Digging through Earthworms
Jiakai Pan Earthworm Dissection Pre-AP Biology Vu Period 1
Annelida Lumbricina
Earthworms are tube-shaped, segmented, and long animals that can be found living in soil. They belong to the kingdom Animalia, under the phylum Annelida. Earthworms are indigenous to Europe, but they are can now be found almost anywhere in North America and Western Asia.
To intake nutrients, earthworms consume soil, extracting nutrients from decomposing organic material, such as leaves and roots. Earthworms are vital to the health and fertility of the soil because they transport nutrients and minerals from below to the surface, through their waste.
To intake nutrients, earthworms consume soil, extracting nutrients from decomposing organic material, such as leaves and roots. Earthworms are vital to the health and fertility of the soil because they transport nutrients and minerals from below to the surface, through their waste.
Today's Objectives
Students will be learning about the organs, functions, and structures of the digestive system of an earthworm. In addition, students will be learning about the ecological role of the earthworm.
Life Cycle of an Earthworm
Earthworms hatch from a cocoon at about 3 weeks, and become adults at about 3 months. They are hermaphrodites, but they do not self-reproduce. Following each mating, each worm forms a cocoon from its clitellum, and sperm and egg cells are deposited in the cocoon. The cocoon is buried into the ground, and after 4 weeks, the baby worms emerge from the cocoon.
Habitat
Earthworms tend to live at or under the surface of the soil, in moist and wet conditions. Most live in decaying compost and mud around freshwater, but a few species live under the sea. They are abundant in rainy forest conditions.
Predators
Earthworms have a multitude of predators, including birds, rats, and toads.
Evolutionary Relationships of an Earthworm
Earthworms are generally considered good animals that help the soil and are labeled as a gardener's best friend. But recently, earthworms are invading the earth, setting foot on almost every continent.
Earthworm Dissection Tutorial
Earthworm Dissection Lab
Digestive System of an Earthworm
Mouth- The structure through which food goes into, using a muscular pharynx.
Pharynx- A muscular organ that is used to help consume soil, which contains nutrients.
Gizzard- A muscular organ where food is forced up from the crop. It helps to crush and grind food.
Crop- A thin-walled organ that acts as a temporary storage place for food.
Esophagus- A passage that helps move food through the use of muscular contractions.
Intestine- An organ which contains enzymes that help break down food, allowing it to be absorbed by the earthworm.
Buccal Cavity- Structure that begins the digestive process by chewing food into smaller and smaller pieces.
Pharynx- A muscular organ that is used to help consume soil, which contains nutrients.
Gizzard- A muscular organ where food is forced up from the crop. It helps to crush and grind food.
Crop- A thin-walled organ that acts as a temporary storage place for food.
Esophagus- A passage that helps move food through the use of muscular contractions.
Intestine- An organ which contains enzymes that help break down food, allowing it to be absorbed by the earthworm.
Buccal Cavity- Structure that begins the digestive process by chewing food into smaller and smaller pieces.
Another digestive system diagram
A labeled diagram with, the mouth, esophagus, pharynx, and crop labeled.
Digestive System
A simpler diagram of an earthworm's digestive system.
In addition, the typhlosole, which is a folded structure that hangs inside the intestine from the dorsal wall, is included. The typhlosole allows for faster digestion.
In addition, the typhlosole, which is a folded structure that hangs inside the intestine from the dorsal wall, is included. The typhlosole allows for faster digestion.
The Digestive System At A Glance
Earthworms have a digestive system that contains a mouth, an esophagus, a crop, a gizzard, a pharynx, an intestine, a typhlosole, and a buccal cavity. The function of the digestive system is to ingest food, digest food, and absorb nutrients from the food.
Works Cited
http://www.biokids.umich.edu/critters/Oligochaeta/
animals.nationalgeographic.com/animals/invertebrates/earthworm/
http://www.sas.upenn.edu/~rlenet/Earthworms.html
http://www.biologyjunction.com/earthworm_dissection.htm
animals.nationalgeographic.com/animals/invertebrates/earthworm/
http://www.sas.upenn.edu/~rlenet/Earthworms.html
http://www.biologyjunction.com/earthworm_dissection.htm