WORM DISSECTION
KIDSPIRATION by Riedell
CLASSIFICATION Kingdom: Phylum: ANIMALIA Annelida little rings Class: OLIGOCHAETA few bristles
SETA (plural: setae) BRISTLES on VENTRAL surface http://www.pgjr.alpine.k12.ut.us/science/whitaker/animal_kingdom/earthworm/earthworm.html
SETAE- Provide traction http://www.greatbluemarble.com/robin_pulling_worm_ground_md_wht.gif http://www.dof.virginia.gov/images/anim-worm-crawl.gif
Segmentation Compartments allow http://sps.k12.ar.us/massengale/earthworm_dissection.htm individual parts to move independently Damage insurance BIODIDAC If one section is damaged, others can still function
Cartoon by: Gary Larson
WHICH END IS WHICH? Image by Riedell/VanderWal 2005 CLITELLUM = ring Doesn t go all the way around Closest to anterior end Makes mucous for reproduction
2 opening digestive system Image by Riedell/VanderWal 2005 Image by Riedell/VanderWal 2005 MOUTH ANUS Prostomium covers/protects mouth opening senses light/dark, chemicals (food), vibration
EXTERNAL STRUCTURES PROSTOMIUM
EXTERNAL STRUCTURES http://biog-101-104.bio.cornell.edu/biog101-104/tutorials/animals/earthworm.html DORSAL BLOOD VESSEL CAMOUFLAGE
CUTICLE (non-cellular protective layer) http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/cuticle.html http://www.flushing.k12.mi.us/srhigh/tippettl/biology/lum/cuticle.html
RESPIRATORY No respiratory organs Skin must stay moist for gas exchange Glands produce mucous http://www.wildlifetrust.org.uk/cheshire/images/watch_earthworm.jpg
SURVIVING HOT DRY CONDITIONS Worms tunnel deeper into the soil Roll into a ball Cover themselves with mucous Slow their body functions down Suspended animation = ESTIVATION Wait for conditions to improve http://www.backyardnature.net/earthwrm.htm
SEXUAL REPRODUCTION Earthworms are hermaphrodites HAVE BOTH MALE & FEMALE REPRODUCTIVE ORGANS in same worm
SEXUAL REPRODUCTION OVARIES make eggs TESTES- make sperm
http://sps.k12.ar.us/massengale/earthworm_dissection.htm EXTERNAL STRUCTURES MALE GENITAL PORE- releases sperm to give away FEMALE GENITAL PORE- releases eggs OPENINGS to SEMINAL RECEPTACLES- receive sperm from other worms when trade
EXTERNAL STRUCTURES Image by Riedell/VanderWal 2005 SPERM GROOVE- carries sperm from MALE GENITAL PORE down to CLITELLUM
SEXUAL REPRODUCTION http://upload.wikimedia.org/wikipedia/commons/f/f6/mating_earthworms.jpg Earthworms are HERMAPHRODITES BUT... DON T fertilize themselves!
SEXUAL REPRODUCTION EXTERNAL FERTILIZATION Produce COCOONS made of MUCOUS and CHITIN (tough carbohydrate)
Animated images from: http://www.urbanext.uiuc.edu/worms/anatomy/anatomy5.html DIRECT DEVELOPMENT Earthworms produce between 4-70 cocoons per year. Each cocoon may contain 2-20 embryos. Baby worms hatch after a few weeks http://blogs.salon.com/0003248/images/worm_cocoons.jpg
LOOK INSIDE
COELOM = space around organs Image by Riedell/Vanderwal 2005
INTERNAL STRUCTURES http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/annelidbodyxs.gif EUCOELOMATES true coelom http://www.lander.edu/rsfox/310images/310bilatimage.html
SEPTUM (pl. SEPTA) Dividing walls separate coelom into compartments Image by Riedell/Vanderwal 2005 Image from: BIODIDAC
SKELETAL hydrostatic skeleton Fluid in coelom protects organs and provides support http://www.wildlifetrust.org.uk/cheshire/images/watch_earthworm.jpg http://blog.tricerion.com/wp-content/uploads/2010/01/balloon.jpg
EXCRETORY SYSTEM http://www.pleasanton.k12.ca.us/avhsweb/thiel/apbio/review/excretory.html Collect & excrete NITROGEN WASTE Osmoregulation NEPHRIDIUM EXCRETORY TUBULES pl. NEPHRIDIA
INTERNAL STRUCTURES http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg3_files/wormnephridia.jpg
REPRODUCTIVE SYSTEM SEMINAL VESICLES Image by Riedell/Vanderwal 2005 STORE SPERM MADE BY WORM TO GIVE AWAY TO OTHERS
REPRODUCTIVE SYSTEM Image by Riedell/Vanderwal 2005 SEMINAL RECEPTACLES Store sperm received from other worms during sex
CLOSED circulatory system DORSAL BLOOD VESSEL VENTRAL BLOOD VESSEL
DORSAL BLOOD VESSEL Images by Riedell/VanderWal 2005 Image by Riedell/Vanderwal 2005
5 AORTIC ARCHES act as heart to pump blood Image Image by by Riedell/Vanderwal Riedell/Vanderwal 2005
Image from: http://www.urbanext.uiuc.edu/worms/anatomy/anatomy6.html
INTERNAL STRUCTURES http://sps.k12.ar.us/massengale/earthworm_dissection.htm
PHARYNX Image by Riedell/Vanderwal 2005 Muscular tube pulls in food PHARYNX
INTERNAL STRUCTURES Image by Riedell/Vanderwal 2005 CROP-stores food waiting to be digested GIZZARD- grind and mash food
INTESTINE- absorbs nutrients Images by Riedell/Vanderwal 2005 ADAPTATIONS for getting nutrients out of SOIL 1. REALLY LONG INTESTINEso food spends long time passing through 2. TYPHLOSOLE- ridge inside increases surface area for more absorption
increases surface area so more nutrients are http://www.uleth.ca/bio/bio1020/images/worm2.jpg absorbed TYPHLOSOLE Ridge inside intestine
TYPHLOSOLE inside intestine Image by Riedell/Vanderwal 2005
Earthworms play an important role in soil fertility "...it may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures." ~ Charles Darwin intestines of the earth ~ Aristotle Decompose organic matter (dead leaves, animal waste, etc) Return nutrients to soil Burrowing allows air and water to penetrate to roots Tunnels loosen soil so roots can grow more easily http://www.semioticon.com/seo/n/images/niche_3.png
Image by: Riedell/Vanderwal 2005 UNDERNEATH DIGESTIVE SYSTEM VENTRAL NERVE CORD (nerves usually white) VENTRAL BLOOD VESSEL (usually dark)
REMEMBER embryo orientation is flipped in vertebrates and invertebrates! Images modified from: http://io.uwinnipeg.ca/~simmons/16cm05/1116/16anim3.htm
BODY PLANS are also flipped! Most INVERTEBRATES have a DORSAL HEART & a VENTRAL NERVE CORD ALL VERTEBRATES have a DORSAL NERVE CORD & a VENTRAL HEART.
GANGLIA= nerve center If in located in head and acting as brain = CEREBRAL GANGLIA http://biog-101-104.bio.cornell.edu/biog101-104/tutorials/animals/earthworm.html
MUSCULAR SYSTEM Image from: http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/animal%20 Diversity/Protostomes/mollusks.htm#Chelicerates%20(subphylum%20Chelicerata
Image from: http://www.urbanext.uiuc.edu/worms/anatomy/anatomy8.html