Exam 25: The History of Life on Earth

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 the following is a limit of evolution that results in exaptations?

Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the

One explanation for the evolution of insect wings suggests that wings began 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,and selection later refined them as flight-producing wings.If this hypothesis is correct,modern insect wings could best be described as

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 existence of the phenomenon of exaptation is most closely associated with which of the following observations that natural selection cannot fashion perfect organisms?

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

What is true of the fossil record of mammalian origins?

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. -How many other bands of sea-floor crust in the figure have the same magnetic polarity as the crust that directly straddles the rift valley?

Which measurement(s)would help determine absolute dates by radiometric means?

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. -If a particular marine organism is fossilized in the sediments immediately overlying the igneous rock at the arrow labeled "II," at which other location,labeled A-E,would a search be most likely to find more fossils of this organism?

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

All the following statements are misconceptions,with the exception of

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. -Anatomically,what was true of Lystrosaurus?

Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth.Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it?

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

The existence of evolutionary trends,such as increasing body sizes among horse species,is evidence that

The snowball Earth hypothesis provides a possible explanation for the

If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found in 3.2-billion-year-old stromatolites,then one should be surprised to observe evidence of which of the following within such microfossils? I.double-stranded DNA II.a nuclear envelope III.a nucleoid IV.a nucleolus V.ribosomes

The first terrestrial organisms probably were considered which of the following? 1)burrowers 2)photosynthetic 3)multicellular 4)prokaryotes 5)eukaryotes 6)plants and their associated fungi

Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?