What is a Postanal tail?
A post-anal tail is a muscular region of the body that extends posterior to the anus. The post-anal tail may aid locomotion and balance.
What does the Postanal tail become in humans?
In humans and other apes, the post-anal tail is present during embryonic development, but is vestigial as an adult.
What animals have a Postanal tail?
All chordates have a post-anal tail. A post-anal tail is an extension of the body that runs past the anal opening. In some species, like humans, this feature is only present during the embryonic stage. The chordata phylum is divided into three groups or subphylums: lancelets, tunicats, and vertebrates.
What type of support system do chordates have?
However, during the embryonic stage of development, you had a notochord, which makes you a member of the chordata phylum. Just like a sea squirt! A notochord helps support the body, and in vertebrates (like you) it eventually becomes the spinal column.
What is the function of endostyle?
An endostyle is a longitudinal ciliated groove on the ventral wall of the pharynx which produces mucus to gather food particles. It is found in urochordates and cephalochordates, and in the larvae of lampreys. It aids in transporting food to the esophagus.
What is the function of a notochord?
The notochord is the defining structure of the chordates, and has essential roles in vertebrate development. It serves as a source of midline signals that pattern surrounding tissues and as a major skeletal element of the developing embryo.
What support can be provided for the argument that hagfish are not fish?
What support can be provided for the argument that hagfish are not fish? They are not truly aquatic.
What is the function of pharyngeal slits in chordates?
In primitive chordates and fish, the pharyngeal slits function in respiration and feeding: water that comes in the mouth leaves through the slits. Organisms can filter this water for food and in fish gills became associated with these slits.
What is the function of the gill slits?
n. Pouches or slits in the front region (pharynx) of the digestive tract in chordates. These function in feeding and gas exchange in fishes and some amphibians, but appear during development in all vertebrates.
What is the function of endostyle in chordates?
What is endostyle structure?
The endostyle is a longitudinal, ciliated, grooved organ on the ventral wall of the pharynx that secretes mucoproteins into the alimentary canal for filter feeding (Fig. 7.8).
What is the function of the notochord how does its structure give it its stiffness?
The notochord is oriented head to tail and is found between the digestive tube and the nerve cord. Since it is composed of stiffer tissue, it allows for skeletal support of the organism. In certain chordates, like the lamprey and the sturgeon, the notochord remains there for life.
What is the function of the notochord what happens to the notochord in humans?
The most commonly cited functions of the notochord are: as a midline tissue that provides directional signals to surrounding tissue during development, as a skeletal (structural) element, and as a vertebral precursor. In lancelets the notochord persists throughout life as the main structural support of the body.
How is hagfish slime used as a defense mechanism?
The hagfish, an eel-shaped deep sea creature, has a defence mechanism of mucus that explodes into slime to choke any attacker, according to international researchers. When threatened, the hagfish will rapidly eject slime from their slime glands.
How do hagfish defend themselves?
The hagfish has a unique way of defending itself from attack: it produces a slime using sea water. If a potential predator gets too close, the hagfish will release a chemical from a row of pores along its side. This chemical reacts instantly with the sea water and produces a stringy slime.
What does the endostyle become in vertebrates?
It is found in adult urochordates and cephalochordates, as well as in the larvae of the vertebrate lampreys, but has been transformed through evolutionary time into the thyroid in all other vertebrates.
Do vertebrates have endostyle?
In fishes and amphibians, an endostyle-like organ is never seen during embryogenesis, and the thyroid is formed in the juvenile stage. Because the endostyle absorbs iodine, an evolutionary link has been suggested between this organ and the follicular thyroid of vertebrates.
What is the function of pharyngeal gills?
In primitive chordates, these slits are used to filter food particles from the water but now the slits bear gills and are used for gas exchange, in fishes and some amphibians.
What is the difference between gill slits and pharyngeal slits?
The true gill slits in embryonic fish develop into fish gills. However, the slits in tetrapods do not, so a more general name for the vertebral structures is pharyngeal slits. Gill slits likely originated from pharyngeal slits in tunicates that were used for filter-feeding.
What is a postanal tail?
A postanal tail is an extension of the spinal chord that extends beyond the animal’s anus. Postanal tails are a feature of all chordates, which is a phylum that includes vertebrates. All chordates have a postanal tail at some point, but they may not have that tail for their entire lives.
Do all chordates have a tail?
All chordates have a postanal tail at some point, but they may not have that tail for their entire lives. As vertebrates, humans are part of the chordata phylum, but most adult humans don’t have postanal tails.
What is a chordate?
This is any part of the body that extends beyond the anus; in many cases, a chordate’s anus isn’t at the posterior tip of the body. A dog’s tail is considered a postanal tail, for example.
What is the function of the tail of a fish?
The post-anal tail is a posterior elongation of the body, extending beyond the anus. The tail contains skeletal elements and muscles, which provide a source of locomotion in aquatic species, such as fishes. In some terrestrial vertebrates, the tail also helps with balance, courting, and signaling when danger is near.