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52 Cards in this Set

  • Front
  • Back
Small scale changes, the do not lead to new species
Large Scale changes, that do lead to new species
Cell Differentiation
As cell division continues and the embryo develops, mechanisms that selectively control gene expression lead to cell cell differenttiation, the specialization of cells in the their structure and function.
the process bye which an animal takes shape and the differentiated cells end up in the appropriate locations.
main function of fertilization
s to combine haploid sets of chromosomes from two individuals into a single diploid cell, the zygote.Another key function is activation of the egg: Contact of the sperm with the egg′s surface initiates metabolic reactions within the egg that trigger the onset of embryonic development.
Acrosomal Reaction
When the head of a sperm cell comes into contact with the jelly coat, molecules present in the egg′s coat trigger the acrosomal reaction. The discharge of a sperm′s acrosome when the sperm approaches an egg.
A vesicle at the tip of a sperm cell that helps the sperm penetrate the egg.
fast block to polyspermy
The depolarization of the egg membrane within 1–3 seconds after sperm binding to the vitelline layer. The reaction prevents additional sperm from fusing with the egg′s plasma membrane.
cortical reaction
Exocytosis of enzymes from cortical granules in the egg cytoplasm during fertilization.
The process in the ovary that results in the production of female gametes.
fertilization envelope
The swelling of the vitelline layer away from the plasma membrane. Which resists the entry of additional sperm. The fertilization envelope and other changes in the egg′s surface function together as a longer–term slow block to polyspermy
Orgin and devolopment of the embryo
The development of body shape and organization.
The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane. Also, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells.
During this period, called cleavage, the cells undergo the S (DNA synthesis) and M (mitosis) phases of the cell cycle. The embryo does not enlarge during this period of development.
Cleavage simply partitions the cytoplasm of one large cell, the zygote, into many smaller cells called blastomeres, each with its own nucleus
The first five to seven divisions form a cluster of cells known as the morula (Latin for “mulberry,” in reference to the lobed surface of the embryo at this stage). A fluid–filled cavity called the blastocoel begins to form within the morula and is fully formed in the blastula.
The fluid–filled cavity that forms in the center of the blastula embryo. form within the morula and is fully formed in the blastula.
The hollow ball of cells marking the end stage of cleavage during early embryonic development.
In vegetal pole, Nutrients stored in an egg. In many frogs and other animals, the distribution of yolk is a key factor influencing the pattern of cleavage. Yolk retards cleavage.
The portion of the egg where most yolk is concentrated; opposite of animal pole. (lighter)
animal pole
Cytoplasm, The portion of the egg where the least yolk is concentrated; opposite of vegetal pole. Blastocoel located here. (darker)
gray crescent
A light–gray region of cytoplasm located near the equator of the egg on the side opposite the sperm entry.
meroblastic cleavage
A type of cleavage in which there is incomplete division of yolk–rich egg, characteristic of avian; Chick development.(Teloecithal eggs)
holoblastic cleavage
A type of cleavage in which there is complete and equal division of the egg, as in eggs having little yolk (sea urchin) or a moderate amount of yolk (frog).
An embryonic cap of dividing cells resting on a large undivided yolk. (chick)
The mass of cells that rests on top of the yolk mass
a rearrangement of the cells of the blastula to form a three–layered embryo with a primitive gut
The three–layered, cup–shaped embryonic stage.
germ layers
Three main layers that form the various tissues and organs of an animal body.
(ectoderm, mesoderm,endoderm)
The opening of the archenteron in the gastrula that develops into the mouth in protostomes(earthworm)and the anus in deuterostomes(star fish, chick, frog).
The outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye.
The middle primary germ layer of an early embryo that develops into the notochord, the lining of the coelom, muscles, skeleton, gonads, kidneys, and most of the circulatory system.
The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract.
dorsal lip
The dorsal side of the blastopore.
archenteron or primative gut
The endoderm–lined cavity, formed during the gastrulation process, that develops into the digestive tract of an animal.(future digestive tube)
Gastrulation in a frog embryo.
In the frog blastula, the blastocoel is displaced toward the animal pole and is surrounded by a wall several cells thick. The cell movements that begin gastrulation occur on the dorsal side of the blastula
The infolding of cells.
Gastrulation in a sea urchin embryo.
The movement of cells during gastrulation forms an embryo with a primitive gut and three germ layers
a process that future endoderm and mesoderm cells on the surface of the embryo roll over the edge of the lip into the interior of the embryo
Gastrulation in a chick embryo.
During gastrulation, some cells of the epiblast migrate (arrows) into the interior of the embryo through the primitive streak, shown here in transverse section. Some of these cells move downward to form endoderm, while others migrate laterally to form mesoderm. The cells left behind on the surface of the embryo at the end of gastrulation will become ectoderm.
yolk plug
Large food–laden endodermal cells surrounded by the blastopore of an amphibian gastrula
primitive streak
A groove on the surface of an early avian(chick) embryo along the future long axis of the body.
The development of organ rudiments from the three germ layers.
the neural tube and the notochord
The organs that begin to take shape first in the embryos of frogs and other chordates > mammals, fish, birds and reptiles
A longitudinal, flexible rod that runs along the dorsal axis of an animal′s body in the future position of the vertebral column
neural tube
A tube of cells running along the dorsal axis of the body, just dorsal to the notochord. It will give rise to the central nervous system.
neural crest
A band of cells along the border where the neural tube pinches off from the ectoderm. The cells migrate to various parts of the embryo and form the pigment cells in the skin, bones of the skull, the teeth, the adrenal glands, and parts of the peripheral nervous system
“fourth germ layer.”
Paired blocks of mesoderm just lateral to the notochord of a vertebrate embryo.
What is the only rement of notocord in humans?
Intervertebral Disc
Optic Vesicle
Embrogical Eye
Otic Vesicle
Embrogical Ear
Free living sexual immature stage of living.