Enter your Sign-on user name and password.

Forgot password?
  • Follow us on:
Loading video...

Start Learning Now

Our free lessons will get you started (Flash® 10 required).
Get immediate access to our entire library.

Sign up for Educator.com

Features Overview

  • Get on-demand access to our complete library
  • Search and jump to exactly what you need to learn
  • Track your progress
  • Download practice and lesson files
  • *Ask questions and get answers from our community & instructors

Invertebrates

  • Invertebrates are animals that lack a backbone and spinal cord.
  • Major phyla of invertebrates are:
  • Porifera – Sponges are sessile filter feeders that do not have a symmetrical body plan and lack specialized tissues and organs.
  • Cnidaria - Includes jellies, hydra, corals and sea anemones. Cnidaria have true tissues and either polyp or medusa body plans. Their nervous system is composed of a nerve net.
  • Platyhelminthes - Flatworms have body plans that exhibit bilateral symmetry and cephalization.
  • Rotifera - Rotifers are microscopic aquatic animals. They are filter feeders with a pseudocoelem and a complete digestive tract.
  • Nematoda - Roundworms are unsegmented worms with a complete GI tract.
  • Annelida - Annelids are segmented worms such as earthworms and leeches. They have a ceolom and a closed circulatory system as well as a complete GI tract.
  • Mollusca - Molluscs include octopuses, chitons, squids, snails, slugs and clams. Molluscs have a head-foot region, a visceral mass and a mantle.
  • Arthropoda - Arthropoda is the largest phylum. Its members have segmented bodies with three regions, a head, thorax and abdomen. They have an exoskeleton and jointed appendages.
  • Echinodermata -Sea stars, sea urchins and sand dollars are echinoderms. Members of this phylum are deuterostomes.

Invertebrates

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

AP Biology Intro