Section 31.1 (Exam 3) Flashcards
Deuterostomes Include Echinoderms, Hemichordates, and Chordates
What are the three developmental patterns that distinguish deuterostomes from protostomes?
Cleavage
development of the coelom
fate of the blastopore
What type of cleavage do deuterostomes tend to have?
radial cleavage
How does a deuterostome coelom develop?
from the folds of archenteron, which can also be called mesodermal outpocketing
What is it called when the coelom develops from folds of archenteron or mesodermal outpocketing? Which group exhibits this behavior?
enterocoelous; deuterostomes
In regards to coelom development, deuterostomes are ________________.
enterocoelous
What is the fate of the blastopore in deuterostomes?
It becomes the anus
In regards to coelom development, protostomes are _______________.
schizocoelous
What provides the strongest evidence for monophyly of the deuterostomes?
DNA sequencing
How do coeloms form in protostomes?
Solid masses of mesoderm split to form coelom
What are the three clades of deuterostomes?
Echinoderms
Hemichordates
Chordates
Deuterostomes have three defining characteristics. What are they?
Triploblastic
Coelomates
Have internal skeletons (when present)
What is it called when solid masses of mesoderm split to form a coelom? Which group exhibits this behavior?
schizocoelous; protostomes
What are the two traits present in the common ancestor of all deuterostomes?
Bilateral symmetry and pharyngeal slits
