At the end of the first full paragraph on p. 703, Lauder and colleagues point out that closely related species can differ for two very different reasons. What are these two causes of species differences? I'm confused about what those two reasons are as I can't find the reasons. outlines as well as discrete land- being based increasingly on phylo-marks, and traditional multivariate genetic information. The diversityof organismal function (and its rela-tended to deal more effectively with tionship to structure) is a vast areaof unexplored biology. With the in-shape. In particular, the traditional fusion of historical methods andconcepts from systematics, the fu-ture promises exciting advances asnot possible with a one- or two-taxon study.In many other comparative stud-. statistical methods have been ex-ies the explicit intent is to addressevolutionary issues such as physi- such biological problems as size andological adaptation to an extremeenvironment. For such studies, thechoice of species for analysis can beguided by systematic information domain, with the benefit that many physiologists and morphologists(Burggren 1991, Garland et al. 1991,Huey 1987). A comparison of closerelatives reduces, for instance, theprobability that observed differencesbetween taxa are an artifact of long-separate phylogenetic history rather statistical tools for the study ofthan of adaptation to a particular morphology has had on research onenvironmental feature.bivariate approach to allometry hasbeen extended into the multivariatestudies of form today, whatever their bring new tools to bear on the analy-purpose, are multivariate in nature.It would be difficult to overesti-mate the impact that the develop-ment of both data acquisition andsis of structural and functional di-versity.AcknowledgmentsWe gratefully acknowledge the con-tributions of the many members ofthe last decade has the promise of the original two committees (espe-cially T. Garland) for SystematicsAgenda 2000 (Quantitative and Evo-organismal form; in truth, only inDetecting evolutionary anachro- Thompson's approach to structurenisms. A systematic and historicalperspective also is useful in detect- study the deformation of one shape lutionary Morphology, Comparativeing evolutionary anachronisms (i.e.,traits that evolved in response to largely qualitative and inaccurateconditions no longer existing). Forexample, the giant fruits of someNeotropical trees might have evolvedas adaptations for dispersal by Pleis-tocene megafauna (Janzen and Mar- analytical methods used to study ously supported by the Nationaltin 1982), and the presence of flight form, there is no doubt that themotor neurons (currently nonfunc-tional) in flightless crickets probably metrics and phylogenetics has manuscript was supported by: NSFreflects the evolution of flightless grass- opened up a broad array of newhoppers from ancestors that could fly questions. It has also raised the stan-(Dumont and Robertson 1986).Thus, an appreciation of phylo- (Zelditch et al. 1992, 1995).genetic history sometimes clarifiesthe function-or the lack thereof-of an otherwise puzzling physiologi-cal trait (Huey 1987). A phyloge- Physiological and functional traitsnetic analysis may reveal that thetraits thought to represent novel evo-lutionary responses to current envi-ronments may have been retained sity recognition and preservation hasfrom an ancestral condition that hadlittle in common with current envi-ronmental conditions.been realized. Early attempts tointo another, for example, werePhysiology and Biochemistry) whoassisted in the preparation of theand not readily amenable to statisti- original reports that formed the ba-sis of this article. This article is aproduct of the initiative Systemat-ics Agenda 2000, which was gener-cal study.Although vigorous debate con-tinues on the assumptions of theScience Foundation through grantrecent rapprochement of morpho- DEB-9396035. Preparation of theIBN-9119502 to George Lauder,NSF DEB-9301151 to Ray Huey,and NSF BSR-8604960 and BSR-8911433 to Russell Monson.dards to which answers will be heldConclusionsReferences citedAllen G. 1975. Life science in the twentiethof plants and animals are not well-preserved in fossils. Unfortunately,much of the effort toward biodiver-focused on biogeographic and taxo-nomic concerns rather than on theanalysis of functional diversity. Formost clades, a comparative analysisof physiological traits is in its in-fancy. In part, perhaps because ofthe past tendency of physiologists tocentury. New York: John Wiley.Bennett AF, Ruben J. 1986. The metabolicand thermoregulatory status of ther-apsids. Pages 207-218 in Hotton N,MacLean PD, Roth JJ, Roth EC, ed. Theecology and biology of mammal-like rep-tiles. Washington (DC): Smithsonian In-stitution Press.Bookstein F, Chernoff B, Elder R, HumphriesJ, Smith G, Strauss R. 1985. Morpho-metrics in evolutionary biology. Phila-delphia (PA): Academy of Natural Sci-Morphometrics. Systematics has hadconsiderable influence recently inthe quantitative description of mor-phology. Two distinct avenues of focus on a few organisms consid-progress are evident. First, manybiometricians have developed newmethods for archiving the shape of the study of organismal function isbiological structures (and whole or-ganisms). These methods are rigor-ous, quantitative, and lend them- because methodologies for quanti-selves to multivariate statisticalanalysis (reviewed in Rohlf and soming, organismal biologists areBookstein 1990).Some of these methods deal with beyond one-taxon analyses, and theorganismal shape data presented asences.Briggs DEG, Fortey RA, Wills MA. 1992.Morphological disparity in the Cambrian.Science 256: 1670–1673.Brooks DR, McLennan DA. 1991. Phylog-eny, ecology and behavior. Chicago (IL):University of Chicago Press.Burggren WW. 1991. Does comparative res-piratory physiology have a role in evolu-tionary biology (and vice versa)? Pages1-13 in Woakes AJ, Grieshaber MK,Bridges CR, ed. Physiological strategiesfor gas exchange and metabolism. Cam-bridge (UK): Cambridge University Press.Burggren WW, Bemis WE. 1990. Studyingphysiological evolution: paradigms andered to be good models, a broadlycomparative historical approach tojust beginning. This beginning oc-curs at an opportune time, however,tative comparative methods are blos-becoming interested in expandingchoice of species to be analyzed isNovember 1995703

By analyzing the question, We need to tell What are these two causes of species differences Below…

Answered: What are these two causes of species…

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...