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.