Enter your Sign-on user name and password.

Forgot password?
  • Follow us on:
Loading video...
Text Comments (10)

0 answers

Post by Dr Carleen Eaton on February 23, 2011

Correction at 45:41 in the slide titled "Arthropoda"
In most arthropods, hemolymph, the circulatory fluid, does not carry oxygen. It does, however, deliver nutrients and other materials.
Oxygen is delivered to the cells of the arthropod body via the tracheal system.

2 answers

Last reply by: Dr Carleen Eaton
Mon Apr 18, 2011 2:09 PM

Post by Amirali Aghili on April 17, 2011

There seems to be couple of mistakes in the summary chart because Platyhelmenthes can't be protostomes because they are not coelomates in the first place(dont have mesoderm).

Rotifera and nematoda can't be protostomes as well.

1 answer

Last reply by: Dr Carleen Eaton
Sat Feb 4, 2012 4:31 PM

Post by Valtio Cooper on February 1, 2012

your amazing!

1 answer

Last reply by: Carina Tull
Fri Nov 9, 2012 1:53 PM

Post by Carina Tull on November 9, 2012

I thougt it was indeterminant cleavage, am i wrong?

1 answer

Last reply by: Dr Carleen Eaton
Sun Mar 3, 2013 5:04 PM

Post by Lyn Lee on February 25 at 01:17:53 AM

I thought Porifera is parazoa which is no tissue complexity.
How come porifera is dipoblstic?

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