1. Invertebrates
Unit 2
Kingdom Animalia

2. Developmental trends for invertebrates:
As we move through the phylum's we go from
simple to complex
The simplest organisms have asymmetry. As complexity increases, we go to radial and finally bilateral symmetry
Organisms go from having no cavity (acoelomates) to a false cavity (pseudocoelomates), to a true cavity (eucoelomates).

3. 3. Simpler organisms may reproduce sexually and asexually
3. Simpler organisms may reproduce sexually and asexually. As complexity increases, they can only reproduce sexually. 4. Simpler organisms have 2 tissue layers, more complex have 3 tissue layers. 5. They go from sessile to motile. 6. Simpler organisms have no tissues or systems. As complexity increases, the more systems an organism has.

4. Phylum Porifera
Symmetry: Asymmetrical Coelom: none Digestion: none Reproduction: - asexual/sexual - external fertilization - hermaphrodites (both male & female parts) Example: Sponge

5. Phylum Cnidarians (Coelenterata)
Symmetry: radial Coelom: none Digestion: one opening (food enters & wastes are removed from this opening ;called two-way) Reproduction: - asexual/sexual - external fertilization - hermaphrodites and separate sexes Example: jellyfish, hydra

6. Phylum Platyhelminthes
Symmetry: bilateral
Coelom: none
Digestion: one opening,
two way flow
Reproduction:
- asexual/sexual
- internal fertilization
- hermaphrodites and
separate sexes
Example: Planaria, tapeworm

7. Phylum Nematoda
Symmetry: bilateral Coelom: present Digestion: two openings, One-way flow (mouth to anus) Reproduction: - sexual - internal fertilization - separate sexes, few hermaphrodites Example: hookworm, pinworm

8. Phylum Annelida Symmetry: bilateral Coelom: present
Digestion: two openings,
One-way flow
(mouth to anus)
Reproduction:
- sexual
- internal fertilization
-hermaphrodites and
separate sexes
Example: Earthworm, leech

9. Phylum Mollusca Symmetry: bilateral Coelom: present
Digestion: two openings,
One-way flow
(mouth to anus)
Reproduction:
- sexual
- external & internal
fertilization
-hermaphrodites and
separate sexes
Examples: clams, squids, snails

10. Phylum Arthropoda Symmetry: bilateral Coelom: present
Digestion: two openings,
One-way flow
(mouth to anus)
Reproduction:
- sexual
- internal fertilization
- separate sexes,
few hermaphrodites
Example: spiders, insects, lobster

11. Phylum Echinodermata Symmetry: bilateral Coelom: present
Digestion: two openings,
One-way flow
(mouth to anus)
Reproduction:
- sexual (some asexual)
- external fertilization
- separate sexes,
few hermaphrodites
Example: Starfish, sea urchin, sand dollar