| A | B |
|---|
| Vertebrate | An animal with a backbone. |
| Invertebrate | An animal without a backbone. |
| Specialization | The adaptation of a cell for a particular function. |
| Cell junctions | Connections between cells that hold the celss together as a unit. |
| Ingestion | When an animal takes in organic material, usually in the form of other living things. |
| Zygote | The first cell of a new individual. |
| Differentiation | Cells become different from each other. |
| Neurons | Cells of nervous tissue. |
| Symmetry | A consistent overall pattern of structure. |
| Radial Symmetry | Animals that have a top side and a bottom side, but no front, back, left, or right side. |
| Dorsal | Top side (back). |
| Ventral | Bottom side (belly). |
| Anterior | Head (Front). |
| Posterior | Tail (Back). |
| Bilateral symmetry | Animals that have two similar halves on either side of a central plane. |
| Cephalization | The concentration fo sensory and brain strucutres in the anterior end of an animal. |
| Germ Layers | Fundamental tissue types found in the embryos of all animals except sponges. |
| Chordate | An animal with a notochord. |
| Notochord | A firm, flexible rod of tissue located in the dorsal part of the body. |
| Dorsal Nerve Chord | A hollow tube lying just above, or dorsal to, the notochord. |
| Pharyngeal pouches | Small outpockets of the anterior part of the digestive tract. |
| Postanal tail | Muscle tissue that lies behind the posterior opening of the digestive tract. |
| Segmentation | A body composed of a series of repeating simialr units. |
| Exoskeleton | A rigid outer covering that protects the soft tissues of many animals. |
| Gas exchange | The exchange of oxygen and carbon dioxide in animals usually across a moist membrane. |
| Gills | Organs specialized for gas exchange in water. |
| Circulatory system | Moves blood or similar fluid throught the body to transport oxygen and nutrients to cells. |
| Open Circulatory System | When blood-like circulatory fluid is pumped from vessles in the body into the body cavity and then is returned to the vessels. |
| Closed Circulatory System | When blood circulates through the body in tubular vessels. |
| Hermaphrodite | An organism that produces both male and female gametes. |
| Indirect development | Animals that have an intermediate larva stage. |
| Larva | A free-living, immature form of an organism. |
| Direct development | When an animal has the same appearance and way of life at birth and at adult stages. |
| Endoskeleton | An internal skeleton that can support a large, heavy body. |
| Vertebrae | The repeating bony units of the backbone. |
| Integument | The outer covering of an animal. |
| Lungs | Organs for gas exchange composed of moist, membranous surfaces deep inside the animal's body. |
| Kidneys | Organs that filter wastes from the blood while regulating water levels in the body. |
| Cleavage | The divisions of the zygote immediately following fertilization. |
| Blastula | The result of cleavge in the zygote, a hollow ball of cells. |
| Blastocoel | The central cavity of the blastula. |
| Blastopore | The first indent made in the blastula. |
| Gastrulation | The formation of a multilayered embryo that begins with the formation fo the blastopore. |
| Gastrula | A multilayered embryo. |
| Archenteron | The cavity in the gastrula that will become the gut. |
| Ectoderm | The outer germ layer, becomes skin and nervous tissue. |
| Endoderm | The inner germ layer, becomes the digestive system. |
| Mesoderm | The middle germ layer, becomes muscle and skeletal tissue. |
| Protostomes | Animals that form the mouth forst in development. |
| Deuterostomes | Animals that form the anus first in development |
| Acoelomates | An animal where the body cavity is absent. |
| Pseudocoelom | False body cavity. |
| Pseudocoelomates | Animals that have mesoderm lines the fluid-filled coeleom, and the endodermic gut is suspended in the fluid of the coelom. |
| Coelomates | Animals with a true coelom, where the mesoderm lines the body cavity and surrounds and supports the endodermic gut. |
