phylum annelida 1. mcdougall ch. 23 annelids video mcdougall videos ch 14 symbitotic relationships
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Phylum Annelida
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• McDougall ch. 23 annelids video• McDougall videos ch 14 symbitotic relationships
Annelids
• Annelids range in size from the Giant Earthworms, of which Michrochaetus rappi (Michrochaetus michrochaetus) is the largest• average length of 1.36 m (54 ins) and a record
breaking specimen has been recorded that measured 6.7 metres (22 ft) in length, it was 2cm (0.8 ins) in diametre.
• The smallest Annelid known to science is Chaetogaster annandalai • full grown at 0.5 mm (0.02 ins).
Phylum Annelida
• From the Latin Annellus a “little ring”. • Segmented body
•Metamere – segment in the body• Setae
•Small hair-like structures•Absent in leeches
• Coelom divided by septa •Separating tissue
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• Closed circulatory system•Have vessels and a pump
• Nephridia for each segment (metamere)•Excretory structures
• Nervous system – ganglia = brain; lateral nerve cords
• Reproduction•Most sexual•Some hemaphrodites
Phylum Annelida
Segmented Worms
• Body divided into repeating segments
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Metamerism
Setae – help in movement
ALL SEGMENTED WORMS are
EUCOELOMATES! “True coelom”
SEGMENTED WORMS (PHYLUM: ANNELIDA)
http://www.lander.edu/RSFOX/310images/310bilatImage.html10
SeptaSepta
MetamerismMetamerism
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Closed Circulatory System
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Ventral vesselVentral vesselVentral vesselVentral vessel
DorsalDorsalvesselvesselDorsalDorsalvesselvessel
BladderBladderBladderBladder
NephridioporeNephridioporeNephridioporeNephridiopore
NephrostomeNephrostomeNephrostomeNephrostome
Metanephridium – excretion of wastesMetanephridium – excretion of wastes
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Fig. 17.14
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Nervous SystemNervous System
Earthworm Reproduction
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Trochophore larvaTrochophore larvaApical tuftApical tuftApical tuftApical tuft
MouthMouthMouthMouth
AnusAnusAnusAnus
Ciliary bandCiliary bandCiliary bandCiliary band
StomachStomachStomachStomach
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Annelid developmentAnnelid development
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SEGMENTED WORMSAnnelida
FREE LIVING PARASITIC
Earthworms Leeches
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Sedentary/Sessile – don’t move
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Terrestrial
• Earthworm
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Feed on Blood
• Leech
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Class Polychaeta
• Many setae• Parapodia =
“paired feet”
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Class PolychaetaHeadParapodium
Tentacle
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JawJawJawJaw
Everted pharynxEverted pharynxEverted pharynxEverted pharynx
EyeEyeEyeEyeCirrusCirrusCirrusCirrus
PalpPalpPalpPalp
TentacleTentacleTentacleTentacle
ParapodiumParapodiumParapodiumParapodium
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• Polychaete Worm• Predatory
Nereis
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Class PolychaetaFireworm
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Sedentary Polychaete LugwormSedentary Polychaete Lugworm
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Pelagic* Polychaete
*Drift in the open ocean32
Just Slinking or Wriggling in the Rain
• Have you ever noticed that after a spring rain, earthworms come out of the soil and appear on driveways, in puddles, and on sidewalks? Why does this happen?
1. An earthworm breathes through its skin. If its skin dries out, it cannot breathe. Why would an earthworm be more likely to “surface” during the rain than at other times?
2. What types of weather conditions might be fatal for an earthworm?
Class Oligochaeta
• Few setae• Clitellum• No parapodia• Monoecious
•Both male and female parts
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Lumbricus terrestris - earthworm• Feed on decaying organic
matter• Enrich soil• Exceedingly important in
soil creation, particularly in temperate areas.
• Without them, agriculture and perhaps the whole of human society as we know it would never have evolved.
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• Return nutrients to soil by decomposing dead leaves and organic matter
• 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
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
External Structures of an Earthworm
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Section 27-3Anus
Clitellum
Circular muscle
Longitudinalmuscle
Nephridia Ganglia Ringvessels
Reproductiveorgans
Ventralblood vessel
Ganglion
Brain
Mouth
Dorsalblood vessel
CropGizzard
Body segments
Setae
The Anatomy of an Earthworm
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Internal Structures of an Earthworm
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Body wallBody wall
EpitheliumEpitheliumEpitheliumEpithelium
Circular muscleCircular muscleCircular muscleCircular muscle
Longitudinal muscleLongitudinal muscleLongitudinal muscleLongitudinal muscle
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• Worms• Worms2
Class Hirudinea
• Anterior & posterior sucker
• No setae• Most live in fresh
water• Feed
•Invertebrates•Body fluids•Blood
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PARASITIC SEGMENTED WORMSLEECHES
Medical uses
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Man vs. Wild - Leeches
• Annelid• Annelid 3• Annelid 4
• Dirty Jobs – Bloodworms• http://www.youtube.com/watch?v=FX8DQ436F4g• Dirty Jobs worm grunting part 1• http://videos.howstuffworks.com/discovery/
38849-dirty-jobs-shorts-an-introduction-to-worm-grunting-video.htm
• Worm grunting part 2• http://www.yourdiscovery.com/video/dirty-jobs-
worm-grunting/• Earth watch – worm grunting• http://www.youtube.com/watch?v=D0YjFT8F7RU