Deuterostomes vs Protostomes Flashcards
What taxonomic rank are Deuterostomes and Protostomes, what is the rank immediately preceding them, and when did they diverge?
Subphylum, Bilateria, ~600 mya
What are the main Deuterostome phyla?
Chordates, hemichordates, echinoderms
In deuterostome development, the blastopore (first opening) becomes the ____ on the _____ end
anus, posterior
Where is the nerve cord on deuterostomes?
Dorsal
What happens if the blastomere separates in a deuterostome and what is that called?
Each becomes an individual, indeterminate cleavage
How is the cleavage in deuterostomes shaped?
Radial
How is the mesoderm formed in deuterostomes?
Outgrowth of endodermal wall of archenteron
How is coelem formed in deuterostomes?
Outpouches of archenteron
How many species are deuterostomes?
~60,000
What are the major protostome phyla?
arthropods, nematodes, molluscs, annelids, rotifers, platyhelminths
During development, protostome blastopore forms ____ on the _____ end
mouth, anterior
Where is the protostome nerve cord located?
Ventral
What happens to protostome blastomeres and what is this called?
They will form into known organs early in cleavage. Determinate cleavage.
What shape is protostome cleavage?
Spiral
How is protostome mesodermal tissue formed?
By division of single blastomere cell
What is a blastomere?
A cell formed by cleavage of a fertilized ovum
How does the coelem originate in a protostome?
By splitting the mesodermal cell mass.
About how many species are protostomes?
~1million.
What are some explanations for protostomic diversity?
The ability to live in terrestrial environments
was a key event in the evolution of several protostome phyla. In addition, the evolution of specialized body plans provided a foundation for diversification in the most species-rich lineages of protostomes—arthropods and mollusks. In large part, the remainder of protostome evolution was driven by innovations in feeding, moving, and reproducing.
