Animals with out Backbones
Asymmetrical animals that are a variety of colors, shapes, and
sizes
Sponges
 Phylum Porifera- means pore-bearer
 Sessile organisms
 Filter Feeders
 Feed by filtering small particles of food from water
 Reproduction
 Hermaphrodites- produce both sperm and eggs
 Fertilization
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Internal
External
Jellyfish, Corals, and Sea Anemones
Cnidarians
 Two body forms
 Polyp- the stage that has a tube-shaped body form with
a mouth surrounded by tentacles
 Medusa- body form shaped like an umbrella with
tentacles hanging down
 Digestion
 Nematocyst- a capsule that contains a coiled, threadlike
tube that may be sticky or barbed and contain a toxin.

Capture prey
 Gastrovascular Cavity- a space inside the body where
digestion takes place, one opening (Mouth)
Cnidarians
 Nerve Net
 Conducts nerve impulses from all parts of the body
 No control center
 Impulses produce contractions of the muscle like cells
 Reproduction
 Asexually- budding of the polyp
 Sexually- eggs and sperm released into the water
Tapeworms, Flukes, Planarians
Flatworms
 Contain a brain like structure called the Ganglion
 Sends messages to body through two nerve cords
 Receive messages from Eyespots and Sensory Pits
 Digestive System
 Contains one opening the Mouth
 Tapeworms and Flatworms are parasitic
Roundworms
 Smaller then Flatworms
 Tapered at both ends
 First Animals with two openings in the digestive
system
 Free-living and Parasitic
Mollusks
 Bilateral Symmetry
 Two body openings
 Muscular Foot
 Mantle
 A thin membrane that surrounds the internal organs
 Secretes the shell
Mollusks
 Gastropods- one shelled mollusk
 Stomach-footed
 Includes
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Snails, Slugs, and Sea Slugs
 Simple Nervous System
 Small Brain and associated nerves
 Circulatory System
 Contain a heart
 Have open circulatory system- heart pumps blood to vessels then to
open spaces
 First with Respiratory structures called Gills
 First with Evolved Excretory structures
 Nephridia- organs that remove waste from body
Mollusks
 Bivalves- two shelled mollusks
 Clams, oysters, and scallops
 Sessile animals- filter feed
 Cephalopods- head footed mollusks
 Octopus, squid and chambered nautilus
 Closed Circulator System
 Foot is Tentacles
 Advanced Nervous System
Bristleworms, Earthworms, Leeches
Segmented Worms
 Body divided into Segments
 Allows for specialization
 Bilateral with two digestive openings
Jointed-Leg Animals
Arthropods
 Jointed appendages allowed for more powerful movements
and increased locomotion
 Exoskeleton-protects and provides structure for internal
organs
 Most Molt (Shedding of Exoskeleton) in order to increase
size
 Respiration- three types of respiration structures
 Gills- Crabs, Lobsters
 Tracheal Tubes- branching networks of hollow air passages
with openings in side called Spiracles- Insects
 Book Lungs- air-filled chambers that contain leaflike platesSpiders
Arthropods
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Groups of Arthropods
Arachnids- Spiders, Scorpions, Mites, Ticks
Crustaceans- Crabs, Lobsters, Shrimps, Crayfish,
Barnacles, water fleas, Pill bugs
Centipedes
Millipedes
Insects
Starfishes, Brittle Stars, Sea Urchins and Sand Dollars, Sea
Cucumbers, Sea Lilies and Feather Stars
Echinoderms
 Contain an Internal Skeleton
 Radial Symmetry
 Water Vascular System- used to move, exchange gas,
capture food, and excrete waste
 Tube-Feet with Suction Cups on the end with the
Ampulla (round muscular structure) on the opposite
end that works like an eyedropper
 Hydraulic water pressure system
 Simple Nervous System-Nerve Net with cells that
detect light and touch
Sea Squirts and Lancelets
Invertebrate Chordates
 Contain no Backbone
All Chordates have the following
 Notochord- long, semi-ridgid, rod-like structure
 Dorsal Nerve Cord- a bundle of nerves housed in a
fluid filled canal above the notochord
 Gill Slits
Invertebrate Chordates
Sea Squirts
 Sessile
 As adults the y only contain Gill Slits
 As larva they posses all the features common to
chordates
Lancelets
 Retain all Chordate features in Adult life
 Live in Borrows