Chapter 25 Quiz

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

only early Earth was intensely bombarded by large space debris

Which if the following factors weaken(S) the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere

1 and 3 1) the relatively short time between intense meteor bombardment and the appearance of the first life-forms 3) uncertainty about which gases comprised early Earth's atmosphere

The first terrestrial organisms probably were considered which of the following?

2) photosynthetic and 4) prokaryotes

If the half-life of carbon-14 is about 5,730 years then fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old?

22,900

Approximately how far back in time does the fossil record extend?

3.5 billion years

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

Permian extinctions

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?

How did RNA sequences come to carry the code for amino acid sequence?

On the basis of the morphologies, how might Linnaeus have classified the Hawaiian silverswords?

He would have placed them in more species than modern botanist do

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

There feathers originally served as insulation, and only later became flight surfaces

If two continents converge and are united, then the collision should cause

a net loss of intertidal zone and coastal habitat

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

a surrounding membrane or membrane-like structure

The first genes on Earth were probably

auto-catalytic RNA molecules

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

cause iron in ocean water and terrestrial rocks to rust

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

in particular environments, similar adaptions can be beneficial in more than one species

What is true of the fossil record of mammalian origins?

it includes transitional forms with progressively specialized teeth

What is true of the Cambrian explosion?

recent evidence supports the contention that the Cambrian explosion may not have been as "explosive" as was once thought

Which of the following is the correct sequence of events in the origin if life?

synthesis of organic monomers, synthesis of organic polymers, formation of protobionts, formation of DNA-based genetic systems

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

the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts

What is true of the amino acids that might have been delivered to Earth within carbonaceous chondrites

there were more kind of amino acids on the chondrites than are found in living organisms today

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

two of the responses above are correct