Progress vs. Variation Part II
Feb. 16th, 2004 10:46 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
prof_pangaeaAn argument against "progress" and instead for INCREASING VARIATION in evolution, from Full House, by Stephen Jay Gould
2. Stability through time of the initial bacterial mode.
If we are particularly parochial in our concern for multi-cellular creatures, we place the division in life between plants and animals (as the Book of Genesis in both creation myths of chapters 1 and 2). If we are more ecumenical, we generally place the division between unicellular and multicellular forms. But most professional biologists would argue that the break of maximal profundity occurs within the unicells, separating the prokaryotes (or cells without organelles -- no nuclei, no chromosomes, no mitochondria, no chloroplasts) from the eukaryotes (organisms like amoebae and paramecia, with all the complex parts contained in the cells of multi-cellular organisms). Prokaryotes include the amazingly diverse groups collectively known as "bacteria" and also the so-called "blue-green algae" which are little more than photosynthesizing bacteria, and are now generally know as Cyanobacteria.
All the earliest forms of life in the fossil record are prokaryotes -- or, loosely, "bacteria". In fact, more than half the history of life is a tale of bacteria alone. In terms of preservable anatomy in the fossil record, bacteria lie right next to the left wall of minimal conceivable complexity. Life therefore began with the bacterial mode. Life still maintains a bacterial mode in the same position. So it was in the beginning, is now, and ever shall be -- at least until the sun explodes and dooms the planet. How then, using the proper criterion of variation in life's full house, can we possibly argue that progress provides a central defining thrust to evolution if complexity's mode has never changed? [Life's mean complexity may have increased, Gould states, but he maintains that modes, not means, are the proper measures of central tendency in strongly skewed distributions such as the distribution of complexity in living organisms. You might have ten kids, nine with no money and one with a ten dollar bill, but that doesn't mean the average amount each kid has is one dollar.] The modal bacter has been life's constant paradigm of success.
2. Stability through time of the initial bacterial mode.
If we are particularly parochial in our concern for multi-cellular creatures, we place the division in life between plants and animals (as the Book of Genesis in both creation myths of chapters 1 and 2). If we are more ecumenical, we generally place the division between unicellular and multicellular forms. But most professional biologists would argue that the break of maximal profundity occurs within the unicells, separating the prokaryotes (or cells without organelles -- no nuclei, no chromosomes, no mitochondria, no chloroplasts) from the eukaryotes (organisms like amoebae and paramecia, with all the complex parts contained in the cells of multi-cellular organisms). Prokaryotes include the amazingly diverse groups collectively known as "bacteria" and also the so-called "blue-green algae" which are little more than photosynthesizing bacteria, and are now generally know as Cyanobacteria.
All the earliest forms of life in the fossil record are prokaryotes -- or, loosely, "bacteria". In fact, more than half the history of life is a tale of bacteria alone. In terms of preservable anatomy in the fossil record, bacteria lie right next to the left wall of minimal conceivable complexity. Life therefore began with the bacterial mode. Life still maintains a bacterial mode in the same position. So it was in the beginning, is now, and ever shall be -- at least until the sun explodes and dooms the planet. How then, using the proper criterion of variation in life's full house, can we possibly argue that progress provides a central defining thrust to evolution if complexity's mode has never changed? [Life's mean complexity may have increased, Gould states, but he maintains that modes, not means, are the proper measures of central tendency in strongly skewed distributions such as the distribution of complexity in living organisms. You might have ten kids, nine with no money and one with a ten dollar bill, but that doesn't mean the average amount each kid has is one dollar.] The modal bacter has been life's constant paradigm of success.
