The Invertebrates What is an invertebrate?

Look at pg in your textbook

Porifera (The Sponges) Sponges are aquatic animals that represent a transition from unicellular to multicellular life. Of the 10,000 species of sponges, only about 150 species live in fresh water.

Immobile as adults but larva are mobile. Filter feeders.

Calcerea Hexactinella Demospongiae Sclerospongaie

Cnidaria is a phylum which consists of hydras, jellies (or jellyfish), sea anemones, and corals. Cnidaria

 Gastrovascular cavity- takes in food and releases waste  Most prey on animals ranging from small plankton to animals several times larger than itself  A few are parasites, some get nutrition from endosymbiotic algae  Cnidocytes-stinging cells used mainly for capturing prey Finding Food

 Phylum Cnidaria includes the following classes: Class SchphozoaClass Schphozoa (The jellyfish, or jellies) Class Hydrozoa (Diverse polyps, including hydras) Class Cubozoa (A minor tropical class with cuboidal swimming cups) Class Anthozoa (Sea anemones, corals) Class Hydrozoa Class Cubozoa Class Anthozoa

Platyhelminthes (the flatworms)

Phylum name: Platyhelminthes Meaning: Platy (Flat) helminthes (Worm)

Classes in the phylum Platyhelminthes... Class TurbellariaClass Turbellaria - Free Living Worms Class Trematoda - Flukes Class Monogenea - Flukes Class Cestoidea - Tapeworms Class Trematoda Class Monogenea Class Cestoidea

Nematoda  Roundworms have a long, slender body that tapers at both ends. They range in length from 1 millimeter to 4 feet in length.

-Has a complete digestive tract from mouth to anus -Has a tough outer layer called a cuticle -many are parasitic

Reproduction: -Produce sexually using internal fertilization -Similar to humans like how the male inserts sperm into the female Movement: -Use their body-length muscles to form a somewhat skeleton/backbone to move. -Moves like a worm

Nematodes: some are parasitic to humans Filarial worms may cause Elephantiasis by blocking the flow of fluids in the lymph vessels Ascaris worms cause malnutrition by absorbing digestive food from the small intestine Hook worms travel in humans and cause weakness and poor growth by sucking blood from the intestines RAWR!

Mollusca  Snails, clams squids and octopi  From Latin word Molluscus meaning “soft body”

Internal structure  There are different types of mollusks who have different body structures.

Movement/reproduction  Clams use a “foot” to move  Foot is good for digging into the ground Snails use a “foot” as their form of movement but it slides on the ground and helps them to slither. Squids have a very different form of movement. Pump water through their bodies like a jet propeller Mollusks reproduce sexually Some are seasonal hermaphrodites so they can change their sex from one to another.

Annelida  Segmented worms are more “advanced” than roundworms.  They have many body segments that make an annelid look like it is composed of a series of "rings".  Unlike roundworms, the segmented worms have an obvious head and tail.

Three main types:  Oligochaeta: earthworms  Polychaeta: two-thirds of all annelids are polychaetes. they have antennae and specialized mouth parts, mostly marine  Hirudinea: leeches, mostly live in freshwater

Arthropoda  The Arthropods, the largest animal phylum, includes insects, spiders, crustaceans

 Arthropods range in distribution from the deep sea to mountain peaks, in size from the king crab with its 12-foot armspan to microscopic insects and crustaceans.

Two groups of subphyla exist: arthropods with jaws and arthropods with fangs or pincers

 Arthropods have a segmented body, jointed appendages and a hard exoskeleton

Exoskeleton: composed of chitin, provides protection and helps prevent water loss

Echinodermata Meaning: spiny skin

Most of the 7,000 species of echinoderms have a type of radial symmetry called pentaradial symmerty, in which the body parts extend from the center along five spokes.

Structure Hard, internal calcite skeleton Tube feet, which they get from a water vascular system Regenerate limbs Five-point radial symmetry (at some point in life)