Exploring with Earthworms

Earthworm Dissection Vu PAP Biology April 7, 2014

Lumbricus terrestris

Earthworms belong to Animalia kingdom under the phylum Annelida, class Clitellata, order Haplotaxida,and the family Lumbricidae. Earthworms feed on organic matters found in soil and decayed plant material. They provide as a food source to a number of animals such as birds, rats, toads,snakes, insects, and other small mammals. Their main habitat is soil where the burrow through and live in. The holes created provide benefits to plants and overall, improves soil quality.

Objectives

Students will be learning about the anatomy of earthworms, external and internal. The digestive system's organs and function will be focused upon by students. Students will be able to label body parts and organs by the end of today.

Adaptations and Characteristics

Earthworms are made up of ring- like segments and cylindrical bodies. Earthworms have no eyes and rely on vibrations detected by their organs. They also posses no teeth and instead have a gizzard which digests the food the worm intakes. Earthworms are also hermaphrodites, meaning they have both female and male reproductive organs. Earthworms respire through their skin so moist environments are needed. Earthworms are labeled as decomposers and are located on the last trophic level.
The Amazing World Of Earthworms In The UK - Springwatch - BBC Two

A Farmer's Best Friend

Worms have proved to be very useful in agriculture. They aid in retaining moisture and help add nutrients to the soil. Earthworms till the ground providing air and water to pass through which in turn boosts healthy plant growth.

Cladogram

Earthworm Dissection

Earthworm Anatomy

Delving into the Digestive System

The digestive system of the earthworm is an important system that processes and digests the soil that the worm sucks in through its prostomium. The broken down soil particles are passed to the pharynx where it then travels to the esophagus. This process was made smoother by the mucus secretions in the pharynx. The esophagus gets rids of the excess calcium and the particles soon end up in the crop where it is stored and awaits to be moved to the next compartment of the worm's digestive system, the gizzard. The main digestion of the food occurs in the gizzard;stones are used to grind up the food. Bacteria in the intestine also helps further break down the food particles. The intestine then leads straight to the anus. The nephridin then proceeds to get rid of wastes.

List of organs(functions mentioned above)

Mouth

pharynx

espohagus

crop

gizzard

intestine

anus

nephridin