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#7 Earthworms

#7 Earthworms. Holy Cross School 7 th Grade Biology Wong. External Anatomy. Anterior -the front end of a worm is the thicker and fleshier part of the body. Posterior - the thinner back end. http://www.pgjr.alpine.k12.ut.us/science/whitaker/Animal_Kingdom/Earthworm/Earthworm.html.

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#7 Earthworms

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  1. #7 Earthworms Holy Cross School 7th Grade Biology Wong

  2. External Anatomy • Anterior -the front end of a worm is the thicker and fleshier part of the body. • Posterior- the thinner back end http://www.pgjr.alpine.k12.ut.us/science/whitaker/Animal_Kingdom/Earthworm/Earthworm.html

  3. External Anatomy continued • Ventral side- the bottom side of the worm. It is usually lighter color than the top in living worms. • Dorsal side- the top side of the worm. http://www.pgjr.alpine.k12.ut.us/science/whitaker/Animal_Kingdom/Earthworm/Earthworm.html

  4. External Anatomy continued • Clitellm is about 1/3 back from the anterior of the worm. It is thick and cylindrical. (1) • Setae are bristles on the ventral side of the worm. These hair-like structures help the worm move and sense its environment. http://biog-101-104.bio.cornell.edu/BIOG101_104/tutorials/animals/worm_stuff/worm_dorsal.html

  5. External Anatomy continued • Segments are little raised sections that look like rings around the earthworm’s body. The grooves between each segment are called septum. http://www.pgjr.alpine.k12.ut.us/science/whitaker/Animal_Kingdom/Earthworm/Earthworm.html

  6. Next Up...Internal Anatomy…

  7. Earthworms are invertebrates- they have no backbone.

  8. Get ready now….We are going to look inside the earthworm…

  9. Circulatory System • Dorsal blood vessel • Is the main vessel of the system and is on top of the digestive track. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  10. Circulatory System • Ventral blood vessel • Is on the opposite side of the dorsal vessel, below the digestive track. • The two vessels cross over at the digestive tract. Earthworms have five pairs of “hearts” the pump and exchange blood. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  11. Digestive System

  12. Digestive System • Earthworms are not picky eaters. They will eat anything from decay plants to animals. • Mouth is located at the anterior end. • Pharynx is a muscle that provides worms with a suction to pull food in its mouth. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  13. Digestive System continued… • From there the food travels down the tube like structure called an esophagus. People have an esophagus as well. • The food is temporary stored in a part of the body called the crop. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  14. Digestive System continued… • The food is move from the crop into the gizzard. This is where food is ground up by strong muscle contractions. • Food is next moved in the intestine for absorption. • Material that is not absorbed is pass out through the anus on the anterior end. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  15. Reproductive System • Earthworms are hermaphrodites. This means they male and female reproductive organs. Even though they have both male and female organs, they reproduce through cross-fertilization. http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/

  16. Nervous System • Ventral nerve cord is the major component of the nervous system. It runs the entire length of the worm on the ventral side. (2) http://biog-101-104.bio.cornell.edu/BIOG101_104/tutorials/animals/worm_stuff/worm_dorsal.html

  17. Nervous System continued… • The brain is located at the anterior end of the worm and is connected to the ventral nerve cord. (9) http://biog-101-104.bio.cornell.edu/BIOG101_104/tutorials/animals/worm_stuff/worm_dorsal.html

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