Describe the fossil and embryological evidence for the terrestrial origins of cetaceans
What will be an ideal response?
Fossil records show massive animals, with four limbs, that resemble modern day whales. Other evidence is observed in modern cetaceans. First, the embryos of whales, like all mammals, have four limbs. The hindlimbs eventually disappear during the development of the embryo and all that remains is an obsolete pelvic girdle. The embryos of whales also show a normal mammalian nostril arrangement, but this does not persist, as the nostrils migrate to the dorsal side of the animals to become the blow holes.
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Experiments on the feeding preferences of newborn garter snakes born to coastal vs. inland California revealed that
even in the same species, differential instinctive responses can be ____.
a. learned b. genetic c. forgotten d. homozygous e. sex-linked
Natural selection acts on ________, and ________ evolve.
A. individuals; populations B. populations; individuals C. individuals; individuals D. populations; populations
Receptors for fast pain
A) generally arise from muscles or internal organs. B) give rise to a phenomenon called referred pain. C) transmit action potentials to the brain along the same neurons used by spinal neurons. D) generally occur in or near skin. E) initiate action potentials that travel more quickly.
Which of the following statements concerning the heart is false?
a. It is an organ. b. It contains endothelium. c. It contains nerves
d. It is an organ system. e. Its muscles contain elongated fibers.