Circulatory system of an Earthworm
Earthworm Dissection-PAP Bio- 3/12/14- Xiong, Lizi
While earthworms are known for the ability to live after being cut into two, this is in fact, a myth. Earthworms have their entire digestive system running down the length of its body. It also has a simple, closed blood circulatory system. Earthworms have also been placed int eh suborder Lumbricina of the order Haplotaxida due to Theoretical cladistic studies. This may soon change.
Earthworm Life Cycle
Earthworms are hermaphrodites. All worms have both male and female parts. When mating, both participants become impregnated and store the fertilized sperm in their clitellum. When conditions are right, five baby worms will be born. They fully mature in 4-6 weeks! Earthworms can live for years, but many die early due to dehydration.
Earthworms' bodies are 90% water. They require moist conditions that is not cold. They typically live right under the soil. In this habitat, they ingest much dead, organic matter.
Being full of protein, earthworms are targets of various organisms. Beside nature, such as moles, snakes, birds, insects, rodents, etc..., humans are consistently spraying pesticides that kill these earthworms.
Earthworm Life Cycle
Evolution of Annelids
Circulatory system at a glance
The earthworm has a closed circulatory system where the blood is recirculated throughout the body.Oxygen is absorbed directly from the soil. Earthworms do not have lungs. Oxygen is entered through the dorsal blood vessel where it travels to the five aortic arches (hearts). The esophagus pumps the blood to the lower, ventral blood vessel. Blood is then sent to all segments and organs in need of oxygen. A small blood vessel sends blood back from the ventral vessel to the dorsal vessel in each segment.
Five aortic arches: pump blood
Dorsal vessels: take blood back to front
Ventral vessels: take blood front to back
Capillaries: carries blood to proper areas and helps absorb nutrients
The circulatory system is one of the seven systems of the earthworm: respiratory, muscular, digestive, excretory, nervous, reproductive.