Nightcrawlers Gastronomical Tract
By: Ania Lewis ~ Ms. Vu - PAP Biology - Period 4th
Earthworm Digestive System
We will explore the internal and external parts of an earthworm
We will cover the organs and other parts of the earthworm
We will learn the functions and locations of these organs
We will study the structure and functions of segmented worms
The scientific name for an earthworm is Lumbricus terrestris
Live in warm, moist soil
Preyed on by birds, snakes, and beetles
Earthworms are decomposers and eat decaying matter in the ground
Found in gardens and other areas with soil, Earthworms act as decomposers and fertilize the soil and provide as a food source for birds, snakes, and beetles
Species: Lumbricus terrestris
Rise to surface of soil when it rains to mate
Tube-like shape helps to move easily through the soil.
Segments of an earthworm have setae, bristly hairs, to help it move through soil.
Earthworm uses pharynx to grasp its food. Pharynx pushes out of its mouth.
Human Impact/ Influence:
Humans use earthworms to break down dead materials to re-fertilize soil
Earthworms are used for bait for fishing
Organs: pharynx, esophagus, crop, intestine, gizzard
Earthworms posses a full digestive tract running from the mouth to the anus. First, food enters the mouth and is passed on to the pharynx. In the pharynx, glands secrete mucous and enzymes to help pass the food down the esophagus. The crop, a thin- walled sac that holds soil before it is passed to the gizzard. the jub of the thick- walled gizzard grinds food up so that the nutrients can be absorbed as they travel through the intestine. Undigested food and any remaining parts are excreted from the body through the anus.
The esophagus is located under parts of the circulatory and reproductive systems.
A worms digestive system is extracellular which means that food is broken down into nutrients by enzymes.
- Earthworms have male and female reproductive parts.
- Intestinal deposits representing earthworm diggings are called custings.
- Earthworms do not have a system for respiration, therefore, they must breathe using diffusion through moist skin.
- The seminal receptacles receive and store sperm from other worms
- The aortic arches are five pairs of enlarged tubes that function like hearts
- The niphridia are pairs of excretory structures that function like kidneys
- An earthworm has a closed circulatory system