates the problem. Clearly though, the specifications and assembly procedure are contained within the cell wall of the egg. The rest of the egg consists of trillions of atoms more or less precisely arranged. The potential information carrying capacity of those trillions of atoms is orders of magnitude greater than the nuclear contents. Thus I believe the larger information repository is outside the nucleus. This is studied under the rubric "epigenetics". A horse is a horse and not a fly not because of its DNA but because its mother was a horse. We really don't know any more than that at this point. Geneticist Giuseppe Sermonti wrote a book on the question titled Why is a Fly not a Horse? which may be of interest to you. In computer hardware and software design, which is my area of professional expertise, we have an analogous design methodology where we have common component libraries that are shared between programs that are very different in how and what they actually do. Often, in order to save space, we cull those libraries to the components that are actually used by the program. What the program actually does is dependent not on the library but on how the components are called upon and is external to the library itself. I'm very interested in Craig Venter's work at assembling a global gene library from tens of thousands of different microorganisms he is shotgun sequencing from samples obtained from the ocean depths in a circumnavigational cruise. This may represent an uber library of all the component parts used in all forms of life sans culling for individual species. My experience has been that many if not most aspects in the design of life have analogous design methodologies independently discovered and employed by human engineers. DaveScot
February 6, 2008
February
02
Feb
6
06
2008
06:32 AM
6
06
32
AM
PDT
Gerrym Rzeppa, it's Eazy... This small larva went to sleep during winter... soon it developed it's cocon as good warm house... But suddenly during sleep cosmic rays, bla bla bla... all that recombined larvas body into butterfly... Pure chance and NS :) NS in this case is... larvas which could fly was better suited for survival...Shazard
February 6, 2008
February
02
Feb
6
06
2008
01:04 AM
1
01
04
AM
PDT
So how do you think the butterfly/caterpillar thing came to be, Dave?Gerry Rzeppa
February 5, 2008
February
02
Feb
5
05
2008
08:52 PM
8
08
52
PM
PDT
"metomorphosis was some sort of amalgamation of two separate organisms" The hypothesis is that metamorphosis results from hybridization of two species. Darwin dismissed hybrid evolution, but there is now considerable evidence that it is more important than long believed. The notion that the "tree of life" is actually a network seems to be catching on with scientists.Cloud of Unknowing
February 5, 2008
February
02
Feb
5
05
2008
08:22 PM
8
08
22
PM
PDT
jerry, "As humans we see this in growth and maturity especially in adolescence. Where in the body is the control for these processes? Anyone have any good sources or is it a mystery?" Certainly development is genetically directed, but there is nothing like a blueprint of the adult encoded in the DNA. And there is certainly no centralized control. A biologist once told me that he marveled at people's arms growing to the same length.Cloud of Unknowing
February 5, 2008
February
02
Feb
5
05
2008
08:03 PM
8
08
03
PM
PDT
bFast, I doubt that many biologist share the view of metamorphosis being an amalgamation of two separate organisms. It would be truly remarkable if the fruitfly, THE model organism for genetic studies (and on of the earliest fully sequenced multicellular organisms) had a mashup of two genomes without anybody actually finding any evidence for it. There are indeed speculations about metamorphosis in insects. For a good (albeit somewhat dated) review on competing hypothoses: http://www.nature.com/nature/journal/v401/n6752/full/401447a0.html As to the answer to DaveScot's question, I guess there are two, depending on what meaning the question is supposed to have. Literally, the answer is neither: Butterflies and caterpillars are the same species and thus appeared at the same time. However, if it is not meant literally, then the butterfly appeared first. The earliest insect showed direct development (ametabolous). Only later insects, the Holometabola exhibit the different larval, pupal and adult stages we find in butterflies. So the butterfly (or fully differentiated insects) came before the complex metamorphosis of the Holometabola. As for gradualism, it might be interesting to study the hemimetabolous groups of insects that fall in complexity of metamorphosis between the ametabolous and holometabolous groups. Jerry, if you are interested in insect development, I would suggest you start looking at Drosohpila development first. It has been used as a model organism (in particular for developmental studies) for so long, that a tremendous wealth of information is available.hrun0815
February 5, 2008
February
02
Feb
5
05
2008
07:40 PM
7
07
40
PM
PDT
Does anyone know of any good sources on development? Like the caterpillar to butterfly, nearly every multi-cellular organism changes form after gestation. What controls these changes. It cannot be the egg as this is long gone but something in nearly every organism controls the expression of genes over time. As humans we see this in growth and maturity especially in adolescence. Where in the body is the control for these processes? Anyone have any good sources or is it a mystery?jerry
February 5, 2008
February
02
Feb
5
05
2008
07:24 PM
7
07
24
PM
PDT
It is my understanding that metomorphosis is one of the great puzzles of biology. I recently read a blerp on either livescience.com or PhysOrg.com that suggested that metomorphosis was some sort of amalgamation of two separate organisms. That said, it seemed terribly speculative to me -- like the guys recognized that they were only speculating.bFast
February 5, 2008
February
02
Feb
5
05
2008
07:18 PM
7
07
18
PM
PDT
1 2

Leave a Reply