BINARY FISSION - division a prokaryotic cell into two cells by an apparently simple division of nucleus and cytoplasm.
BIOASSAY- an experimental method for determining the influence of an environmental component on an organism.
BLASTULA - a hollow ball of cells, one layer thick, formed by cleavage in the early development of the embryo (follows the morula stage).
CENTROSOME - along with its associated proteins, the centrosome is THE structural organizing center of the cell. All microtubules originate at a protein on the centrosome. A folded centrosome can become a centriole or basal body for cillia and flagella.
CONCENTRATION - the amount of a specified substance in a unit measure of another substance.
CONTROL - the group in which all variables remain constant including the independent variable.
CORTICAL GRANULE - a large membrane bound vesicle near the surface of the egg that fuses with the plasma membrane during fertilization releasing its contents to raise and harden the fertilization membrane.
CYTOKINESIS - the separation of the cytoplasm of the parent cell into two daughter cells following nuclear division.
DEPENDENT VARIABLE - in an experiment, any change that results from the manipulation of the independent variable.
DEVELOPMENT - the changes undergone by an organism from its beginning to maturity. One of the four functions that distinguish life.
EMBRYO - a young organism in the early stages of development.
ENVIRONMENT - the sum total of external influences acting on an organism or on part of an organism.
EPA - Environmental Protection Agency
FERTILIZATION - the union of egg and sperm to form the zygote.
FERTILIZATION CONE - a protuberance on the egg at the point of contact and entry of the sperm during fertilization.
FERTILIZATION MEMBRANE - a membrane formed by an egg in response to
its union with a
sperm, which grows rapidly from the point of union and covers the egg,
excluding other sperm.
FERTILIZATION, EXTERNAL - fertilization outside the body of the parents
FERTILIZATION, INTERNAL - fertilization inside the body of a parent
GAMETES - haploid cells which fuse to form a zygote in sexual reproduction, usually refers to an egg or sperm cell.
GASTRULATION - the process in which the migration of cells through the bastopore produces the primitive gut and the two layered gastrula.
GONAD - the ovaries or testes, the organ that produces gametes, eggs or sperm.
HATCHING - in sea urchins, when the blastula breaks free of the fertilization membrane and becomes free swimming.
INDEPENDENT VARIABLE - the only variable to be manipulated or changed
in a controlled
experiment.
MEIOSIS - production of haploid cells, usually eggs or sperm, through division of diploid cells, a source of genetic variation.
METAPHASE - the stage in mitosis or meiosis when the chromosomes gather at the equator of the spindle and become aligned.
MITOSIS - the process by which chromosomes are duplicated and distributed to form daughter nuclei identical to the parent cell, followed by cytokinesis (cell division).
NUCLEAR FUSION - the joining of the male and female pronuclei into one nucleus.
PARTHENOGENESIS - activation of an egg to induce reproduction without fertilization by a male gamete.
PASTEUR PIPET - a glass tube approximately 6mm in diameter pulled to a tapered tip to facilitate transport of liquids.
pH - a measure related to the hydrogen ion content of a solution which represents the acidity or alkalinity of that solution.
PLASMA MEMBRANE - the cell membrane consisting of a bilayer of phospholipids and proteins.
PLUTEUS - the free swimming larva of sea urchins, sand dollars and brittle stars which resembles on upturned easel.
POTASSIUM CHLORIDE - as opposed to sodium chloride, used to cause muscular contraction in the body of the sea urchin, thus inducing spawning.
SALINITY - the measure of the salt content of a solution.
SKELETON, SEA URCHIN - the hard framework which supports and protects the softer parts. External "test with spines attached" in the adult and internal in pluteus.
SPAWNER - an organism that reproduces by expelling eggs and sperm into the water to facilitate external fertilization.
SPERM MOTILITY - the ability of sperm to move.
ZYGOTE - the diploid cell that results from the union of gametes.