Invertebrates Unit 2 Kingdom Animalia
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. 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.
Phylum Porifera Symmetry: Asymmetrical Coelom: none Digestion: none Reproduction: - asexual/sexual - external fertilization - hermaphrodites (both male & female parts) Example: Sponge
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
Phylum Platyhelminthes Symmetry: bilateral Coelom: none Digestion: one opening, two way flow Reproduction: - asexual/sexual - internal fertilization - hermaphrodites and separate sexes Example: Planaria, tapeworm
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
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
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
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
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