A remarkable machine butall developed from a conventional petal, a part readily avail-able in an orchid's ancestor
It is so interesting to me that these mechanisms can be naturally created in nature.
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Yet the tibial sesamoid sup-ports no new digit, and its increased size confers no advan-tage, so far as we know.
The panda species took the radial seasmoid mutation to their advantage, while the tibial sesamoid mutation was not advantageous to them, so it never turned into a "thumb".
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It is constructed from a bone called the radial sesamoid,normally a small component of the wrist. In pandas, theradial sesamoid is greatly enlarged and elongated
Pandas must have evolved from having 4 fingers to having 5 when pandas with longer/larger radial sesamoids survived and reproduced while those with shorter/smaller radial sesamoids were less able to consume bamboo and thrive.
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I had learned that a dexterous, opposablethumb stood among the hallmarks of human success.
I wonder if having an opposable thumb is a sign of LACK OF struggle, because pandas and humans are both lacking predators and any real struggle for existence.
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paths that a sensible God
He also keeps randomly bringing up theological arguments for some reason, I wonder if this is a regular 'scientific' topic of the time?
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Orchids were notmade by an ideal engineer
The idea that natural selection is not 'engineered' keeps appearing, Gould is trying to emphasize the imperfect nature of natural selection.
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They have evolved an astonishing variety of"contrivances" to attract insects, guarantee that sticky pol-len adheres to their visitor, and ensure that the attachedpollen comes in contact with female parts of the next orchidvisited by the insect.
While not necessarily caused by variation in heredity, orchids have found a mechanism to combat the struggle for existence, otherwise they would have likely gone extinct as a species.
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But thesurface of a wheel as large as a humanfoot could not provision the wheelfulof organic matter within.
Since it is advantageous for the bacterium to have wheel-like features, they have evolved to use them. However, humans have no use for a wheel-like body part and would ultimately be less efficient with one; so while rotating wheels seem modern and efficient, they aren't in the case of large creatures.
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the bacterialflagellum operates as a wheel. It ro-tates rigidly like a propeller, drivenby a rotatory “motor” in the basalportion embedded in the cell wall.Moreover, the motor is reversible.
All modern technologies have parallels found in nature, even if they were discovered afterwards, like in this case.
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Mostmodels assumed that flagella are fixedrigidly to the cell wall and that theypropel bacteria by waving to and fro.
This was actually the impression I had from my high school biology class!
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But animals cannotconstruct wheels from the parts thatnature provides.
Gould is saying that natural selection has its limits and is not a perfect science.
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henotion that God's existence can beproved by the harmonies of natureand the clever construction of organ-isms
We are reading texts with this exact argument in my Problem of God class right now!
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adaptation, be it biological orcultural, represents a better fit to spcific, local environments, not anevitable stage in a ladder of progress.
The main point of this sentence is very interesting-- evolution is not a linear path that creates 'better and better' species, rather, evolution can go in many directions based on the specific environment and location.
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The Romanroads had begun to deteriorate andcamels were not bound to them.Craftsmanship in harnesses and wag-ons had suffered a sharp decline.
There are examples of changes in environment that made the shape and function of wheels less advantageous.
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