1. Invertebrate- animal that does not have a backbone
Vertebrate- animal that has a backbone
Radial Symmetry- all parts of an animal’s body are organized in a circle around a central axis
Bilateral Symmetry- body parts are organized into two equal halves which mirror each other
Protostome- an organism whose embryonic tissue develops into the mouth first and anus second.
Cephalization- Concentration of sensory organs in an anterior head.
Deuterostome- an organism whose embryonic tissue develops into the anus first and mouth second.

2. Phylum Porifera (1) Example: Sponges
Sponges are the simplest of animals that carry out all processes by the movement of water through pores
Characteristics:
Lack definite symmetry
No germ layers or mouth.
Reproduce both sexually and asexually
All process carried out a few specialized cells
Internal Fertilization – Sperm travels to another sponge, fertilizing another sponge internally.
Immobile (sessile)

3. Phylum Platyhelminthes (2) Example: Flatworms
Characteristics:
Bilateral symmetry
Protostome
Digestive system is branched with a single opening (mouth) with a specialized pharynx that pumps food into the digestive system
Cephalization – in some the head encloses ganglia – a group of nerve cells
Some are parasitic (ex: Flukes and tapeworms)
A flatworm has a very simple nervous system with two nerve cords running down either side. It has two simple brains called ganglia, which are simple bundles of nerves.

4. Acoelomates:
an invertebrate lacking a coelom; especially the group comprising the flatworms, having bilateral symmetry and one internal digestive cavity.

5. Phylum Nematoda (3) Examples: Roundworms Characteristics:
Body cavity, pseudocoelom, located between endoderm and mesoderm
Three Germ layers. Have complete, one-way digestive tracts (mouth and anus)
Protostome
Bilateral symmetry
Nematoda contains the most members, most are microscopic, many parasitic
These parasites can affect nearly any plant or animal.
The three types of parasitic roundworms are: Hookworms, Pinworms, and Guinea worms.

6. Phylum Arthropoda (4)
Examples (most species) : insects, crabs, centipedes, spiders
Characteristics:
Arthropods have a segmented body, tough exoskeleton (on outside), and jointed appendages.
Most successful of all invertebrates
Many specialized organs
Three Germ Layers with coelom
Bilateral symmetry

7. Phylum Echinodermata (5)
Examples: sea stars, sea urchins, sea cucumbers, and sand dollars.
Characteristics:
Most have spiny skin, an internal (endo) skeleton, a water vascular system, and suction-cuplike tube feet.
Adults have radial symmetry (can be split in two halves).
Adults possess five-part body plan
Deuterstome
Three germ layers with a coelom

8. Phylum Chordata (6) Chordates all had/have a notochord, a hollow nerve cord, pharyngeal slits, and a tail at some stage of development.
Examples (All vertebrates and some invertebrates):
Mammals, Reptiles, Birds, Amphibians
Characteristics (at some stage of development):
Notochord – back skeletal support
Hollow nerve cord – nervous system integration
Pharyngeal slits – Water passage
Tail – Has segments used for movement
Therm ~ Endo regulate their own body temperature whereas Ecto cannot.

9. Phylum Mollusca (7) Examples: snails, slugs, clams, squids, octopi
Characteristics:
Soft-bodied that usually have a shell
4 part body plan
Foot – movement
Mantle – layer of tissue covering body
Shell – created my mantle, lost in some members
Visceral mass – internal organs
Three germ layers with coelom
Bilateral symmetry.
Open Circulatory System:
The hemocoel is the space between cells within tissues. Blood is pumped through the hemocoel and cells receive oxygen by diffusion (No blood vessels).

10. Phylum Annelida (8)
Examples: earthworm, leeches, polychaetes, and feather dusters
Characteristics:
Worms with segmented bodies. Three germ layers and a true coelom (muscle-covered space)
Bilateral symmetry
Cephalization
Protostome
Closed Circulatory system – Blood flows in a circuit through actual vessels.

11. Aquatic Annelid Adaptations

12. Phylum Cnidarians (9)
Examples: Jellyfish, Hydra, Sea Anemones and Corals
Characteristics:
Two layers – an endoderm and ectoderm, with a layer of jelly-like material between.
A single mouth/anus surrounded by stinging tentacles
A nerve net to detect stimuli
Hydrostatic skeleton allow the animal to move
External fertilization – fertilization of sperm and egg takes place outside of the organism.

13. Hydrostatic Skeleton:
is a structure found in many soft-bodied animals consisting of a fluid-filled cavity, the coelom, surrounded by muscles.