Exam 25: The History of Life on Earth

What is true of the Cambrian explosion?

The Permian period ended and then rapid speciation occurred as new animal and plant forms evolved. The most likely explanation for this is ________. I adaptive radiation II ecological opportunity III lack of competition IV morphological innovation

Which of the following showed their greatest diversity during the Mesozoic era but were a small, less diverse group during the Paleozoic era?

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in, and there is an immediate glitch-the date readout fails so that when you land, you are not sure what era you are in. Your professor begins to panic, but you see something that tells you are in the Cenozoic era. Which of the following could it be?

Use the following information to answer the question. A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life. To assign absolute dates to fossils in this sediment core, it would be most helpful if ________.

Use the following information to answer the question. A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life. If arrows indicate locations in the column where fossils of a particular type (see key)first appear, then which core in the figure above has the most accurate arrangement of fossils?

Refer to the following information to answer the question. Fossils of Lystrosaurus, a dicynodont therapsid, are most common in parts of modern-day South America, South Africa, Madagascar, India, South Australia, and Antarctica. The animal apparently lived in arid regions and was mostly herbivorous. It originated during the mid-Permian period, survived the Permian extinction, and dwindled by the late Triassic, though there is evidence of a relict population in Australia during the Cretaceous period. Some dicynodonts had two large tusks, extending down from their upper jaws. The tusks were not used for food gathering, and in some species were limited to males. Food was gathered using an otherwise toothless beak. Judging from the fossil record in sedimentary rocks, these pig-sized organisms were the most common mammal-like reptiles of the Permian. What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1)origin of mitochondria 2)origin of multicellular eukaryotes 3)origin of chloroplasts 4)origin of cyanobacteria 5)origin of fungal-plant symbioses

According to the theory of seafloor spreading, oceanic islands, such as the Hawaiian Islands, form as oceanic crustal plates move over a stationary "hot spot" in the mantle. Currently, the big island of Hawaii is thought to be over a hot spot, which is why it is the only one of the seven large islands that has active volcanoes. What should be true of the island of Hawaii? I Scientists in search of ongoing speciation events are more likely to find them here than on the other six large islands. II Its species should be more closely related to those of nearer islands than to those of farther islands. III It should have a rich fossil record of terrestrial organisms. IV)It should have species that are not found anywhere else on Earth. V On average, it should have fewer species per-unit surface area than the other six islands.

One hypothesis that has been proposed regarding the origin of life suggests that life evolved from an "RNA world" to today's "DNA world." Considering the properties of RNA and DNA molecules, which questions would direct an investigation of the most insightful test of this hypothesis?

Which of the following is the correct sequence of events in the origin of life? I Formation of protocells II Synthesis of organic monomers III Synthesis of organic polymers IV Formation of DNA-based genetic systems

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene ________.

Which of the following characteristics are expected in the first animals to have colonized land? I They were probably herbivores (ate photosynthesizers). II Animals had four appendages. III Animals had the ability to resist dehydration. IV Animals had lobe-finned fishes as ancestors. V Invertebrates

In 2013, researchers constructed a vesicle with replicated RNA. Why was this significant evidence for abiotic origin of life?

Which of the following would be least likely to appear in the fossil record?

What is the most accurate method used to measure the age of a fossil?

Which of the following steps has not yet been accomplished by scientists studying the origin of life?

Which of the following organisms would be most likely to form a fossil?

Insect wings may have begun to evolve as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air. Additional selection refined them as flight-producing wings. If this hypothesis is correct, modern insect wings would be an example of ________.

Fossilized stromatolites