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Generation of Earth's first-order biodiversity pattern.
Astrobiology. 2009 Jan-Feb; 9(1):113-24.A

Abstract

The first-order biodiversity pattern on Earth today and at least as far back as the Paleozoic is the latitudinal diversity gradient (LDG), a decrease in richness of species and higher taxa from the equator to the poles. LDGs are produced by geographic trends in origination, extinction, and dispersal over evolutionary timescales, so that analyses of static patterns will be insufficient to reveal underlying processes. The fossil record of marine bivalve genera, a model system for the analysis of biodiversity dynamics over large temporal and spatial scales, shows that an origination and range-expansion gradient plays a major role in generating the LDG. Peak origination rates and peak diversities fall within the tropics, with range expansion out of the tropics the predominant spatial dynamic thereafter. The origination-diversity link occurs even in a "contrarian" group whose diversity peaks at midlatitudes, an exception proving the rule that spatial variations in origination are key to latitudinal diversity patterns. Extinction rates are lower in polar latitudes (> or =60 degrees) than in temperate zones and thus cannot create the observed gradient alone. They may, however, help to explain why origination and immigration are evidently damped in higher latitudes. We suggest that species require more resources in higher latitudes, for the seasonality of primary productivity increases by more than an order of magnitude from equatorial to polar regions. Higher-latitude species are generalists that, unlike potential immigrants, are adapted to garner the large share of resources required for incumbency in those regions. When resources are opened up by extinctions, lineages spread chiefly poleward and chiefly through speciation.

Authors+Show Affiliations

Department of Geophysical Sciences, University of Chicago, Chicago, Illinois, USA. akrug@uchicago.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19215204

Citation

Krug, Andrew Z., et al. "Generation of Earth's First-order Biodiversity Pattern." Astrobiology, vol. 9, no. 1, 2009, pp. 113-24.
Krug AZ, Jablonski D, Valentine JW, et al. Generation of Earth's first-order biodiversity pattern. Astrobiology. 2009;9(1):113-24.
Krug, A. Z., Jablonski, D., Valentine, J. W., & Roy, K. (2009). Generation of Earth's first-order biodiversity pattern. Astrobiology, 9(1), 113-24. https://doi.org/10.1089/ast.2008.0253
Krug AZ, et al. Generation of Earth's First-order Biodiversity Pattern. Astrobiology. 2009 Jan-Feb;9(1):113-24. PubMed PMID: 19215204.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Generation of Earth's first-order biodiversity pattern. AU - Krug,Andrew Z, AU - Jablonski,David, AU - Valentine,James W, AU - Roy,Kaustuv, PY - 2009/2/14/entrez PY - 2009/2/14/pubmed PY - 2010/9/15/medline SP - 113 EP - 24 JF - Astrobiology JO - Astrobiology VL - 9 IS - 1 N2 - The first-order biodiversity pattern on Earth today and at least as far back as the Paleozoic is the latitudinal diversity gradient (LDG), a decrease in richness of species and higher taxa from the equator to the poles. LDGs are produced by geographic trends in origination, extinction, and dispersal over evolutionary timescales, so that analyses of static patterns will be insufficient to reveal underlying processes. The fossil record of marine bivalve genera, a model system for the analysis of biodiversity dynamics over large temporal and spatial scales, shows that an origination and range-expansion gradient plays a major role in generating the LDG. Peak origination rates and peak diversities fall within the tropics, with range expansion out of the tropics the predominant spatial dynamic thereafter. The origination-diversity link occurs even in a "contrarian" group whose diversity peaks at midlatitudes, an exception proving the rule that spatial variations in origination are key to latitudinal diversity patterns. Extinction rates are lower in polar latitudes (> or =60 degrees) than in temperate zones and thus cannot create the observed gradient alone. They may, however, help to explain why origination and immigration are evidently damped in higher latitudes. We suggest that species require more resources in higher latitudes, for the seasonality of primary productivity increases by more than an order of magnitude from equatorial to polar regions. Higher-latitude species are generalists that, unlike potential immigrants, are adapted to garner the large share of resources required for incumbency in those regions. When resources are opened up by extinctions, lineages spread chiefly poleward and chiefly through speciation. SN - 1557-8070 UR - https://www.unboundmedicine.com/medline/citation/19215204/Generation_of_Earth's_first_order_biodiversity_pattern_ L2 - https://www.liebertpub.com/doi/10.1089/ast.2008.0253?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -