4 earthworm dissection

WORM
DISSECTION
KIDSPIRATION by Riedell
CLASSIFICATION
Kingdom: ANIMALIA
Phylum: 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
individual parts to
move independently
http://sps.k12.ar.us/massengale/earthworm_dissection.htm
BIODIDAC
Damage insurance
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
MOUTH
Prostomium
Image by Riedell/VanderWal©2005
ANUS
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
http://www.lander.edu/RSFOX/310images/310bilatImage.html
EUCOELOMATES
“true” coelom
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://blog.tricerion.com/wp-content/uploads/2010/01/balloon.jpg
http://www.wildlifetrust.org.uk/cheshire/IMAGES/watch_earthworm.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
Imageby
byRiedell/Vanderwal
Riedell/Vanderwal©2005
Image
Image from:
http://www.urbanext.uiuc.edu/worms/anatomy/anatomy6.html
INTERNAL STRUCTURES
http://sps.k12.ar.us/massengale/earthworm_dissection.htm
PHARYNX
Muscular tube
PHARYNX
pulls in food
Image by Riedell/Vanderwal ©2005
INTERNAL STRUCTURES
Image by Riedell/Vanderwal ©2005
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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
http://www.uleth.ca/bio/bio1020/images/worm2.jpg
increases
surface area
so more
nutrients are
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
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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