4/16 & 4/17- 7th Grade Agenda Learning Objective: Learn about worms Collect HW: Reading & Notetaking p.197-199 Earth Worm Observation Lab Pass back graded HW & Test & Grade Print Out Textbook Reading 417 – 421 HW: Reading & Notetaking 200-201 HW: Signed Grade Printout

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

Sea anemone and many circular animals exhibit R______ S_______ adial ymmetry What are some characteristics of Radial Symmetry Animals? Do not have distinct front or back ends Lives in the ocean Senses their environment in all directions

The balanced arrangement of a butterfly’s body is called B_______ S________ ilateral ymmetry What are some characteristics of Bilateral Symmetry Animals? Larger & More complex than radial symmetry animals Moves more quickly Sense organ in the front

Usually Perfect Symmetry is not attractive Right Side Symmetrical True Portrait Left Side Symmetrical

Usually Perfect Symmetry is not attractive True Portrait Left Side Symmetrical Right Side Symmetrical

Is a Sponge an animal or a plant? Sponge is an animal Although it cannot move around from place to place sponge take food into their bodies

What do sponges eat? Tiny organisms such as bacteria and protists Sponge gets its oxygen from water Network of spikes support the sponge

Sponge Larva Sponge reproduce asexually and sexually Sponges do not have separate sexes At any one time of the year, some sponges are producing eggs and others are producing sperms

What are Cnidarians?

Jellyfish Facts They are not used to make Jelly 98% Water No Heart or Blood Most don’t have a brain (except Box Jellyfish) Most only detect light. Some have 24 eyes (Box Jellyfish) When stung, Vinegar (not urine) is the best treatment Irukandji Jellyfish (size of fingernail) can kill you with a single sting.

More on Cnidarians Unlike sponges, cnidarians have specialized tissues Muscle like tissues for swimming Anemones stretch out

How does cnidarians obtain and digest food? Cnidarians captures its prey by using its stinging cells to inject venom Then the cnidarian’s tentacles pull the prey animal to its mouth From there the food passes into a body cavity where it is digested.

How are coral reefs made? Built by cnidarians Free swimming coral larva attaches to a solid surface ( broken shell, sunken ship) The coral polyp produces a hard, stony skeleton around its soft polyp body Over thousands of years, as live corals add their skeletons, the reef grows

What are the major type of worms Flatworms Roundworms Segmented Worms

Lifecycle of a tapeworm

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

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

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

Can earthworms regenerate themselves? Yes, but only the front or head end of the earthworm will survive and the amputated tail portion will die.

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