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Modern Biology: Ch. 34 Vocabulary

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vertebrate
an animal with a backbone
invertebrate
an animal without a backbone
specialization
the adaptation of a cell for a specific function
cell junctions
connections between the cells that holds the cells together as an entire unit
ingestion
a process in which an animal takes in organic material
zygote
the first cell of a new individual
differentiation
process in which cells become different from each other
neurons
cells of nervous tissue which conduct electrical signals throughout an animal's body
symmetry
consistent overall pattern of structure
radial symmetry
symmetry in which the animal has a top and bottom side, but no front, back, left or right; symmetry in which similar parts branch out in all directions from a central line
dorsal
top
ventral
bottom
anterior
head
posterior
tail
bilateral symmetry
symmetry in which an animal has two similar halves on either side of a central plane
cephalization
the concentration of sensory and brain structures in the anterior end of the animal; animal has a head which proceds the rest of the body
germ layers
fundamental tissues found in the embryo of all animals except sponges
chordate
animals that have a notochord, dorsal nerve chord, pharyngeal pouches, and a postanal tail in some stage of development
notochord
a firm, flexible rod of tissue located in the dorsal side of an animal
dorsal nerve chord
hollow tube lying just above (or dorsal to) the notochord
pharyngeal pouches
small outpockets of the anterior part of the digestive tract
postanal tail
consists of muscle tissue and lies behind the posterior opening of the digestive tract
Segmentation
refers to a body composed of similar and repeating units
exoskeleton
a rigid outer covering that protects the soft tissue of many animals (eg arthropods); limits the size and impedes the movement of the organism, and does not grow (has to be shed)
gas exchange
the exchange of carbon dioxide with oxygen
gills
organs specialized for gas exchange in water
circulatory system
system that moves blood or a similar fluid through the body to supply oxygen and nutrients to the cells
open circulatory system
circulatory system in which blood like fluid is pumped from vessels in the body into the body cavity
closed circulatory system
circulatory system in which blood circulates through the body in tubular vessels
gut
digestive tract
hermaphrodite
an organism that produces both male and female gametes
indirect development
animals that undergo an intermediate larva stage
larva
a premature free-living form of an organism
direct development
an organism that is born or hatched with the same appearance and way of life as it will when it is an adult; no larva stage
endoskeleton
an internal skeleton that can support a large, heavy body; grows as the animal grows
vertebrae
the repeating bony units of a backbone
integument
the outer covering of an animal
lungs
organs for gas exchange composed of moist, membranous surfaces
kidneys
organs that filter waste from blood while regulating water levels in the body
cleavage
divisions of the zygote immediately after fertilization
blastula
a hollow ball of cells
blastocoel
central cavity of the blastula
blastospore
the infolded region of the blastula
gastrulation
process that transforms a blastula into a gastrula
gastrula
multilayered embryo
archenteron
deep cavity formed as the cup shape embryo enlarges; serves as gut
ectoderm
outer germ layer of the gastrula
endoderm
inner germ layer
mesoderm
third layer formed between ectoderm and endoderm
coelom
a body cavity completely lined by mesoderm
protosomes
describing development of the mouth before development of the anus in arthropods, annelids, and mollusks
spiral cleavage
cleavage in which cells divide in a spiral arrangement
deuterosomes
describing development of anus before the mouth in echinoderms and chordates
radial cleavage
cleavage in which the cell divisions are parallel to or at right angles to the axis from one pole of the blastula to another
determinate cleavage
A type of embryonic development in protostomes that rigidly casts the developmental fate of each embryonic cell very early.
indeterminate cleavage
A type of embryonic development in deuterostomes, in which each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.
schizocoely
in protosomes; process in which cells divide rapidly in the blastocoel to form the mesoderm
enterocoely
in deuterosomes; process in which cells in the archenteron divide rapidly and roll outward into the blastocoel to form the mesoderm
acoelomates
organisms in which the body cavity is absent
pseudocoelomates
organisms containing pseudocoeloms
psuedocoelom
body cavity in which the mesoderm lines the interior of the coelom but does not surround the exterior of the endodermic gut
coelomates
animals with a true coelom