Biology 1001 Chapter15 Thinking Critically

Evidence indicates that the first prokaryotes arose at least __________ years ago; the first eukaryotes arose about __________ years ago; and the first large organisms that colonized land arose about __________ years ago. Our species arose about __________ years ago. SHOW HINT 3.5 billion years; 1.8 billion; 200 million; 300,000 3.5 billion years; 3.0 billion; 500 million; 100 million 3.5 billion years; 1.8 billion; 500 million; 195,000 6,000; 6,000; 6,000; 6,000

3.5 billion years; 1.8 billion; 500 million; 195,000

What is one hypothesis about the formation of the first polymers? SHOW HINT Extreme heat from volcanic vents on the seafloor caused monomers to spontaneously form complex polymers. Amino acids, or RNA, in solution could have splashed on hot rocks, sand, or clay, causing them to bond together in chains. Abiotically generated enzymes catalyzed dehydration synthesis of the first polypeptides and nucleic acids. Very high concentrations of salt are thought to have spurred abiotic dehydration synthesis, forming the first polypeptides and other polymers.

Amino acids, or RNA, in solution could have splashed on hot rocks, sand, or clay, causing them to bond together in chains.

Which of the following choices has the correct sequence of stages by which life is likely to have arisen? Here are the stages: A. origin of self-replicating molecules B. abiotic synthesis of small organic molecules C. packaging of molecules into "protocells" D. joining of small organic molecules into polymers SHOW HINT C, D, B, A A, B, C, D B, D, C, A D, B, C, A

B, D, C, A

A tremendous increase in the diversity of life forms took place during the _____, which began about _____ years ago. ANSWER Cambrian explosion: 535 million Cambrian explosion: 34 million Permian explosion: 66 million Permian explosion: 252 million years ago Mesozoic era: 252 million

Cambrian explosion: 535 million

Which option accurately describes continental drift? SHOW HINT Continents float and slide around on a stable, underlying crust. Huge plates of Earth's crust float on the mantle and change position relative to one another. The shape and relative positions of coastlines change due to changes in sea level. The continents floating on the oceans change position relative to one another.

Huge plates of Earth's crust float on the mantle and change position relative to one another.

When you hear "iridium," what do you think? SHOW HINT I think of an element used in radiometric dating of fossils. I think of a big crater in the Caribbean Sea. I think of the color "blue." I think of an epoch within a period within an era within an eon of the geologic record.

I think of a big crater in the Caribbean Sea.

Why is rRNA such a useful tool in molecular systematics? SHOW HINT It evolves quite rapidly. Only advanced organisms have rRNA, so it is a useful derived character. It evolves quite slowly, allowing comparisons to be made between distantly related organisms, such as eukaryotes and bacteria. It doesn't change at all, so it is a useful control to ensure that the sequence data is accurate.

It evolves quite slowly, allowing comparisons to be made between distantly related organisms, such as eukaryotes and bacteria.

A shared derived character has all of the following characteristics EXCEPT? ANSWER It was not present in ancestors of the clade. It is present in all members of the clade. It marks a branch point in evolution. It was present in the ancestors of the clade. It is unique to that clade.

It was not present in ancestors of the clade.

What enabled mammals to experience an increase in diversity shortly after the Cretaceous period? SHOW HINT Aquatic mammals thrived in the low coastal areas formed because of continental drift. Mammals diversified to take advantage of ecological niches that were previously filled by the dinosaurs. Mammals thrived on iridium, which can be used as an energy source by mammals but not dinosaurs. The mammals evolved to be strong enough to fight and outcompete the dinosaurs.

Mammals diversified to take advantage of ecological niches that were previously filled by the dinosaurs.

Experiments in the mid-20th century tried to determine how organic molecules might have been synthesized from abiotic components. What was one limitation in interpreting these results that was posed by the technology of the era? ANSWER Many organic molecules that were generated could not be identified. No organic molecules that were generated could be identified. Only organic molecules that contained carbon could be identified. The experimental apparatus could not be properly set up. Molecular samples of the correct size could not be collected

Many organic molecules that were generated could not be identified.

The earliest ancestor of the modern horse (Equus) had several toes and consumed shrubs and trees. How did Equus evolve from this ancestor? SHOW HINT It is likely that earlier horse-like species were eliminated in one of the mass extinctions, leaving only Equus. Evolution was essentially linear from Hyracotherium to Equus. Many speciation episodes occurred, but only one led to Equus. Having hooves and grazing makes Equus more suited for its present habitat than Hyracotherium would be.

Many speciation episodes occurred, but only one led to Equus.

What is the cause of an earthquake due to a "strike-slip fault"? ANSWER Opposing crustal plates stick together, then suddenly jerk forward. Earth's mantle suddenly "sinks," taking crustal plates with it. Opposing crustal plates slide smoothly past each other at a rapid rate. Crustal plates suddenly collapse. One crustal plate collapses and an opposing plate moves into the space.

Opposing crustal plates stick together, then suddenly jerk forward.

Which of the following taxonomic categories contains all the others? ANSWER Phylum Genus Family Subclass Order

Phylum

Which of the following is an INCORRECT pairing of a period or epoch of the geologic record and the approximate date on which it ended? ANSWER Pleistocene: 34 million years ago Cretaceous: 66 million years ago Jurassic: 145 million years ago Ediacaran: 541 million years ago Cambrian: 485 million years ago

Pleistocene: 34 million years ago

Scientists working in the field "evo-devo" have disovered which of the following facts about spined stickleback fish? ANSWER Sticklebacks from the ocean and from lakes have the same gene for spines, but it is not turned on in adult lake sticklebacks. Sticklebacks from the ocean and from lakes have different genes for spines that are turned on at different times for adult lake and ocean fish. Sticklebacks from the ocean and from lakes have different genes for spines, but they are turned on at the same time for adult fish in both settings. Sticklebacks from the ocean and from lakes have the same gene for spines, but other genes in lake sticklebacks serve to "weaken" the spines. Sticklebacks from the ocean and from lakes have the same gene for spines, but it is turned on in embryonic lake sticklebacks only.

Sticklebacks from the ocean and from lakes have the same gene for spines, but it is not turned on in adult lake sticklebacks.

How is radiometric dating of fossils performed? ANSWER The relative concentrations of the radioactive and stable isotopes of an element are compared. The rate of decay of a radioactive element is noted in the fossil and in surrounding geologic materials. The concentration of the radioactive isotope of carbon or potassium is recorded at specific dates as it decays. The concentration of the radioactive isotope of carbon or potassium is recorded and the rate of decay noted in a laboratory setting. The concentration of a radioactive isotope in a sample is measured against a decay curve.

The relative concentrations of the radioactive and stable isotopes of an element are compared.

In the geologic record, what events or developments separate geologic eras? SHOW HINT The estimated time of life on Earth was divided by four. Each unit represents one era. Each time a new phylum emerged, it marked the beginning of a new era. The transition point for each era is marked by a mass extinction or significant species radiation. The transition point for each era is marked by a catastrophic geologic event.

The transition point for each era is marked by a mass extinction or significant species radiation.

What is the relationship between the two animal species Miratus pardus and Panthera pardus? ("Pardus" means "leopard.") ANSWER There is no relationship except that they are both animals. They belong to the same genus. They share a recent common ancestor. They belong to the same genus and the same species. They belong to the same order.

There is no relationship except that they are both animals.

What do earthquakes, volcanoes, and the formation of mountain ranges have in common? SHOW HINT They are the result of continental drift and are common near the boundaries of the crustal plates. They are the result of continental drift and are common near the centers of the crustal plates. They only occur on islands. They are disasters that permanently eliminate life and its diversity.

They are the result of continental drift and are common near the boundaries of the crustal plates.

Which of the following statements is correct regarding the evolution of the modern horse (Equus)? ANSWER This an example of branched evolution, with the line that led to Equus just one of many branches. This an example of branched evolution, but the line that led to Equus was the main branch. Equus evolved from a larger, single-toed grazing ancestor. Hyracotherium became extinct after the Cretaceous extinction, and a horselike ancestor resulted in Equus. The adaptations of Equus that distinguish it from Hyracotherium are better described as exaptations.

This an example of branched evolution, with the line that led to Equus just one of many branches.

The cause of the Cretaceous mass extinction that is regarded by scientists as most likely was due to _______. ANSWER a large asteroid crashing to Earth that sent up a huge cloud of hot vapor and debris a large asteroid crashing to Earth that sent up a huge cloud of radioactive iridium a large asteroid crashing to Earth that crushed most keystone species intense volcanic activity that emitted hot vapor and debris intense eartquake activity that destroyed the habitats of most keystone species

a large asteroid crashing to Earth that sent up a huge cloud of hot vapor and debris

What is an exaptation? SHOW HINT gradual refinement of a feature for a particular function a single mutation that produces a new, fully functional structure in a single step evolution of new traits through modification of developmental genes a structure that initially served a different purpose, becoming adapted for a new function

a structure that initially served a different purpose, becoming adapted for a new function

Which of the following is thought to have been the first step in the origin of life? ANSWER abiotic synthesis of organic molecules origin of self-replicating molecules formation of protocells replication of primitive "genes" formation of polymers

abiotic synthesis of organic molecules

The Permian extinction, which occurred about 251 million years ago, resulted in the extinction of __________. Between which two eras did the Permian extinction occur? SHOW HINT about 10% of all marine animals and 30% of terrestrial animals; Paleozoic and Mesozoic about 50% of marine and terrestrial species; Paleozoic and Mesozoic about 96% of marine animals and 70% of terrestrial species; Paleozoic and Mesozoic most marine and terrestrial species; Mesozoic and Cenozoic

about 96% of marine animals and 70% of terrestrial species; Paleozoic and Mesozoic

Mammalian species expanded and diversified due to ______, during a period that followed ______. ANSWER adaptive radiation: the fifth mass extinction natural selection: the Permian extinction exaptations: the Cretaceous extinction their ability to outcompete dinosaurs: the fifth mass extinction the pollination of land plants: the Permian extinction

adaptive radiation: the fifth mass extinction

The body shapes of porpoises and sharks are similar in appearance, but these animals do not share a recent common ancestor. Therefore, the similar streamlined shapes of these two animals are likely to be an example of __________. SHOW HINT exaptation homology neutral variation analogy (similarity due to convergent evolution)

analogy (similarity due to convergent evolution)

Fetal human and chimpanzee skulls resemble each other more closely than adult skulls from these two species. This is an example of which of the following? SHOW HINT differences between the two species in timing of the rate of growth of the jaw Homeotic genes work differently in the two species. This is an example of paedometamorphosis. Differences between the two species in gene regulation.

differences between the two species in timing of the rate of growth of the jaw

Which pair of organisms, if found together in the same well-defined fossil layer, would cause a major rethinking of our current understanding of the fossil record? SHOW HINT marine algae and bony fish dinosaurs and primates dinosaurs and gymnosperms prokaryotes and bony fish

dinosaurs and primates

How are periods of time designated in the geologic record? SHOW HINT eras, periods, eons, epochs eons, eras, periods eons, eras, periods, epochs eons, periods, epochs

eons, eras, periods, epochs

All of the following were probably functions of feathers in dinosaurs, with one exception. Which choice is the exception? ANSWER flight insulation mating displays thermoregulation camouflage

flight

Stromatolites are _____. ANSWER fossilized rocks made of layers of sediment built up by photosynthetic prokaryotes about 3.5 billion years ago fossilized rocks made of layers of sediment built up by photosynthetic prokaryotes about 1.5 billion years ago photosynthetic prokaryotic organisms that bound layers of sediment together to form fossilized rocks about 1.5 billion years ago the first eukaryotic organisms that bound layers of sediment together to form fossilized rocks about 3.5 billion years ago fossilized rocks made of layers of sediment built up by photosynthetic eukaryotes about 3.5 billion years ago

fossilized rocks made of layers of sediment built up by photosynthetic prokaryotes about 3.5 billion years ago

According to the latest theories of evolutionary history, which of the following paired groups of organisms are the most closely related? SHOW HINT plants and bacteria bacteria and fungi fungi and animals protists and archaea

fungi and animals

In the Linnaean classification system, members of the same __________ are closely related. Members that share the same __________ name share some characteristic that biologists consider relevant to identifying them. SHOW HINT taxon; species genus; species species; taxon species; genus

genus; species

Divergence of snakes and tetrapods from their common ancestor was largely due to the influence of ______. ANSWER homeotic genes the fifth mass extinction habitat loss exaptations macroevolution

homeotic genes

The transfer of genes between early mitochondria and early eukaryotes is an example of __________. SHOW HINT a molecular clock vertical gene transfer adaptive radiation horizontal gene transfer

horizontal gene transfer

"Molecular clock" data allowed researchers to estimate when _______? ANSWER humans began wearing clothes humans began to bathe polar bears and the line leading to black bears diverged Eukarya diverged from Bacteria and Archaea Monera diverged into Protista and Bacteria

humans began wearing clothes

You are studying a group of related rodent species that are native to central portions of South America and Africa. Both the rodents and their fossils are entirely absent from other continents. These rodents slowly disperse over land but do not cross areas of salt water. With reference to Figure 17.7C, when did this group probably originate? SHOW HINT in the early Cenozoic era, about 64 million years ago in the Mesozoic, about 135 million years ago in the late Mesozoic, about 70 million years ago in the late Paleozoic, about 251 million years ago

in the Mesozoic, about 135 million years ago

Stromatolite fossils that formed 3.5 billion years ago indicate that __________. SHOW HINT life originated 3.5 billion years ago the first life-forms were photosynthetic life must have arisen earlier, perhaps 3.9 billion years ago the first organisms were eukaryotes

life must have arisen earlier, perhaps 3.9 billion years ago

All animals with eyes have _____. ANSWER light-sensitive cells lenses a cornea an optic nerve color vision

light-sensitive cells

Continental drift probably resulted in which of the following? SHOW HINT localization of marsupial species to Australia and the Americas localization of marsupial species mainly to the Americas localization of marsupial species to Australia only natural selection that favored marsupials over placental mammals in Australia

localization of marsupial species to Australia and the Americas

Large-scale changes in the history of life—such the development of legs, the impact of mass extinctions, and the appearance of "novel traits"—are termed _______. ANSWER macroevolution adaptation exaptation microevolution paedomorphosis

macroevolution

When a volcano erupts, material from Earth's _____ is thrown into the air. What is the most likely way that volcanoes contributed to the Permian mass extinction? ANSWER mantle: caused a global temperature increase of about 6 degrees Centigrade crust: caused a global temperature increase of about 6 degrees Centigrade mantle: caused toxic gases to spread throughout the atmosphere core: caused acid precipitation that killed both aquatic and terrestrial life mantle: produced ash and debris that blocked the sun

mantle: caused a global temperature increase of about 6 degrees Centigrade

Continental drift is caused by movements in Earth's _____. It is a process that ______. ANSWER mantle: is ongoing and causes Earth's plates to move toward and away from one another crust: is ongoing and causes Earth's plates to move toward and away from one another mantle: slowed during the Cenozoic era and stopped shortly before the present epoch crust: is causing the Himalaya Mountains to slowly decline in height mantle: is causing the Himalaya Mountains to slowly decline in height

mantle: is ongoing and causes Earth's plates to move toward and away from one another

Molecular clocks are __________. SHOW HINT used to confirm or correct the divergence dates documented in the fossil record one of several ways to estimate divergence times between taxa, by comparing their gene sequences and assuming a constant rate of evolution over time isotopes that decay to produce other isotopes at a constant rate in buried samples, allowing precise estimates of the ages of fossils superior to other methods of reconstructing the past because they are based on high-tech, molecular data

one of several ways to estimate divergence times between taxa, by comparing their gene sequences and assuming a constant rate of evolution over time

Miller and Urey's groundbreaking experiments showed that __________. ANSWER organic molecules could have been generated from inorganic precursors organic molecules could be generated even in a highly oxidizing atmosphere organic molecules could interact to produce inorganic moleucules organic molecules may have been present in extreme environments on Earth organic molecules "arrived" on Earth as part of a meteorite

organic molecules could have been generated from inorganic precursors

The appearance of which of the following took place between 2.7 and 1.2 billion years ago? ANSWER photosynthetic prokaryotes: oxygen in atmosphere: multicellular organisms photosynthetic prokaryotes: oxygen in atmosphere: large organisms on land oxygen in atmosphere: multicellular organisms: animals oxygen in atmosphere: multicellular organisms: our own species prokaryotes: oxygen in atmosphere: multicellular organisms

photosynthetic prokaryotes: oxygen in atmosphere: multicellular organisms

You have found a fossil of a soft-bodied animal. You suspect it is from the late Proterozoic eon. Which isotope would be the best choice to approximate the actual age of the fossil? SHOW HINT potassium-40 carbon-14 carbon-12 a combination of radioactive tracers

potassium-40

Bloom's level: Applying/Analyzing 15.16 Look at Figure 15.16A,and number the nodes "1," "2," "3," and "4," going from left to right. Which of the following organisms make up the monophyletic clade derived from the ancestor at node 3? SHOW HINT duck-billed platypus, red kangaroo, and the North American beaver iguana, duck-billed platypus, red kangaroo, and North American beaver red kangaroo red kangaroo and North American beaver

red kangaroo and North American beaver

Molecular data based on __________ was used to do which of the following? SHOW HINT ribosomal RNA; establish the ancestry of the bear family mitochondrial DNA; establish the three-domain system of classifying living things ribosomal RNA; examine mitochondrial DNA for similar ancestral patterns ribosomal RNA; establish the three-domain system of classifying living things

ribosomal RNA; establish the three-domain system of classifying living things

In the "RNA world" that scientists believe existed before the first cells formed, ______ may have catalyzed the replication of _____ nucleotides. ANSWER ribozymes: RNA ribosomes: RNA ribozymes: DNA vesicles: RNA enzymes: RNA

ribozymes: RNA

The first "genes" were probably __________. SHOW HINT short strands of RNA that could form complementary chains and replicate themselves short strands of DNA in prokaryotes present in protocells short strands of DNA that could form complementary chains

short strands of RNA that could form complementary chains and replicate themselves

Protocells are __________. SHOW HINT organelles within the earliest cells the first life-forms self-replicating strands of RNA small vesicles formed abiotically that can grow and divide

small vesicles formed abiotically that can grow and divide

Species A, B, and C are in the same phylum. Species A and species B are in the same order. Species C is in a different order. From this information, you can conclude with certainty that __________. SHOW HINT species A and B are in the same class species A and B are in the same family species B and C share a more recent ancestor than do species A and B all three species are members of the same genus

species A and B are in the same class

The pioneering experiments of Miller and Urey were designed to demonstrate __________. SHOW HINT that organic molecules can be made from inorganic building blocks in the absence of living organisms how the first functional cells originated that functional proteins could be built from inorganic molecules the molecular composition of the atmosphere on the early Earth

that organic molecules can be made from inorganic building blocks in the absence of living organisms

Continental drift is a likely explanation for all of the following EXCEPT _______. ANSWER the formation of Pangaea near the end of the Paleozoic era the distribution of marsupials worldwide the presence of 50 species of lemur on Madagascar observable changes in the height of mountain ranges fossils from the same species that are separated by great distances

the formation of Pangaea near the end of the Paleozoic era

What evidence do systematists use to hypothesize that dinosaurs, now extinct, had four-chambered hearts and built nests? SHOW HINT extrapolation from the behavior of birds, the closest living relative of dinosaurs the principle of parsimony the presence of those traits in birds and crocodiles, which share a common ancestor with dinosaurs evidence from fossils and molecular data

the presence of those traits in birds and crocodiles, which share a common ancestor with dinosaurs