Exam 25: The History of Life on Earth

Which of the following is a defining characteristic that all protocells had in common?

Use the following figure to answer the questions below. -Upon being formed,oceanic islands,such as the Hawaiian Islands,should feature what characteristic,leading to which phenomenon?

Fossilized stromatolites

Use the following figure to answer the questions below. -According to the theory of sea-floor spreading,oceanic islands,such as the Hawaiian Islands depicted in the above figure,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 islands that has active volcanoes.What should be true of the island of Hawaii? 1)Scientists in search of ongoing speciation events are more likely to find them here than on the other six islands. 2)Its species should be more closely related to those of nearer islands than to those of farther islands. 3)It should have a rich fossil record of terrestrial organisms. 4)There is a good chance of finding endemic species on this island. 5)On average,it should have fewer species per unit surface area than the other six islands.

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?

Refer to the following information to answer the questions below. Fossils of Lystrosaurus,a dicynodont therapsid,are most common in parts of modern-day South America,South Africa,Madagascar,India,South Australia,and Antarctica.It 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.The 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 period. -A hypothetical island lies far from any other landmasses.There are many different types of plants,but only one animal,a beetle,that can fly or walk from plant to plant and feeds by chewing leaves.Given that the beetle is not exploiting all of the resources on the island,which morphological change would be most likely to trigger an adaptive radiation of the beetles?

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.

An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to

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

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. -In order to properly interpret sediment cores,it is necessary to apply the principle of

Which of the following is the correct sequence of events in the origin of life? I.formation of protobionts II.synthesis of organic monomers III.synthesis of organic polymers IV.formation of DNA-based genetic systems

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 major evolutionary episode corresponding most closely in time with the formation of Pangaea was the

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. -Assuming the existence of fossilized markers for each of the following chemicals,what is the sequence in which they should be found in this sediment core,working from ancient sediments to recent sediments? 1)chitin coupled with protein 2)chlorophyll 3)bone 4)cellulose

How many of the following statements concerning the loss of hind limbs during whale evolution are true? 1)It is well documented by a series of transitional fossils. 2)It explains why modern whales have vestigial pelvic girdles. 3)It involved changes in the sequence or expression of Hox genes. 4)It is an example of macroevolution. 5)It,and the loss of limbs by snakes,are examples of similar adaptations to a similar environment.

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. -The appearance of Pax-6 in all animals with eyes can be explained in multiple ways.Based on the information above,which explanation is most likely?

A swim bladder is a gas-filled sac that helps fish maintain buoyancy.The evolution of the swim bladder from lungs of an ancestral fish is an example of

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

Which of the following events would be least likely to trigger an adaptive radiation?

The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers.On Earth,these primers are small RNA molecules.This latter observation is evidence in support of the hypothesized existence of