Life Sciences Commons^™

Demographic Parameters Of Yellowfin Croaker, Umbrina Roncador (Perciformes: Sciaenidae), From The Southern California Bight, Daniel Pondella, John Froeschke, Lynne Wetmore, Eric Miller, Charles Valle, Lea Medeiros

Daniel Pondella

The yellowfin croaker, Umbrina roncador Jordan & Gilbert, 1882, is a common nearshore and surf-zone species in the southern California bight. Age was determined for individuals (n = 1,209) using annual increments in otoliths, and size at age was modeled using the von Bertalanffy growth curve (L∞ = 307.754 mm, k = 0.278 yr−1, t0 = −0.995 yr; maximum age = 15 yr). Females (L∞= 313.173 mm, k = 0.307 yr−1, t0 = −0.771 yr) grew significantly faster and larger than males (L∞= 298.886, k = 0.269 yr−1, t0 = −1.072 yr). Age and growth modeling based upon otolith length …

Mexican Jay (Aphelocoma Ultramarina), John Mccormack, L. Brown

John E. McCormack

No abstract provided.

Niche Expansion Leads To Small-Scale Adaptive Divergence Along An Elevation Gradient In A Medium-Sized Passerine Bird, John Mccormack, Thomas Smith

John E. McCormack

Niche expansion can lead to adaptive differentiation and speciation, but there are few examples from contemporary niche expansions about how this process is initiated. We assess the consequences of a niche expansion by Mexican jays (Aphelocoma ultramarina) along an elevation gradient. We predicted that jays at high elevation would have straighter bills adapted to feeding on pine cones, whereas jays at low elevation would have hooked bills adapted to feeding on acorns. We measured morphological and genetic variation of 95 adult jays and found significant differences in hook length between elevations in accordance with predictions, a pattern corroborated by analysis …

Integrating Paleoecology And Genetics Of Bird Populations In Two Sky Island Archipelagos, John Mccormack, Bonnie Bowen, Thomas Smith

John E. McCormack

Background: Genetic tests of paleoecological hypotheses have been rare, partly because recent genetic divergence is difficult to detect and time. According to fossil plant data, continuous woodland in the southwestern USA and northern Mexico became fragmented during the last 10,000 years, as warming caused cool-adapted species to retreat to high elevations. Most genetic studies of resulting 'sky islands' have either failed to detect recent divergence or have found discordant evidence for ancient divergence. We test this paleoecological hypothesis for the region with intraspecific mitochondrial DNA and microsatellite data from sky-island populations of a sedentary bird, the Mexican jay (Aphelocoma ultramarina). …

Speciation In The Highlands Of Mexico: Genetic And Phenotypic Divergence In The Mexican Jay (Aphelocoma Ultramarina), John Mccormack, A. Peterson, E. Bonaccorso, Thomas Smith

John E. McCormack

The pine-oak woodlands of the Mexican highlands harbour significant biological diversity, yet little is known about the evolutionary history of organisms inhabiting this region. We assessed genetic and phenotypic differentiation in 482 individuals representing 27 populations of the Mexican jay (Aphelocoma ultramarina) — a widespread bird species of the Mexican highlands — to test whether populations in the central and northern Mexican sierras display discrete breaks between groups, which would be consistent with a role for the different mountain chains in divergence and speciation. We found abrupt breaks in mitochondrial DNA (mtDNA; ND2 and control region) delineating four major genetic …

Why Are Incubation Periods Longer In The Tropics? A Common-Garden Experiment With House Wrens Reveals It Is All In The Egg, Given Harper, W. Douglas Robinson, John D. Styrsky, Brian J. Payne, Charles F. Thompson

Given Harper

Gene Expression Reveals Unique Skeletal Patterning In The Limb Of The Direct-Developing Frog, Eleutherodactylus Coqui, Ryan Kerney, James Hanken

Ryan Kerney

The growing field of skeletal developmental biology provides new molecular markers for the cellular pre- cursors of cartilage and bone. These markers enable resolution of early features of skeletal development that are otherwise undetectable through conventional staining tech- niques. This study investigates mRNA distributions of skeletal regulators runx2 and sox9 along with the cartilage-dominant collagen 2a1 (col2a1) in embryonic limbs of the direct- developing anuran, Eleutherodactylus coqui. To date, distri- butions of these genes in the limb have only been examined in studies of the two primary amniote models, mouse and chicken. In E. coqui, expression of transcription factors runx2 …

Inheriting Inherit The Wind: Debating The Play As A Teaching Tool, Edward Larson, David Depew, Ronald Isetti

David J Depew

No abstract provided.