Biology Ch. 24 Vocabulary Flashcards
Animal without a backbone; between 95 and 99 percent of animal species are invertebrates
Invertebrate
Hard or tough outer covering of many invertebrates that provides support, protects body tissues, prevents water loss, and protects the organism from predation
Exoskeleton
Internal skeleton that protects internal organs, provides support for the organism’s body, and can provide an internal brace for muscles to pull against
Endoskeleton
Animal with an endoskeleton and a backbone.
Vertebrate
Animal that produces both sperm and eggs in its body; generally at different times.
Hermaphrodite
Fertilized egg formed when a sperm cell penetrates an egg
Zygote
Type of fertilization that occurs when sperm and egg combine inside an animal’s body.
Internal fertilization
Type of fertilization that occurs when sperm and egg combine outside an animal’s body.
External fertilization
Fluid-filled ball of cells formed by mitotic cell division of the embryo.
Blastula
Two-cell-layer sac with an opening at one end that forms from the blastula during embryonic development
Gastrula
Inner layer of cells in the gastrula that develops into digestive organs ad the digestive tract lining
Endoderm
Outer layer of cells in the gastrula that develops into nervous tissue and skin.
Ectoderm
Layer of cells between the endoderm and the ectoderm that can become muscle tissue and tissue of the circulatory, respiratory, and execretory systems
Mesoderm
Balance or similarity in body structures of organisms
Symmetry
Body plan that can be divided along any plane, through a central axis, into roughly equal halves
Radial symmetry
Body plan that can be divided into mirror images along only one plane through the central axis
Bilateral symmetry
Toward the head end of an animal with bilateral symmetry
Anterior
Away from the head end of animal with bilateral symmetry
Posterior
Tendency to concentrate sensory organs and nervous tissue at an animal’s anterior end.
Cephalization
Backside of an animal with bilateral symmetry
Dorsal
Underside or belly of an animal with bilateral symmetry
Ventral
Fluid-filled body cavity completely surrounded by mesoderm
Coelom
Fluid-filled body cavity between the mesoderm and the endoderm
Pseudocoelom
Animal with a solid body that lacks a fluid-filled body cavity between the gut and the body wall.
Acoelomate
Coelomate animal whose mouth develops from the opening in the gastrula
Protostome
Coelomate animal whose anus develops from the opening in the gastrula
Deuterostome
Organism that filters small particles from water to get its food
Filter feeder
Organism permanently attached to one place
Sessile
Nematocyst-containing stinging cell on a cnidarians tentacle
Cnidocyte
Capsule whose threadlike tube contains poison and barbs and is discharged when prey touches a cnidarian
Nematocyst
In cnidarians, the space surrounded by an inner cell layer, where digestion take place
Gastrovascular cavity
Nervous system that conudcts impulses in cnidarians and echinoderms
Nerve net
Tube-shaped, sessile body form of cnidarians
Polyp
Umbrella-shaped, free-swimming body form of cnidarians.
Medusa
