Animal Diversity and Classification

A group of multicellular organisms that are heterotrophic, meaning they obtain nutrients by consuming other organisms.

A type of body plan where the body can be divided into two equal halves along a central axis.

A type of body plan where the body can be divided into multiple equal parts radiating from a central point.

Sponges are a simple group of animals that lack tissues and organs. They have a porous body that allows water to flow through, filtering out food particles. These are also characterized by the extra-cellular matrix.

Cnidarians are animals with a simple body plan that includes a sac-like body with a single opening that serves as both the mouth and anus. Their body is made of two layers of tissue and has specialized stinging cells called cnidocytes. Ex: jellyfish.

Annelids are segmented worms, having a body composed of repeating sections called segments. They possess a well-developed digestive system, a closed circulatory system, and a body cavity called a coelom. The digestive system is fully developed and is usually a tube, with a separate mouth and anus.

Mollusks are a diverse group of animals that possess a soft body usually enclosed in a hard shell. They have a muscular foot for locomotion, a mantle that secretes the shell, and a radula for feeding. The shell, when present, is secreted by a specialized mantle epithelium.

Nematodes are roundworms that have a cylindrical body shape and a tough, flexible cuticle that protects their body. They have a complete digestive system, a pseudocoelom, and a muscular system. They are very common and are found in a variety of habitats.

The specialized cell that draws water containing food particles into the sponge's interior.

The stinging cells found on the tentacles of Cnidarians. They are used for defense and capturing prey.

The type of symmetry exhibited by Cnidarians, where the body can be divided into equal halves along any plane passing through the central axis.

The process of developing a distinct head and tail, with the sense organs clustered at the anterior (head) end.

The invagination of the blastula during gastrulation forms the mouth first. The anus forms later.

The mouth forms second during gastrulation.

The repeating body segments of Annelid worms, allowing for greater complexity and independent movement.

The distinctive larva of Mollusks, characterized by a tuft of cilia at its top and additional cilia bands around its middle.

A group of mollusks with a well-developed head and a muscular siphon used for propulsion.

A group of mollusks with two hinged shells and a reduced head.

A large group of animals that includes annelids and mollusks, characterized by a distinctive larva called a trochophore.

A process where an animal sheds its outer covering, usually to grow larger, often accompanied by metamorphosis.

A group of unsegmented roundworms known for their tough cuticle and abundance in diverse habitats.

A group of microscopic animals known for their extreme resilience and ability to survive in harsh environments.

A hard, protective outer covering found in arthropods, made primarily of chitin.

The process where an animal undergoes significant changes in its form as it develops from a larva to an adult.

A tough, external covering that provides protection and support to the organism.

The process of shedding the exoskeleton and growing a new one.

A tough, nitrogen-containing polysaccharide found in the exoskeletons of arthropods, providing strength and rigidity.

A group of animals characterized by their radial symmetry, water vascular system, and tube feet for locomotion.

A hydraulic system in echinoderms that utilizes pressure to move the tube feet.

A flexible rod of tissue that supports the body and provides a point of attachment for muscles in chordates.

A hollow tube of nerve tissue located along the back of the body in chordates.

A series of openings in the pharynx (throat region) of chordates, which play a role in filter feeding and respiration.

A cartilaginous rod that serves as a structural support in the early development of all chordates. It eventually develops into the vertebral column in vertebrates.

A tail that extends beyond the anus, present in some early developmental stage of all chordates. It helps with swimming and balance.

Group of animals with heads and skulls, vertebrae and spinal cord, and many other characteristics that we have in common with fish, frogs, flamingos and zebras.

The group of animals that includes tunicates (sea squirts) and cephalochordates (lancelets).

The most diverse group of chordates. They all share a common ancestor and have many similarities, despite the wide range of species.

The muscular, perforated part of the pharynx that is responsible for feeding in vertebrates.

These glands secrete hormones directly into the blood or lymph. They help regulate many important processes in the body.