By contrast, plumaceous feathers possess barbules lacking hamuli. The final section of any essay should provide a short Why do small African island nations perform better than African continental nations, considering democracy and human development? Weighted gene co-expression network analysis (WGCNA) was used to construct a gene co-expression network of all DEGs and identify the key modules and hub genes associated with feather morphogenesis.4. 1. The major types of wing feathers are illustrated below, and defined in the Glossary. 1. Subadult: a bird that is not fully adult, in species that require more than one year to achieve adult plumage (e.g. Best Answer. Contour feathers provide colorful plumage, which is useful in identifying different bird species. Vanes of contour feathers must be rigid and flexible at the same time. Soft, fluffy down feathers give adult birds a layer. Plumaceous feathers are more fluffy and less structured than pennaceous feathers. Face width is 3.0 in., P=6, and =20\phi=20^{\circ}=20. The Quarterly Review of Biology, 77(3), 261295.4. Output torque is taken by a flexible coupling connected to a driven machine. BMC Genomics. These birds have developed feather-covered feet which help to increase the surface area, and thus, prevent the birds from sinking into the snow while walking. This is why the outer wing feathers of many birds with white wings, such as gulls, have black tips. Feather library support and maintenance made me initially concerned, however the file format has good integration with pandas and I could install the dependencies using. Vane: the smooth feather surface formed by the interlocked pennaceous barbs. For example, the iridescent spiral from a King Bird-of-Paradise (Cicinnurus regius) tail functions as an ornament in the males courtship display. Bristles consist of a rachis with a few barbs at the base of the feather. A quill is usually made by cutting the tip of a feather in a specific way. Structurally, the feather is bizarre, with a bare rachisrachisRAY-kissthe stiff central shaft of a feather from which barbs branch that ends in a tight spiral of barbsbarbone of the main branches off the central shaft of a feather and barbulesbarbulebarb-YOOLone of the secondary branches off a feather barb arranged only on one side of the rachis to form an eye-catching brilliant medallion. She spent years piecing together how the birds accomplish this feat mechanically, but she did not stop there. Fortunately, during molt the bird grows a completely new set. The upper portion of the feather is called the "rachis". Quills are used for writing, and they were popular during medieval times because of their parchment and vellum friendly nature. The central rachis of flight feathers is stiff and lined on either side with branching barbs that form flat, aerodynamic vanes. __________ is the lower shaft of a feather, specifically the region lacking barbs. At the base of each feather lies a naked portion of the rachis called the calamus or quill. Plumulaceous Barbs: barbs without interlocking barbules, forming a loose fluffy layer at the base of a contour feather; or making up the entirety of a down feather. This method of producing sound is called stridulationstridulationstri-du-LAY-
shunthe act of rubbing together body parts to make a sound and also occurs in insects, such as crickets. Like stability? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Contour feathers are part pennaceous and part plumaceous. What is aFeather Feathers are highly engineered structures that perform essential functions. The drab contour feathers covering the body of some birds may seem lackluster, but subtle brown patterns can create an impressive degree of camouflage in forested environments. Siberian geese are raised for down harvesting where down . Making statements based on opinion; back them up with references or personal experience. down. : The Aerial Display of the Common Nighthawk, Storing Food: The Granaries of Acorn Woodpeckers, Brilliant Flash: Red-winged Blackbird Territorial Displays, Common Loon by U.S. Feathers are one of the main characteristics that distinguish birds from other animals. As verbs the difference between feather and quill All rights reserved. Aside from these two broad divisions, there are also six main types of feathers found in birds: These six feather types will be further described below. Similar to semiplumes with an even looser branching structure but little or no central rachis, down feathers are relatively short and positioned closest to the body where they trap body heat. The adjacent feather is slender, and bent at a 45-degree angle. Provide layer of insulation; lack central rachis. rev2023.3.3.43278. 2. 2. Tips of the barbs crumble into a powder when bitten. A duck is a waterfowl with a flat beak. Feathers are dead structures that cannot repair themselves when damaged. The evolutionary origin and diversification of feathers. Birds are the only animals with feathers. From the fossil record, we know that birds evolved from dinosaurs, some of which had feathers. Just to add an observation, 200,000 images in parquet format took 4 GB, but in feather took 6 GB. We'll dive into the two further but a down pillow is made with quill-less feathers from the chest and underbelly of a duck or goose, while a feather pillow is made of feathers with quills from the wings and backs. Overview and Key Difference Dataframe but to give you some impression if you never Some birds even have a crest of feathers on their heads. 2. Located beneath the contour feathers, down feathers provide insulation to the bird. sharing sensitive information, make sure youre on a federal Parquet is more expensive to write than Feather as it features more layers of encoding and compression. She enjoys writing on topics like art, music, dancing, travel, nature, and food. Parquet? Both the down and semiplume feathers help to trap air close to the body to keep birds warm in cold weather. We now recognize that how feathers function is intricately connected to how theyre structured, and how they grow is closely linked to how they evolved. A feather can be just plucked from birds, cleaned to get rid of any residue or germs and then sold or can be put on display. Each new feather grows from a small outgrowth of skin called the papilla. I would also include in the comparison between parquet and feather different compression methods to check for importing/exporting speeds and how much storage it uses. Long flexible barbs: filaments of down feathers, which are not attached to each other. Contour feathers give a bird its coloring and smooth shape. Basic vaned feathers of body and wings. Feathers are the ultimate characteristic of birds. This activity will help you assess your knowledge of the types and parts of bird feathers. 2. In some the first phenomenon is the . Zelenitsky, D. K., Therrien, F., Erickson, G. M., DeBuhr, C. L., Kobayashi, Y., Eberth, D. A., & Hadfield, F. (2012). Reference: @WesMcKinney I noticed your answer was written back in 2018. 2022 Oct;63(5):605-612. doi: 10.1080/00071668.2022.2061839. "Least Astonishment" and the Mutable Default Argument. Downs are softer and lighter than feathers. They are made by cutting the tip of the feather in a specific way. At the base of the rachis is the naked portion of the shaft known as the calamus or quill. BirdWatching Birds apply the powder to other feathers while preening, which serves to waterproof them. Bristles are short and stiff and lack barbs along most of the rachis but the base. Discover how bird feathers are constructed, uses for the different types of feathers, and a bird feather diagram. good thermal insulators. Some bird species will flash conspicuously colorful feathers or feign injury in order to scare or lure away predators from the nest. Contour feathers (including the flight and tail feathers) define the body outline and serve as aerodynamic devices; filoplumes (hair feathers) and plumules (down feathers) are used principally as insulation, to conserve body heat. and transmitted securely. An outline, boundary or border, usually of curved shape. 5. (music) The tube of a musical instrument. This study examined the transcriptomic profiles of contour and flight feather follicles from two duck breeds to determine the molecular network and the candidate genes associated with contour and flight feather morphogenesis.2. Some hatching birds have a special type of natal down feathers that are pushed out when the normal feathers appear. Quills are made using the flight feathers of a large bird. Compare the Difference Between Similar Terms. 9 chapters | It is labeled with the calamus (quill), rachis (shaft), barbs, and vane. What is the difference between Python's list methods append and extend? The RACHIS is the main feather shaft. I would definitely recommend Study.com to my colleagues. In appearance, Semiplume feathers look like a combination of contour and down feathers. 6. Other birds can use feather coloring and patterns to help them blend into their environments. As the feather grows, it stays curled in a tubular shape around the papilla until it is pushed away from the growth area. Is a PhD visitor considered as a visiting scholar? Smaller contour feathers cover the body and leading edges of the wings. A line on a map or chart delineating those points which have the same altitude or other plotted quantity: a contour line or isopleth. Down is the soft feathers of a bird, the ones under the stiff One such scientist is Kim Bostwick, who used this integrated approach to untangle the mysteries of a bird whose feathers work like a musical instrument. 4. Many feathers have both fluffy plumulaceous regions and more structured pennaceous regions. To unlock this lesson you must be a Study.com Member. As a result, the rachis takes the form of a hollow tube from which the barbs branch off. High-throughput RNA sequencing was performed to compare differences in feather follicles between contour and flight . Sometimes, the barbules are missing hamuli near the base of the feather. Reproductive fitness refers to an individual's ability to pass on genes to the next generation. Bookshelf The Condor, 83(4), 383.3. Possessing both a rachis and side barbs with smooth barbules, semiplumes are located between the contour feathers and provide the bird with extra insulation. Feathers Feathers: organ composed of a supple shaft with barbs and barbules. The qualifier is required because feathers have now been found in fossil imprints of some dinosaurs and related reptiles. Barb, 4. pd.read_parquet took around 4 minutes, but pd.read_feather took 11 seconds. Adjacent barbs interlock together to form the flat surface of the feather, also known as the These are the largest feathers and form the external appearance of adult birds. This is a rare example of feathers that allow birds to both hide and show off.1. copyright 2003-2023 Study.com. This moltingmoltin birds, the process of losing and regrowing feathers on a regular cycle process is a carefully timed affair in which feathers are shed and regenerate in turn over a period of weeks so the bird can maintain its protective outer layer and ability to fly. To turn to a horizontal plane; -- said of oars. Not all fancy feathers are used to woo a partner; some are used in displays of aggression. Notch: a distinct narrowing in the posterior vane of a primary flight feather. One of these feathers is club-shaped with ridges along its edge. She has taught a combination of ESL and STEM courses to secondary and university students. The storage is around 32% from the original file size, which is 10% worse than parquet "gzip" and csv zipped but still decent. Keep learning, participate in group conversations. This suggests that even as dinosaurs started to evolve wings, the wing feathers were likely used for courtship or territorial display, not flight.4. Down feathers lack both the rachis and hooked barbules found on other feathers. To crush or dash to pieces. made up of very fine feathers, often from geese, which are very Perrone, M. (1981). The small white feathers that lie between and beneath the __________ feathers are called semiplumes. Basic terms that describe parts of a feather are illustrated below, and defined in the Glossary. John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine, Unit 5 - wiat przyrody - Czci ciaa zwierz. W. McKinney indicates that feather (v2) is now stable here: Nice benchmark! Liu H, Xu Q, Xi Y, Ma S, Wang J, Bai L, Han C, He H, Li L. Br Poult Sci. As a verb quill is to pierce or be pierced with quills. Abrasion causes their tips and edges to wear, but this is natural and remedied periodically through molt. Most bird species have 10-12 rectrices. How can this new ban on drag possibly be considered constitutional? The posterior vane is the trailing edge of the feather. Secondary: one of the wing's inner flight feathers, which are attached to the ulna bone in the bird's "forearm." official website and that any information you provide is encrypted These colours are formed by pigments that are usually recognized as melanin. Both are integrated within Apache Arrow (pyarrow package for python) and are What is the answer punchline algebra 15.1 why dose a chicken coop have only two doors? Downy feathers look fluffy because they have a loosely arranged plumulaceousplumulaceousploom-yoo-LAY-shusshaving a loose, non-interlocking feather structure microstructure with flexible barbs and relatively long barbules that trap air close to the birds warm body. However, unlike mammalian hair or fur, bird feathers provide more than just a method for thermoregulation. or? (a) The base of the barbs fused together to form a central rachisrachisRAY-kissthe stiff central shaft of a feather from which barbs branchand (b) barbulesbarbulebarb-YOOLone of the secondary branches off a feather barb branched from the barbs, as we see in modern-day down feathers. "Actual information from a book, better use it, 'cause you'll probably need it for the Seventh Grade, right ? A magnifying glass reveals that each barb has smaller barbs, called barbules, projecting from either side, toward the adjacent barbs. Elizabeth, a Licensed Massage Therapist, has a Master's in Zoology from North Carolina State, one in GIS from Florida State University, and a Bachelor's in Biology from Eastern Michigan University. Text is available under the Creative Commons Attribution/Share-Alike License; additional terms may apply.See Wiktionary Terms of Use for details. Coverts: the contour feathers that cover the bases of the flight feathers. Filoplumes provide sensory information pertaining to temperature, wind speed, and feather movements needed for birds to fly efficiently. Much like a stealth fighter plane, feathers can be used by certain predatory birds, like owls, to muffle the sound of their wings in flight. Flight feathers, with their intricate microstructure, are impressive examples of natural engineering. Feathers allow birds to fly, but they also help them show off, blend in, stay warm, and keep dry. This may sound like an outrageous idea, but male Club-winged Manakins of Central and South America use a highly modified feather structure to play a powerful one-note tune. Fish and Wildlife Service | She has taught college level Physical Science and Biology. Filoplume feathers are very small in size, containing a rachis and only a few sparse barbs at the tip. Terms of Use and Privacy Policy: Legal. Remiges: the flight feathers of the wing, including the primaries, secondaries, and tertials. other way round? Can I tell police to wait and call a lawyer when served with a search warrant? Feathers are comprised of two main parts, the rachis and the barbs. Barbs bear even smaller branches called barbules . During this transformation, the bird elevates thousands of tiny feathers in unison by manipulating muscles just under the skin. Bethesda, MD 20894, Web Policies Creative Commons Attribution/Share-Alike License; The lower shaft of a feather, specifically the region lacking barbs. Adding to the disguise, the potoo will adjust its posture and close its eyes into tiny slits, making itself appear to be an extension of the tree. What is the correct way to screw wall and ceiling drywalls? Feather seems better for light weight data, as it writes and loads faster. I found some hints here https://github.com/wesm/feather/issues/188, To have the appearance of a feather or of feathers; to be . Theyre thought to be sensory in nature and are found around eyes and near the base of the beak. Dynamic transcriptome profiling reveals essential roles of the receptor tyrosine kinases (RTK) family in feather development of duck. Ventral: the under surface of the body, or of any body part oriented in a normal horizontal postion. @media (max-width: 1171px) { .sidead300 { margin-left: -20px; } } Continue Learning about English Language Arts. Enrolling in a course lets you earn progress by passing quizzes and exams. A thin piece of bark, especially of cinnamon or cinchona, curled up into a tube.
shunthe act of rubbing together body parts to make a sound and also occurs in insects, such as crickets. Like stability? Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Contour feathers are part pennaceous and part plumaceous. What is aFeather Feathers are highly engineered structures that perform essential functions. The drab contour feathers covering the body of some birds may seem lackluster, but subtle brown patterns can create an impressive degree of camouflage in forested environments. Siberian geese are raised for down harvesting where down . Making statements based on opinion; back them up with references or personal experience. down. : The Aerial Display of the Common Nighthawk, Storing Food: The Granaries of Acorn Woodpeckers, Brilliant Flash: Red-winged Blackbird Territorial Displays, Common Loon by U.S. Feathers are one of the main characteristics that distinguish birds from other animals. As verbs the difference between feather and quill All rights reserved. Aside from these two broad divisions, there are also six main types of feathers found in birds: These six feather types will be further described below. Similar to semiplumes with an even looser branching structure but little or no central rachis, down feathers are relatively short and positioned closest to the body where they trap body heat. The adjacent feather is slender, and bent at a 45-degree angle. Provide layer of insulation; lack central rachis. rev2023.3.3.43278. 2. 2. Tips of the barbs crumble into a powder when bitten. A duck is a waterfowl with a flat beak. Feathers are dead structures that cannot repair themselves when damaged. The evolutionary origin and diversification of feathers. Birds are the only animals with feathers. From the fossil record, we know that birds evolved from dinosaurs, some of which had feathers. Just to add an observation, 200,000 images in parquet format took 4 GB, but in feather took 6 GB. We'll dive into the two further but a down pillow is made with quill-less feathers from the chest and underbelly of a duck or goose, while a feather pillow is made of feathers with quills from the wings and backs. Overview and Key Difference Dataframe but to give you some impression if you never Some birds even have a crest of feathers on their heads. 2. Located beneath the contour feathers, down feathers provide insulation to the bird. sharing sensitive information, make sure youre on a federal Parquet is more expensive to write than Feather as it features more layers of encoding and compression. She enjoys writing on topics like art, music, dancing, travel, nature, and food. Parquet? Both the down and semiplume feathers help to trap air close to the body to keep birds warm in cold weather. We now recognize that how feathers function is intricately connected to how theyre structured, and how they grow is closely linked to how they evolved. A feather can be just plucked from birds, cleaned to get rid of any residue or germs and then sold or can be put on display. Each new feather grows from a small outgrowth of skin called the papilla. I would also include in the comparison between parquet and feather different compression methods to check for importing/exporting speeds and how much storage it uses. Long flexible barbs: filaments of down feathers, which are not attached to each other. Contour feathers give a bird its coloring and smooth shape. Basic vaned feathers of body and wings. Feathers are the ultimate characteristic of birds. This activity will help you assess your knowledge of the types and parts of bird feathers. 2. In some the first phenomenon is the . Zelenitsky, D. K., Therrien, F., Erickson, G. M., DeBuhr, C. L., Kobayashi, Y., Eberth, D. A., & Hadfield, F. (2012). Reference: @WesMcKinney I noticed your answer was written back in 2018. 2022 Oct;63(5):605-612. doi: 10.1080/00071668.2022.2061839. "Least Astonishment" and the Mutable Default Argument. Downs are softer and lighter than feathers. They are made by cutting the tip of the feather in a specific way. At the base of the rachis is the naked portion of the shaft known as the calamus or quill. BirdWatching Birds apply the powder to other feathers while preening, which serves to waterproof them. Bristles are short and stiff and lack barbs along most of the rachis but the base. Discover how bird feathers are constructed, uses for the different types of feathers, and a bird feather diagram. good thermal insulators. Some bird species will flash conspicuously colorful feathers or feign injury in order to scare or lure away predators from the nest. Contour feathers (including the flight and tail feathers) define the body outline and serve as aerodynamic devices; filoplumes (hair feathers) and plumules (down feathers) are used principally as insulation, to conserve body heat. and transmitted securely. An outline, boundary or border, usually of curved shape. 5. (music) The tube of a musical instrument. This study examined the transcriptomic profiles of contour and flight feather follicles from two duck breeds to determine the molecular network and the candidate genes associated with contour and flight feather morphogenesis.2. Some hatching birds have a special type of natal down feathers that are pushed out when the normal feathers appear. Quills are made using the flight feathers of a large bird. Compare the Difference Between Similar Terms. 9 chapters | It is labeled with the calamus (quill), rachis (shaft), barbs, and vane. What is the difference between Python's list methods append and extend? The RACHIS is the main feather shaft. I would definitely recommend Study.com to my colleagues. In appearance, Semiplume feathers look like a combination of contour and down feathers. 6. Other birds can use feather coloring and patterns to help them blend into their environments. As the feather grows, it stays curled in a tubular shape around the papilla until it is pushed away from the growth area. Is a PhD visitor considered as a visiting scholar? Smaller contour feathers cover the body and leading edges of the wings. A line on a map or chart delineating those points which have the same altitude or other plotted quantity: a contour line or isopleth. Down is the soft feathers of a bird, the ones under the stiff One such scientist is Kim Bostwick, who used this integrated approach to untangle the mysteries of a bird whose feathers work like a musical instrument. 4. Many feathers have both fluffy plumulaceous regions and more structured pennaceous regions. To unlock this lesson you must be a Study.com Member. As a result, the rachis takes the form of a hollow tube from which the barbs branch off. High-throughput RNA sequencing was performed to compare differences in feather follicles between contour and flight . Sometimes, the barbules are missing hamuli near the base of the feather. Reproductive fitness refers to an individual's ability to pass on genes to the next generation. Bookshelf The Condor, 83(4), 383.3. Possessing both a rachis and side barbs with smooth barbules, semiplumes are located between the contour feathers and provide the bird with extra insulation. Feathers Feathers: organ composed of a supple shaft with barbs and barbules. The qualifier is required because feathers have now been found in fossil imprints of some dinosaurs and related reptiles. Barb, 4. pd.read_parquet took around 4 minutes, but pd.read_feather took 11 seconds. Adjacent barbs interlock together to form the flat surface of the feather, also known as the These are the largest feathers and form the external appearance of adult birds. This is a rare example of feathers that allow birds to both hide and show off.1. copyright 2003-2023 Study.com. This moltingmoltin birds, the process of losing and regrowing feathers on a regular cycle process is a carefully timed affair in which feathers are shed and regenerate in turn over a period of weeks so the bird can maintain its protective outer layer and ability to fly. To turn to a horizontal plane; -- said of oars. Not all fancy feathers are used to woo a partner; some are used in displays of aggression. Notch: a distinct narrowing in the posterior vane of a primary flight feather. One of these feathers is club-shaped with ridges along its edge. She has taught a combination of ESL and STEM courses to secondary and university students. The storage is around 32% from the original file size, which is 10% worse than parquet "gzip" and csv zipped but still decent. Keep learning, participate in group conversations. This suggests that even as dinosaurs started to evolve wings, the wing feathers were likely used for courtship or territorial display, not flight.4. Down feathers lack both the rachis and hooked barbules found on other feathers. To crush or dash to pieces. made up of very fine feathers, often from geese, which are very Perrone, M. (1981). The small white feathers that lie between and beneath the __________ feathers are called semiplumes. Basic terms that describe parts of a feather are illustrated below, and defined in the Glossary. John David Jackson, Patricia Meglich, Robert Mathis, Sean Valentine, Unit 5 - wiat przyrody - Czci ciaa zwierz. W. McKinney indicates that feather (v2) is now stable here: Nice benchmark! Liu H, Xu Q, Xi Y, Ma S, Wang J, Bai L, Han C, He H, Li L. Br Poult Sci. As a verb quill is to pierce or be pierced with quills. Abrasion causes their tips and edges to wear, but this is natural and remedied periodically through molt. Most bird species have 10-12 rectrices. How can this new ban on drag possibly be considered constitutional? The posterior vane is the trailing edge of the feather. Secondary: one of the wing's inner flight feathers, which are attached to the ulna bone in the bird's "forearm." official website and that any information you provide is encrypted These colours are formed by pigments that are usually recognized as melanin. Both are integrated within Apache Arrow (pyarrow package for python) and are What is the answer punchline algebra 15.1 why dose a chicken coop have only two doors? Downy feathers look fluffy because they have a loosely arranged plumulaceousplumulaceousploom-yoo-LAY-shusshaving a loose, non-interlocking feather structure microstructure with flexible barbs and relatively long barbules that trap air close to the birds warm body. However, unlike mammalian hair or fur, bird feathers provide more than just a method for thermoregulation. or? (a) The base of the barbs fused together to form a central rachisrachisRAY-kissthe stiff central shaft of a feather from which barbs branchand (b) barbulesbarbulebarb-YOOLone of the secondary branches off a feather barb branched from the barbs, as we see in modern-day down feathers. "Actual information from a book, better use it, 'cause you'll probably need it for the Seventh Grade, right ? A magnifying glass reveals that each barb has smaller barbs, called barbules, projecting from either side, toward the adjacent barbs. Elizabeth, a Licensed Massage Therapist, has a Master's in Zoology from North Carolina State, one in GIS from Florida State University, and a Bachelor's in Biology from Eastern Michigan University. Text is available under the Creative Commons Attribution/Share-Alike License; additional terms may apply.See Wiktionary Terms of Use for details. Coverts: the contour feathers that cover the bases of the flight feathers. Filoplumes provide sensory information pertaining to temperature, wind speed, and feather movements needed for birds to fly efficiently. Much like a stealth fighter plane, feathers can be used by certain predatory birds, like owls, to muffle the sound of their wings in flight. Flight feathers, with their intricate microstructure, are impressive examples of natural engineering. Feathers allow birds to fly, but they also help them show off, blend in, stay warm, and keep dry. This may sound like an outrageous idea, but male Club-winged Manakins of Central and South America use a highly modified feather structure to play a powerful one-note tune. Fish and Wildlife Service | She has taught college level Physical Science and Biology. Filoplume feathers are very small in size, containing a rachis and only a few sparse barbs at the tip. Terms of Use and Privacy Policy: Legal. Remiges: the flight feathers of the wing, including the primaries, secondaries, and tertials. other way round? Can I tell police to wait and call a lawyer when served with a search warrant? Feathers are comprised of two main parts, the rachis and the barbs. Barbs bear even smaller branches called barbules . During this transformation, the bird elevates thousands of tiny feathers in unison by manipulating muscles just under the skin. Bethesda, MD 20894, Web Policies Creative Commons Attribution/Share-Alike License; The lower shaft of a feather, specifically the region lacking barbs. Adding to the disguise, the potoo will adjust its posture and close its eyes into tiny slits, making itself appear to be an extension of the tree. What is the correct way to screw wall and ceiling drywalls? Feather seems better for light weight data, as it writes and loads faster. I found some hints here https://github.com/wesm/feather/issues/188, To have the appearance of a feather or of feathers; to be . Theyre thought to be sensory in nature and are found around eyes and near the base of the beak. Dynamic transcriptome profiling reveals essential roles of the receptor tyrosine kinases (RTK) family in feather development of duck. Ventral: the under surface of the body, or of any body part oriented in a normal horizontal postion. @media (max-width: 1171px) { .sidead300 { margin-left: -20px; } } Continue Learning about English Language Arts. Enrolling in a course lets you earn progress by passing quizzes and exams. A thin piece of bark, especially of cinnamon or cinchona, curled up into a tube.