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Phylum Annelida: Segmented Worms

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Presentation on theme: "Phylum Annelida: Segmented Worms"— Presentation transcript:

1 Phylum Annelida: Segmented Worms
Annelida: “annulus”- ring, annual Body divided into repeating segments= metamerism- each segment contains body systems, excretory, circulatory, nervous, digestive

2 Phylum Annelida 1. Bilateral symmetry two body openings (mouth & anus)
3. “ True” Eucoelomates- Live in every environment Reproduce sexually (hermaphrodites) Setae- hair or bristles- except for leeches 7. Trochophore LARVAE Examples: bristleworms, earthworms, leeches

3 Body Systems No Respiratory- gas exchange through skin *Circulatory
Complete Digestion Nervous Muscular Excretory Reproductive

4 * Circulatory System Closed – blood always in closed vessel
Five pairs of aortic arches(hearts) Ventral and dorsal blood vessels and capillaries Hemoglobin

5 Digestive system Crop-”stomach”- stores food Gizzard- grinds food
Intestine- nutrient absorption anus

6 Nervous System Pair of cephalic ganglia(bundle of nerves)
Ventral nerve cord with ganglia in each segment (segmental ganglia)

7 Muscular System Longitudinal and Circular muscles
Allows for better movement- can thrash and inch, raise head, etc.

8 Body wall Epithelium Circular muscle Longitudinal muscle

9 Excretory System Wastes processed through two nephridia(kidney) in each segment Nephridia, bladder and excretory pore

10 Fig Fig

11 Reproductive System -Hermaphrodites -sexual reproduction
- trochophore larvae

12 Trochophore larva- paddlelike, bristles
Apical tuft Stomach Ciliary band Mouth Anus

13 Annelid development

14 Class Polychaeta Many setae(bristles) Parapodia(paddlelike appendages
Marine Gonads only appear during breeding season Predators of small animals, prey for larger

15 Class Polychaeta Parapodium Head Tentacle

16 Polychaete Worm Predatory
Jaw Tentacle Everted pharynx Palp Eye Cirrus Parapodium

17 Class Polychaeta Fireworm

18 Sedentary Polychaete Lugworm
Fig. 17.5

19 Fig. 17.4

20 PEACOCK WORM VIDEO

21 Class Oligochaeta Few setae(bristles) Clitellum No parapodia
Hermaphroditic Decomposers (aerate soil) food for larger animal Ex. Giant Gippsland earthworm, earthworms

22 External Structures of an Earthworm
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. External Structures of an Earthworm

23 Lumbricus terrestris Feed on decaying organic matter Enrich soil

24 Fig. 17.1

25 Internal Structures of an Earthworm
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Internal Structures of an Earthworm

26 Fig c

27 Earthworms Digestive structures:
Crop: temporary storage sac after mouth Gizzard: sac with muscular walls to grind soil Intestine: stretches length of body to aid in digestion of soil Anus: wastes are removed Other structures: Setae: bristles used for movement (ventral side) Clittelum: enlarged segment; secretes mucus & contains reproductive parts Anus Setae gizzard crop Clittelum Mouth

28 Earthworm Reproduction-sexual
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Earthworm Reproduction-sexual

29 Folds in an organ inc. surface area for the organ’s function

30 Class Hirudinea Anterior & posterior sucker-ectoparasite No setae
hermaphrodites Most live in fresh water Dorsoventrally compressed(flat) Ex. leeches Feed Invertebrates Body fluids Blood

31 Fig

32 Leeches Parasitic segmented worm Most live in fresh water
Have no bristles for movement move with muscular contractions Suckers used for attachment to host Some have suckers on tail also

33 Secrete anesthetic during bite and release anticoagulant into blood during feeding (to keep blood flowing) Leeches were used in medical procedures years ago to “bleed” the sick remove “bad blood” now they are used in cosmetic surgery, digit and limb reattachment, and blood removal from bruises

34 Checkpoint List key adaptations that all Annelids share.
What are the three classes of annelids? Explain traits and examples of each class. Which class contains decomposers? Which class is used medicinally for digit or limb reattachment?___________


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