1. Turn in your phylum requests to the inbox

2. Invertebrates!!

3. Review: What is an Animal?
A multicellular eukaryotic heterotroph whose cells lack cell walls
Invertebrates have no backbone or vertebral column. 95% of animals are invertebrates.
Vertebrates have a backbone. Only 5% of animals are vertebrates.

4. What are the Invertebrates?
Multicellular animals
Heterotrophs – take in food, digest it, distribute it to cells
No backbone
Have locomotion, special parts for locomotion
Some are sessile
Some invertebrates can regenerate lost parts or even a complete individual from a broken piece.

5. Phylum Porifera Sea Sponges Means “pore bearing” Asymmetric
Natural sea sponges: dead material that remains after decay

6. Sessile: live attached to a surface
Do not have nerve cells or tissue
Filter feeders: pump water in and out and feed on the organic material in water
Many are hermaphrodites: able to produce male and female gametes – an advantage for sessile organisms
Can reassemble when fragmented

7. Phylum Cnidaria
Coral, jellyfish, sea anemones

8. Cnidocytes: cells that contain stinging poisonous barbs with which they paralyze prey
Radial symmetry
Two body forms:
polyp: sessile, tentacles up (coral, hydra, anemone)
medusa: free swimming, tentacles down (jellyfish)

9. Digestive body cavity surrounded by two layers of cells
Sexual or asexual reproduction – hydra reproduces by budding
Coral reefs build up and are important ocean habitats

10. Phylum Platyhelminthes
Examples: flatworms, tapeworms, flukes

11. Many parasitic forms - cause many diseases of people and livestock
Bilateral symmetry and cephalization
One digestive opening (pharynx) to take in food and release waste – most don’t need complex digestive systems because food has already been digested by their host
Most are hermaphroditic, some can regenerate lost body parts

12. Phylum Nematoda
Examples: roundworms (pinworms, hookworms, heartworms)

13. Many are microscopic
Two digestive openings: mouth and anus – food moves only one way
Sexual reproduction
Most are free-living, many are parasitic – you can be infected by consuming contaminated food/water or by being bitten by insects

14. Phylum Annelida
Examples: segmented worms, earthworms, leeches

15. Closed circulatory system: blood stays within vessels
Earthworm is hermaphroditic; others have separate sexes
Earthworms are important in the soil ecosystem– provide passageways for plant roots and water.
Aristotle called earthworms “the intestines of the soil”. What did he mean by this?

16. Phylum Mollusca Mollusks have an internal or external shell.
Examples: snails, slugs, clams, octopus, squid, cuttlefish

17. Main groups of mollusks: 1. Gastropods are “stomach-footed”
univalves: one shell (snail)
bivalves: two shells (clam)
2. Cephalopods are “head-footed”
Foot is modified into tentacles.
They breathe with gills.
(octopus, squid)
Have you hugged your octopus today?

18. Sexual reproduction: most have separate sexes, some are hermaphrodites
Most have an open circulatory system (blood is contained within vessels that empty into sinus cavities). Cephalopods have a closed system (blood remains within vessels).
Most mollusks are marine, but some live in fresh water or on land

19. Phylum Arthropoda Arthropod means “jointed foot”
Largest phylum – found almost everywhere!

20. Characteristics:
1. exoskeleton
a. Outside the body
b. Very good protection
c. Does not grow, so it must be shed periodically (molting)
2. paired, jointed appendages
(legs, antennae)
3. segmentation

21. Centipedes and Millipedes
most primitive arthropods
obvious segmentation
Centipedes (Class Chilopoda)
a. one pair of legs per segment
b. venomous fangs for killing prey
c. long antennae

22. Millipedes (Class Diplopoda)
a. two pairs of legs per segment
b. one pair of short antennae
c. usually harmless vegetarians

23. Crustaceans (Class Crustacea)
Examples: lobster, crayfish, shrimp, crab

24. Arachnids (Class Arachnida)
Examples: spiders, ticks, mites, scorpions

25. two body regions: a. cephalothorax (where legs come from) b. abdomen
no antennae
simple eyes
4 pairs of walking legs
mouthparts modified as fangs (chelicerae) to stab prey and suck out body fluids
book lungs (gills modified for breathing on land)

26. Insects (Class Insecta)
Over 75% of all animal species
First animals to evolve the ability to fly
6 legs and 3 body parts

27. Insects undergo metamorphosis:
a series of changes during which young insects develop into adults.
Incomplete Metamorphosis (grasshopper)
Gradual changes from nymph to adult
1. egg nymph adult

28. Complete Metamorphosis (butterflies, bees)
1. egg 2. larva (caterpillar) pupa adult

29. Phylum Echinodermata Name means “spiny skin” Marine environment
Radial symmetry
Deuterostomes - indicates a fairly close relationship to vertebrates

30. Water vascular system
1. system of internal tubes
2. carries out functions of circulation, respiration, and movement
Tube feet
1. act like living suction cups
2. help in movement and feeding

31. Examples: sea urchins, sand dollars, starfish (sea stars)

32. Which invertebrate phyla are represented here?