Post on 05-Jul-2020
WORM DISSECTION
KIDSPIRATION by Riedell
CLASSIFICATION
Kingdom: Phylum: Class:
ANIMALIA
Annelida “little rings”
OLIGOCHAETA “few bristles”
SETA (plural: setae)
http://www.pgjr.alpine.k12.ut.us/science/whitaker/Animal_Kingdom/Earthworm/Earthworm.html
BRISTLES on VENTRAL surface
SETAE- Provide traction
http://www.dof.virginia.gov/images/anim-worm-crawl.gif
http://www.greatbluemarble.com/robin_pulling_worm_ground_md_wht.gif
Segmentation
Compartments allow
individual parts to move independently
Damage insurance
If one section is damaged, others can still function
http://sps.k12.ar.us/massengale/earthworm_dissection.htm
BIODIDAC
Cartoon by:
Gary Larson
WHICH END IS WHICH?
CLITELLUM = ring • Doesn’t go all the way around
• Closest to anterior end
• Makes mucous for reproduction
Image by Riedell/VanderWal©2005
2 opening digestive system
MOUTH ANUS Prostomium
covers/protects mouth opening senses light/dark, chemicals (food), vibration
Image by Riedell/VanderWal©2005 Image by Riedell/VanderWal©2005
EXTERNAL STRUCTURES
PROSTOMIUM
EXTERNAL STRUCTURES
DORSAL BLOOD VESSEL CAMOUFLAGE
http://biog-101-104.bio.cornell.edu/BioG101-104/tutorials/animals/earthworm.html
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
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
http://sps.k12.ar.us/massengale/earthworm_dissection.htm
EXTERNAL STRUCTURES
SPERM GROOVE- carries sperm from MALE GENITAL PORE down to CLITELLUM
Image by Riedell/VanderWal©2005
SEXUAL REPRODUCTION
Earthworms are HERMAPHRODITES BUT. . . DON’T fertilize themselves!
http://upload.wikimedia.org/wikipedia/commons/f/f6/Mating_earthworms.jpg
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
http://blogs.salon.com/0003248/images/worm_cocoons.jpg
Earthworms produce between 4 - 70 cocoons per year. Each cocoon may contain 2-20 embryos. Baby worms hatch after a few weeks
LOOK INSIDE
COELOM = space around organs
Image by Riedell/Vanderwal ©2005
INTERNAL STRUCTURES
EUCOELOMATES “true” coelom
http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/annelidbodyxs.gif
http://www.lander.edu/RSFOX/310images/310bilatImage.html
SEPTUM (pl. SEPTA)
Dividing walls separate coelom into compartments
Image from: BIODIDAC
Image by Riedell/Vanderwal ©2005
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
NEPHRIDIUM pl. NEPHRIDIA EXCRETORY TUBULES
http://www.pleasanton.k12.ca.us/avhsweb/thiel/apbio/review/excretory.html
Collect & excrete NITROGEN WASTE Osmoregulation
INTERNAL STRUCTURES
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg3_files/wormnephridia.jpg
REPRODUCTIVE SYSTEM
SEMINAL VESICLES
STORE SPERM MADE BY WORM TO “GIVE AWAY” TO OTHERS
Image by Riedell/Vanderwal©2005
REPRODUCTIVE SYSTEM
SEMINAL RECEPTACLES Store sperm received from other worms during sex
Image by Riedell/Vanderwal©2005
CLOSED circulatory system
DORSAL BLOOD VESSEL VENTRAL BLOOD VESSEL
DORSAL BLOOD VESSEL
Image by Riedell/Vanderwal ©2005
Images by Riedell/VanderWal©2005
Image by Riedell/Vanderwal
5 AORTIC ARCHES act as “heart” to pump blood
Image by 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 PHARYNX Muscular tube pulls in food
Image by Riedell/Vanderwal ©2005
CROP-stores food waiting to be digested
GIZZARD- grind and mash food
Image by Riedell/Vanderwal ©2005
INTERNAL STRUCTURES
INTESTINE- absorbs nutrients
ADAPTATIONS for getting nutrients out of SOIL
1. REALLY LONG INTESTINE- so food spends long time passing through
2. TYPHLOSOLE- ridge inside increases surface area for more absorption
Images by Riedell/Vanderwal ©2005
TYPHLOSOLE Ridge inside intestine
increases surface area so more nutrients are absorbed
http://www.uleth.ca/bio/bio1020/images/worm2.jpg
TYPHLOSOLE inside intestine
Image by Riedell/Vanderwal ©2005
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
Earthworms play an important role in soil fertility
“intestines of the earth”
~ Aristotle
http://www.semioticon.com/seo/N/images/niche_3.png
"...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
UNDERNEATH DIGESTIVE SYSTEM
VENTRAL NERVE CORD
(nerves usually white)
VENTRAL BLOOD VESSEL (usually dark)
Image by: Riedell/Vanderwal © 2005
REMEMBER embryo orientation is flipped in vertebrates and invertebrates!
Images modified from: http://io.uwinnipeg.ca/~simmons/16cm05/1116/16anim3.htm
Most INVERTEBRATES have a DORSAL HEART & a VENTRAL NERVE CORD
ALL VERTEBRATES have a DORSAL NERVE CORD & a VENTRAL HEART.
BODY PLANS are also flipped!
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%20Diversity/Protostomes/mollusks.htm#Chelicerates%20(subphylum%20Chelicerata
Image from: http://www.urbanext.uiuc.edu/worms/anatomy/anatomy8.html