4/21 & 4/22 - 7th Grade Agenda Learning Objective: Learn about mollusks & worms Collect HW:Reading & Notetaking p.203 – 204 Squid Dissection Video Video: BBC Life (Creatures of the Deep) Textbook Reading 428 – 432 HW: Reading & Notetaking 205 – 206

Reflection Prompt: Write 3 questions that you have about squids.

What are the major type of worms Flatworms Roundworms Segmented Worms

Do worms have brains? Yes They also have a heart, digestive tract and reproductive organs

Lifecycle of a tapeworm

An organism that lives inside or on another organism and takes its food from that organism is a P_______ arasite

Is an earthworm helpful? Yes. Earthworm dropping make the soil fertile. Earthworm tunnels loosen the soil and allow air, water, and plant roots through it

How do Earthworms Mate? Earthworms are hermaphroditic meaning each worm has organs of both sexes. One worm has to find another worm in order to mate

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)

Insides of a Squid