Adam D. Gordon

I am currently involved in multiple collaborative and solo research projects. A few of these are listed below.

Sex-specific body size response to ecological factors.
Published work by myself and others suggests that body size may respond differently in male and female primates to ecological pressures such as resource stress, implying that a portion of sexual size dimorphism may be due to natural selection rather than sexual selection. I have been developing quantitative genetics models and phylogenetic comparative approaches to attempt to identify the relative contributions of sexual selection and natural selection on sex-specific patterns of size, shape, growth, and scaling in human and primate evolution. I am also in a collaboration with Steig Johnson of the University of Calgary and Ed Louis of the Henry Doorly Zoo and the Madagascar Biodiversity Partnership to test models regarding the effects of differences in ecological variables on sex-specific body size in wild lemur populations from across Madagascar.

Sexual dimorphism in primate postcrania.
Research performed by myself and others has investigated the relationship between postcranial size dimorphism, craniodental size dimorphism, and body mass size dimorphism, demonstrating that each of these types of dimorphism can vary partially independently of the other two. However, postcranial size variation still provides the promise of reconstructing body mass dimorphism in the hominin fossil record. I was co-PI on an NSF grant with Mike Plavcan and Jackson Cothren of the University Jackson Cothren of the University of Arkansas and Mike Lague of Stockton College that funded research on 3-dimensional measures of size and shape dimorphism in extant primates. We laser-scanned postcranial collections of extant and fossil primates to identify techniques for extracting size and shape information from partial fossil specimens in order to expand sample sizes in analyses of fossil taxa. These data are now being used in a variety of analyses.

Diversity in size and shape variation in fossil hominins.
A large amount of postcranial size variation is well-documented in Australopithecus afarensis, presumably reflecting high sexual dimorphism in body size. However, the degree of postcranial size dimorphism present in other australopiths and early Homo is not as well known. I have developed techniques to compare the degree of postcranial size variation between these fossil hominin taxa in collaboration with colleagues from the Center for the Advanced Study of Human Paleobiology at the George Washington University, and have worked with various colleagues examining proportions of fore- and hind-limb articular measurements as well as ratios of manual elements in comparisons between fossil hominins and extant taxa in an attempt to get at variation in the locomotor habits and grasping abilities of fossil hominins.

Footprint morphology in modern humans and Laetoli hominins.
A collaborative effort with David Raichlen and Adam Foster of the University of Arizona and Will Harcourt-Smith of Lehman College-CUNY investigated the relationship between different modes of bipedalism in modern humans and the morphology of footprints produced in soft substrates. We compared the results of experimental data to data from the 3.6 million year old hominin footprints preserved at Laetoli, Tanzania.

	Sex-specific body size response to ecological factors. Published work by myself and others suggests that body size may respond differently in male and female primates to ecological pressures such as resource stress, implying that a portion of sexual size dimorphism may be due to natural selection rather than sexual selection. I have been developing quantitative genetics models and phylogenetic comparative approaches to attempt to identify the relative contributions of sexual selection and natural selection on sex-specific patterns of size, shape, growth, and scaling in human and primate evolution. I am also in a collaboration with Steig Johnson of the University of Calgary and Ed Louis of the Henry Doorly Zoo and the Madagascar Biodiversity Partnership to test models regarding the effects of differences in ecological variables on sex-specific body size in wild lemur populations from across Madagascar.
	Sexual dimorphism in primate postcrania. Research performed by myself and others has investigated the relationship between postcranial size dimorphism, craniodental size dimorphism, and body mass size dimorphism, demonstrating that each of these types of dimorphism can vary partially independently of the other two. However, postcranial size variation still provides the promise of reconstructing body mass dimorphism in the hominin fossil record. I was co-PI on an NSF grant with Mike Plavcan and Jackson Cothren of the University Jackson Cothren of the University of Arkansas and Mike Lague of Stockton College that funded research on 3-dimensional measures of size and shape dimorphism in extant primates. We laser-scanned postcranial collections of extant and fossil primates to identify techniques for extracting size and shape information from partial fossil specimens in order to expand sample sizes in analyses of fossil taxa. These data are now being used in a variety of analyses.
	Diversity in size and shape variation in fossil hominins. A large amount of postcranial size variation is well-documented in Australopithecus afarensis, presumably reflecting high sexual dimorphism in body size. However, the degree of postcranial size dimorphism present in other australopiths and early Homo is not as well known. I have developed techniques to compare the degree of postcranial size variation between these fossil hominin taxa in collaboration with colleagues from the Center for the Advanced Study of Human Paleobiology at the George Washington University, and have worked with various colleagues examining proportions of fore- and hind-limb articular measurements as well as ratios of manual elements in comparisons between fossil hominins and extant taxa in an attempt to get at variation in the locomotor habits and grasping abilities of fossil hominins.
	Footprint morphology in modern humans and Laetoli hominins. A collaborative effort with David Raichlen and Adam Foster of the University of Arizona and Will Harcourt-Smith of Lehman College-CUNY investigated the relationship between different modes of bipedalism in modern humans and the morphology of footprints produced in soft substrates. We compared the results of experimental data to data from the 3.6 million year old hominin footprints preserved at Laetoli, Tanzania.