Animal Diversity Lecture 6

Deuterostomia

Hemichordata, Echinodermata, Chordata

Early cell divisions after fertilization

Cleavage

Fate of Blastopore

protostomes, deuterostomes

Cleavage

spiral, radial

Spiral

Protostomes

Radial

deuterostomes

Protostome Development

Mollusca, annelida, arthropoda

Deuterostome Development

Echinoderms, Chordates

Spiny Skin

Echinoderma

All marine and exist in almost all marine environments

Echinoderma

Some free living, others sessile

Echinoderma

Calcified plates below the skin that are mesodermally derived

Echinoderma

Thin outer epidermis has pigment, mechanoreceptors, and sometimes toxic secreting cells

Echinoderma

Symmetry of Echinoderma?

Radial

Sea lilies and feather stars

Crinoidea

Filter feeders

Crinoidea

Sessile or free-swimming

Crinoidea

Sea stars

asteroidea

Mostly active predators

asteroidea

Brittle Stars

Ophiuroidea

No suckers on feet

Ophiuroidea

Sea cucumbers

Holothuroidea

Relatively Sessile

Holothuroidea

Scavengers or filter feeders

Holothuroidea

Sea urchins and sand dollars

Echinoidea

Relatively Sessile, Grazers or scavengers or predators

Echinoidea

Keystone Species

Pisaster and Mytilus

Predation by seastars prevents mussels from

taking over

Predation by seastars allows for

a larger species diversity

move by lashing arms

Ophiuroidea

active predators or filter feeders

Ophiuroidea