Lecture 9 PowerPoint

Platyhelminths

A phylum consisting of flatworms, characterized by an unsegmented, dorsoventrally flattened body.

Nematodes

A phylum of roundworms, characterized by a cylindrical body and a pseudocoelom.

Triploblastic

Organisms with three embryonic germ layers: ectoderm, mesoderm, and endoderm.

Acoelomate

Organisms that lack a coelom or body cavity.

Bilateral symmetry

Symmetry where the body can be divided into two equal halves along one plane.

Protostome

An organism whose blastopore develops into the mouth during embryonic development.

Turbellaria

A class of flatworms that are mostly free-living and non-parasitic.

Trematoda

A class of parasitic flatworms, commonly known as flukes.

Cercomeromorpha

A class of parasitic flatworms, including tapeworms.

Ecdysis

The process of shedding the outer cuticle, common in nematodes.

Protonephridia

A simple excretory apparatus found in flatworms, involved in osmoregulation.

Cephalization

The concentration of sensory and neural organs at the head end of an organism.

Scolex

The head of a tapeworm, equipped with attachment organs such as suckers and hooks.

Hermaphrodite

An organism that has both male and female reproductive organs.

Saprophytes

Organisms that feed on dead organic matter, acting as decomposers.

Diecious

Organisms that have distinct male and female individuals.

Hydrostatic skeleton

A structure found in many soft-bodied animals, providing support based on fluid pressure.

Alimentary canal

A complete digestive tract with a mouth and anus.

Ocelli

Light-sensitive eye spots found in some flatworms.

Lymphatic vessels

Vessels that are part of the lymphatic system, involved in fluid balance and immune response.