What is Life? (Chapter 2) - Schrodinger

Summary

Whereas organisms contain large quantities of atoms which can follow statistical rules which prevent the influence of random behavior of single atoms, reproductive processes involve systems of small numbers of atoms which can not operate merely according to statistical physical laws.  Despite this, genes are responsible for transmitting unchanged data across centuries of generations.

Persons

John Burdon Sanderson Haldane FRS – nicknamed “Jack” or “JBS”, was a British-Indian scientist who worked in physiology, genetics, evolutionary biology, and mathematics. With innovative use of statistics in biology, he was one of the founders of neo-Darwinism.

Cyril Dean Darlington FRS – an English biologist, cytologist, geneticist and eugenicist, who discovered the mechanics of chromosomal crossover, its role in inheritance, and therefore its importance to evolution. He was Sherardian Professor of Botany at the University of Oxford from 1953 to 1971.

Terms

dilettante – amateur

ontogeny – the structure and function an organism will develop throughout its entire life, from its beginnings as a fertilized egg cell to the state of maturity when it begins to reproduce.

prolixity – use of excessive words

Notes

Although biological structures have “many atomic” structures which can protect against haphazard “single atomic” events, small groups of atoms play a dominating role in “the very orderly and lawful events within a living organism.”  These events involving small amounts of atoms follow strict biological laws.  

Of interest, all cells contain a complete (double) copy of the code-script (chromosomes) which is the equivalent of a general giving every soldier copies of campaign battle plans.  The only exception to this are gametes which are reproductive cells. 

**Schrodinger mentions that humans have 48 chromosomes, which was the belief in 1944.  The correct determination of the human diploid chromosome number as 46, by J-H Tjio and A Levan, at the University of Lund, Sweden, occurred 50 years ago, in December 1955; the finding was published in April 1956, ending a period of more than 30 years when the number had been thought to be 48.

Biologists describe organisms as “four dimensional patterns” – a pattern which includes time

Mitosis vs Meiosis

Mitosis produces two diploid (2n) somatic cells that are genetically identical to each other and the original parent cell, whereas meiosis produces four haploid (n) gametes that are genetically unique from each other and the original parent (germ) cell.

Haploid Individuals

Some male bees and plants are haploid – they have no father, and are the result of multiple divisions from unfertilized eggs, which indicates a complete code-script pattern exists in every set of chromosomes.  

Genes

Genes are the locus of what causes properties such as eye color.  The space of a gene is approximately 300 angstrom – approximately a few million atoms.  That quantity is too small to follow “orderly and lawful” behavior based on statistical physics.  Unlike a drop of liquid, genes likely require each atom to play an individual role.  

Genetics transmit information without appreciable change for generations – permanent within centuries.  All this occurs in the beginning with the transmission by the material structure of the nuclei of the two cells which unite to form the fertilized egg cell. 

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