Animals Invertebrates Characteristics of Invertebrates What is the

Animals: Invertebrates

Characteristics of Invertebrates • What is the difference between a vertebrate and an invertebrate? – Vertebrates are animals with a backbone, invertebrate are animals without a backbone • Do you think there are more vertebrates or invertebrate? – Invertebrates make up 90% of all animal species • All animals, including invertebrates are multicellular, and most have specialized cells

• Grows attached to one spot on the ocean floor • Body of sponges have many pores, or holes • Moving ocean water carries food and oxygen through the pores into the sponge • At the same time it releases waste products into the water • Sponges function on their own Sponges

Coelenterates • All contain a central cavity with only one opening • Have a cup-shaped body • Most of their mouths are surrounded by tentacles with stinging cells called nematocysts • They use these stingers to kill or stun other animals • Once food is stunned and eaten, waste product will exit through the same opening • Unlike sponges, coelenterates contain groups of cells that perform specialized functions • Examples: coral, sea anemones, jellyfish

Corals • Corals, like all coelenterates, are soft-bodied organisms • They use minerals in the water to build a hard protective covering of limestone • Corals live together in colonies, grow into wide variety of shapes and colors • Algae live inside coral’s body and help make them food

Sea Anemones • Look like underwater flowers • Have stinging cells that poison fish when they swim over , then they eat the fish • Clownfish, however, are not harmed by the anemones Jellyfish • Can deliver a painful poison through its stinging cells • Also use their tentacles to gather food • Move by jet propulsion • Overview video

Worms • Worms take part in the formation of some pearls • They act as an irritant • Worms are classified into 3 groups – Flatworms – Roundworms – Segmented worms

Flatworms • Have flat bodies and live in ponds and streams • Can regrow missing or cut off body parts • Examples: Planarians , and tapeworm(attach themselves to a host and takes food and water from it) Roundworms • Resemble strands of spaghetti • Food passes from the mouth end to the tail end through a digestive tube • Trichinosis is a disease caused by eating pork containing roundworms, that is painful and harmful to cure

Segmented Worms • Example: Earthworm • Have a digestive system with a crop and gizzard – Crop is a saclike organ that stored food – Gizzard grinds up food and then passes it into the worm’s intestine • • Closed circulatory system Moist skin for gas exchange Sexual reproductive system Simple nervous system

Mollusks • “Mollusks” means soft in Latin • Examples are snails, clams, octopus, and squids • Mollusks have a soft fleshy body • Most have a strong muscular foot • Head region contains the mouth and sense organs such as the eyes • A soft mantle covers much of the body, this produces the material that make up the hard shell • Grouped according to characteristics such as a shell presence, shell type, and foot type

One-Shelled Mollusks • Called univalves • Only have 1 shell • Have interesting features in their mouths called radula – It resembles a file and is used to file off bits of plant matter into smaller pieces to be swallowed Two-shelled Mollusks • Called bivalves • Have two shells • Move through the water by clapping their two shells together, which force water out between the shells • Do not have radula • Often called filter feeders since they spend most of their time straining the water food

Head-Footed Mollusks • Most highly developed mollusks • Include the octopus, squid, and the nautilus • Most do not have an outer shell, but have some type of shell somewhere on their bodies • Move by water propulsion • Watch video “Mollusks”

Spiny-Skinned Animals • Spiny-skinned animals are invertebrates with rough, spiny skin – Starfish, sand dollar, sea cucumber, sea urchins • Starfish are not really fish they are a type of spiny-skinned animal – Have 5 or more arms with tubes that resemble suction cups on the bottom of them – These tubes help the animal move and help open clam shells to eat them

Arthropods • Most successful invertebrates on the earth • The name arthropod mean jointed legs • Their jointed legs and exoskeleton are main characteristics • An exoskeleton is a ridge outer covering, it does not grow as the animal grows • Some types are crustaceans, centipedes, millipedes, arachnids, and insects

• • Crustaceans Examples: crabs, lobsters, crayfish, and shrimp All live in a watery environment Obtain oxygen from the water through their gills Bodies are divided into segments • • Centipedes/Millipedes Described as worms with legs Centipedes have 1 pair of legs on each segment, while millipedes have 2 Centipedes eat animals, millipedes eat plants Centipedes can inject poison, while millipedes cannot Arachnids • Includes spiders, scorpions, ticks, and mites • Bodies are divided into 2 main sections – Head-chest section – Abdominal section • Very in shape and size, however, all have 8 legs

INSECTS Section 10 -8 • There are more kinds of insects than all other animal species combined. • It is estimated that there are over 300 MILLION insects for every single person alive on the earth!

INSECTS A little about insects! • Insects can fly • They vary in appearance • Insects eat the plants we use for food • Others eat the clothes we wear • Some even eat your house!

INSECTS Insect Anatomy • Divided into three main sections – Head – Thorax – Abdomen • Insects have three pairs of legs • Most have wings • Have an open circulatory system – Their blood is not contained in blood vessels

INSECTS Simple vs Compound Eye • Insects have compound eyes – More than one lens • We have simple eyes – Only one lens

INSECTS METAPHORSIS • Insects go through several stages of growth and development • Many change in appearance • Different stages include – Eggs – Larva: stage that the insect emerges from the egg – Pupa: stage in an insects life when it is wrapped in a cocoon. – Adult