Biology, Eighth Edition (Raven)

Chapter 26: The Tree of Life

Post Test

The most likely contributor to the high abundance of oxygen in present-day Earth's atmosphere was (p. 506)
D)Outgassing of the cooling crust of Earth
E)All of the above may have contributed oxygen as science cannot explore the past effectively.
What is one drawback from the Linnaean system for taxonomy? (p. 509)
A)All human-created systems are by nature based on highly artificial similarities.
B)There are few evolutionary connections between organisms within the various groups.
C)Evolutionary hypothesis are often mutually incompatible with each other, leading to confusion within Linnaean groups.
D)Many groups in the Linnaean system do not contain a common ancestor and all its descendants, which hides evolutionary connections.
E)The Linnaean system neglects most of the diversity seen in nature.
What is the most likely origin of chloroplasts and mitochondria? (p. 512)
A)Serial endosymbiosis of first a heterotrophic bacterium, and then in plants, a subsequent acquisition of cyanobacteria.
B)Endosymbiosis of an ancestral prokaryote which diverged to form these organelles in a host which eventually gave rise to eukaryotes.
C)Uptake of DNA of eukaryotes from dead bacteria gave rise to new combinations, eventually forming these organelles through natural selection.
D)Ancestors to plants picked up a cyanobacterium which gave rise to chloroplasts. Animal ancestors did the same to a heterotrophic bacterium to establish mitochondria.
E)More than one of these answers is believed to be correct by most scientists.
Of the organisms which are usually classified as protista, which one seems to share a common ancestor with members of the sponges? (p. 515)
A)Green algae
E)Any of the aerobic protists are considered candidates for this assignment.
Why is there a move among some taxonomists to define land plants as members of the algal group Streptophyta, rather than as a separate kingdom? (p. 517)
A)Red algae are closely related to Chlorophyta, which confuses the determination of ancestral lineage.
B)Groups that include red algae and land plants are monophyletic as long as you don't include Chlorophyta.
C)Until molecular data were routinely included in cladistics, formation of groups was largely arbitrary.
D)Cell biology, biochemistry, and molecular systematics are providing consistent, clear evolutionary patterns upon which to base new evolutionary hypotheses.
E)All of the above make this new way of grouping more consistent with current data.
Egg laying while yet producing milk (despite predating the evolution of nipples for efficient dispensing of the milk) is a characteristic of which primitive branch of the mammals? (p. 520)
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