Endoderm
Mesoderm
Ectoderm - Three embryonic layers. Endoderm being the inner most layer and
Ectoderm being the outermost.
What traits are present in the early stages of development that would not allow you to
determine if the animal is a protostome or deuterostome?
A) Radial Cleavage
B) presence of endoderm, mesoderm, and ectoderm
c) Coelom formed by splitting the mesodermal mass
D) Anus forms from blastopore
E) The developmental fate of each embryonic cell is fully determined - B) presence of
endoderm, mesoderm, and ectoderm
Coelom - Internal body cavity derived from the mesoderm
Blastopore - The opening that develops into the mouth in protostomes and the anus in
deuterostomes
Radial Symmetry - Can be split on multiple planes and be symmetrical (Circle)
Ex. Adult Cnidaria
Bilateral symmetry - Will only be symmetrical if split on one line, all others will not be
symmetrical (humans)
Ex. Nematoda
Rotational symmetry - Division of the body into two halves divides it into two copies of
the same half with one rotated 180 degrees.
Ex. Ctenophora
Asymmetry - No symmetry in any split
Ex. Porifera
Which is not a monophyletic group?
A) Opisthokonta
B) Bilateria
C) Cnidaria
D) Ctenophora
E) Porifera - A) Opisthokonta
,Which is true about animal evolutionary history?
A) the Cambrian explosion led to the appearance of the Ediacaran biota
B) the Cambrian explosion occurred around 100 MYA
C) several extant phyla first appear in the fossil record from the Cambrian period
D) many fossils dating from the Cambrian explosion represent species that survive
today
E) the Cambrian explosion was caused by a rapid increase in Earth's atmospheric
nitrogen - C) Several extant phyla first appear in the fossil record from the Cambrian
Period
Ediacaran Period - before Cambrian period, about 635-543 MYA
Cambrian Explosion/Period - the most rapid evolution of new animal phyla and animal
diversity in Earth's history about 542-488 MYA
Which of the following is not typical of most animals?
A) Specialized tissues
B) a stage of development called gastrulation
C) possession of hox genes
D) alternation of generations between diploid and haploid lifestages
E) food obtained via heterotrophy - D) Alternation of generations between diploid and
haploid lifestages
Hox Genes - Responsible for the general body pattern of most animals
Gastrulation - results in the formation of the primitive gut (archenteron) or digestive
cavity and the formation of the embryonic layers.
Organogenesis - formation of organs
Which of the following is true of the animal phylogenetic tree?
A) fossils provide the best source of information for determining the animal phylogenetic
tree
B) major accepted clades of the animal phylogeny have remained constant over the
past 50 years
C) Future DNA evidence is likely to demonstrate that the Bilateria is the most primitive
animal clade
D) Eumetazoans include more species than Metazoans
E) As more DNA is sequenced and analyzed from more animals, future changes to
major surviving clades of the animal phylogenetic tree become less likely. - E) As more
DNA is sequenced and analyzed from more animals, future changes to major surviving
clades of the animal phylogenetic tree become less likely
, Which of the following is not true of the coelom?
A) it may be present in triploblastic organisms
B) it is a cavity the houses internal organs
C) it is derived from mesoderm
D) it is present in all animals
E) it usually contain fluids - D) it is present in all animals
Triploblastic - Having 3 embryonic layers (endoderm, mesoderm, and ectoderm)
Diploblastic - Having 2 embryonic layers (endoderm and ectoderm).
Which of the following does not play a major role in Earth's post-Cambrian animal
evolution?
A) evolution among plants
B) meteor strikes
C) Change in distance between the Earth and the sun
D) shift in Earth's geography
E) cataclysmic volcanic eruptions - C) change in distance between the Earth and the
sun
Which of the following is not found in Cnidarians?
A) planula larvae
B)medusae
C)cnidocytes
D)mesoderm
E)polyps - D) mesoderm
planula larvae - larvae of various cnidarians
medusae - free-floating aquatic animals with a structure similar to a jellyfish
cnidocytes - stinging cells
Gemmules - Environmentally resistant structures produced by adult sponges
Which of the following is not a component of a sponge?
A) osculum
B)mesohyl
C)endoderm
D)amoebocytes
E)ostia - C) endoderm
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