Chapter 23 Flashcards
amniotic egg
an egg with a hard outer casing and an inner series of membranes and fluids that provide protection, nutrients, and waste disposal for a growing embryo. The evolution of the amniotic egg, in reptiles, freed them from the constraint of having to reproduce near water
bilateral symmetry
a bodily symmetry in which opposite sides of a sagittal plane are mirror images of one another. Animals generally are bilaterally symmetrical
body segmentation
a repetition of body parts in an animal. An example can be found in the vertebrae that make up the human vertebral column or backbone
Example of body segmentation
vertebrae that make up the human vertebral column or backbone
bud
an undeveloped plant shoot, composed mostly of meristematic tissue
closed circulation system
a type of circulatory system, found in all vertebrates and in some invertebrates, in which blood stays within vessels
coelom
a central body cavity, found in most animal phyla
copulation
the release of sperm within a female by a male reproductive organ
exoskeleton
an external material covering the animal body, providing support and protection
hermaphrodite
a state in which one animal possesses both male and female sex organs
hydrostatic skeleton
a skeleton in which the force of muscular contraction is applied through a fluid
invertebrate
an animal without a vertebral column
molting
a periodic sheding of an old exoskeleton followed by the growth of a new one; practiced by animals in the phyla Nematoda and Arthropoda
organ
a highly organized unit within an organism, performing one or more function, that is formed of several kinds of tissue
Examples of organs
kidneys, heart, lungs, and liver
open circulation
a type of circulation, found in many invertebrates, in which arteries carry blood into open spaces called sinuses. The blood then bathes surrounding tissues and is channeled into veins, through which it flows back to the heart
oviparous
a condition, seen in all birds and many reptiles, in which fertilized eggs are laid outside the mother’s body and then develop there
parasite
organisms that feed off their prey but do not kill them, at least not immediately and perhaps not ever
parthenogenesis
a form of asexual reproduction in which an unfertilized egg develops into an adult organism
radial symmetry
a type of animal symmetry in which body parts are distributed evenly about a central axis
examples of radially symmetrical animals
jellyfish
symmetry
an equivalence of size, shape, and relative position of parts across a dividing line or around a central point
tissue
an organized assemblage of similar cells that serves a common function
Examples of tissue
nervous, epithelial, and muscle tissue
vertebral column
a flexible column of bones extending from the anterior to posterior end of an animal. Also known as a backbone, the vertebral column distinguishes vertebrates from other chordates
viviparous
a condition in animals in which fertilized eggs develop inside a mother’s body
