Dr. Terence Lee
Protostomes and Deuterostomes
Symmetry
• Asymmetry – no symmetry • Radial Symmetry – circular or round • Bilateral Symmetry – usually has a head and tail
1 Sponges
• Asymmetrical • No true tissues
Jellies • Ctenophores • Cnidarians
Cnidarians
• Named after their stinging cells • Radially symmetrical • First true tissues
2 Cnidarians
Sea Anemone
Coral Coral Reef
Alternation of Generations
Protostomes and Deuterostomes
3 Protostomes and Deuterostomes
• Name comes from embryonic development – Protostome = As the embryo develops, the first opening becomes the mouth – Deuterostome = As embryo develops, the first opening becomes the anus .
The Worms
1. Flatworms 2. Roundworms 3. Segmented Worms
Flatworms
• Playhelminthes – First with bilateral symmetry – Only one opening to gut
planarians
4 Round Worms
• Nematoda – One-way digestive tract
Segmented Worms
•Annelids –Body is divided into sections –Lives in many different habitats
Annelids
• Polychaetes are marine worms • Means “many feet”
6 Annelids
This plan most Mollusks resembles the chiton body plan
• Major Characteristics 1. Mantle – secretes the shell
Mollusks
• Live in very diverse habitats (aquatic and terrestrial) • Very diverse body plans – Some have shells while others are soft bodied • Very diverse locomotion
7 Mollusks
Types of Mollusks: 1.Chitons – this is the most primitive 2.Bivalves – clams, oysters, mussels, etc.
Chitons
Bivalves
• Two shells attached by a hinge • All are filter feeders • Mostly immobile but some species can swim • Good fossil record
8 Bivalves (Clams)
Filter feeders
Muscular foot for digging
Bivalves (Clams)
Bivalves (Oysters)
9 Bivalves (Oysters)
Bivalves (Mussels)
Bivalves (Mussels)
10 Bivalves (Scallops)
Gastropods (Snails)
Gastropods (Slugs)
11 Gastropods (Slugs)
Cephalopods
Octopus Squid
Cuttlefish Nautilus
Arthropods
• Major Characteristics – Exoskeleton – Needs to molt – Jointed Limbs – Lives in very diverse habitats
12 Structural Support
• Exoskeleton – external – Arthropods (shell) – Size limitations • Endoskeleton – internal – Vertebrates (bones)
Arthropods (Insects) • Three body parts
Arthropods (Arachnids) • Two body parts 1. Head/Thorax 2. Abdomen
13 Arthropods (Arachnids)
Arthropods (Crustaceans)
• Copepods • Crabs • Lobsters • Isopods
Arthropods (Crustaceans)
14 Protostomes and Deuterostomes
Echinoderms • Spiny Skin • Pentamerous Symmetry • Marine • Hydrostatic Skeleton • Representatives
Echinoderms
15