BIOLOGY
12th Edition
ISBN: 9781260169614
Author: Raven
Publisher: RENT MCG
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Chapter 21, Problem 7U
The possession of fine fur in 5-month human embryos indicates
a. that the womb is cold at that point in pregnancy.
b. humans evolved from a hairy ancestor.
c. hair is a defining feature of mammals.
d. some parts of the embryo grow faster than others.
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Students have asked these similar questions
Which of the following statements relating to axis formation in chickens is FALSE?
a. Henson's node secretes proteins that antagonize BMPs.
b. The side of the epiblast facing the negative, basic albumin will become the ventral side of the embryo.
c. Cells of the posterior marginal zone secrete Nodal to initiate the primitive streak.
d. Water and sodium ions are transported from the albumin through the blastodisc cells and into the subgerminal space.
Scientists compare the structures of a chicken embryo and a human embryo at the same stage of development. They find that both vertebrates have similar shapes and structures, including the presence of gill slits and tails. How is this comparison of the embryos used as supporting evidence of evolution?
A. The similarities suggest that chickens and humans are the direct descendants of modern day fish with tails and gill slits.
B. The similarities suggest that vertebrates passthrough each of the adult stages of their evoluntionary history as they develop.
C. The similarities suggest that vertebrates can undergo genetic changes during development that lead to the evolution of new species
D. The similarities suggest that chickens and humans descend from ancestors with genes that code for the development of tails and gill slits
Researchers searched for an activator of neural tissue formation. What is the real pathway for this developmental phenomenon?
a. Neural tissue formation occurs via BMP inhibition by proteins secreted from the organizer.
b. Noggin activates ectoderm to become neural tissue.
c. Nodal activation induces mesoderm to make neural tissue.
d. Beta-catenin is required for formation of neural tissue.
Chapter 21 Solutions
BIOLOGY
Ch. 21.1 - Prob. 1LOCh. 21.1 - Prob. 2LOCh. 21.2 - Prob. 1LOCh. 21.2 - Distinguish between demonstrating that evolution...Ch. 21.3 - Contrast the processes of artificial and natural...Ch. 21.3 - Prob. 2LOCh. 21.4 - Prob. 1LOCh. 21.4 - Prob. 2LOCh. 21.4 - Prob. 3LOCh. 21.5 - Explain the evolutionary significance of...
Ch. 21.5 - Prob. 2LOCh. 21.6 - Prob. 1LOCh. 21.6 - Prob. 2LOCh. 21.7 - Characterize the criticisms of evolutionary theory...Ch. 21.7 - Prob. 2LOCh. 21 - Suppose that a male with a beak depth of 10 mm...Ch. 21 - Prob. 1IQCh. 21 - Prob. 2IQCh. 21 - Prob. 3IQCh. 21 - Why might the evolutionary line leading to...Ch. 21 - Artificial selection is different from natural...Ch. 21 - Gaps in the fossil record a. demonstrate our...Ch. 21 - The evolution of modern horses (Equus) is best...Ch. 21 - Homologous structures a. are structures in two or...Ch. 21 - Convergent evolution a. is an example of...Ch. 21 - Prob. 6UCh. 21 - The possession of fine fur in 5-month human...Ch. 21 - In Darwins finches, a. occurrence of wet and dry...Ch. 21 - Prob. 2ACh. 21 - Convergent evolution is often seen among species...Ch. 21 - What conditions are necessary for evolution by...Ch. 21 - Explain how data shown in figure 21.2a and b...Ch. 21 - Prob. 3SCh. 21 - Refer to figure 21.5, artificial selection in the...Ch. 21 - The ancestor of horses was a small, many-toed...
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- Observation of the development of embryos in sea stars shows the mesoderm forming pouches bulging from the archenteron to form the coelom. From this observation, you can predict that A. the cleavage of the embryo is radial. B. the adult animal will have bilateral symmetry. C. the mouth forms from the first opening in the gastrula. D. the animal is diploblastic.arrow_forwardObservations of the developing chick embryo reveal that skeletal muscles develop from the transplanted somites even though motor neurons innervating those muscles arise from chick neural crest cells. Based on these observations, what is MOST likely true? A. Neural crest cells differentiate into somites. B. Neural crest cells fuse with developing somite cells. C. Neural crest cells develop from migrating somite cells. D. Neural crest cells send projections into developing somites.arrow_forwardWhich of the following is false? a. The endoderm, mesoderm, ectoderm are germ layers. b. The trophoblast is a germ layer. c. The inner cell mass is a source of embryonic stem cells. d. The blastula is often a hollow ball of cells.arrow_forward
- which of the following a correct development sequence a. Neural plate, proliferation, neural groove, neural tube b. Neural plate, neural groove , neural tube, proliferation c. Neural groove, neural tube, proliferation, neural plate d. Proliferation, neural plate, neural groove , neural tubearrow_forwardDuring morphogenesis, gastrulation does which of the following?A. Gastrulation produces the ectoderm through formation of a blastocyst.B. Gastrulation produces the mesoderm to form the lining of the digestive tract.C. Gastrulation provides the mechanisms whereby cells can form the neural tube.D. Gastrulation produces the endoderm through invagination of the blastula.arrow_forwardWhich of the following is not true about avian eggs? Choose all possible answers. a. exhibit holoblastic cleavage b. first cleavages are perpendicular to the plane of the blastodisc, and approximately at right angles to one another c. at the time of the fourth cleavage, a furrow running parallel to the circumference of the blastodisc separates central from peripheral forming blastomeres. d. portion of the undersurface of the blastoderm that is farthest from the source of gravity becomes the anterior end of the embryo. e. All of the following are true about eggs of frogs.arrow_forward
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