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Earthworms nature’s recyclers. Digestion. Earthworms eat soil and release “good stuff” for the soil Mouth-- crop (a sac for storage)----- gizzard (muscular structure that grinds)----- intestine--- anus. Nervous system. They have small simple brains in the anterior segment
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Digestion • Earthworms eat soil and release “good stuff” for the soil • Mouth--crop (a sac for storage)-----gizzard (muscular structure that grinds)-----intestine---anus
Nervous system • They have small simple brains in the anterior segment • Nerves in each segment join to form a main nerve cord • an earthworm is sensitive to touch, light, moisture, chemicals, temperature, and vibrations
Reproduction • All worms carry two sets of sexual organs, they are hermaphrodites, but they cannot fertilize their own eggs—mating is still a necessary part of reproduction.
How do earthworms exchange gases? • No gills or lungs • Exchanges oxygen and carbon dioxide by diffusion through its skin
definition • Diffusion - the process by which molecules spread from areas of high concentratiion, to areas of low concentration. When the molecules are even throughout a space - it is called EQUILIBRIUM
Muscular system • Circular muscles surround the worm's body and can make the body shrink or spread out. • Longitudinal muscles run the length of the body and can shorten or lengthen the worm
Circulatory system • Have blood to carry nutrients, gases and wastes • Blood is carried in vessels • Across center of body earthworms have 5 “hearts” or pairs of vessels • Also has 2 large vessels that run the length of the body
Anatomical terms • Dorsal Upper or back surface • Ventral Lower or front (belly) surface • Anterior Front side • Posterior Back side