Chapter 7 - Worms - Fort Thomas Independent Schools
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Transcript Chapter 7 - Worms - Fort Thomas Independent Schools
Chapter 34/35 : Worms
I. Body Positions
Dorsal (Back)
Posterior
(Rear)
Anterior
(Head)
Ventral (Belly)
*Bilateral symmetry – cut down middle and both
halves the same
II. Phylum
Platyhelminthes – flat worm
1.) Planarian – aquatic
A.
2 eyespots (sense light)
Hermaphrodite (male & female)
Regenerate – regrow missing parts
Scavenger
II. Phylum : Platyhelminthes
○ 2.) Fluke
Parasite
Thick cuticle & suckers
Hermaphrodite
Common in Orient, Cuba
Life cycle with a snail
II. Phylum : Platyhelminthes
○ 3.) Tapeworm
Head contains
suckers scolex
Proglottid – each contains sex
organs (hermaphrodite)
Passes through feces eaten by pigs or
cows
Causes organisms to lose nutrients,
weight, weakness
II. Phylum : Nematoda
Nematoda – round worm
1.) Ascaris
B.
Pigs, horses, humans through dirt or
contaminated food
2.) Hookworms – bore into feet
Common in south and tropics
Cause anemia and slows growth
II. Phylum: Nematoda
3.) Trichina – found in contaminated
pork
4.) Pin Worms – found in soil
Phylum : Annelida – segmented
worms, earthworm, leech
C.
II. Phylum : Annelida
○ 1.) Characteristics of Annelida
Soil or no soil
Not parasite
Called tube within a tube
Fertilize and aerate soil
Hermaphrodites
II. Phylum: Annelida
○ 2.) External Parts
Prostomium – lip
Clitellum – band of reproduction
segments – 32-37
Setae – bristles on ventral surface
used for clinging
II. Phylum : Annelida
○ 3.) Digestive System
Pharynx – sucks soil
To Esophagus then to crop (stores
food)
To Gizzard (grinds food)
Through Intestine and out anus
II. Phylum : Annelida
○ 4.) Circulatory System
Dorsal Blood Vessel – blood flows
through anterior end
Ventral Blood Vessel – blood from
posterior end
Aortic Arches – 5 pairs-like heart –
pumps blood
Closed Circulatory System – blood
remains in tubes
II. Phylum : Annelida
○ 5.) Respiration & Excercretion
Absorb O2 and releases CO2 through
skin.
Mucus from skin helps moisten air for
easier respiration. Also slides
through soil better.
Waste excreted by anus and
nephridia (holes on segments that act
like kidneys- excrete liquid waste)
II. Phylum : Annelida
○ 6.) Nervous System
Ventral nerve cord (white)
Sensitive to sound and light
Brain Tissue
II. Phylum : Annelida
○ 7.) Reproduction
Hermaphrodite but eggs must be
fertilized by another worm
*Sperm made in testes and stored in
seminal vessicles. Received sperm is
stored in the Seminal Recepticles.
* During Reproduction *
Worms line up upside-down.
Eggs Released into slime ring around
clitellum.
Sperm released to fertilize eggs.
Slime ring slips off to form protective
cocoon for developing young.