Chapter 25 Study Module

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

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

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

1.5 billion years

Currently scientists think the early atmosphere probably consisted of __________.

N2, H2O, CO2, NH3, CH4, H2, and H2S

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

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 __________.

exaptation

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

Plants colonized land in the company of __________; their symbiotic relationships still exist today.

fungi

Ancient cyanobacteria were very important in the history of life because they __________.

produced atmospheric oxygen.

The products of Hox genes __________.

provide positional information in animal embryos

Fossilized stromatolites __________.

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

How does continental drift affect speciation?

All listed responses

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.

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

It leads to predictions that can be tested.

What does the snowball Earth hypothesis propose?

Larger multicellular eukaryotes are scarce in the fossil record until the late Proterozoic because an ice age limited life to deep-sea vents and hot springs.

Abiotically produced vesicles display which of the following rudimentary qualities necessary for life?

The ability to perform simple reproduction and metabolism

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

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.

Lake Malawi, in the African Rift Valley, is home to more than a hundred species of cichlid fishes, each with slightly different diets and habits. All these species probably evolved from a common ancestor, making them an example of __________.

adaptive radiation