Lecture 11 PowerPoint

Annelids

A phylum of segmented worms that includes earthworms, leeches, and polychaetes.

Polychaeta

A class of annelids that are mostly marine and have a variety of life forms and feeding types.

Clitellata

A class of annelids that includes earthworms and leeches, characterized by the presence of a clitellum.

Metameric segmentation

Segmentation of the body into repeated units, allowing for specialization of body segments.

Hydrostatic skeleton

A fluid-filled internal cavity that provides support and movement in soft-bodied animals.

Coelomate

Animals that possess a true coelom, a body cavity fully lined with mesoderm.

Cerebral ganglia

A primitive brain structure found in some annelids that coordinates nerve responses.

Chaetae

Hair-like structures found on the body of some annelids, used for locomotion and grip.

Epitoky

A reproductive strategy in some polychaetes where the rear segments of the worm fill with gametes and are released.

Hermaphroditic

Organisms that have both male and female reproductive organs.

Trochophore larvae

Free-swimming larval stage characteristic of some marine annelids.

Parapodia

Fleshy extensions on the body segments of polychaetes used for locomotion and respiration.

Circulatory system in annelids

System that typically consists of a closed circulatory system, where blood is contained within vessels.

Oligochaeta

A subclass of clitellate annelids, primarily earthworms, that are important for soil health.

Hirudinea

A subclass of clitellate annelids, commonly known as leeches, which are primarily freshwater and terrestrial.

Metanephridia

Excretory structures in annelids that perform osmoregulation and excretion of waste.

Echinoderms

A phylum of marine animals characterized by their radial symmetry and a calcium carbonate skeleton.

Cnidarians

A phylum that includes jellyfish, corals, and sea anemones, known for their stinging cells.

Radial symmetry

Body plan in which body parts are arranged around a central axis.

Deuterostomes

A group of animals in which the blastopore becomes the anus, and the mouth forms later.

Protostome

A group of animals in which the mouth develops from the blastopore and the anus forms later.

Acoelomate

Animals that lack a true body cavity, such as flatworms.

Bilateral symmetry

A symmetrical body plan in which the left and right sides of the organism are mirror images.

Free-living annelids

Annelids that live independently in various environments, as opposed to parasitic forms.

Alimentary canal in annelids

A complete digestive tract that allows for efficient processing of food.

Sedentary

Organisms that are primarily inactive and remain in one place.

Filter feeders

Organisms that feed by filtering small particles from the water.

Depositing feeder

Organisms that feed on organic matter found on substrates.