1. Part II: Invertebrates
Diversity of Life
Part II: Invertebrates

2. What is an animal? Celltissueorganorgan systemorganism
Major functions: obtain food and oxygen, keep internal conditions stable, move and reproduce
Vertebrates (have backbone) and invertebrates(do not have backbone – 97%)
Symmetry: Balanced arrangements of parts -Bilateral, radial, none

3. Sponges Live in water (oceans, lakes, rivers)
No symmetry, no tissues or organs
Gets food by filtering the water that flows over it
Reproduce by budding or sexual reproduction (sperm released into water and fertilize eggs from another sponge)

4. Cnidarians Ex: Jellyfish, corals and sea anemones
Use stinging cells to capture food and defend themselves
2 Body structures: either polyp or medusa
Both have radial symmetry, central hollow cavity and stinging cells
Some just one body type, others go through stages of both
Obtain food by first stinging then using tentacles
Food goes to central cavity, digests and undigested food expelled out the mouth

5. Worms Invertebrates with long, narrow bodies
Bilateral symmetry, head and tail end
Have tissues, organs and body systems
Simplest organisms with a brain (detect objects, food, mates, responses to environment with sense organs)
Reproduce sexually (contain both sex organs, exchange sperm) and asexually (breaking into pieces)

6. Types of worms
Flatworms: flat and soft as jelly. Most are parasites (lives inside or on another organism -host), some are free-living (Ex: Tapeworm)
Roundworms: Live in any moist environment, cylindrical bodies, have digestive system that is open at both ends (food travels 1 direction)
Segmented worms: Bodies made up of many linked sections (ex: earthworm), closed circulatory system (blood vessels). Quicker blood flow

7. Mollusks Ex: Clams, oysters, scallops, snails, squid
Invertebrates with soft bodies often protected by hard outer shell
Has a thin layer of tissue called a mantle that covers its internal organs, and has an organ called a foot.
Open circulatory systems
Water mollusks have gills for oxygen
Gastropods, Bivalves and cephalopods

8. Types of mollusks
Gatropods: (snails, slugs) single external shell or no shell. Move with foot that secretes mucous.
Bivalve: (oysters, clams ) 2 shells held together by hinges and strong muscles. Uses foot to move. (Pearls form to cover unwanted grain of sand that gets stuck in shell)
Cephalapods: (octopus) ocean dwelling mollusk whose foot is adapted to form tentacles around its mouth. CLOSED circulatory system (only mollusks to have this)

9. Arthropods
Invertebrates that have external skeleton, segmented body, and jointed attachments called appendages
Exoskeleton (waxy, waterproof covering):keep them from drying out, and protection
First animals to live on land
Molts when it needs to get a new exoskeleton (b/c growing)

10. Types of Arthropods
Crustaceans: 2-3 body sections, 5+ pairs of legs, 2 pairs of antennae (crayfish)
Arachnids: 2 body sections, 4 pairs of legs, no antennae (spiders, scorpians)
Centipedes and Millipedes: 2 body sections and many pairs of legs
Insects: 3 body sections(head, thorax, abdomen), 6 legs, 1 pair antennae, 1-2 pairs of wings

11. Echinoderms
Invertebrates with an internal skeleton (endoskeleton) and a system of fluid-filled tubes called a water vascular system.
Move using water vascular system squeezing water into sticky tube feet
Sea stars, sea urchins, sea cucumbers