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- Antitrust laws make certain “anticompetitive” practices illegal because these practices raise prices andreduce output, which reduces the total amount of consumer surplus. Why are antitrust laws uncommon inmarkets that are highly contestable?
a. Since the market is contestable, antitrust laws are illegal.
b. In contestable markets, there is always the threat of losing the monopoly to another monopoly, whichtends to keep consumers’ surplus higher than it would for a noncontestable market.
c. Antitrust laws are common in contestable markets.
d. In contestable markets there aren’t many monopolies. - What does competition “for the market” mean?
a. It means competing to exist at all.
b. It is the same as competing “in the market.”
c. It means competing to rule the market, instead of competing within the market for sales.
d. It means you don’t face competition at all. - Assess the validity of each of the following statements.
I. The only clothing store in a small town is in a more contestable market than the only natural gas provider in a small town
II. The only clothing store in a small town is in a more contestable market than the only cable TV provider in a small town
III. De Beers diamond mining is in a more contestable market than H&R Block tax preparation services. - The mantra of Amazon.com CEO Jeff Bezos is “Get big fast.” As we saw in our monopoly chapter, one reason to “get big fast” is because in some industries the firm’s average cost will plummet as the firm expands—so size helps on the supply side. In this chapter, network effects illustrated how size helps on the demand side. With this in mind, explain the following real-world drives to get big fast: Do you think it’s mostly about increasing returns or mostly about network effects?
I. Adobe Acrobat Reader is free, but the software to create sophisticated Adobe documents is not.
II. Match.com, the online dating site, lets people post profiles, look at other people’s profiles, and even get mail from other members for free. To send an e-mail to a member, you have to pay.
Terms and answers to learn
The _______ of a phylogenetic tree represents the common ancestor, the _______ represent events where lineages diverged, and the _______ axis represents time. Assume that the tree is oriented as described in the textbook.
root; nodes; horizontal
Which of the phylogenies shown below are equivalent?
A and B
A _______ is any group of organisms we name, while a _______ is any _______ that consists of all the evolutionary descendants of a common ancestor.
taxon; clade; taxon
All clades are subsets of larger clades. The most inclusive clade in the figure below are the _______; the least inclusive clade includes the _______.
vertebrates; chimpanzee
Which statement about traits is false?
Synapomorphies are shared ancestral traits.
The bones in the wings of birds and bats are _______ because they derived from a _______ ancestor, while the wings are _______ traits.
homologous; common; homoplastic
Refer to the phylogenetic tree shown below. Which statement is true?
Gizzards are a synapomorphy uniting pigeons and crocodiles.
A sea squirt is thought to be more closely related to vertebrates than once thought because
both vertebrate embryos and sea squirt larvae have notochords.
Three character sets are being considered for inclusion in a phylogenetic analysis of lizards. The first (A) is fossil data on lizards from 10 to 20 million years ago. The second (B) is on a variety of mating behaviors that have been shown to be learned. The third (C) is from a few nuclear genes that have variable rates of evolution. Which is least likely useful to the analysis of phylogenetic relationships, and why?
B, because it involves learned traits.
The best way to assess the accuracy of methods to reconstruct phylogenetic history is to
use experimental tests of organisms with known evolutionary histories.
Refer to the figure below showing a polygenetic tree of immunodeficiency viruses. Based on the figure, which statement is false?
HIV-1 and HIV-2 are more closely related to each other than to any of the simian immunodeficiency viruses.
Phylogenetic analyses of opsin pigments have allowed scientists to infer that ancestral archosaurs
may have been nocturnal.
Suppose that mice and humans differ by 30 substitutions in their globin genes, and rats and mice differ by five substitutions. On the basis of other evidence, we know that the ancestor to humans and mice lived 84 million years ago. Assuming the molecular clock is operating, rats and mice split from each other _______ million years ago.
14
A molecular clock assumes that the genes used
are evolving slowly.
The studies of self-incompatible (outcrossing) species of Leptosiphon illustrate
how phylogenetic systematics can reveal convergent evolution.
In the classification system devised by Linnaeus, the names of _______ of plants end with the suffix _______, while those of animals end with _______.
families; -aceae; -idae
Which statement about biological classification is false?
The same binomial name may be given to two different organisms as long as they are in different phyla.
A taxon that contains organisms that do not share a common ancestor is referred to as
polyphyletic
Based on the figure below, which taxon/taxa are monophyletic?
Both blue and red
Refer to the figure below. If birds are not considered reptiles, but reptiles include turtles, lizards and crocodiles, the group called “Reptiles” is
paraphyletic.
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