Animal Characteristics

Flashcards for Animal Characteristics and Development

Multicellular

Made of more than one cell and contain eukaryotic cells.

Heterotrophs

Animals that consume other organisms to obtain energy.

Mobile

Able to move around for at least a portion of their lives.

Sessile

Permanently attached to one spot during their adult life.

Zygote

The first cell produced after a sperm fertilizes an egg.

Blastula

A stage in embryo development that is a ball of hollow cells.

Gastrula

A two-layered, cup-shaped embryo formed from the blastula folding inward.

Blastopore

The opening formed from the inward folding of the blastula, which will become either the mouth or anus.

Protostome

An animal in which the blastopore becomes the mouth.

Deuterostome

An animal in which the blastopore becomes the anus.

Germ Layers

The layers that specialized cells in animals arise from ex. nerve, skin, blood.

Endoderm

The innermost germ layer that gives rise to the digestive tract and the respiratory system.

Mesoderm

The middle germ layer that gives rise to muscles, circulatory system, reproductive system, and excretory systems.

Ectoderm

The outermost germ layer that gives rise to the sense organs, nerves, and skin.

Body Cavity

A fluid-filled space that lies between the digestive tract and body wall (skin & muscle) where internal organs are suspended.

Coelom

A body cavity that allows for development of specialized organs.

Coelomate

An organism with a coelom fully lined with mesoderm.

Pseudocoelomate

An organism with a coelom that is not fully lined with mesoderm.

Acoelomate

An organism without a coelom.

Radial Symmetry

Body parts radiating from a central point.

Bilateral Symmetry

Body parts arranged in pairs on either side of an axis.

Anterior

The head end of an animal with bilateral symmetry.

Posterior

The tail end of an animal with bilateral symmetry.

Segmentation

Body constructed of many repeated and similar parts.

Cephalization

Concentration of sense organs at the anterior end of an organism.

Invertebrates

Animals that lack a backbone.

Vertebrates

Animals with a backbone.

Exoskeleton

A hard encasement on the surface of the animal.

Hydrostatic Skeleton

A body plan that is supported by a water filled cavity.

Endoskeleton

A rigid framework inside the animal.