Life of an Earthworm
By: Katherine Yin- PAP Bio-Guzman-7
Objective
In this investigation, you will observe the external and internal structure of an earthworm.
Interesting facts
- Earthworms breathe through their skin.
- Earthworms do not have eyes but they do possess light- and touch-sensitive organs.
- Earthworms live from 4-8 years.
- Snakes, birds, moles, toads and even foxes are known to eat earthworms.
- Earthworms can regenerate themselves.
Taxonomy
The earthworm is classified as the Lumbricus terrestris.
Human impact
Humans impact earthworms negativley, humans are earthworms biggest predators.
Evolution
It has been suggested that segmented worms evolved from such chains of worms that failed to
separate.
separate.
Habitat
Earthworms live in soil. Earthworms tend not to live in exceptionally dry or cold places, they are most commonly found in cultivated soils such as pasture, croplands and lawns.
Digestive system
The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard. Food starts at the earthworm’s mouth where it is swallowed by the pharynx. Food passed through the esophagus, where calcium carbonate is released to rid the earthworm’s body of excess calcium. After it passes through the esophagus, the food moves into the crop where it is stored and then eventually moves into the gizzard. The gizzard uses stones that the earthworm eats to grind the food completely. The food moves into the intestines and fluids are released to aid in the digestive process. Then a blood vessels absorbs the nutrients from the food and transports it all over the body
Bibliography
http://www.biologyjunction.com/earthworm%20facts.htm#eyes
http://www.sas.upenn.edu/~rlenet/Earthworms.html
http://wiki.answers.com/Q/Is_human_interaction_of_a_earthworm_positive_or_negative?#slide=3
http://cronodon.com/BioTech/Earthworm_evolution.html
http://i.telegraph.co.uk/multimedia/archive/01488/EARTHWORM_1488955i.jpg