Annelids Tube shaped worms with rings Segmented Worms Annelids Tube shaped worms with rings

New Words Setae- bristle-like structures Crop- a sac used for food storage Gizzard- a muscle that grinds up bits of soil and organic matter Anterior- front end of an organism Posterior –back end of an organism Hermaphrodites- organisms that produce sperm & eggs in the same body

Segmented Worms Use setae to hold onto soil and move Have bilateral symmetry Body cavity that holds organs Two body openings (mouth & anus) Annelids are found in freshwater, saltwater & moist soil

Earthworm Body Systems Have a definite anterior- front end Have a definite posterior- back end Each body segment (except the first and last) have a pair of setae & 2 sets of muscles

Earthworms burrow through soil They take soil into their mouth

They get energy from soil & other organic matter found in the soil The soil moves to the crop and into the gizzard to be ground, broken down, and the nutrients absorbed my the blood

Waste leave the worm through the anus

A thick ring structure used in reproduction Clitellum A thick ring structure used in reproduction

When earthworms take in soil, they provide spaces for air and water to flow through it and mix the soil

Their wastes pile up a the openings to their burrows We call these wastes “castings” The castings help fertilize the soil

Vermicompost

We call these casting VERMICOMPOST They are used as an organic fertilizer in gardens

Earthworms have a closed circulatory system

Two blood vessels run from the top to the bottom of their bodies They have a heartlike structure called “aortic arches” which pump blood to the body

Oxygen and carbon dioxide are exchanged through their skin They DO NOT have gills or lungs! You can suffocate an earthworm by touching it with dry hands or by wiping off their mucous layer However – they cannot survive submerged in puddles of water either It is a delicate balance Watch them

Earthworms have a small brain in their front segment of their body Nerves in each segment form a main nerve cord that connects to the brain

Explain this adapatation Earthworms respond To light Temperature moisture Explain this adapatation

Earthworms are Hermaphrodites They have body male and female reproductive structures in one body One individual CANNOT fertilize its own eggs It must receive sperm from another earthworm in order to reproduce

Earthworms mating

Why would earthworms be healthy to have in a garden or compost pile?

Are you ready to dissect?