Bio II exam 3 flashcards 2
protostomes
What is cephalization?
Concentration of sensory and neural organs at the anterior end, forming a head.
Which phylum includes flatworms?
Phylum Platyhelminthes.
What kind of body cavity do flatworms have?
Acoelomate (no body cavity).
How do flatworms exchange gases and circulate nutrients?
By diffusion (no specialized systems).
What are the three major classes of Platyhelminthes?
Turbellaria, Trematoda, Cestoda.
What kind of coelom do mollusks have?
True coelom (coelomate).
What are the main body parts of a mollusk?
Foot, visceral mass, and mantle.
Which phylum includes segmented worms?
Phylum Annelida.
What is segmentation?
Repetition of body segments.
What circulatory system do annelids have?
Closed circulatory system.
What are the three major classes of annelids?
Polychaeta, Oligochaeta, Hirudinea.
Which phylum includes insects?
Phylum Arthropoda.
Key characteristics of arthropods?
Exoskeleton, jointed appendages, segmented bodies, open circulatory system.
What is molting in arthropods?
Shedding the exoskeleton (ecdysis) to grow.
Main groups of arthropods?
Chelicerates, Myriapods, Crustaceans, Hexapods.
What symmetry do echinoderms have as adults?
Radial symmetry.
Function of the water vascular system in echinoderms?
Movement, feeding, and respiration.
