Biology 109 Chapter 15: History of Life

The earliest discovered fossils are of ________ dating back to ________ years ago.

The findings of Pasteur and others have established that

What was the probable role of oxygen gas in the early stages of life's appearance on Earth?

Miller-Urey-type experiments have shown that

Which of the following environments is thought to have promoted the dehydration synthesis of polypeptides and other macromolecules from smaller organic monomers on a prebiotic Earth?

________ are membranes containing concentrated organic molecules and have some lifelike properties, but are not alive.

Plants and fungi first became established on land during the

If all of Earth's history were compressed into an hour, humans would first appear less than

The 14C:12C ratio can be used to date fossils that are up to approximately how old?

You find the frozen remains of a woolly mammoth in an Alaskan glacier. You analyze a bit of the tusk and find that its 14C:12C ratio is about one-fourth (25%) of the baseline level typically found in living organisms. Given that the half-life of 14C is 5,730 years, when did the mammoth die?

Potassium-40 can be used to date ________ that are ________ old.

The Mesozoic era is often called the age of reptiles. Which of the following also occurred during this era?

The earliest known land plants date to the

Which of the following options correctly lists the varieties of life in the order that they appear in the geologic record, from earliest to most recent?

The earliest known flowering plants date to the

Geologists have evidence that over the past 1.5 billion years,

It is estimated that the modern continents began to take shape

When the continent of Pangaea first split apart, it formed

Geological evidence indicates that two land masses became separated by a deep ocean channel 45 million years ago and have been moving apart ever since. You are studying a group of organisms that is widespread as a native part of the biota on both of the land masses. What can you conclude about the group's evolutionary history?

During the ________, over 96% of marine species and many terrestrial species became extinct, possibly because intense volcanic activity warmed Earth's climate.

How can the success of one group of organisms promote the adaptive radiation of a second group?

In the axolotl, development is altered. Adult axolotls retain features (external gills and aquatic life) that were juvenile in its ancestors, a phenomenon known as

Studies of skull structure suggest that the main genetic differences between humans and chimpanzees are

The example of the stickleback indicates that morphology can be altered

Anti-evolutionary thinkers sometimes argue that natural selection could not produce a complex structure like the vertebrate eye. They claim that all of the parts of the eye must have arisen at once, asking why natural selection would favor the development of part of an eye that is not yet capable of forming a focused image. Which of the following statements is consistent with a survey of eye structure in the molluscs?

The concept of ________ suggests that feathers originally evolved ________.

The model of species selection is analogous to natural selection. In this analogy, ________ are like individuals within a population, and ________ is analogous to reproduction.

Cave-dwelling catfish and cave-dwelling salamanders share striking similarities: both organisms lack pigmentation and their eyes are reduced or absent. The most recent common ancestor to these organisms had normal pigmentation and fully developed eyes. The similarities between cave catfish and cave salamanders are an example of

The similarities in function of hummingbird wings and the wings of a butterfly reflect

You notice that a structure is similar between two organisms. The outward appearance of the structure is not very similar, but the feature is quite complex and there are many striking similarities in the fine details of how it is put together. Which of the following is most probable?

The situation in which a structure that evolved in one context is later adapted for another function is called

In mammals, the presence of four limbs is ________ and hair is ________.

A systematist includes a lizard in a phylogenetic analysis of relationships among bird families. In this analysis, the lizard would be treated as

The existence of nest-building in crocodiles and birds led to a prediction that this behavior was also present in ________.

________ makes it possible to trace phylogenies among microbial groups for which there is no fossil record.

A(n) ________ has been used to estimate that HIV-1 M first spread to humans in the 1930s.

You compare homologous nucleotide sequences between several pairs of species with known divergence times. A pair of species that diverged 1 million years ago has two nucleotide differences, a pair that diverged 2 million years ago has four nucleotide differences, and a pair that diverged 3 million years ago has six nucleotide differences. You have sequence data for another pair of species where the divergence time is unknown. There are five nucleotide differences between them. Based on your clock, when did their line of ancestry diverge?

The branching "tree of life" analogy