So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

The principles of classification and a classification of mammals. Bulletin of the AMNH ; v. 85

The new Conductivity Bridge derives its bridge source. voltage from a self-contained vacuum tube oscilltor adjusted to approximately 1,000 cycles. Voltage for the amplifier and null indicator tubes is provided by a.builtin D.C. power supply which operates directly from the A.C. power source. 9-324 Conductivity Bridge, without Conductivity Cell, for use with 110 volts 5060 cycle A.C. 9-351.Cosi~uCvity Cell, for use with Conductivity Bridge, constant 0.8, $20.00

The Vertebrate Eye and Its Adaptive Radiation.

Estimates of body weight, group size, home range size, day range length, socionomic sex ratio and sexual dimorphism are compared between 100 primate species, allocated to seven ecological categories. As would be predicted on energetic grounds, home range size and day range length are positively related to group weight and are greater in frugivores than in folivores; population density is negatively related to body weight; and group size is positively related to body weight. The adaptive significance of Variation in body size, sexual dimorphism and socionomic sex ratio is also discussed.

Primate ecology and social organization

To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.

http://science.sciencemag.org/content/sci/339/6120/662.full.pdf

The Placental Mammal Ancestor and the Post–K-Pg Radiation of Placentals

The abundance and biomass of species of nonvolant mammals on Barro Colorado Island are estimated and compared with data from other areas. The edentates, particularly the sloths, are shown to be dominant elements in neotropical forests. The sloths and howler monkeys together constitute more than 50 percent of the biomass of mammals, emphasizing the importance of the forest canopy. The bulk of the mammalian biomass is maintained by species which are browsers or frugivores and browsers. The total energy consumption of each species is estimated and the metabolic rate of the whole mammalian fauna is judged to be between 3000 and 4000 kilocalories per hectare per day on Barro Colorado Island. THE OBJECTIVE of this paper is to assess the biomass and the numbers of different mammalian species in a defined area of neotropical forest. For almost a decade we have been concerned with this assessment and with defining the trophic structure of the major species of nonvolant terrestrial mammals within a neotropical rainforest ecosystem. It is most important to determine the biomass and the trophic role of each major species for the following

A Preliminary Analysis of a Neotropical Mammal Fauna

"Squirrels of the World", written by scientists with more than 100 years of collective experience studying these popular mammals, is the first comprehensive examination of all 285 species of squirrels worldwide. The authors reveal virtually every detail of the family Sciuridae, which includes ground squirrels, tree squirrels, flying squirrels, prairie dogs, and chipmunks. Each species-from the familiar gray squirrel of American backyards to the exotic and endangered woolly flying squirrel of Pakistan-is described in a detailed account that includes distinguishing characteristics, ecology, natural history, conservation status, and current threats to its existence. "Squirrels of the World" includes: stunning color photographs that document rare and unusual squirrels as well as common varieties; evolution, morphology, ecology, and conservation status; colorful range maps marking species distribution; images of the skull of each genus of squirrel; and extensive references.

Squirrels of the World

Flying squirrels range in length of head and body from less than 90 mm to more than 400 mm. Large flying squirrels are more slender than tree squirrels or small flying squirrels. They have proportionately longer tails than small flying squirrels, but large tree squirrels have the longest tails of all, both absolutely and proportionately. Relative limb lengths decrease with size among flying and tree squirrels, but the ratio of forelimb to hindlimb length is generally higher for flying squirrels than for tree squirrels. The styliform cartilage adds to the area of the patagium, but it is isometric with respect to size. Weight varies by a factor of almost 64 and the area of the patagium by a factor of almost 16, with little divergence from the expected isometric relationship. Therefore “wing loading” varies almost by a factor of four and is estimated to be as low as 30 Newtons/square meter (N/m2) in small petauristines and as great as 110 N/m2 in large ones.

Hang gliding seems to provide a good analogue for the gliding of flying squirrels, although the squirrels have lower aspect ratios (l.0 to 2.2) and lower glide ratios (less than 3) than do most hang gliders. From this analogy it seems probable that the heavier “wing loading” of large flying squirrels does not affect the glide ratio (horizontal distance/vertical drop) but that the larger flying squirrels must “fly” faster to maximize their glide ratio. It is also probable that small flying squirrels with lower “wing loadings” are more maneuverable, but large flying squirrels with heavier loadings are less affected by air turbulence.

Body Proportions and Gliding Adaptations of Flying Squirrels (Petauristinae)

Data from 3991 records of museum collections representing 421 species of plants, arthropods, amphibians, fish, and primates were analyzed with GIS to identify areas of high species diversity and endemism in Amazonia. Of the 472 1 · 1∞ grid cells in Amazonia, only nine cells are included in the highest species diversity category (43‐67 total species) and nine in the highest endemic species diversity category (4‐13 endemic species). Over one quarter of the grid cells have no museum records of any of the organisms in our study. Little correspondence exists between the centers of species diversity identified by our collections-based data and those areas recommended for conservation in an earlier qualitative study of Amazonian biodiversity. Museum collections can play a vital role in identifying species-rich areas for potential conservation in Amazonia, but a concerted and structured eAort to increase the number and distribution of collections is needed to take maximum advantage of the information they contain.

/pdf/amazonian-biodiversity-assessing-conservation-priorities-sqbc2kcgp6.pdf

Amazonian biodiversity: assessing conservation priorities with taxonomic data

Emry, Robert J., and Richard W. Thorington, Jr. Descriptive and Compar¬ ative Osteology of the Oldest Fossil Squirrel, Protosciurus (Rodentia: Sciuridae). Smithsonian Contributions to Paleobiology, number 47, 35 pages, 16 figures, 3 tables, 1982.—The early history of the Sciuridae is not well known, squirrels being generally poorly represented in the Tertiary fossil record. A nearly complete skeleton, recently discovered in early Oligocene deposits of Wyoming, repre¬ sents what may be the oldest fossil squirrel known. For the first time, this early squirrel can be compared fully with its extant relatives. The specimen, assigned to Protosciurus jeffersom, retains the primitive protrogomorphous zygomasseteric structure, as in other known Protosciurus, but the masseteric fossa of the mandible is farther forward than in most nonsciurid protrogomorphs. The auditory region of the skull has derived squirrel characters, but it is in the postcranial skeleton where similarities to extant squirrels are most apparent. Except for minor differences in joint construction, the skeleton is strikingly similar to that of Sciurus mger, the living fox squirrel. It differs from extant ground squirrels in the more gracile proportions of its long bones and asymmetry of foot construction. This early member of the squirrel family was clearly an arboreal squirrel, with morphology, and presumably habits, very similar to those of extant Sciurinae. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution’s annual report, Smithsonian Year. Series cover design: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Emry, Robert J. Descriptive and comparative osteology of the oldest fossil squirrel (Protosciurus: Sciuridae: Rodentia) (Smithsonian contributions to paleobiology ; no. 47) Bibliography: p. 1. Protosciurus. I. Thorington, Richard W. II. Title. III. Series QE701.S56 no. 47 [QE882.R6] 560s [569’.323] 81-14440 AACR2

Richard W. Thorington

Papers

A Preliminary Analysis of a Neotropical Mammal Fauna

Squirrels of the World

Body Proportions and Gliding Adaptations of Flying Squirrels (Petauristinae)

Amazonian biodiversity: assessing conservation priorities with taxonomic data

Descriptive and comparative osteology of the oldest fossil squirrel Protosciurus (Rodentia: Sciuridae)