Hemichordates Flashcards
(23 cards)
What are the 2 classes of hemichordata?
Enteropneusta
Pterobranchia
What type of taxonomic group is hemichordata?
Phylum
What 2 key features make hemichordates similar to chordates?
Pharangeal gill slits
Dorsal nerve cord
What are enteropneusta known as?
Acorn worms
What time of circulatory system do hemichordates have?
Open circulatory system
Why was hemichordata once a sub phylum of chordata?
Hemichordates’ buccal diverticulums resemble notochords
What is the main difference between hemichordates and chordates?
They do not have homologous notochords
What is a buccal diverticulum?
An extension of the mouth cavity
What unique structure do hemichordates possess?
A glomerulus
In what type of habitat to hemichordates live?
Marine, intertidal
How do pterobranchs feed?
Filter feeding using a lophophore-like feeding structure
What are pharyngeal gill slits?
Repeated openings along the pharynx, caudal to the mouth, allowing movement of water in the mouth and out the slits
What is a key use of pharyngeal gill slits in hemichordates?
Filter feeding
What is a hemichordate glomerulus?
A sac at the rear of the mouth with finger-like projections, containing waste products and nutrients
How do hemichordates use their glomerulus?
Blood leaving the system passes through the glomerulus to extract nutrients
Which marine zone do most adult hemichordates live in?
Benthic zone
Where do hemichordates burrow?
In mud and soft sediments
True or false: most hemichordates are dioecious.
True
What type of feeders are enteropneusts?
Deposit/suspension feeders
How do enteropneusts reproduce?
Asexually and sexually
How to pterobranchs reproduce?
Mostly asexually
What is a Tornaria?
The free-swimming larval stage of enteropneusts
True or false: pterobranchs are solitary
False - pterobranchs live in colonies, with some being connected to each other by tissue extensions called stolons
