Bio 1407 Ch. 14: Speciation and Extinction
Select all the lines of evidence used by biologists to construct phylogenetic trees
-fossils -behaviors -molecular sequences -physiological adaptations
Select all the true statements regarding polyploidy in plants and animals
About 95% of ferns are natural polyploids. About 50% of flowering plants are polyploid. Polyploidy is rare in animals.
What organisms can be considered a clade
Archaeopteryx, modern birds, and the ancestor at 5
______ extinction results from a gradual loss of a species as populations face new challenges, whereas ______ extinction results from the loss of a great number of species in a relatively short time period
Background; mass
Select the true statement about the cladogram
Birds and nonavian dinosaurs form a clade
Select all of the statements that correctly interpret the cladogram
Birds and nonavian dinosaurs have a common ancestor. Crocodiles are more closely related to nonavian dinosaurs than they are to lizards and snakes.
Linnaeus designed a system of assigning names to organisms. The first word in an organism's scientific name designates the broader classification level called the ________ of the organism, and the second word designates the ________
Blank 1: genus or genera Blank 2: species
The current taxonomic hierarchy is based on the ideas of ______, whose hierarchical classification scheme made a lasting contribution to systematics
Carolus Linnaeus
______ was the first scientist to give every species a two-word name
Carolus Linnaeus
Select the accurate statement that defines cladistics
Cladistics is a phylogenetic system that defines groups by distinguishing between ancestral and derived characters
Using the chart, what organism is a common ancestor to all the other organisms, meaning that all the other organisms share an ancestral trait with it but also exhibit derived characters not present in the ancestor
Coelophysis
In the cladogram shown, what organism is the outgroup to the clade of species that have a wishbone and a breastbone
Coleophysis
What is a drawback of basing a phylogeny solely on common characteristics between organisms
Common characteristics may be the result of convergent evolution.
Based on your knowledge, what was used to construct the cladogram in the figure
DNA mutations
Select the true statement regarding the use of molecular sequence data to construct cladograms
DNA sequence variations can be used to construct cladograms.
Select all of the following that are true of the two types of little greenbul birds that occupy neighboring habitats in the image
Disruptive selection may be driving microevolution. Parapatric speciation may be occurring.
Select all of the drawbacks of a possible sixth mass extinction caused by human activities
Ecosystems can take millions of years to recover. Species may be lost that provide food, medicine, energy, and clean air. Future generations will not be able to enjoy species that are extinct.
Think about fish and amphibians (frogs, toads, and salamanders). Select all the statements that are correct in reference to ancestral and derived characteristics
Eggs laid in water would be ancestral. Gills in amphibians are homologous to gills in fish. Forelimbs would be derived in the amphibian lineage.
Select the correct sequence of groups for a taxonomic classification of orangutans and humans
Eukarya - Animalia - Chordata - Mammalia - Primates - Hominidae
Select the most accurate statement about gradualism and the fossil record
For organisms such as diatoms that existed in large, connected populations, the fossil record shows a slow pace of gradual changes
Select the true statement about punctuated equilibrium and the fossil record
Fossils of mollusks and mammals indicate that speciation occurred in bursts followed by periods of stability.
Select all the situations that could lead to adaptive radiation
Individuals are isolated on an island where there is little competition for resources. A few individuals colonize a new, isolated habitat with new resources.
Adaptive radiation may occur in what situation? Select all that apply
Individuals exploit a new habitat opportunity. Some members of a population inherit a combination of adaptations that enables them to survive a major environmental change. Some members of a population inherit an advantageous key adaptation.
_______ tends to span very long periods of time, whereas ______ events can be observed over a few years
Macroevolution; microevolutionary
The fact that some organisms could produce fertile offspring in captivity but usually do not interbreed in nature is a limitation of
Mayr's biological species concept
What advantage does Mayr's biological species definition have over Linnaeus's system of defining species
Mayr's definition does not rely solely on appearance of organisms.
______ are evolutionary trees that are used by biologists to represent hypothesized relationships among species or groups
Phylogenies
Select all the correct examples of monophyletic, paraphyletic, and polyphyletic groups. Refer to the cladogram if needed
Plants are a monophyletic group. The Protista of the domain Eukarya is paraphyletic because it excludes animals, plants, and fungi.
What describes the postzygotic isolating mechanism called hybrid breakdown
Second-generation hybrid offspring are unable to reproduce.
Select all of the following that might cause smaller populations to be more vulnerable to extinction
Small populations inbreed more, which can bring together lethal recessive alleles. Small populations experience fewer genetic mutations. Small populations might contain too few beneficial alleles to withstand a challenge.
Select the correct statement from the ones below with respect to how speciation may occur
Speciation may be gradual or occur quickly in bursts.
Select all the reasons why it is difficult for biologists to determine whether a speciation event is allopatric, sympatric, or parapatric
The definitions of allopatric, parapatric, and sympatric speciation represent three points along a continuum. It is hard to detect all the barriers that are important to different species.
Select the statement from the choices below that accurately reflects a relationship between shared features and taxonomic levels
The more features that two organisms have in common, the more taxonomic levels they share.
Why might a plant invest energy to produce and store nectar in extrafloral nectaries
The nectar recruits plant-defending insects.
Select the true statement about the hierarchical system of taxonomy currently in use
The ranks are somewhat arbitrary and do not necessarily reflect evolutionary relationships
Select the common features of cladograms from the choices below
The tips of the branches represent the taxa being studied. All cladograms depict nested hierarchies of evolutionary relationships. Each node indicates where two groups arose from a common ancestor.
Select all of the reasons why the fossil record for species that evolved by punctuated equilibrium shows few transitional forms
Transitional forms were too rare to leave any fossils. Natural processes may have destroyed many of the transitional fossils. Biological material is often poorly preserved.
A taxon is a general term for
a family, order, species, or any rank in classification.
Allopatric speciation occurs when a single population is split and the two populations become isolated from each other by
a geographical barrier
Carolus Linnaeus developed a system of taxonomy in which organisms are classified into
a nested hierarchy of groups.
Over many hundreds of years, the definition of ______ has changed several times as scientists have refined ideas
a species
Select all of the following that describes background extinction
accounts for most extinctions of species steady, gradual loss of species
________ radiation is a situation in which a population inhabiting an environment with new resources gives rise to multiple specialized forms in a relatively short time.
adaptive
Speciations can happen in rapid bursts during a(n) ______, in which a population inhabiting a patchy or heterogeneous environment gives rise to multiple specialized forms in a relatively short time period
adaptive radiation
Caribbean anole lizards have diversified into 150 species that live on different islands and that are adapted to use different resources. These anoles provide evidence of
adaptive radiation.
The relatively rapid evolution of new mammal species in response to niches that became available after the dinosaurs went extinct is an example of
adaptive radiation.
The Devil's Hole pupfish has been geographically isolated from other pupfish for a very long time. This is an example of ______ speciation
allopatric
The punctuated equilibrium model of speciation proposed by Gould and Eldredge fits well with the type of speciation known as ______ speciation because populations could be isolated, then diverge, and then could rejoin with ancestors but be different species
allopatric
The type of speciation that occurs when two populations are separated by a physical barrier so that they cannot interbreed is called ______ speciation
allopatric
What mechanism of speciation is considered the most common because the evidence for it is abundant
allopatric
______ speciation resulted in the diversification of tortoises on different Galápagos islands, eventually leading to 11 different subspecies
allopatric
speciation is a type of speciation in which a barrier physically separates a population into two groups that cannot interbreed
allopatric
Match the type of speciation on the left with its description on the right
allopatric no contact between the populations parapatric populations sharing a border sympatric continuous contact between populations
Rank the three types of speciation, from the form with complete reproductive isolation at the top to the form with continuous intermingling of the species at the bottom
allopatric parapatric sympatric
Match the type of speciation on the left with its correct figure on the right, using the letters on the diagram
allopatric speciation A parapatric speciation B sympatric speciation C
If two populations of rodents become separated by a river such that gene flow between the populations no longer occurs, and then natural selection occurs in each population separately for thousands of years, the populations may become two separate species due to
allopatric speciation.
A polyphyletic group excludes the most recent common ________ shared by all members of the group
ancestor
In cladistics, ________ characters are inherited attributes that resemble those of past relatives of the organism, whereas ________ characters are features that are different from those found in the group's past relatives
ancestral derived
Match the term on the left with its definition on the right
ancestral characters features present in the common ancestors of a clade clade group of organisms consisting of a common ancestor and all its descendants cladogram phylogenic tree built on shared derived characters outgroup comparator organism outside the group being studied
Select all of the following that were used in the past to construct evolutionary trees
as many characteristics as possible similarities in characteristics
Ernst Mayr's definition of a biological species does not fit all organisms. Groups of organisms that reproduce ______ do not fit his definition of species
asexually
According to the fossil record, there were about 0.1 to 1.0 extinctions per year per million species; this type of ______ extinction accounts for most extinctions overall
background
What type of extinction results from the gradual loss of a species due to normal evolutionary processes
background
Ernest Mayr proposed that the definition of biological species should be a population whose members
can interbreed and produce fertile offspring.
In phylogenetic analyses, a group of species united by a single evolutionary pathway is called a(n)
clade.
The ______ approach creates phylogenies based on shared derived characters and ancestral characters
cladistic
Select all the areas covered by the definition of taxonomy
classifying organisms describing organisms naming organisms
In cladistics, the outgroup is the
comparator organisms that do not possess the derived traits being examined.
Select all of the following that are true about Linnaeus' system of classification
consists of hierarchical groups helped scientists communicate with each other included orders, classes, and kingdoms
Cladistics bases evolutionary trees on ______ features, which are different from those found in a group's ancestor, and ______ features, which resemble those found a group's ancestor
derived; ancestral
What is taxonomy?
describing and naming organisms
In parapatric speciation, disruptive selection may favor
different phenotypes in different habitats
What type of selection can begin the process of parapatric speciation by favoring one phenotype in one habitat and a different phenotype in a neighboring area
disruptive
To differentiate species of bacteria or archaea, scientists often examine differences in
dna
Rank the following taxonomic groups into a hierarchy, from the most inclusive group at the top to the most specific group at the bottom
domain, Kingdom, phylum, class, order, family
Select the correct order of the taxonomic groups from the most inclusive to the most specific from the choices below
domain, kingdom, phylum, class, order, family, genus, species
Bacteria, Archaea, and Eukarya are the names of the three ______ of life
domains
The increased rate of extinctions due to human activities may have effects that are difficult to predict because of the many interactions in ______, on which humans and other species rely
ecosystems
As the image shows, mass extinctions have had the greatest influence on Earth's history because
enormous adaptive radiation can occur after mass extinction.
The root cause of extinction is when microevolution in a species doesn't keep up with
environmental change.
Phylogenies are trees of organisms that depict hypotheses about
evolutionary relationships
A species becomes ______ when all members of that species have died
extinct
If speciation is the beginning of a species, then ________ is the end of a species
extinction
True or false: Because there are eight main levels of the hierarchical system of taxonomy, most species required eight steps to evolve
false
True or false: Linnaeus based his classification system on evolutionary relationships among organisms
false
The geologic timescale indicates that there have been ______ mass extinctions in the past 500 million years
five
In a cladistic analysis of terrestrial vertebrates, what feature would be considered ancestral
four limbs
Suppose different species of sea urchins release gametes into the ocean at the same time. The inability of sperm and egg cells of different species to unite and form a zygote due to structural differences is an example of
gametic isolation
A population's entire collection of genes and their alleles is called its ______, which does not mix with the genes of different species
gene pool
Small, incremental changes over numerous generations is the model of speciation described by Darwin and is known as
gradualism.
Match the type of prezygotic reproductive barrier on the left with its example on the right
habitat isolation Herbivorous ladybird beetles feed on different types of plants. temporal isolation Field crickets mature at different times. behavioral isolation Frog mating calls differ.
Match the name of the type of prezygotic reproductive barrier on the left with its description or an example on the right
habitat isolation species live in different environments behavioral isolation courtship rituals are different between species mechanical isolation reproductive structures do not fit together gametic isolation sperm is unable to fertilize the egg temporal isolation species are active at different times of day
What may be causing a current sixth mass extinction on Earth at a rate of about 20 to 200 extinctions per million species per year
humans
Match the postzygotic reproductive barrier on the left with its description on the right
hybrid inviability Embryo may die before reproductive maturity. hybrid infertility Hybrid is not able to produce offspring. hybrid breakdown The offspring of hybrids in future generations have abnormalities.
Match the postzygotic reproductive barrier on the left with its example on the right
hybrid inviability Hybrid eucalyptus seeds do not germinate; seedlings die very early. hybrid infertility The offspring of a lion-tiger mating (liger) is infertile. hybrid breakdown Offspring of hybrid mosquitoes have abnormal genitalia.
Select all the postzygotic reproductive barriers
hybrid inviability hybrid infertility hybrid breakdown
Successful ______ is rare in animals but frequent in plants
hybridization
Plants often can form viable ______ between species, whereas it is very rare for this to occur in animals
hybrids
After Darwin's theory of natural selection became widely accepted, classification systems of organisms began to be viewed as possible
hypotheses of evolutionary relationships
A cladogram depicts
hypothesized evolutionary relationships
Rank the following in chronological order of how scientists think meteorites or comets striking Earth caused mass extinctions, beginning with the first event at the top of the list
impact of meteor of comet onto Earth's surface dust and debris sent into the atmosphere sunlight blocked from plants animals die
The two theories that attempt to explain the causes of mass extinctions on Earth are the ______ theory and the movement of the Earth's crust due to ______
impact; plate tectonics
Select the element that is common in meteorites but rare on Earth, which provides evidence to support the impact theory of mass extinction on Earth
iridium
Organisms have changed over time; new species have appeared while other species have gone extinct. This is a description of
macroevolution.
The accumulation of small changes in a population by microevolution can eventually lead to large-scale
macroevolution.
The speciation and extinction of the dinosaurs are examples of _______, and the increased frequency of a particular genotype that specifies a color pattern in fish is an example of _____
macroevolution; microevolution
The disappearance of a great number of species over a relatively short expanse of time is called ________ extinction
mass
Movement of Earth's tectonic plates and the impact theory are two explanations for Earth's
mass extinctions.
The biological species concept proposed by ______ states that a biological species is a population whose members can interbreed and produce fertile offspring
mayr
If two species of plants live in the same place but have flowers that attract different pollinators such that the two species never interbreed, what reproductive isolating mechanism is operating
mechanical isolation
Select all the examples of prezygotic isolation mechanisms
mechanical isolation gametic isolation
Select mechanisms that can cause polyploidy
meiosis fails, leading to diploid gametes that fuse during self-fertilization gametes from two different species fuse
The element iridium, which appears as a thin layer on many parts of Earth, provides the evidence that ______, which may have led to mass extinctions
meteorites impacted the surface of the Earth
The impact theory suggests that mass extinctions in Earth's history may be due to
meteorites that crashed to Earth.
Natural selection, genetic drift, and mutation are ______ that can lead to divergence of gene pools between groups of organisms
microevolutionary forces
What type of organisms appear to have evolved by gradualism, as evidenced by the fossil record
microscopic protists
A group of organisms can be referred to as being ______ if it consists of a common ancestor and all of its descendants
monophyletic
In cladistics, a clade is a ______ group
monophyletic
Match the terms on the left with the example on the right
monophyletic mammals paraphyletic traditional class Reptilia polyphyletic endothermic animals
Select three ways that genetic divergence can occur between two separated populations
natural selection genetic drift mutation
Select all the reasons that could cause a species to go extinct
new predator new disease habitat loss natural disaster
When a portion of a population can no longer breed and produce fertile offspring with the rest of the population, then a ______ has formed
new species
A population of snails is separated when an eight-lane highway is built. After 50 years, the two separate populations can no longer interbreed. This describes the process of
new species forming.
Match each feature of a cladogram to its correct description
node divergence of two species or groups from a common ancestor tips of long branches existing species clade any ancestor and all of its descendants
Prezygotic barriers to reproduction ______, while postzygotic barriers to reproduction ______
occur before fertilization; reduce fitness of hybrid offspring
Adaptive radiation of organisms on Socotra, the Galápagos, the Malay Archipelago, and Hawaii are all examples of speciation bursts that occurred
on islands.
Adaptive radiations of organisms are especially common
on islands.
Select scenarios that may lead to allopatric speciation
organisms are unable to reach part of an ecosystem where other members of the species live rivers or glaciers divide a habitat rising sea levels trap a population on an island
In cladistics, the ______ consists of comparison organisms that possess ancestral features but do not possess derived features present in the group being examined
outgroup
Bill depth and wing length differences between populations of the little greenbul that live in the tropical rain forest and populations that live in the neighboring transitional ecotones indicate that ______ speciation might be occurring
parapatric
If a new species begins to form when a portion of a population enters a new habitat bordering the rest of the population, this represents a case of ________ speciation
parapatric
The type of speciation that occurs when part of a population enters a new habitat bordering the range of the parent species is ______ speciation
parapatric
What is occurring when natural selection or genetic drift acts on two populations occupying bordering areas such that, over time, the populations can no longer interbeed
parapatric speciation
Match each type of speciation with its correct description
parapatric speciation occurs between populations that inhabit neighboring habitat and have minimal gene flow allopatric speciation occurs between populations that are physically separated and do not exchange genes sympatric speciation occurs between populations that live in the area but specialize in different environments
A(n) ______ group of organisms contains a common ancestor and some, but not all, of its descendants
paraphyletic
If a group of species contains a common ancestor and some but not all of its descendants, it is referred to as being
paraphyletic.
In cladistic analyses, the most ______ cladogram is often regarded as the best one because it requires the fewest evolutionary changes needed to explain the data.
parsimonious
The study of evolutionary relationships among species is called
phylogenetics.
Movements of the Earth's crust cause a shifting of continents and oceans. These shifts lead to the creation of new environments and thus affect organisms living in those environments. This ______ theory is an explanation of some mass extinctions on Earth
plate tectonic
A group of organisms is referred to as ______ if it excludes the most recent common ancestor that is shared by all members of the group
polyphyletic
Crop plants, such as wheat, corn, sugar, and coffee, are all derived from ______ plants, in which chromosome sets have increased
polyploid
A condition called ______ occurs when the number of sets of chromosomes increases
polyploidy
What can lead to sympatric speciation due to doubling of chromosomes or errors in meiosis
polyploidy
______ is rare in animals possibly because having extra chromosomes is often fatal
polyploidy
Assuming fertilization occurs during a mating between two different species, viable and fertile offspring are prevented by ______ barriers
postzygotic
Hybrid inviability, hybrid infertility, and hybrid breakdown are examples of ______ reproductive barriers
postzygotic
What type of reproductive isolating barrier occurs after the formation of a zygote and reduces the fitness of the hybrid
postzygotic
A ______ reproductive barrier affects the ability of two species to combine gametes and form a zygote
prezygotic
If a zygote cannot form between two organisms, then a type of ________ reproductive barrier is present
prezygotic
Allopatric speciation seems to support what model of speciation
punctuated equilibrium
Fossil records of bryozoans and mollusks provide examples of the ______ model of speciation because macroevolution appears to have occurred in brief bursts
punctuated equilibrium
What model of speciation proposes that bursts of rapid evolution give rise to species and are followed by long periods of little change
punctuated equilibrium
Select all of the following that are true about adaptive radiation
rapid speciation different adaptations simultaneously selected for different types of new resources available
Select all the ways in which humans are creating situations that cause extinctions of animals and plants on Earth
releasing pollution into the atmosphere and water introducing nonnative species into new habitats fragmentation of habitat destruction of habitat
Mechanisms of ______ prevent successful reproduction and include prezygotic barriers and postzygotic barriers
reproductive isolation
Select all the criteria biologists can use to define species
reproductive isolation DNA sequence analysis
All of the members in a clade
share a common ancestor.
A cladogram is a treelike diagram that shows hypothesized evolutionary relationships among organisms based on
shared derived characteristics.
Low genetic diversity, fewer genetic mutations, and inbreeding are characteristic of ______ populations, and any one of these could lead to extinctions of those populations
small
Select the population that would be most at risk of extinction
small population in a quick-changing environment
Select the types of populations that are more vulnerable to extinction
small populations populations that experience a drastic climate change
Select all the reasons why Mayr's biological species concept is not a perfect definition of a species
some distinct species can occasionally produce fertile offspring reproduce of fossil species is difficult to determine
Allopatric, parapatric, and sympatric are types of ______ in which populations genetically diverge and reproductive barriers arise
speciation
Two different models of ______ are gradualism and punctuated equilibrium
speciation
When a population contains two separate groups that can no longer interbreed and produce fertile offspring, then ______ has occurred
speciation
Select all the characteristics of allopatric speciation
speciation that occurs in isolated bodies of fresh water accounts for diversification of organisms on islands most common mechanisms of speciation
The formation of a new species is called
speciation.
Biologists group distinct types of organisms into ______, which may also be defined as a group of interbreeding organisms
species
Linnaeus proposed that ______ were creatures that were alike in minute details of body structure, and he gave them two-word names
species
In the scientific name for humans, Homo sapiens, the word sapiens designates the
species.
What definition best describes phylogenetics
studying evolutionary relationships among species
If a population diverges genetically from its parent population while remaining in the same physical area, this is an example of ________ speciation
sympatric
Polyploidy is one mechanism of ______ speciation among plants because new species can arise due to errors in meiosis and fusion of gametes from two different species
sympatric
The type of speciation that occurs when populations diverge genetically while living in the same physical area is called ______ speciation
sympatric
What type of speciation gave rise to these two species of cichlid fish that occupy the same lake but have feeding and breeding differences
sympatric
If two fly populations live in the same field but one begins to feed on a type of fruit that matures earlier in the year while the other population prefers to feed on a later-maturing fruit, genetic divergence of the populations may lead to
sympatric speciation.
The study of classification is called ______, which incorporates both taxonomy and phylogenetics
systematics
In the hierarchical classification system, a group at any rank is called a
taxon
Systematics, the study of classification, incorporates two interrelated specialties, which are
taxonomy and phylogenetics.
The movement of ______ over time, which affected environments on Earth, has been offered as a possible explanation of mass extinctions of organisms on Earth
tectonic plates
Suppose an error in meiosis produces diploid gametes and these gametes fuse during self-fertilization, which doubles the chromosome number. The resulting ______ organism is reproductively isolated because it will produce ______ hybrids with the parent species
tetraploid; infertile triploid
Among the possible phylogenetic trees for a set of organisms being examined with cladistics, the most parsimonious tree is the one that requires
the fewest steps, or evolutionary changes, to construct.
Polyploidy is a condition in which
the number of sets of chromosomes has increased.
What phrase describes macroevolution
the process of new species appearing and other species going extinct on Earth over long periods of time
What evolutionary tree in the image represents the gradualism model of speciation
the tree on the left
What evolutionary tree represents the punctuated equilibrium model of speciation proposed by Gould and Eldredge
the tree on the right
How many domains of life, the most inclusive level of taxonomic hierarchy, are organisms grouped into
three
True or false: Microevolution can eventually lead to macroevolution
true
Gossypium hirsutum, the cotton plant that is cultivated all over the world, was developed when
two species of cotton interbred and the chromosome number eventually doubled.