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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

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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

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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

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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

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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

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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

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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

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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