Paper 33: "Determinants of Diversity in Higher Taxonomic Categories" - Valentine (1980)
Blurb Author: David Jablonski
Dave Jablonski is an extremely well renowned paleobiologist at the University of Chicago. We've already covered him pretty well in the class in terms of his paper on background vs mass extinction.
Paper Author: James W. Valentine
James Valentine is an emeritus prof. of evolutionary biology at UC Berkeley (and also not related to the lead guitarist of Maroon 5 by the same name). His ResearchGate profile says he has 155 papers (the most recent of which was December of last year) and over 7500 citations. His research is largely concentrated around biodiversity through both space (especially latitudinally) and time.
Paper Cliff Notes:
Valentines paper is concerned with how diversity operates on taxonomic levels higher than the traditional genus or species level. He mentions early in the paper about how richness trends are essentially useless at the phylum and even class level, and since species are often harder to identify/differentiate from one another, these effectively meso-taxonomic levels are an effective method of looking at biodiversity.
Valentines main points of the paper are articulated through his idea of the adaptive kaleidoscope. This starts off as a single point (i.e. new species/clade/etc.) and radiates outward through the other tessera through changing environments in what is modeled as a logistic growth. Periodically, the numbers of higher taxa equilibrate and extinction reduces the number of higher order taxa so that new forms can take place. Valentine also mentions that most of this change is minute and largely insignificant and trivial. However, a few large scale changes can dramatically alter the number of higher order taxa. The most notable example of this is the Cambrian Explosion, where a vast number of large changes happened fairly rapidly (i.e. at the onset of the logistic growth) resulted in many different forms in a short amount of time.
The main issue that I have from this paper is derived from Valentines conclusion. He states that his adaptive kaleidoscope model is "not meant to be an accurate simulation of the diversity of the taxonomic hierarchy during the Phanerozoic but rather to generate plausible explanations from the trends and patterns there." 😑😑😑 Why would he use this model to explain hierarchical patterns? And what might be a better way to look at the patterns?
Dave Jablonski is an extremely well renowned paleobiologist at the University of Chicago. We've already covered him pretty well in the class in terms of his paper on background vs mass extinction.
Paper Author: James W. Valentine
James Valentine is an emeritus prof. of evolutionary biology at UC Berkeley (and also not related to the lead guitarist of Maroon 5 by the same name). His ResearchGate profile says he has 155 papers (the most recent of which was December of last year) and over 7500 citations. His research is largely concentrated around biodiversity through both space (especially latitudinally) and time.
Paper Cliff Notes:
Valentines paper is concerned with how diversity operates on taxonomic levels higher than the traditional genus or species level. He mentions early in the paper about how richness trends are essentially useless at the phylum and even class level, and since species are often harder to identify/differentiate from one another, these effectively meso-taxonomic levels are an effective method of looking at biodiversity.
Valentines main points of the paper are articulated through his idea of the adaptive kaleidoscope. This starts off as a single point (i.e. new species/clade/etc.) and radiates outward through the other tessera through changing environments in what is modeled as a logistic growth. Periodically, the numbers of higher taxa equilibrate and extinction reduces the number of higher order taxa so that new forms can take place. Valentine also mentions that most of this change is minute and largely insignificant and trivial. However, a few large scale changes can dramatically alter the number of higher order taxa. The most notable example of this is the Cambrian Explosion, where a vast number of large changes happened fairly rapidly (i.e. at the onset of the logistic growth) resulted in many different forms in a short amount of time.
The main issue that I have from this paper is derived from Valentines conclusion. He states that his adaptive kaleidoscope model is "not meant to be an accurate simulation of the diversity of the taxonomic hierarchy during the Phanerozoic but rather to generate plausible explanations from the trends and patterns there." 😑😑😑 Why would he use this model to explain hierarchical patterns? And what might be a better way to look at the patterns?
I understand why Valentine's paper is viewed as important for macroecology. The adaptive kaleidoscope is an interesting model to simulate taxonomic diversity but I agree with Nick that there is too many missing variables to simulate accurately the diversity of the taxonomic hierarchy... I think is a good first approach to a complicate concept but still too far from anything close to the reality.
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