Bio 211 Chapter 25

Single-celled prokaryotes had the Earth to themselves for approximately __________.

1.5 billion years

What is macroevolution?

Major evolutionary change and it applies mainly to the evolution of whole taxonomic groups over long periods of time.

What were the two major "problems" that had to be solved before plants, animals, and fungi could move into terrestrial habitats?

Reproduction and prevention of dehydration

Which of the following is a true statement concerning the history of Earth's biological diversity?

The majority of species that have ever lived are now extinct

Fossilized stromatolites __________.

Resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of __________.

A change in a developmental gene or in its regulation that altered the spatial organization of body parts

What are adaptive radiations?

Adaptive radiations are periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles, or niches, in their communities.

What was one ecological change that occurred following the Permian mass extinction?

After both the Permian and the Cretaceous mass extinctions the percentage of marine predators increased

Which of the following would not have been a consequence of tectonic plate movements bringing previously separated landmasses together in the formation of the supercontinent of Pangaea about 250 million years ago?

Allopatric speciation increased.

Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting approximately 65 million years ago. Why?

Between 180 and 65 million years ago, mammals were outcompeted by the well-established dinosaurs.

The fossil record is __________.

Biased in favor of species that existed for a long time

The ratio of carbon-14 to carbon-12 in a fossil can be used to determine the age of the fossil because __________.

Carbon-14 (nitrogen 14 as well), unlike carbon-12 (common carbon isotope), decays at a continuous rate after the death of an organism

The original atmosphere of Earth had little oxygen. What was the likely first source of oxygen that led to an oxygen atmosphere?

Cyanobacteria

In the species selection model, __________ is to macroevolution as __________ is to microevolution

Differential speciation success; differential reproductive success

What does endosymbiont refer to?

Endosymbiont refers to a cell that lives within another cell, called the host cell.

Which of the following is the correct ordering of divisions of the geologic record from largest to smallest?

Eon, era, period, epoch

What is microevolution?

Evolutionary change within a species or small group of organisms, especially over a short period.

If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the bird wings could be accurately described as __________.

Exaptation

What is exaptation?

Exaptations are structures that had one function originally, and later evolved other, or different, functions.

How many extinctions are documented in the fossil record over the past 500 million years, from the Paleozoic to the Cenozoic era?

Five

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

Genetic drift

Macroevolution differs from microevolution in that macroevolution __________.

Includes broad evolutionary changes above the species level

Why is the four-stage hypothesis for the abiotic origin of life useful?

It leads to predictions that can be tested

When does allopatric speciation mean?

It occurs when biological populations of the same species become isolated from each other to an extent that interferes with genetic interchange.

The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely place for the abiotic synthesis of organic molecules to have occurred?

Near volcanoes (organic compounds near sea vents)

Retention of juvenile body features into sexual maturity is referred to as the presence of __________.

Paedomorphosis

The correct order of the geologic eras, from most ancient to most recent, is __________.

Paleozoic, Mesozoic, and Cenozoic

Why is RNA, rather than DNA, thought to have been the first genetic material?

RNA can also function as a catalyst

What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the extinction of the dinosaurs?

Sedimentary rocks contain a layer of iridium, a mineral uncommon on earth

The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that __________.

Simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history

What are analogous structures?

Structures that have the same function but no common ancestry

What is sympatric speciation?

Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

Which of the following is not a unique anatomical feature of mammals that can be recognized in the fossil record?

Temporal fenestra

The amphibians, reptiles, and mammals comprise which group?

Tetrapods

Which of the following is a true statement about the current status of Earth's biodiversity?

The current rate of extinctions is as high as 1,000 times the typical rate seen in the fossil record.

What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts?

They have a single circular chromosome similar to bacterial chromosomes; their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes

Prior to the Cambrian explosion, all large animals had what characteristic in common?

They were all soft bodied

You are watching a movie in which one of the characters excitedly claims to have found human remains in Asia dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction?

This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years.

Which of the following is an internal structure that appears in eukaryotic cells and is also present in more ancient prokaryotic cells?

Vesicles

What are vestigial structures?

Vestigiality refers to genetically determined structures or attributes that have lost some or all of their ancestral function in a given species, but have been retained during the process of evolution.