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91 Cards in this Set

  • Front
  • Back
  • 3rd side (hint)
balance organs

balance organs

Statocyst

Dactylozooid

specialized for defense or prey capture

Osmoregulation

Hypoosmotic fluid is secreted into gastrovascular cavity, periodically expelled

Theory of atoll formation

1.. Volcanic eruption

2. Fringing reefs form in shallows around the edges of the new island

3. Erosion leads to a gap between dry land & edges of the reef = barrier reef

4. Island erodes away beneath ocean level, leaving a ring of coral = atol

Ctenophora and Cnidarian similarities

Radial symmetry
Two cell layers plus mesoglea
• Diploblastic embryo (?)
• Mostly predatory
Gastrovascular cavity with canals
• Tentacles used to capture prey, bring it to mouth
• Gametes released through mouth, fertilization in water
• Simple nerve net coordinates movement

Peristaltic motion

waves of contraction of circular muscles

Phylum of flatworms

Phylum of flatworms

Platyhelminthes

Class of Planarians and other free-living flatworms

Class of Planarians and other free-living flatworms

Turbellaria

Class of tapeworms

Class of tapeworms

Cestoda

Class of flukes

Class of flukes

Trematoda

Class of Nereis

Class of Alitta

Polychaetes

Class of earthworms and leeches

Class of earthworms and leeches

Clitellata

Class of spoonworms
Class of spoonworms
Echiura
echidna

Ctene

long, fused cilia in distinct comb rows

Characteristics of flatworms

-Three embryonic tissue layers (ectoderm, mesoderm, & endoderm)


-True organs, but no circulatory system


-Diffusion used for gas exchange, movement of nutrients & wastes


-Acoelomate


-Gastrovascular cavity present, with one opening

Exceptions to why flatworms are most primitive

-protostome like development suggests secondary lost of coelom


-No helpful fossil record

Movement of Turbellarians
cilia and muscles
involves two components.

Characteristics of Cestodans

-Scolex


-Progglotoids


-Lack of digestive tract

Definitive host

host species in which the tapeworm can achieve sexual maturity

Intermediate host

usually eggs do not reach the definitive host right away; the immature stages spend time in at least one intermediate host first

Definitive hosts for beef tapeworms

humans

Intermediate hosts for beef tapeworms

cows

Characteristics of Tremetoda

oral sucker

Problems for parasitic worms

-Must reproduce in definitive host


-Must get fertilized eggs out of the host


-Must contact & recognize appropriate host -Must enter host


-Must find correct tissues in the host


-Must avoid digestion by host, and attack by host’s immune system


-Must avoid killing the host

Characteristics of Nematoda

-Unsegmented


-Slender


-Circular in cross-section


-Unique amphids (sensory organs) on sides of head


-Shed (molt) their skins


-Complete digestive tract – two openings


-Most species have separate sexes (not hermaphroditic)


-Includes free-living species and parasites of plants and animals


-Life cycles usually simpler than those of flatworms

Locomotion of Nematoda

longitudinal muscles only

Support that echiurans are annelids

1) Segmentation in embryo
2) Segmental ganglia in larval nervous system
3) Nephridia
4) Trochophore larvae
5) Chitinous setae (a few)
6) Molecular/genetic data

Class of peanut worms

Class of peanut worms

sipunculans

Reasons why sipunculans were classified as seperate phylum
-Unsegmented
-Lack circulatory system
-Lack setae
Things they don't have that other Annelids do.
Distinctive traits for sipunculans
fully protractible probiscis
-U-shaped digestive tract
-Urn cells
Two of the three start with U
Distinct traits for echiurans
-anal sacs
Uranus
Excretory system of polychaeta
paired nephiridia
"Poly" means...

Excretory system of Clitella (earthworms)

many, well-developed nephiridia

Excretory system of Clitella (leeches)

simpler, fewer nephiridia

Excretory system of echiurans
one to many pairs of nephridia (plus anal sacs)
uranus
Excretory system of Sipunculans
one pair of nephridia (plus urn cells)
uno
Circulatory system of Polychaeta
closed system with vessels
Same as Clitelleta

Circulatory system of Clitellata (earthworms)

closed system with vessels (similar to Polychaeta)

Circulatory system of Clitellata (leeches)

lack a discrete system (coelomic fluid circulates in channels)

Circulatory system of Echiurans
simple closed system
similar to clitellatea and polychaeta but one aspect is missing.

Circulatory system of Sipunculans

none – but cells in coelomic fluid carry respiratory pigments

Support that sipunculans are Annelids

• Coelomate, with protostome development
• Nephridia
Similar nervous system, with brain & ventral nerve cord
• Trochophore larvae
• Molecular/genetic data

Most common respiratory pigament in Annelids

hemoglobin

Reproduction in Polychaeta, Echiurans Sipunculan

-No gonads
-Usually separate sexes
-External fertilization
-Trochophore larvae

Reproduction in Clitellata

-Well developed, permanent gonads
-Usually hermaphroditic
-Usually mate, with either internal or external fertilization

Distinguishing characteristics of Anthozoa

-No medusa stage
-Ciliated groove (siphonoglyph) leads down from mouth
-Gastrovascular cavity partitioned by sheets of tissue (septa/mesenteries)

Distinguishing characteristics of Hydrozoa

Polyp typically prominent in life cycle

Body plan of Platyhelminthes

Acoelomate

Body plan of Nematoda

Pseudocoelomate

Body plan of Annelida

Coelomate

Life cycle of Ascaris
1. Eggs swallowed with food or water
2.Eggs hatch in small intestine
3. Juveniles penetrate intestinal wall and travel to lungs
4. Juveniles molt twice in lungs
5. Move up bronchi to pharynx, swallowed, mature in intestine
6. So they end up where they started!
lungs
Life cycle of Trichinosisa
1. After mating, males die, females burrow into intestinal wall, enter lymph vessels, & migrate to lymph nodes
2. While migrating, females release ~1500 juveniles over 4-16 weeks
3. Juveniles enter bloodstream & are distributed throughout the body, eventually encysting in muscle tissue
Mating similar to salmon

Life cycle of Whipworm

1. Eggs swallowed, larvae hatch in small intestine
2. Worms burrow into intestinal wall, consume blood
3. Small numbers of worms = usually symptomless

Life cycle of Filariasis
1. Adults live in lymphatic ducts of humans, usually in the lower half of body
2. Juveniles move from lymph vessels into blood
3. Juveniles are ingested by mosquitoes with blood meal
4. Juveniles molt twice in mosquito
5. Migrate to mosquito mouthparts, emerge while mosquito feeds, enter wound
Mosquitoes are intermediate hosts

Defining characteristic of monogea

-haptor


Reasons behind many parasitic platyhelminthes

-Possible predatory ancestors


-No transport system


-No respiratory system


-Limited locomotion

Intermediate hosts of Chinese liver fluke

snails and fish

Life cycle of Dicrocoelium
1. Eggs hatch when eaten by a land snail
2. Larvae migrate to “lung” of snail, become engulfed in mucus
3. Snail expels mucus balls
4. Ants seek out and collect mucus balls
5. Infected ants climb up grass blades, sit on the tips
6. Grass tips are eaten by the definitive host (sheep)
7. Ants only climb during cool morning & evening hours!
Two intermediate hosts

Definitive hosts of Leucochloridium

birds

Intermediate hosts of Leucochloridium

snails

Life cycle of Leucochloridium

1. Eggs hatch when eaten by a snail
2. Larvae gather in the snail’s tentacles
3. The tentacles become big & colorful, wave around, cannot be withdrawn
4. The snails wander out in the open (not normal!)
5. Birds notice the tentacles, rip them off and eat them

Life cycle of Monogea

1. Reaches maturity while attached to the host


2. Fertilized eggs are released while adult is attached to the host
3. Free-swimming larva looks for a host
4. Larva attaches to host, begins to feed

Definitive hosts for Fish tapeworm

humans

Intermediate hosts for Fish tapeworm

crustaceans and fish

Definitive hosts for Cat tapeworms

cats

Intermediate hosts for Cat tapeworms

fleas

Definitive hosts for Hydatid Cyst Disease

Dogs and other canids

Intermediate hosts for Hydatid Cyst Disease

humans and livestock

Cestodan lifecycles in definitive hosts

adult tapeworm resides in intestines



How trematode larva enter host

1. Enzymes dissolve host tissue
2. Once inside, larva loses its tail
3. Then begins to move deep into the host’s body

General characteristics of Platyhelminthes

-Flat and thin


-No specialized respiratory or circulatory organs
-Several organ systems are present
-Centralized nervous system
-Mostly hermaphroditic

Shared characteristic of Cestoda, Monogenea, and Trematoda
syncitial epidermis
skin

Feeding habits of turbellarians

-Adults are predators and scavengers
-Immatures eat algae
-Pharynx leads into gastrovascular cavity
-Mouth position varies from mid-ventral to anterior
-Glands in pharynx produce mucus and digestive enzymes
-Many species can protrude & retract the pharynx

Benefits for having coelom

-Gut and body wall are separate, can move independently
-The worm can bend without pushing food along the gut
-Fluid in coelomic space serves as hydrostatic skeleton

Trochophores

free-swimming larvae with distinctive ciliation, u-shaped gut

Reproduction in Clitellata

-Fertilization is internal
-Fertilized eggs are secreted onto the clitellum
-Clitellum produces a cocoon and nutritive substances, immatures are incubated inside the cocoon

Function of Pharynx and esophagus in Clitellata

ingestion

Fuction of crop in Clitellata

storage

Function of gizzard in Clitellata
grinding
also starts with g

Fuction of gizzard in intestine

digestion and absorption

Clitellum

glandular region involved in reproduction

Ways nutrients are acquired by beard worms

-absorption through skin


-absorption through bacterial symbiots

Reproduction in earthworms
sperm is stored in internal storage organs, later extruded onto clitellum for external fertilization
similar to some hymenopterans
Reproduction in leeches
sperm is injected, migrates to reproductive tract for internal fertilization
similar to ours

Parapodia

lateral extensions of body wall, found on most segments

Characteristics of Cnidarians

-Diploblastic


-Muscle cells develop from epidermis or endodermis


-Cnidocysts


-Polyps


-Polymorphism (over life cycle or within polyp colonies)


-Locomotion uses muscles


-Usually two separate sexes


-One opening to gastrovascular cavity

Characteristics of Ctenophora

-Triploblastic ??


-Muscle cells develop from amoeboid cells in mesoglea


-Colloblasts


-No polyps


-No polymorphism


-Locomotion uses cilia


-Usually hermaphrodites


-Mouth plus anal pores

Class of jellyfish

Schyphozoa

Class of Box jellyfish and sea wasps

Cubozoa

Class of hydras and Portugese Man-o-Wars

Hydrozoa

Class of sea anemones and corals

Anthozoa