Hemichordates and Chordates Flashcards
(13 cards)
Are hemichordates marine or freshwater animals?
Exclusively marine.
What type of habitat do hemichordates occupy?
They are benthic, living on or in the seabed, from intertidal zones to the abyssal plain.
What are the two main forms of hemichordates?
Burrowing acorn worms and colonial zooids (which superficially resemble bryozoans).
What kind of body symmetry do hemichordates have?
Bilateral symmetry.
What are the three subphyla of Chordata?
Tunicata (Urochordata), Cephalochordata, Vertebrata.
Which subphyla of chordates are invertebrates?
Tunicata and Cephalochordata.
Why is the focus on invertebrates in this module important?
To highlight the greater diversity and abundance of invertebrates compared to vertebrates.
Approximately how many species are in Tunicata?
About 3,000 species.
What are two forms tunicates can take?
Small, free-swimming individuals and larger, colonial forms like pyrosomes.
What notable feature do giant pyrosomes display?
They are colonial chordates, forming large tube-like structures in the ocean.
What are cephalochordates commonly known as?
Lancelets or amphioxus.
How many species of cephalochordates are there?
Around 30 species.
What is the typical appearance of a cephalochordate?
Small, fish-like, bilaterally symmetrical animals.
