respiratory structure in hemichordata is
a. Radial
b. Biracial
c. Bilateral
d. 1 and 2
Answers
Answer:
branchial portion of pharynx
Explanation:
Answer:
Humans are pretty familiar with their own respiratory system. We know the basics about how we take in air for oxygen, and filter out carbon dioxide. Animals that breathe through their skin or use gills feel pretty foreign to us, but believe it or not, we're in the same group and have a lot of similarities!
The phylum chordata is a group of animals that have a dorsal hollow nerve tube (for us, our spine), a notochord (the nerves inside the spine), pharyngeal slits (which become gills, we only have these in the womb), and a post-anal tail (for us the tailbone, and in other animals an actual tail).
Classes of chordates
classes of chordates
Let's look at the varied respiratory systems of different groups of chordates.
Aquatic Chordates
Lower chordates don't have a true backbone yet and all are aquatic. They have a variety of respiratory tactics. Most use gills as their respiratory system, though there are exceptions, such as the very primitive chordate called the lancelet. These are small eel-like fishes that only use their skin to breathe and use their gills for filtering food.
The sessile tunicates use a system of many gills on their surface to filter oxygen and carbon dioxide.
Botrylloides violaceus, a colonial tunicate
tunicate
As aquatic animals evolved, so did their gill system. The hagfish (so primitive it's not usually considered a fish) is a jawless chordate known for their ability to secrete mass amounts of slime to escape predators. This fish burrows into dead carcasses on the sea floor to find food. During this time, the gills on the surface which allow for gas exchange are blocked, so the hagfish is thought to effectively hold its breath while eating.
A fisherman handles hagfish slime from a storage tank
hagfish
Fish have an even more advanced gill system, with special coverings called an operculum. These coverings prevent dirt from flowing into the gills and aid in ventilation as water is forced through the mouth and pharynx and out the gill slits.
Exposed gills of a Chinook salmon
Chinook salmon
Sharks and rays do not have the operculum, as other fish do. Sharks use ram jet ventilation, where through swimming, water is forced through the mouth and pharynx and out five sets of gill slits. Sharks can forcefully open and close their jaws to pump water through their gills, but many have to keep swimming to maintain the current.
Gills of a hammerhead shark
shark gills
Explanation:
a mark as braniest