1. Animals – Part 1

2. What is an animal?
Multicellular heterotrophs – take in food, digest it, distribute nutrients to cells
Eukaryotes, cells lack cell walls
Maintain homeostasis
Divided into 2 groups: invertebrates and chordates
Characteristics
of Animals

3. What is an invertebrate?
No backbone
Have special parts for locomotion
Some are sessile
Some reproduce by budding, some with sperm and egg, some by parthenogenesis (unfertilized egg becomes an individual)
some invertebrates can regenerate lost parts or even a complete individual from a broken piece.

4. Porifera – Sponges! Simplest animals
Sac-like bodies – hole in the top leading to open body cavity
Filter feeders - water flows out through top hole and in through pores in body wall.
No tissues, different cells perform different functions
Both sexual and asexual, motile larvae

5. Porifera - sponges
The two pictures on left show living sponges, the two
pictures on right show the skeletons – used commercially.

6. Sponges
Phylum
Porifera

7. Cnidaria Radial symmetry Hollow gut with a single opening
Tentacles with stingers
Prey is stung and stuffed through opening in the gut.
Gets oxygen, water, and gets rid of waste through diffusion

8. Cnidarians - Sea anemones, coral, jellyfish

9. Hydra
Jellyfish

10. Coral
Sea anemones

11. Sea anemone movement Between two cells layers the sea anemone
has a jellylike
layer with
nerve cells and
contractile
fibers –
this is how it
moves.
Stinging
Animals

12. Platyhelminthes (flat worms)
Bilateral symmetry
Most are parasites
Flukes feed on host tissue
Tapeworms feed on materials in the host’s gut.

14. Planarians

15. Tapeworms

16. Flukes

17. Nematoda (round worms)
Most are microscopic
Most hunt for their food
Complete digestive system – two openings
50 species are parasites
transmitted in untreated sewage
Live everywhere, move by long muscles
Sexual reproduction

18. Nematoda
Roundworms
Guinea worm

19. Ascaris (intestinal worms)

20. Necator (hookworm)

21. Annelida (segmented worms)
Segmented bodies help in crawling and burrowing into dirt and holes
Earthworms are hermaphrodites
Most are filter feeders, carnivores or parasites (ex: Leeches feed on animal’s blood)
Over 12,000 known species of earthworms, leeches, and clamworms

22. Earthworms and Leeches

23. Annelida Ocean tubeworms Earthworm – note segments (2) and
Clitellum (1)

24. Annelida
Diagram of
earthworm anatomy-
note development
of organs.

25. Annelida This shows a worm’s five pairs of beating hearts Phylum
of Worms