Year: 2022

THE DRUNKARD’S WALK. “The late Stephen J. Gould strongly cautioned against the temptation to ascribe any overall directionality to biological evolution. In a famous metaphor he compared the evolution of a species in complexity space to the random walk of a drunkard who starts out leaning against a wall, but whose movement towards the gutter is unrestricted.” https://lnkd.in/euEN3Eh View in LinkedIn

CONTEXTUAL. “One cannot isolate the complexity of biological organisms from the complexity of their environment. Whether the inhabitants of newly available niches will become simpler or more complex depends on the complexity and simplicity of those new niches. Random walks that elevate complexity are driven by the complexity of the environment being walked in.” https://lnkd.in/euEN3Eh View in LinkedIn

COMPLEXITY REVERSALS. “Biological complexity, both genotypic and phenotypic, may trend upward, but can go the other way, sometimes dramatically (as after mass extinctions).” https://lnkd.in/euEN3Eh View in LinkedIn

EPIGENETIC INFORMATION. “Adami et al. (2000) identify genomic complexity with the amount of information DNA sequences store about their environments. I want to emphasize that not only is the information in DNA about the environment, but that the information in DNA came from the environment.” https://lnkd.in/euEN3Eh View in LinkedIn

IMPACT OF CONTEXT. “The information in DNA comes from the environments and it has been put into the DNA by selection. Darwinian evolution involving selection of all kinds (natural, sexual, and artificial) is the channel through which the complexity and information of the environment creates and shapes the complexity and information of biological organisms.” https://lnkd.in/euEN3Eh View in LinkedIn

THE MANTRA. “Biology's First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems. "In any evolutionary system in which there is variation and heredity, there is, in the absence of constraint, a tendency for diversity and complexity to increase." http://ndpr.nd.edu/news/24573-biology-s-first-law-the-tendency-for-diversity-and-complexity-to-increase-in-evolutionary-systems/ View in LinkedIn

THE QUESTION. “Whether or not complexity increases through evolution has become a contentious issue.” https://lnkd.in/eHHiAUS View in LinkedIn

WOBBLY COMPLEXITY. “Gould, for example, argues that any recognizable trend can be explained by the “drunkard's walk” model, where “progress” is due simply to a fixed boundary condition. McShea investigates trends in the evolution of certain types of structural and functional complexity, and finds some evidence of a trend but nothing conclusive. In fact, he concludes that “something may be increasing. But is it complexity?”” http://www.pnas.org/content/97/9/4463.full View in LinkedIn

GENOMIC VS PHENOTYPIC. “It is tempting to believe that genomic complexity is mirrored in functional complexity and vice versa. Such an hypothesis, however, hinges upon both the aforementioned ambiguous definition of complexity and the obvious difficulty of matching genes with function.” http://www.pnas.org/content/97/9/4463.full View in LinkedIn

GENOMIC COMPLEXITY. “If an organism's complexity is a reflection of the physical complexity of its genome (as we assume here), the latter is of prime importance in evolutionary theory. Physical complexity, roughly speaking, reflects the number of base pairs in a sequence that are functional.” http://www.pnas.org/content/97/9/4463.full View in LinkedIn