Chapter 14

The typical tempo of extinctions within a particular taxon is called...

Background Extinction

Why is Wallace's line significant in biogeography?

Because Wallace's line divides two very distinctive faunas that are geographically very close together.

Punctuated equilibra is a hypothesis about the evolution of species. According to this hypothesis, why should macroevolutionary biologists expect abrupt breaks in the fossil records?

Because significant changes in phenotypes may occur within small isolated populations on the fringes of a species' range, leading to rapid speciation and little fossil evidence.

Why don't scientists agree on a single definition of species? -Because research method can dictate which definition is most useful -Because they have not discovered the true definition of a species -Because different scientists have different philosophies about defining species -All of the above -A and B only -A and C only

-A and C only -Because research method can dictate which definition is most useful -Because different scientists have different philosophies about defining species

Which of the following is NOT a hypothesis about the conditions that can lead to adaptive radiations? -Adaptive radiations occur as a result of the absences of competition for ecological resources -Adaptive radiations occur as a result of island formation Adaptive radiations occur as a result of key innovations -None of these is a hypothesis about the conditions that can lead to adaptive radiations -All are hypotheses about the conditions that can lead to adaptive radiation.

-All are hypotheses about the conditions that can lead to adaptive radiation.

Why do scientists argue that climate change may be leading to a mass extinction (Figure 14.27)? -Because according to models incorporating a variety of scenario,projected temperatures could rise 2-3 times temperatures observed in 2000 -Because four of the five big mass extinctions were related to climate changes -Because the average temperate has increased by 0.8 in the last 80 years -Because although carbon dioxide concentrations clearly cycle, in the last 100 years they have become 100 parts per million greater than the highest concentrations recorded for the last 600,000 years -All of the above

-All of the above

What is speciation? -The process by which new species arise -Cladogenesis -When one lineage splits into two or more lineages. -All of the above -A and C only

-All of the above -The process by which new species arise -Cladogenesis -When one lineage splits into two or more lineages.

Which of these statements about vicariance is TRUE? -Plate tectonics are a primary mechanism of vicariance -Vicariance led to Australian and South American lineages of marsupials -Vicariance prevents dispersal -Both A and B are true. -All of the above are true.

-Both A and B are true. -Plate tectonics are a primary mechanism of vicariance -Vicariance led to Australian and South American lineages of marsupials

Which of the following statements about biogeography is FALSE? -Biogeography is the study of the distribution of species across space and time -Alfred Russel Wallace was responsible for many early ideas about biogeography -Darwin did not believe in vacariance -The discovery of plate tectonics provided a new line of evidence for pattern in biogeography.

-Darwin did not believe in vacariance

Studying the Earth's biodiversity over time is not a straightforward scientific process. Which of the following is NOT a problem for macroevolutionary studies? -Fossil bearing rocks differ in area and volume exposed masking complex geographical patterns of biodiversity -Patterns observed in the fossil record cannot be tested using statistical methods -Groups in the fossil record used to study species diversity over time may not be monophyletic. -Scientists often must use taxonomic units other than species, and these higher order taxa are not necessarily comparable. -All of the above are problems for macro evolutionary studies.

-Patterns observed in the fossil record cannot be tested using statistical methods

Which of the following statements about the Cambrian Explosion is FALSE? -Changing oxygen levels in the Earth's ocean may have created ecological opportunities that organisms were able to exploit. -The emergence of the genetic toolkit may have allowed the evolution of new developmental pathways leading to a diversity of body forms. -The Cambrian Explosion was not really an explosion because the complex body plans of animal taxa evolved from precursors-they did not simply appear -The sudden appearance of sponges marks the beginning of the Cambrian Explosion -Molecular Clocks indicate that the common ancestor of all animals lived about 800 million years ago.

-The sudden appearance of sponges marks the beginning of the Cambrian Explosion

What is the turnover rate in stage B in Figure 14.7?

16 (6 Extinctions plus 10 originations)

Punctuted Equilibra

A model of evolution that proposes that most species undergo relatively little change for most of their geologic history. These periods of stasis are punctuated by brief periods of rapid morphological change, often associated with speciation events.

Mass Extinction

A statistically significant departure from background extinction rates that results in a substantial loss of taxonomic diversity

How are extinctions related to biodiversity?

The Earth's biodiversity is a result of the relationship between alpha and omega

Why isn't the fossil record a complete record of life on Earth? -Because organism eat other organisms -Because conditions have to be just right in order to preserve fossils -Because wind and rain can erode fossils from the substrate -Because rock-bearing fossils can be difficult to access -All of the above -A and B only -C and D only

All of the above

How are mass extinctions defined?

As statistical departure from background extinction rates

Macroevolution

Evolution occurring above the species level, including the origination, diversification, and extinction of species over long period of evolutionary time

Microevolution

Evolution occurring within populations, including adaptive and neutral changes in allele frequencies from one generation to the next.

Adaptive Radiations

Evolutionary lineages that have undergone exceptionally raid diversification into a variety of lifestyles or ecological niches.

Can the Big Five extinctions all be attributed to a single cause? If so, what caused them?

No. The Big Five extinctions were caused by various abiotic and biotic factors that affected different taxa differently.

Turnover

The disappearance of some species and their replacement by others in studies of macroevolution. This rate is the number of species eliminated and replaced per unit of time.

Vicariance

The formation of geographic barriers to dispersal and gene flow, resulting in the separation of once continuously distributed populations.

Dispersal

The movement of populations from one geographic region to another with very limited return exchange, or none at all

Background Extinction

The normal rate of extinction for a taxon or biota

Standing diversity

The number of species present in a particular area at a given time

Biogeography

The study of the distribution of species across space (geographic) and time

What is turnover rate?

The total number of originations and extinctions in a given interval of time.

Anagenesis

Wholesale transformation of a lineage from one form to another. In macroevolutionary studies. this process is considered to be an alternative to lineage spitting or speciation.

What key innovation led to an adaptive radiation of insects?

Wings