Archives for: March 2010, 22

03/22/10

Permalinkby 01:21:54 pm, Categories: Literature - Articles, 957 words   English (UK)

Design Principles in bird feathers and avian respiration

Scientists with an interest in developing design concepts and principles found in the natural world are not instinctively attracted by exhortations to expel design from Biology. However, developing a coherent academic framework that does justice to the design principles being studied has not attracted the attention it deserves. Consequently, many scholars in this field have absorbed views developed by people with a rather different agenda for design. McIntosh recognises there is a problem here, and sets out to provide an alternative perspective.

"Many have taken the view that design is only an illusion in living systems, arguing that such 'apparent design' and accompanying complexity can be explained by the neo-Darwinian paradigm. [. . .] However, [. . .] the inference to original design and intelligence is a perfectly valid alternative from direct analogy to designs within the man-made world."

graphic showing barbule arrangements
An essential aerodynamic surface: barbules in one direction have hooks whereas in the other direction the barbules are ridge-like. (Source here)

After providing an overview of different types of feather, McIntosh develops an argument based on "specified functional complexity". There is a multifunctioning and multi-optimisation in feather construction - characteristics that apply to both modern and to fossil feathers - which is said to be "consistent with the design thesis".

"There are the features which are immediately apparent such as aerodynamic loading and the material construction of rachis and barbs to sustain this. However, there are also more subtle features such as the arrangement of hooks and barbules primarily for keeping the feather together, such that they prevent air from going through them during the downstroke but allowing some air to pass through in the upstroke, thus maximising the efficiency of energy use in wing flap. The keratin itself has an extremely high specific strength, and the shape of the filament cross sections used in rachis construction moves from near circular near the root to a curved and ribbed rectangular shape away from the root for structural efficiency under bending and potentially buckling loads."

Although enough has been said already to associate pennaceous feathers with the concept of irreducible complexity, further aspects of a holistic system emerge with consideration of the uropygial (preening) gland at the base of its spine. Hypotheses about the evolution of these feathers involving unintelligent causation have totally failed to provide credible scenarios.

"The ability to reach this gland is a feat of twisting which a bird performs with ease. However, it raises serious issues concerning the supposed evolution of feathers, since it is necessary for the feather construction (barbule ridge and hook system) to arise concurrently with the preening gland and the ability to manoeuvre the neck a full 180 degrees. None of the fossil evidence shows any evidence of such transitions."

The author elaborates on the crucial importance of functional information and the failure of current evolutionary speculations. The hooks and ridges of barbules are clear examples. These barbules have opposite characteristics: "hooks on one side of the barb and ridges on the other so that adjacent barbs become attached by hooked barbules from one barb attaching themselves to ridged barbules from the next barb. [. . .] It is that vital network of barbules which is necessarily a function of the encoded information (software) in the genes. Functional information is vital to such systems." This leads to a discussion of research into pattern formation, primarily to show that the origin of functional information has not been solved (or even addressed).

"However, correct and enlightening as these models are, it is important to recognise that this is not the same as functional information, where coded instructions are involved, first, in the precise ordered arrangement of nucleotides in DNA, and, secondly, in the multifunctioning construction of items from these codes such as hooked and ridged feather barbules. This is a subject of a separate paper by the author where the argument is made that all living systems have coded machinery which sits on high free energy bonds, all of which have to be in place for the system to work."

The second part of the paper develops the same style of argument for the avian lung: the organ must be considered as an integrated system if it is to be understood as functioning machinery, and a "bottom-up" blind watchmaker approach totally fails to explain the evidence for functional information.

"Science can study the effect on the natural world of systems of pre-existing material, but it cannot preclude the possibility of intelligence extraneous to that very matter and energy being involved in its formation. To say otherwise is effectively wedding science to a narrow philosophical foundation. [. . .] Once one opens the possibility that intelligence is involved, the evidence leads very naturally to the conclusion of design, not by going against the known empirical laws (such as gravity [. . .]), but precisely the reverse. We must keep to the 'nullius in verba' motto of the Royal Society ('on the words of no one'), and not preclude from the outset where the evidence may lead."

This paper provides a helpful contribution to the development of multiple hypotheses in science. It deserves to be widely read and analysed by students of science.

Evidence of design in bird feathers and avian respiration
A. C. McIntosh
International Journal of Design & Nature and Ecodynamics, Vol 4, Issue 2, (2009) 154-169.

This paper explores the evidence for design in living systems. In particular, it considers two of the mechanisms used in bird flight. These include feathers and the remarkable counterflow mass exchanger breathing system used in the avian lung system. Both systems are examples of the principle of specified functional complexity, which occurs throughout nature. There is no known recorded example of this developing experimentally where the precursor information or machinery is not already present in embryonic form. Such design features indicate non-evolutionary features being involved.

Permalink

Science Literature

March 2010
Mon Tue Wed Thu Fri Sat Sun
<<  <   >  >>
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31        

Search

Linkblog

Links - Groups and Organizations

Links - Of General Interest

  • A Brief View of Time and Those That Live There

    Don Cicchetti blogs on: Culture, Music, Faith, Intelligent Design, Guitar, Audio

    Permalink
  • A Quick Guide to Sequenced Genomes Permalink
  • ARN Related Web Links Permalink
  • Creation/Evolution Quotes

    Australian biologist Stephen E. Jones maintains one of the best origins "quote" databases around. He is meticulous about accuracy and working from original sources.

    Permalink
  • CreationEvolutionDesign

    Most guys going through midlife crisis buy a convertible. Austrialian Stephen E. Jones went back to college to get a biology degree and is now a proponent of ID and common ancestry.

    Permalink
  • Darwinian Fairytales by David Stove

    Complete zipped downloadable pdf copy of David Stove's devastating, and yet hard-to-find, critique of neo-Darwinism entitled "Darwinian Fairytales"

    Permalink
  • ID The Future

    Intelligent Design The Future is a multiple contributor weblog whose participants include the nation's leading design scientists and theorists: biochemist Michael Behe, mathematician William Dembski, astronomer Guillermo Gonzalez, philosophers of science Stephen Meyer, and Jay Richards, philosopher of biology Paul Nelson, molecular biologist Jonathan Wells, and science writer Jonathan Witt. Posts will focus primarily on the intellectual issues at stake in the debate over intelligent design, rather than its implications for education or public policy.

    Permalink
  • John Mark Reynolds Blog

    A Philosopher's Journey: Political and cultural reflections of John Mark N. Reynolds. Dr. Reynolds is Director of the Torrey Honors Institute at
    Biola University.

    Permalink
  • NASA Astronomy Picture of the Day Permalink

Misc

Syndicate this blog XML

What is RSS?

powered by
b2evolution