Echinoderms

Echinoderms

Phylum Echinodermata

Endoskeleton

Tube feet.

Radial symmetry

Form and Function

Water vascular system

Madreporite

Feeding

Sea urchins

Sea lilies

Sea cucumbers

Sea stars

Respiration and Circulation

Water vascular system

Diffusion across the tissue of tube feet

Skin gills

Excretion

Anus

Tube feet

Response and Movement

Nerve ring and Radial Nerves

Sensory Cells

Movement is through the tube feet

Sand dollars and sea urchins

Sea and brittle stars

Sea cucumbers

Reproduction

External fertilization

Separate sexes

Bilateral symmetry

Sea Urchins and Sand Dollars

Class Echinoidea

Have a large, solid plate that forms a box around their internal organs

Detritivores or grazers that eat algae

Some have large sharp spines

Brittle Stars

Class Ophiuroidea

Slender, flexible arms and can scuttle around quite rapidly

Can shed one or more arms when attacked. The arms will keep moving to distract the predator

Filter feeders and detritivores that hide by day

Sea Cucumbers

Class Holothuroidea

Detritus feeders

Evisceration

Sea Stars

Class Asteroidea

Carnivorous

As long as it contains a portion of the central part of the body, pieces of sea stars can repair itself

into a new animal

Sea Lilies and Feather Stars

Class Crinoidea

Filter feeders

Sessile

Ecology

Sea urchins

Sea stars

Crown-of-thorns

Invertebrate Evolution

Molecular Paleontology

Microscopic fossils have been preserved that show the embryos of early multicellular animals

Molecular paleontology

The First Multicellular Animals

Ediacaran fossils

They were flat and plate-shaped

Soft tissues

Segmented bodies and bilateral symmetry

Vertebrate Diversity

Cambrian Period (554 mya)

This is when the ancestors of most modern animal phyla first appear in the fossil record

Phylogeny

Single-cell ancestor

Multi-cellularity

Protostome development

TissuesThree Germ layers; bilateral symmetry

Radial symmetry

Radial symmetry

Coelom

Deuterostome Development

Pseudo-coelom

Sponges

Cnidarians

Flatworms

Roundworms

Mollusks

Arthropods

Annelids

Echinoderms

Chordates

Invertebrate Comparison

SPONGES CNIDARIANS FLATWORMS ROUNDWORMS

GERM LAYERS Absent Two Three Three

BODY SYMMETRY

Absent Radial Bilateral Bilateral

CEPHALIZATION

Absent Absent Present Present

COELOM Absent Absent Absent Pseudocoelom

EARLY DEVELOPMENT

________ ___________ Protostome Protostome

Invertebrate Comparison, pt 2

ANNELIDS MOLLUSKS ARTHROPODS ECHINODERMS

GERM LAYERS Three Three Three Three

BODY SYMMETRY

Bilateral Bilateral Bilateral Radial (adults)

CEPHALIZATION

Present Present Present Absent (adults)

COELOM True coelom

True coelom

True coelom True coelom

EARLY DEVELOPMENT

Protostome Protostome Protostome Deuterostome

Feeding and Digestion

The simplest animals break down food primarily through intracellular digestion, but more complex animals use extracellular

INTRACELLULAR DIGESTION

EXTRACELLULAR DIGESTION

BOTH

Sponges Roundworms Cnidarians

Annelids Flatworms

Mollusks

Arthropods

Echinoderms

Aquatic Respiration

DIFFUSION GILLS BOTH

Cnidarians Mollusks Echinoderms

Flatworms Annelids

Roundworms Arthropods

Sponges

Terrestrial Respiration

DIFFUSION BOOK GILLS BOOK LUNGS TRACHEAL TUBES

Flatworms Arthropods (horseshoe crab)

Arthropods (spiders)

Arthropods (insects)

Roundworms

Annelids

Mollusks

Circulation

OPEN CIRCULATORY SYSTEM

CLOSED CIRCULATORY SYSTEM

DIFFUSION WATER VASCULAR SYSTEM

Arthropods Annelids Sponges Echinoderms

Mollusks (Gastropods)

Mollusks (Cephalopods)

Cnidarians

Flatworms

Roundworms

Excretion

DIFFUSION FLAME CELLS NEPHRIDIA MAPIGHIAN TUBLUES

Sponges Flatworms Annelids Arthropods

Cnidarians Mollusks

Roundworms

Echinoderms

Response

NERVE NETS/RING

GANGLIA BRAIN SENSE ORGANS

Cnidarians (net) Flatworms Mollusks (Cephalopods)

Cnidarians

Echinoderms (ring)

Roundworms Arthropods Flatworms

Annelids Roundworms

Annelids

Mollusks

Arthropods

Echinoderms

Skeletons

HYDROSTATIC SKELETON

EXOSKELETON ENDOSKELETON

Annelids Arthropods Echinoderms

Cnidarians

Roundworms

Reproduction

SEXUAL REPRODUCTION SEXUAL/ASEXUAL REPRODUCTION

Roundworms (internal fertilization)

Sponges (internal fertilization/gemmules)

Annelids (external fertilization) Cnidarians (external fertilization/budding)

Mollusks (both types of fertilization)

Flatworms (internal fertilization/fission)

Arthropods (both types of fertilization)

Echinoderms (external fertilization