1. Invertebrates

2. Invertebrate
- Organism without a backbone
3 Main Body Plans
1. Bilateral
2. Radial
3. Asymmetrical
Bilateral
- Two sides of the body mirror each other
Radial
- Symmetry is found all around the center point
Asymmetrical
- There is no line of symmetry

4. Invertebrate Characteristics
Ganglion
- Concentrated mass of nerve cells
- Nerves allow animal to sense environment
- All animals except sponges have nerves
Gut
- A pouch used to break down food
Coelom
- Space surrounding the gut
- Can have other organs within

6. Sponges
- Asymmetrical
- Simplest invertebrates
- Live in water
- Can regenerate broken or missing parts
Regeneration
- Ability to grow back a body part
Pores
-Holes on the outside of body
-Water brings in food and oxygen
Osculum
-Hole on top of sponge that allows water to leave

7. Cnidarians
- Radial symmetry
-complex tissue and a gut
-simple nerve cells
-stinging cells
- Ex: Jellyfish, Anemones
- Two body forms: Medusa or Polyp
Medusa
- Swims through water
- Usually attach to a surface
Polyp

8. Classes of Cnidarians
Hydrozoans
-common cnidarians
-live in both fresh and salt water
-most spend lives as polyps
Jellyfish
-use tentacles to catch food
-spend most of lives as medusas
Sea anemones
-brightly colored
-spend lives as polyps
Coral
-polyps
-brightly colored
-made of calcium carbonate
-live in colonies
-build reefs

9. Round Worms
- Bilateral symmetry
- Simple nervous system
- Brain is a ring of ganglia
Many are parasites Trichinella spiralis
Some infect humans pinworms and hookworms
decomposers

10. Flatworms
- Bilateral symmetry
- Clearly defined head
- Two large eyespots
- Cannot see through eyespots, but sense light
Some can be parasitic
3 main type
Planarian
-Live in freshwater
-predators
-well developed nervous system
Flukes
-parasites
-no eyespots
-contain suckers and hooks to attach to
other animals

11. Tapeworm
-parasites
-no gut or eyespots
-attach to the intestines of other animals
Absorb nutrients
-can infect humans

12. Mollusks and Annelid Worms

13. Mollusks
-Most live in the ocean
-some live in freshwater and land
-complex ganglia
-contain a circulatory system
-Bodies are made of :
-Muscular foot-used for movement
-Visceral mass- contains gut, gills,
and other organs
-Mantle-covering used for protection
if no shell
-Shell-hard covering used for protection

14. -clams and other shellfish -use gills to filter food from water
3 Classes of Mollusks
Gastropods
-slugs and snails
-eat by using a radula  tongue with curved teeth
Bivalves
- 2 shells
-clams and other shellfish
-use gills to filter food from water
Cephalopods
-Octopus and squid
-use tentacles to get food and a powerful jaw to
eat it
-contain large brain connected to ganglia

15. -bodies are in segments  identical repeating body parts
Annelid Worms
-segmented worms
-bodies are in segments  identical repeating
body parts
-bilateral symmetry
-circulatory system
-Complex nervous system with brain
-Live in salt water, freshwater or on land
-3 major groups
Earthworms
-most common
-decomposers
-leave casting in soil  produce rich soil
Use stiff hairs or bristles to move

16. Marine Worms
-Colorful
-Live in ocean
-Polychaetes covered in bristles
-Eat mollusks or filter water for food
Leeches
-Parasites that suck blood produces a chemical
that thins blood can be used medically
-Scavengers that eat dead animals

17. Arthropods and Echinoderms

18. Four Characteristics Shared by Arthropods
1. Segmented and specialized body
2. Jointed limbs
- Body parts bend at joints
3. External Skeleton (Exoskeleton)
4. Compound Eyes
Exoskeleton
- Hard covering of the body
Antennae
- Feelers that sense touch, taste, and smell
Compound Eye
- Several identical light-sensitive units

19. Mandible
- Mouthparts that can pierce objects
Crustaceans
- Have gills, antennae, and mandibles
- Have compound eyes
Ex: Shrimp, Crab, Lobster

20. - 2 body parts: Cephalothorax and Abdomen
Arachnids
- 2 body parts: Cephalothorax and Abdomen
- 4 pairs of legs
- Simple eyes
-spiders, scorpions, mites, ticks

21. Insects
- Largest group of arthropods
- Six legs
- 3 main body parts
1. Head
2. Thorax
3. Abdomen

22. - Change from young to adult
Metamorphosis
- Change from young to adult
- Organism goes through a complete change
Complete Metamorphosis
- No major changes in organism
Incomplete Metamorphosis
- Grows from smaller youth to larger adult

24. Echinoderms
- Means “spiny skinned”
- Radial symmetry
- Simple nervous system
- contains a mouth
Sea stars, Sand Dollars
Endoskeleton
- Internal bones and cartilage

25. - System of canals
Water Vascular System
- Circulates water
- Used to move, eat, sense environment, breathe

26. Types of Echinoderms
Brittle Stars Basket Stars
-long slim arms
-smaller than sea star
Sea Urchins
Sand Dollars
-round with no arms
-shell-like structure
-use spines and tube feet to move
Sea Lilies
Feather Stars
-have multiple feathery arms
Sea Cucumbers
-no arms and worm-shaped