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40 Cards in this Set

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Sessile
firmly attatched to a surface
cleavage
series of mitotic cell divisions
blastula
hollow ball of cells
gastrulation
process of forming and segregating layers of tissue (germ layers)
larva & metamorphosis
a sexually immature form that may look very diffrent from the adult. Which goes thru metmrphss and becomes into a juvenile form
2 classifications of animals
Parazoa & Eumetazoa

Parazoa- no tru tissues. (sponges)
Symmetry
arrangement of body structures in relation to the body axis.

Radial or bilateral
Radial symmetry
body has the general form of a wheel or cylinder. Multiple planes can be drawn.
Bilateral symmetry
can be divided thru only one plane (midline).

Lead to evolutionary trend od cephalization
Cephalization
development of a head
Diploblastic
2 tissue layers.
Ectoderm
skin and the Nervous tissue
Endoderm
forms lining of digestive tube
Triploblastic
have three layers
mesoderm
muscles, skeletal structures, circulatory system.
coelom
body cavity in triploblastics. Fluid-filled space between the body wall & the digestive tube. hydrostatic skeleton
blind-sac body plan
single opening for mouth and anus.
tube w/in a tube body plan (true coelom)
the body wall, forms outer tube, is from ectoderm. tissues from endoderm lines the inner digestive tube.
pseudocoelom
"false coelom". occurs between endoderm and mesoderm.
developmental trend in ceolomates
protostomes & deuterostomia
Protostomes
-spiral cleavage-diagonal to the polar axis
-determinate cleavage-fate of daughter cells fixed
-blastopore becomes the mouth first
-mesoderm splits & widens into the coelom. "Schizocoely"
Deuterostomes
-Radial cleavage-parallel to the polar axis
-indeterminate cleavage-fate of daughter cells not fixed
-blastopore becomes the anus first
-mesoderm forms as "outpackets" , known as "enterocoely". The outpockets pinch off and become pouches.The cavity within the puches become the coelom.
division of protostomes
Lophotrochozoa & Ecdysozoa
Ecdysozoa
protostome animals that shed and replace their outer covering by molting or "ecdysis"
Sponges
phylum: porifera
evolved from: chaonoflagellates
have: choanocytes
choanocytes
collar cells-flagellate cells. make up the inner layer. create the water current that brings food and oxygen to cells and carries away CO2 and other wastes. Trap and phag food.
spongocoel & Osculum
In a sponge, water enters thru the central cavity, spongocoel, and flows out of the osculum.
porocytes
in sponges these form the pores. Regulate the diameter of pores by contracting.
Spicules
skeletal spikes. made by the amoebid cells. consist of calcium carbonate or silica.
Amoebid cells
secrete fibers for support. Transfer nutrients. Secrete spicules (hard) & spongin (soft).
suspension feeders
sponges are adapted for trapping & eating whatever food. food is trapped along the choanocytes. Food is either digested (collar cell) or tansferred to the amoebid cell for digestion and transport of nutrients to epidermal cells.
Sponge reproduction
-In asexual reproduction a fragment breaks off and forms a new sponge.
-Hermaphrodites: produces both egg & sperm. zygote develops into a larva. which attatches to an object for a sessile life.
3 classes of Cnidaria
-Hydrozoa (hydras)
-Scyphozoa (jellyfish)
-Anthozoa (corals)
shape of cnidarians
polyp and medusa
cnidocytes
stinging organelles. that contain stinging "thread capsules" known as nematocysts.
blind sac of cnidarians
diploblastic.
ectoderm- epidermis
endoderm- inner gastrodermis.

seperated by a mesoglea
bicnidarian
polyp give rise asexually to medusa. they reproduce sexually & the zygote develops into a larva, which turns into a polyp.
class and shape of cnidarians
class scyphozoa: medusa
class anthozoan: polyp
planula
fertilized egg of a polyp
Ctenophora
comb jellies. like medusa of cnidarians but without cnidocysts