Lecture 3 - Phyla Platyhelminthes, Nematoda, Rotifera, Nematomorphia, and Acanthocephala

Phylum Platyhelminthes

Flatworms

Body Organization of Flatworms

Triploblastic

Triploblastic

Ectoderm, Endoderm, Mesoderm

Symmetry of Flatworms

Bilateral

Flatworms are the first animals to

Cephalize

Digestion of flatworms

Gastrovascular cavity (Incomplete digestive system)

Excretion of flatworms

Flame cells for fluid balance and nitrogenous waste removal when simple diffusion won't work

Protostomes

blastopore becomes the mouth

Blastopore

the hole formed when the blastula is pushed in

Aceolomate

No coelom

Pseudocoelomate

Fake coelom

Coelomate

True coelom

Class Tubellaria "planarians"

carnivorous

Class Turbellaria Dugesia Sensory Structures

Auricle, Eyespots, and Cephalization

Auricle

Sense environment via touch (thigmotaxis) and olfaction (chemotaxis)

Eyespots

sense light (phototaxis)

Cephalization

concentration of nervous tissue and sensory structures at the anterior end of the body

Class Turbellaria Dugesia Digestion

Gastrovascular cavity and retractive pharnyx and no anus

Class Turbellaria Dugesia Reproduction

Monoecious but reproduction is often sexual and can also undergo transverse fission and regenerate

Class Turbellaria Dugesia Excretion

Flame cells reside in protonephridia (for osmoregulation)

Class Turbellaria Dugesia Nervous Tissues

Cerebral ganglion and transverse nerve cords

Class Trematoda

Parasitic and use suckers to attach to hosts

Class Trematoda has a *blank* to protect from host's digestive enzyme

cuticle layer

Class Trematoda Clonorchis Digestion

Oral sucker anteriorly and ventral sucker to attach to host

Class Trematoda Clonorchis Excretion

Flame cells gather waste and drain it into the excretory bladder then out from there via the excretory pore

Class Trematoda Schistosoma, Human Blood Flukes

Cause the disease schistosomiasis

Class Cestoda

Tapeworms, most specialized endoparasitic flatworms

Class Cestoda Tapeworms

Has protective cuticle and scolex (head region) that has hooks and suchers for attachment

Class Cestoda Tapeworms have *blank* of repeating reproductive segments

Proglottids

Class Cestoda Reproduction

Has gravid proglottids with fertilized eggs towards end of body (so eggs can be released into host's feces)

Phylum Rotifera Symmetry

Bilateral

Phylum Rotifera Coelom?

Pseudocoloemate

Phylum Rotifera Digestive System

Parthenogensis

Parthogensis

Reproduction from ovum without fertilization

Phylum Rotifera Locomotion and feeling

Cilia corona

Phylum Rotifera has mouth with *blank* for chewing prey for food particles

mastax and jaws

Phylum Acanthocephala

“Spiny headed worms” that are parasites

Phylum Acanthocephala Symmetry

Bilateral

Phylum Acanthocephala Example

Roundworm

Phylum Acanthocephala Reproductive System

Dioecious

Phylum Acanthocephala Coelom?

Psudocoelomate

Phylum Nematoda Coelom?

Pseudocolomate

Phylum Nematoda Symmetry

Bilateral

Phylum Nematoda is covered in \*blank\* external to epidermis

cuticle

Phylum Nematoda Trinchinella causes what disease

trichinosis that passed via raw pork consumption

Phylum Nematomorpha

Parasites of arthropods (many insects and crustaceans) when immature and free living as adults

Phylum Nematomorpha Coelom?

Pseudocoelomate

Phylum Nematomorpha Reproductive System

Dioecious