Chapter 32 – Study Module – Flashcards
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Which of the following is associated with bilateral symmetry?
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Cephalisation.
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Many young animals are __________, a sexually immature form that is morphologically distinct from the adult stage. These young animals undergo __________ to become __________, which resemble adults but are not yet sexually mature.
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larvae; metamorphosis; juveniles.
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Which of the following is the defining characteristic of the clade Ecdysozoa for which this group is named?
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The secretion of stiff external skeletons that must be shed to permit growth.
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Triploblastic animals have an _________ as well as _________ symmetry.
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ectoderm, mesoderm, and endoderm; bilateral.
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Cadherins are __________.
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proteins that play key roles in how animal cells attach to one another
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Determinant cleavage refers to the fact that the __________.
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developmental fate of each embryonic cell is determined very early.
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Symmetry is one of the most basic characteristics of animals. The group that has a different symmetry from the other four groups listed here is the __________.
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jellies.
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Radially symmetric animals tend to be __________, while bilaterally symmetric animals ___________.
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sessile and attached or planktonic and drifting; are involved in complex movements that allow them to crawl, burrow, fly, or swim.
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Indeterminate cleavage is a process that produces embryonic cells that __________.
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retain the capacity to develop into a complete embryo.
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Animals have a "toolkit" called the _________ that regulates the _________ of the developing embryo.
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Hox genes; anterior-posterior axis.
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Consider the two phylogenetic hypotheses regarding the relationships of the animal phyla. The tree that is based on molecular evidence differs from the tree based on morphological evidence in that it __________.
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divides protostomes into two taxa.
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The roundworm body cavity is ________, whereas the planarian body cavity is ________.
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pseudocoelomic; acoelomic
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During the development of most animals, cleavage leads to __________.
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a multi-celled blastula.
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Embryonic tissues develop during the _________ stage.
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gastrula.
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Which of the following occurred during the Mesozoic era?
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Flight evolved in pterosaurs and birds.
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Morphological traits, ribosomal RNA genes, Hox genes, protein-coding genes, nuclear genes, and mitochondrial genes all indicate that animals __________.
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are monophyletic and form the clade Metazoa.
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Molecular evidence that points to choanoflagellates as living relatives of animals is that they __________.
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have cadherin proteins but lack the CCD domain that is present in all animals.
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Which of the following is a characteristic of cnidarians?
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Ectoderm and endoderm.
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When using terms such as coelomates and pseudocoelomates, a "grade" is _________.
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a group whose members share key biological features.
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Which of the following correctly lists the embryonic stages in the order that they develop?
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Zygote, blastula, gastrula, larvae.
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Which characteristic below is shared by plants, fungi, and animals?
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They are multicellular eukaryotes.
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Coelomic animals have a body cavity that is formed from _________ and also have __________.
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mesoderm and endoderm; a cavity that is completely surrounded by mesoderm
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An animal with a true coelom that has __________ cleavage must be a __________.
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radial; deuterostome.
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Which example below is a current hypothesis regarding the Cambrian explosion?
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Evolution of the Hox gene complex provided developmental flexibility.
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Animals probably evolved from colonial protists. How do animals differ from these protist ancestors?
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Animals have more specialized cells.
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The protist group that is most closely related to animals is a _________.
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choanoflagellate.
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The three major clades of bilaterian animals are the __________.
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ecdysozoa, lophotrochozoa, and deuterstomia.
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Which of the following is a trait shared by protostomes and deuterostomes?
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A body cavity.
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If the blastopore does not form, ________.
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the archenteron would not form.
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Diploblastic animals have an _________ as well as _________ symmetry.
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ectoderm and an endoderm; radial.
