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"Feathers"
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Why do owls and other birds have feathers?
\"Discover how body coverings vary and the different jobs they do in helping animals to survive. Read this book to find out all about feathers and how they help owls fly, keep warm, hunt, and survive. Discover how feathers can be different and how they change as birds grow up.\"--Back cover.
Book
Structural absorption by barbule microstructures of super black bird of paradise feathers
Many studies have shown how pigments and internal nanostructures generate color in nature. External surface structures can also influence appearance, such as by causing multiple scattering of light (structural absorption) to produce a velvety, super black appearance. Here we show that feathers from five species of birds of paradise (Aves: Paradisaeidae) structurally absorb incident light to produce extremely low-reflectance, super black plumages. Directional reflectance of these feathers (0.05–0.31%) approaches that of man-made ultra-absorbent materials. SEM, nano-CT, and ray-tracing simulations show that super black feathers have titled arrays of highly modified barbules, which cause more multiple scattering, resulting in more structural absorption, than normal black feathers. Super black feathers have an extreme directional reflectance bias and appear darkest when viewed from the distal direction. We hypothesize that structurally absorbing, super black plumage evolved through sensory bias to enhance the perceived brilliance of adjacent color patches during courtship display.
Physical structure is known to contribute to the appearance of bird plumage through structural color and specular reflection. Here, McCoy, Feo, and colleagues demonstrate how a third mechanism, structural absorption, leads to low reflectance and super black color in birds of paradise feathers.
Journal Article
The molecular evolution of feathers with direct evidence from fossils
Dinosaur fossils possessing integumentary appendages of various morphologies, interpreted as feathers, have greatly enhanced our understanding of the evolutionary link between birds and dinosaurs, as well as the origins of feathers and avian flight. In extant birds, the unique expression and amino acid composition of proteins in mature feathers have been shown to determine their biomechanical properties, such as hardness, resilience, and plasticity. Here, we provide molecular and ultrastructural evidence that the pennaceous feathers of the Jurassic nonavian dinosaur Anchiornis were composed of both feather β-keratins and α-keratins. This is significant, because mature feathers in extant birds are dominated by β-keratins, particularly in the barbs and barbules forming the vane. We confirm here that feathers were modified at both molecular and morphological levels to obtain the biomechanical properties for flight during the dinosaur–bird transition, and we show that the patterns and timing of adaptive change at the molecular level can be directly addressed in exceptionally preserved fossils in deep time.
Journal Article
Feathers : the evolution of a natural miracle
A biologist presents the natural history of feathers, applying the findings of paleontologists, ornithologists, biologists, engineers, and art historians to answer questions about the origin of feathers, their evolution, and their uses throughout the ages.
Book
Iridescent structural coloration in a crested Cretaceous enantiornithine bird from the Jehol Biota
A combination of sectioning and microscopy techniques, along with the application of finite-difference-time-domain modeling on a fossil feather, results in the novel estimation of the range of iridescent colors from the fossilized melanosome type and organization preserved in the elongate head crest feathers of a new Cretaceous enantiornithine bird. The densely packed rod-like melanosomes are estimated to have yielded from red to deep blue iridescent coloration of the head feathers. The shape and density of these melanosomes also may have further increased the feather’s structural strength. This occurrence on a likely male individual is highly suggestive of both a signaling function of the iridescent crest and a potential behavioral role in adjusting the angle of light incidence to control the display of this iridescent structural coloration.
Journal Article
Feathers : not just for flying
\"Young naturalists meet sixteen birds in this elegant introduction to the many uses of feathers.\"--Amazon.com.
Book
Sexually dimorphic sail feathers in the Mandarin duck as a model for lifelong developmental modulation
Developmental processes extend beyond embryogenesis to support lifelong tissue adaptations. Avian feather follicles, with their resident stem cells and capacity for cyclic regeneration, provide a dynamic model for postnatal tissue remodeling. Here, we propose the Mandarin duck (
Aix galericulata
) as an ideal model to study lifelong developmental modulation, focusing on the sexually dimorphic “sail feather”—a secondary flight feather in males that undergoes seasonal transformation into a strikingly asymmetric, ornamented phenotype during the breeding season. We identified asymmetric morphogen expression in regenerating male sail feathers and used transcriptome and H3K27ac ChIP-seq to uncover male and female signaling pathways and regulatory elements. Comparative epigenomic profiling reveals enriched estrogen receptor binding motifs in females. Hormone profiling shows seasonal variation, with a marked rise in female estrogen levels preceding the mating season. These results imply Mandarin duck sail feathers integrate local morphogenetic programs, epigenetic regulation, and systemic hormonal cues to orchestrate sexually dimorphic and seasonally dynamic feather morphogenesis. This work establishes a framework for further mechanistic study of the interplay between regeneration, regional identity, and hormonal plasticity in a vertebrate integumentary system.
Journal Article
Birds and their feathers
\"This book tells the story of birds and their feathers for young readers\"--Back cover.
Book
Emergent cellular self-organization and mechanosensation initiate follicle pattern in the avian skin
The spacing of hair in mammals and feathers in birds is one of the most apparent morphological features of the skin. This pattern arises when uniform fields of progenitor cells diversify their molecular fate while adopting higher-order structure. Using the nascent skin of the developing chicken embryo as a model system, we find that morphological and molecular symmetries are simultaneously broken by an emergent process of cellular self-organization. The key initiators of heterogeneity are dermal progenitors, which spontaneously aggregate through contractility-driven cellular pulling. Concurrently, this dermal cell aggregation triggers the mechanosensitive activation of β-catenin in adjacent epidermal cells, initiating the follicle gene expression program. Taken together, this mechanism provides a means of integrating mechanical and molecular perspectives of organ formation.
Journal Article