The Enthusiastic Earthworm
Harlem Murray Pre Ap Biology April 8,2014 - Mitcham
Objective
Students will learn about some internal and external systems of the earthworm. Students will also learn about their in a trophic level, their habitat and human's impact on them.Students will also class get to take a glance at the digestive system of the earthworm and much more!
Background Information
Earthworms are a group of burrowing, spineless worm. They are apart of the kingdom Animalia and are under the phylum Annelida. They eat the live and dead matter that they encounter in the soil when they are in motion. They are an essential resource in the development of soil. Soil would be a lot less rich if it earthworms were not present.
Human impact
Earthworms are essential to the earths soil and our food. Yet, we kill them with pesticides, chemical fertilizers and plowing. After the population is destroyed,we use more chemicals to keep the land productive.
Place in Trophic level
The earthworm acts as a primary consumer/decomposer because of how it eats live plant matter as well as decomposed animal and plant matter as it burrows into the soil.
Earthworm life cycle
After earthworms have mated, their fertilized egg are kept in side of a cocoon. The hatchlings emerge and burrow into the ground until they are adult worms
Earthworm Dissection Lab
Growth
Earthworms come out of their cocoon fully developed except for their reproductive systems which develop two to three months after they hatch. They reach full adult size after a full year.
Eservation
During the winter, earthworms enter a state of of called estivation which is a slowed metabolic state, not true hibernation. They must burrow below the topsoil or they will freeze and die. If they do die, they lay eggs right before so they hatch when it becomes warmer.
Circulatory System
Hearts (aortic arches), mouth, dorsal and ventral blood vessels,
Circulatory System
Earthworms have a closed circulatory system to maximize its use of oxygen. They absorbs oxygen through it's skin, where it is then taken in by the dorsal blood vessels and travels to the 5 aortic arches by the esophagus where it is pumped to the lower, ventral blood vessel. The ventral blood vessel pumps the blood to all segments and organs in need of oxygen. In each segment, there is a small blood vessel that sends the blood from the ventral vessels back to the dorsal vessels, completing the loop.
Citations
http://www.greenlivingtips.com/
cornell.edu/ccecattall/2013/12/11/earthworms-interesting-and-unusual-facts-about-a-gardeners-best-friend/