Biology
Biology
12th Edition
ISBN: 9780134813448
Author: Audesirk, Teresa, Gerald, Byers, Bruce E.
Publisher: Pearson,
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Chapter 18.6, Problem 1CSC

We might be able to more easily distinguish between the African replacement and multiregional origin hypotheses (and to answer a host of other unanswered questions about the origin and early evolution of H. sapiens) if we had access to DNA sequences from the earliest representatives of our genus. Is it possible that researchers will one day extract useable DNA from, say. early H. erectus? Perhaps, but the odds of success are not great. H. erectus fossils are up to 1.8 million years old, but the oldest ancient genome so far obtained is from a 700,000-year-old fossil horse. What’s more, the fossil horse was found in northern Canada, where the cold climate is excellent for preserving DNA. H. erectus. however, inhabited warmer regions where DNA degrades more quickly. Nonetheless, some evolutionary biologists hold out hope that useable DNA might be found in early H. erectus bones that fossilized in an environment conducive to preservation, perhaps in a deep cave or in oxygen-depleted underwater sediments. Could DNA survive for more than a million years under the right conditions? Current evidence says no, but then it wasn’t too long ago that recovering Neanderthal DNA seemed like an impossible dream.

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Chapter 18 Solutions

Biology

Ch. 18.4 - Prob. 1TCCh. 18.4 - Does the mudskippers ability to walk on land...Ch. 18.4 - Can ancient DNA reveal the secrets of dinosaur...Ch. 18.4 - Although it may never be possible to recover DNA...Ch. 18.4 - describe the transitions and innovations...Ch. 18.4 - describe the advantages gained by the first plants...Ch. 18.5 - Scientists have cloned a number of animal species,...Ch. 18.5 - explain how extinction has affected the course of...Ch. 18.5 - describe the likely causes of mass extinctions in...Ch. 18.6 - We might be able to more easily distinguish...Ch. 18.6 - Paleontologists recently discovered fossil...Ch. 18.6 - describe the evolutionary history of humans and...Ch. 18.6 - name and describe some characteristics of the...Ch. 18.6 - describe the key features of the most recent phase...Ch. 18.6 - The unexpected discovery that humans interbred...Ch. 18 - Almost all of the oxygen gas in todays atmosphere...Ch. 18 - Extinction a. generally does not occur except...Ch. 18 - In the endosymbiotic origin of the mitochondrion,...Ch. 18 - Which of the following does not list evolutionary...Ch. 18 - Prob. 5MCCh. 18 - Because there was no oxygen in the earliest...Ch. 18 - The molecule _________ became a candidate for the...Ch. 18 - Complex cells that contain a nucleus and other...Ch. 18 - The Sperm of early land plants had to reach the...Ch. 18 - Prob. 5FIBCh. 18 - Prob. 6FIBCh. 18 - Prob. 7FIBCh. 18 - What is the evidence that life might have...Ch. 18 - How did the origin of photosynthesis affect...Ch. 18 - Explain the endosymbiont hypothesis for the origin...Ch. 18 - Name two advantages of multicellularity for plants...Ch. 18 - What advantages and disadvantages would...Ch. 18 - Prob. 6RQCh. 18 - Prob. 7RQCh. 18 - Extinctions have occurred throughout the history...Ch. 18 - In biological terms, what do you think was the...
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