Invertebrate Zoology Lecture Notes Ppt New [better] Site

Invertebrate zoology is the study of animals without a backbone. These creatures make up about 97% of all animal species on Earth. 🧬 The Basics of Invertebrates

• Polychaeta (Marine worms - parapodia).
• Oligochaeta (Earthworms).
• Hirudinea (Leeches).

Slide 19-25: The Deuterostomes (Our Weird Cousins)

• Echinodermata: Explain pentaradial symmetry as a secondary derivation.
• Hemichordata: The acorn worm – the genetic bridge to chordates.
• New data: Include the latest fossil Saccorhytus (possibly an early deuterostome).

• Animals that molt.
• Ecdysis: Shedding of the cuticle (exoskeleton) to grow.
• Covered in a tough, non-living cuticle (often chitinous).

Slide 8: Platyhelminthes (Flatworms)

• Bilateral symmetry, triploblastic, acoelomate
• Incomplete gut (except some parasites)
• Flame cells for excretion/osmoregulation
• Classes: Turbellaria (free-living), Trematoda (flukes), Cestoda (tapeworms)