Earthworms & More
Earthworm Dissection PreAP Biology March 11, 2014- GABI MATA
Lumbricus terrestris
Get To Know Your Earthworm!
Today's Objectives
Evolutionary Relationships
Habitat
Ecological Niche
Earthworm's Reproductive Life Cycle
Earthworm Dissection 101
Internal Anatomy:
External Anatomy
Digestive System
Circulatory System
Digging into the Digestive System
An earthworm’s digestive system works as a large, single unit with individual parts that each maintain their own certain and unique function. Each of these parts, consisting of the pharynx, the esophagus, the crop, the intestine, and the gizzard, are separated into many different regions and each perform a different function to benefit the earthworm. The system begins when the earthworm intakes food from the soil through its mouth and is then swallowed by its pharynx. The food will then pass through into its esophagus, where special glands will release calcium carbonate to rid the earthworm’s body of any excess. Following the path of the digestive tract, it will then pass through into the crop, where it will be stored for later use. When released from the crop, it will move into the gizzard, where special stones the earthworm ate will help grind the food down. Once completely broken down, the food will head into the intestines. Gland cells within the intestines will then aid in the digestive process. The intestinal walls contain special blood vessels that function to absorb and transport the nutrients from the digested food to the rest of the earthworm’s body or, if not useful to the earthworm, will then be excreted out its anus in small balls known as casts, which withhold bacteria needed for plants to cycle nutrients.
Get to Know the Digestive System Even Better
Works Cited
http://animals.nationalgeographic.com/animals/invertebrates/earthworm/
http://www.friendlywormguy.com/news/predators-of-earthworms/
http://www.sciencelearn.org.nz/Science-Stories/Earthworms/Earthworm-adaptations
http://www.sciencelearn.org.nz/Science-Stories/Earthworms/Niches-within-earthworms-habitat
http://www.sas.upenn.edu/~rlenet/Earthworms.html
https://www.naturewatch.ca/english/wormwatch/virtual_worm/Introduction.htm