Phylum Cnidaria

Question 1

Major clades and distinguishing characteristics

Answer 1

Staurozoa: they have characteristics of both medusa and polyp life forms
Hydrozoa: smaller, velum, few radial chambers, more motile, eyespots, gametes from the epidermis
Scyphozoa: larger, 4 oral lobes, many radial chambers, 8 rhopalium, gametes from the gastrodermis
Octocorallia: 8 tentacles, pinnate, calcium carbonate in internal via spicules, sea pens, soft corals
Hexacorallia: 6 tentacles, non-pinnate, calcium carbonate exoskeleton, hard corals, anenomes

Question 2

Life Cycles of Major Classes

Answer 2

Scyphozoa: Broadcast external fertilization to make a planula larva develops into scyphistoma, forms a strobila, and that forms ephyra through asexual reproduction
Hydrozoa: Broadcast external fertilization to make a planula larva which buds to form a polyp colony, this polymorphic colony produces more adults via gonozooids
Anthozoa: Broadcast spawn external fertilization, planula larva, budding to form a colony
Can undergo asexual reproduction

Question 3

Polymorphic polyp types

Answer 3

Gonozooid: These are the sexual polyps that produce the medusa
Gastrozooid: These are the feeding polyps that provide the organism with nutrients
Dactylozooid: Used for defense of colony