Zoology Symmetry and Body Plans

Acoelomate

• No defined body cavities

• Body cavities present

• Single body cavity

• Multiple body cavities

Radial symmetry

• A body plan in which body parts repeat around the center of the body

• A body plan that is symmetrical along a single axis

• A body plan that has no symmetry

• A body plan with distinct left and right sides

Complete digestive system

• A continuous tube with two openings: a mouth for food intake and an anus for waste elimination.

• A series of organs that break down food into nutrients without any openings.

• A system that only includes the stomach and intestines, with no mouth or anus.

• A collection of organs that filter waste from the blood and excrete it through the skin.

Incomplete digestive system

• A single opening to a pouch-like cavity serves as both mouth and anus.

• Two separate openings for ingestion and excretion.

• A complex system with multiple organs for digestion.

• A system that relies on diffusion for nutrient absorption.

Invertebrate body segmentation

• The division of an animal's body into a series of repeating, similar units called segments.

• A method of locomotion used by invertebrates to move through water.

• The process by which invertebrates reproduce asexually through budding.

• A type of skeletal structure found in vertebrates.

Bilateral symmetry

• Body plan in which only a single, imaginary line can divide the body into two equal halves

• Body plan that can be divided into multiple sections

• Body plan that is asymmetrical and lacks symmetry

• Body plan that is identical on both sides but can be divided into three equal parts

Coelomate

• Tube-shaped body; has coelom; body cavity within mesoderm

• Flat body; lacks coelom; body cavity outside mesoderm

• Round body; has pseudocoelom; body cavity between endoderm and mesoderm

• Segmented body; has coelom; body cavity within ectoderm

Asymmetry

• No symmetry

• Perfect balance

• Equal proportions

• Symmetrical design

Invertebrate

• An animal without a backbone.

• A type of fish with a backbone.

• A mammal that lays eggs.

• A reptile with a hard shell.

Pseudocoelomate

• An animal that possesses a true coelom, a body cavity completely lined by mesodermal tissue.

• An animal that possesses a pseudocoelom, a fluid-filled body cavity not entirely lined by tissue derived from the mesoderm.

• An animal that lacks any body cavity and is solid throughout.

• An animal that has a body cavity lined by endodermal tissue.