Exam 25: The History of Life on Earth

The following questions refer to the paragraph below. 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 above)first appear, then which core in the figure has the most accurate arrangement of fossils?

The following questions refer to the description below. All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago. -Fruit fly eyes are of the compound type, which is structurally very different from the camera-type eyes of mammals. Even the camera-type eyes of molluscs, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions of Pax-6. The fact that the same gene helps produce very different types of eyes is most likely due to

The snowball Earth hypothesis provides a possible explanation for the

Use the following information to answer the questions below. The following questions are based on the observation that several dozen different proteins comprise the prokaryotic flagellum and its attachment to the prokaryotic cell, producing a highly complex structure. -Certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This evidence supports the claim that

If the half-life of carbon-14 is about 5730 years, then a fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old?

The following questions refer to the description below. You were asked to give a presentation about fossils to a group of young students. You tell the students that the fossil record shows how organisms can change over time, but unfortunately the fossil record is incomplete. After your talk a student tells you that his pet salamander has died and he wants his salamander to be fossilized. The boy plans to lay his salamander on the grass and cover the salamander's body with leaves and twigs. You had told the class that a critical step in the fossilization process is the burial of an organism. -Another student asks you why the fossil record is incomplete. Which statement(s)below provide the most likely explanation?

Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that

The following questions refer to the description and figure below. The figure represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labelled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley. -Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted above, what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labelled "II"?

Fossilized stromatolites

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.

Use the following figure to answer the questions below. -Soon after the island of Hawaii rose above the sea surface (somewhat less than 1 million years ago), the evolution of life on this new island should have been most strongly influenced by

Which of these observations gives the most support to the endosymbiotic theory for the origin of eukaryotic cells?

How were conditions on the early Earth of more than 3 billion years ago different from those on today's Earth?

In the 5-7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several species coexisting in time and space. As recently as 30000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following?

The following questions refer to the description below. You were asked to give a presentation about fossils to a group of young students. You tell the students that the fossil record shows how organisms can change over time, but unfortunately the fossil record is incomplete. After your talk a student tells you that his pet salamander has died and he wants his salamander to be fossilized. The boy plans to lay his salamander on the grass and cover the salamander's body with leaves and twigs. You had told the class that a critical step in the fossilization process is the burial of an organism. -Which of the statement(s)below lends support to your claim about the fossilization process?

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

What evidence strongly suggests that RNA instead of DNA was the first genetic material?

The following questions refer to this hypothetical situation. A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (in other words, halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap. -Which of these fly organs, as they exist in current fly populations, best fits the description of an exaptation?

The following questions refer to the paragraph below. 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. -Which of the following reasons may explain why the sediment core lacks fossils of dragonflies with 3-feet wingspans? 1. This particular sediment core includes the correct stratum, but the part of the stratum captured by the core lacks such fossils. 2. The sea was not present at this site during the time that 3-feet dragonflies existed. 3. Dragonflies have no hard parts, such as exoskeletons, to fossilize. 4. The sediments containing these fossils at this site may have been eroded away during a time when the sea had receded from this site. 5. Dragonflies are terrestrial; therefore, fossils of terrestrial organisms should not be expected in the sediments of seas.

Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which graph below, if the results were produced abiotically, would have the greatest promise for revealing important information about the origin of Earth's first genetic system?