Chapter 25

Which of the following is an internal structure that appears in eukaryotic cells and is also present in more ancient prokaryotic cells? ANSWER Vesicles Nuclear envelope Mitochondria Endoplasmic reticulum Well-developed cytoskeleton

Which of the following is not a unique anatomical feature of mammals that can be recognized in the fossil record? ANSWER Temporal fenestra A set of three bones—the hammer, anvil, and stirrup—that transmit sound in the middle ear A lower jaw composed of a single bone Teeth differentiated into incisors, canines, premolars, and molars A dentary-squamosal hinge connecting the upper and lower jaws

The fossil record is __________. ANSWER biased in favor of species that existed for a long time a small but unbiased sample of life on Earth useful for developing, but not testing, hypotheses now complete enough to detail the evolution of most terrestrial species useful only in describing the evolution of vertebrates

The amphibians, reptiles, and mammals comprise which group? ANSWER tetrapods synapsids therapsids cynodonts arthropods

The correct order of the geologic eras, from most ancient to most recent, is __________. ANSWER Paleozoic, Mesozoic, and Cenozoic Paleozoic, Cenozoic, and Mesozoic Proterozoic, Mesozoic, Cenozoic, and Paleozoic Paleozoic, Mesozoic, Cenozoic, and Proterozoic Cenozoic, Mesozoic, and Paleozoic

What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the extinction of the dinosaurs? ANSWER Sedimentary rocks contain a layer of iridium, a mineral uncommon on Earth. Fossils show that dinosaurs suffered from cold and starvation. There have been several near misses in recent years. The dinosaurs disappeared rather abruptly, virtually overnight. Most dinosaur fossils are fragmented, indicating that they were crushed by the asteroid.

The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that __________. ANSWER simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history life can be created in a test tube long chains of DNA can form under abiotic conditions the earliest life-forms introduced large amounts of oxygen into the atmosphere the "concentration gap" probably prevented simple organic molecules from polymerizing

Why is RNA, rather than DNA, thought to have been the first genetic material? ANSWER RNA can also function as a catalyst. RNA molecules are more stable than DNA molecules. The nucleotide building blocks of RNA are much simpler than those of DNA. RNA is the only genetic material of the simplest living multicellular organisms. Unlike DNA, RNA is copied without mistakes.

Fossilized stromatolites __________. ANSWER resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays all date from 2.7 billion years ago formed around deep-sea vents provide evidence that plants moved onto land in the company of fungi around 500 million years ago contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago

Single-celled prokaryotes had the Earth to themselves for approximately __________. ANSWER 1.5 billion years 1.5 million years 3 billion years 150,000 years 3 million years

Which of the following is a true statement about the current status of Earth's biodiversity? ANSWER The current rate of extinctions is as high as 1,000 times the typical rate seen in the fossil record. The current decrease in biodiversity due to human actions represents the largest mass extinction ever. Many extinctions have occurred recently, but the rate of extinctions is decreasing. The number of marine families is lower than it was prior to the last mass extinction, at the end of the Mesozoic era. As global temperatures continue to increase, species diversity will likely increase as well

Which of the following is a true statement concerning the history of Earth's biological diversity? ANSWER The majority of species that ever lived are now extinct. There has been a steady increase in biological diversity at the level of families since the beginning of the Paleozoic era. Prior to the origin of humans, no extinction event had ever affected more than 20% of species. Most animal phyla did not originate until after the last mass extinction event. Typically, extinctions occur only during periods of disruptive change to the global environment.

If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the bird wings could be accurately described as __________. ANSWER exaptations vestigial structures analogous organs degenerate structures anticipatory structures

The ratio of carbon-14 to carbon-12 in a fossil can be used to determine the age of the fossil because __________. ANSWER carbon-14, unlike carbon-12, decays at a continuous rate after the death of an organism the amount of carbon-14 in most environments has steadily decreased since the origin of Earth more recently evolved organisms are more efficient in assimilating carbon-14 the process of fossilization entails absorption of carbon-14 at a continuous rate from surrounding sediment meteorite impacts at known times have periodically increased the amount of carbon-14 on Earth

The original atmosphere of Earth had little oxygen. What was the likely first source of oxygen that led to an oxygen atmosphere? ANSWER Cyanobacteria Cone-bearing plants Flowering plants Mycorrhizae Eukaryotic algae

Retention of juvenile body features into sexual maturity is referred to as the presence of __________. ANSWER paedomorphosis exaptation vestigial structures analogous organs adaptive radiation

Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting approximately 65 million years ago. Why? ANSWER Between 180 and 65 million years ago, mammals were outcompeted by the well-established dinosaurs. Mammals were not well-adapted to the climate that existed before about 65 million years ago. Mammals were mostly nocturnal until 65 million years ago. Fur evolved in mammals around 65 million years ago, enabling them to withstand colder temperatures. All of the listed responses are correct

Prior to the Cambrian explosion, all large animals had what characteristic in common? ANSWER They were all soft-bodied. They were all predators. They were all terrestrial. They were members of only a few phyla. They were all chordates.

What was one ecological change that occurred following the Permian mass extinction? ANSWER The percentage of marine predators increased. Marine community diversity increased at the expense of terrestrial adaptive radiations. Each species lost in the extinction was replaced by a species from the same lineage and filling the same ecological role. The number of marine genera has decreased steadily to the present day. Mammal species became a smaller component of terrestrial food webs.

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of __________. ANSWER a change in a developmental gene or in its regulation that altered the spatial organization of body parts the influence of environment on development Paedomorphosis Heterochrony gene duplicatio

The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely place for the abiotic synthesis of organic molecules to have occurred? ANSWER Near volcanoes Dust particles in the atmosphere Banded iron formations The surface of ancient oceans Stromatolite mounds

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception. ANSWER Genetic drift Vacant ecological niches Colonization of an isolated region that contains suitable habitat and few competitor species Evolutionary innovation An adaptive radiation in a group of organisms (such as plants) that another group uses as food

Why is the four-stage hypothesis for the abiotic origin of life useful? ANSWER It leads to predictions that can be tested. It can be proven. It is true. It provides a reason for the origin of living things. It proves that RNA was the first genetic molecule.

Which of the following is the correct ordering of divisions of the geologic record from largest to smallest? ANSWER eon, era, period, epoch epoch, era, period, eon period, epoch, era, eon epoch, period, era, eon eon, period, epoch, era

Macroevolution differs from microevolution in that macroevolution __________. ANSWER includes broad evolutionary changes above the species level is the evolution of multicellular, rather than unicellular, life is much more rapid than microevolution includes only the evolution that has occurred in the most recent era refers specifically to the evolution of large size in vertebrates

What were the two major "problems" that had to be solved before plants, animals, and fungi could move into terrestrial habitats? ANSWER Reproduction and prevention of dehydration Support and absorption Reproduction and locomotion Prevention of dehydration and locomotion Cell division and absorption of nutrients

Which of the following would not have been a consequence of tectonic plate movements bringing previously separated landmasses together in the formation of the supercontinent of Pangaea about 250 million years ago? ANSWER Allopatric speciation increased. Ocean basins became deeper. Shallow coastal seas were drained. Interior regions of the supercontinent became extremely cold and dry. Habitat destruction led to extinctions.

In the species selection model, __________ is to macroevolution as __________ is to microevolution. ANSWER differential speciation success; differential reproductive success exaptation; adaptation genotype; phenotype disruptive selection; balancing selection allopatric speciation; sympatric speciation

What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts? ANSWER They have a single circular chromosome similar to bacterial chromosomes; their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes They have a single circular chromosome similar to bacterial chromosomes. They have flagella similar to bacterial flagella. Their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes. They divide by a process similar to meiosis.

You are watching a movie in which one of the characters excitedly claims to have found human remains in Asia dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction? ANSWER This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years. This can't possibly be true because humans weren't around 10 million years ago. This would be a surprising finding because so far there is no evidence that humans existed that long ago. This is a perfectly reasonable finding. This can't possibly be true because the earliest humans came from Africa, not Asia.