Chapter 25

The duplication of homeotic (Hox) genes has been significant in the evolution of animals because it

permitted the evolution of novel forms

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

Fossilized stromatolites

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

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

temporal fenestra

Evolution works by *Evolution, and in particular natural selection, can only select for the best available traits. Modifications to those traits are usually made in small, incremental steps, and new inventions are rare.

"tinkering" with existing structures

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

The percentage of marine predators increased.

exaptation

An adaptation that developed for one purpose but is used for another. ex: feathers on a bird (Feathers were probably adaptations for keeping the animal warm that were later used for flight, making feathers an exaptation for flying.)

How do multiple lines of evidence (from the field, the fossil record, and molecular genetics) work together to illustrate stickleback evolution? *Evolution repeats itself. The film uses three complimentary lines of evidence from field studies, molecular genetics, and fossil populations to show evolution of the same trait over and over again, across hundreds of thousands of years.

Genetic evidence reveals the precise molecular mechanism responsible for the change in pelvic structures in stickleback populations. Data obtained by analyzing living fish in lakes show the selective pressures present in different environments. If the same morphological changes occur in the fossil record as in living populations, we might deduce that the genetic mechanism discovered in the living populations might be responsible for the changes observed in fossils. The fossil data show a pattern of evolution over long stretches of time.

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 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.

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

If one organ is an exaptation of another organ, then these two organs

are homologous

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception. a) an adaptive radiation in a group of organisms (plants) that another group uses as food b) genetic drift c) colonization of an isolated region that contains suitable habitat and few competitor species d) evolutionary innovation e) vacant ecological niches

b) genetic drift

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

carbon-14, unlike carbon-12, 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

If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the bird wings could be accurately described as a) anticipatory structures b) degenerate structures c) analogous organs d) exaptations e) vestigial structures

d) exaptations

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

differential speciation success; differential reproductive success

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

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

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

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

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

paedomorphosis

Hox genes are thought to play an important role in the development of different morphologies because *Changes in Hox genes can have large effects on body plans in different organisms.

they provide positional information in the embryo