4/28 & 4/29 - 7th Grade Agenda HW: Reading & Notetaking 205– 206 Worms & Mollusks Worm observation Lab Video: BBC Life (Deep Ocean) Textbook Reading 431 – 432 HW: Chap 11 Section 3 Reading Guide
Reflection Prompt: Write 3 facts you know about squids.
Do worms have brains? Yes They also have a heart, digestive tract and reproductive organs
Do earthworms have eyes? They do not have eyes But they do possess light- and touch-sensitive organs (receptor cells) to distinguish differences in light intensity and to feel vibrations in the ground.
What is the "bump" in the middle of the earthworm? The bump is the clitellum. It contains the gland cells which secrete a slimy material (mucus) to form the cocoon which will hold the worm embryos.
Earthworm Cocoons
Virtual Dissection of Earthworm
What is the difference between front end and back end? Front End (Anterior) Back End (Posterior)
What is the difference between top side and bottom side? Top side (Dorsal) Bottom side (Ventral)
Dissecting the earthworm
Internal View
Aortic Arches (Primitive Heart)
Cross section view
Does earthworm have bilateral or radial symmetry? Bilateral Symmetry
What some common properties of these animals? What are Mollusks What some common properties of these animals? Mollusks are invertebrates with soft unsegmented bodies that are often protected by hard outer shells
Three major groups of mollusks Gastropods (Single Shell) Bivalves (Two Shells) Cephalopods (Mollusks with tentacles)
Comparing Mollusks
Do Mollusks have Open or Closed Circulatory System? Mollusks have Open Circulatory System: Blood is not always in blood vessels
What are Gastropods? Gastro = “stomach” Pod = “Foot” Gastropods are both herbivores and carnivores
Snail’s Radula Tiny teeth act like sandpaper and scrape food from leaf and ground
Valve = “Shell or Opening” What are Bivalves? Bi = “Two” Valve = “Shell or Opening” Mostly Omnivores
How clams dig in
What are Cephalopods? Cephalo = “Head” Pod= “Foot”
Reflection Prompt: Write 5 facts that you learned in the video.