Bio 189: Chapter 14 - Speciation & Extinction

When might speciation occur rapidly? Select all that apply.

- After a major environmental change wipes out many species - After a key adaptation arises

Carolus Linnaeus classified species based upon ___ but not upon ___.

- Body structure - Evolutionary relationships

Select all the criteria biologists can use to define species.

- DNA sequence analysis - Reproductive isolation

Select three ways that genetic divergence can occur between two separated populations.

- Genetic drift - Gene flow - Natural selection

Select the reasons why it is difficult for biologists to determine whether a speciation event is allopatric or sympatric

- It is hard to detect all the barriers that are important to different species - The size of geographic barrier needed to separate populations depends on the species

In the past, scientists constructed evolutionary trees based on which of the following? Select all that apply.

- Similarities in characteristics - As many characteristics as possible

speciation of populations separated by a physical barrier is called ___ speciation, while ___ speciation occurs in populations that live in the same physical area.

- allopatric - sympatric

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

___ 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 all the lines of evidence used by biologists to construct phylogenetic trees

- behaviors - physiological adaptations - fossils - molecular sequences

select all of the statements that correctly interpret the cladogram

- crocodiles are more closely related to nonavian dinosaurs than they are to lizards and snakes - birds and nonavian dinosaurs have a common ancestor

Select the common features of cladograms from the choices below

- each node indicates where two groups arose from a common ancestor - the tips of the branches represent taxa - cladograms depict evolutionary relationships

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 ___

- genus - species

select the two models of speciation

- gradualism - punctuated equilibrium

match the type of prezygotic reproductive barrier on the left with its example on the right.

- habitat isolation: ladybird beetles feed on different 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: populations live in different places - behavioral isolation: a variation in a courtship ritual - mechanical isolation: reproductive structures that do no fit together - gametic isolation: sperm that does not fertilize the egg - temporal isolation: active at different times of day

select all the postzygotic reproductive barriers

- hybrid inviability - hybrid breakdown - hybrid infertility

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 generation 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: lion tiger (liger) is infertile - hybrid breakdown: offspring of hybrid mosquitos have abnormal genitalia

select the two theories that explain what may have contributed to Earth's mass extinction in the past

- impact theory - plate tectonics

select all the reasons why the biological species concept is not a perfect definition of a species

- it doesn't apply to asexually reproducing organisms - it only accounts for absolute reproductive isolation - it is impossible to apply to extinct organisms known only from fossils

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

select mechanisms that can cause polyploid

- meiosis fails, leading to diploid gametes that fuse during self-fertilization - gametes from two different species fuse

select all the examples of organisms from the fossil record that offer evidence of punctuated equilibrium

- mollusks - bryozoans - mammals

select all the reasons that could cause a species to go extinct

- new predator - new disease - natural disaster - habitat loss

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

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

select all the ways in which humans are creating situations that cause extinction of animals and plants on earth

- releasing pollution into the atmosphere and water - fragmentation of habitat - destruction of habitat - introducing species

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

The devil's hole pupfish has been geographically isolated from other pupfish for a very long time. This is an example of ___ speciation.

Allopatric

___ speciation is type of speciation in which a barrier physically separates a population into two groups that cannot interbreed.

Allopatric

The biological species concept 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

The current taxonomic hierarchy is based on the ideas of ___, whose hierarchical classification scheme made a lasting contribution to systematics.

Carolus linnaeus

The ___ approach creates phylogenies based on shared derived characters and ancestral characters

Cladistic

A diagram depicting evolutionary relationships based on shared derived character is called a

Cladogram

Historical relationships rather than similarities of the organisms is the emphasis of a

Cladogram

Select all the areas covered by the definition of taxonomy

Classifying organisms Describing organisms Naming organisms

As the image shows, mass extinctions have had the greatest influence on Earth's history because

Enormous adaptive radiation can occur after mass extinction

A root cause of extinction is when microevolutions in a species doesn't keep up with

Environmental change

Select the correct sequence of groups for a taxonomic classification of orangutans and humans

Eukarya - animalia - chordata - mammalia - primates - hominidae

Phylogenies are trees of organisms that depict hypotheses about

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 or comet onto earth's surface Dust and debris sent into the atmosphere Sunlight blocked Plants die Animals die without food or shelter

Natural selection, genetic drift, and gene flow are ___ that can lead to divergence of gene pools between groups of organisms.

Microevolutionary forces

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 5o years, the two separate populations can no longer interbreed. This describes the process of

New species forming

In cladistics, the ___ consists of comparison organisms that possess ancestral features but do not possess derived features present in the group being examined

Outgroup

Crop plants, such as wheat, corn, sugar, and coffee, are all derived from ___ plants, in which chromosome sets have increased

Polyploid

What can lead to sympatric speciation due to doubling of chromosomes or errors in meiosis?

Polyploid

Hybrid inviability, hybrid infertility, and hybrid breakdown are examples of ___ reproductive barriers

Postzygotic

If a zygote cannot form between two organisms, then a type of ___ reproductive barrier is present

Prezygotic

Select all of the following that are prevented by postzygotic reproductive barriers

Production of fertile offspring Survival of offspring to maturity

What eukaryotic kingdom shares common ancestors with three other kingdoms, and is therefore not a clade?

Protista

The model that proposes that speciation occurs in brief bursts interrupted by long period of little change is ___ ___

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

Mechanisms of ___ prevent successful reproduction and include prezygotic barriers and postzygotic barriers.

Reproductive isolation

The formation of a new species is called

Speciation

Select the correct statement from the ones below with respect to how speciation may occur

Speciation may be gradual or occur in bursts

If a population diverges genetically from its parent population while remaining in the same physical area, this is an example of ___ 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

___ is the study of classification and incorporates both taxonomy and phylogenetics

Systematics

What phrase describes macroevolution?

The process of new species appearing and other species going extinct on earth over long periods of time

True or false: microevolution can eventually lead to macroevolution

True

The cotton species that is cultivated all over the world was developed when

Two species of cotton interbred and the chromosome number eventually doubled

According to the biological species concept, a species is a population

Whose members can interbreed and produce fertile offspring

a taxon is a general term for

a family, order, species, or any rank in classification

clade

a group of organisms believed to have evolved from a common ancestor

species

a group of similar organisms that can breed and produce fertile offspring.

sympatric speciation

a new species arises while living in the same physical area as its parent species

allopatric speciation

a new species forms when a geographical barrier physically separates a population into two groups that cannot interbreed

biological species concept

a species is a population, or group of populations, whose members can interbreed and produce fertile offspring

prezygotic reproductive isolation

affect the ability of two species to combine gametes and form a zygote

___ speciation is a type of speciation in which a barrier physically separates a population into two groups that cannot interbreed

allopatric

what type of extinction results from the gradual loss of a species as populations shrink in the face of new challenges?

background

the definition of a ___ is a population whose members can interbreed and produce fertile offspring

biological species

the name of the botanist who devised a hierarchical system for classifying species was

carolus linnaeus

In cladistics, a ___ is a group of organisms consisting of a common ancestor and all of its descendants

clade

In phylogenetic analyses, a group of species united by a single evolutionary pathway is called a(n)

clade

select the accurate statement that defines cladistics

cladistics is a phylogenetic system that defines groups by distinguishing between ancestral and derived characters

gene pool

combined genetic information of all the members of a particular population

polyploid

condition in which an organism has extra sets of chromosomes

outgroup

consisting of comparator organisms that are not part of the group being studied

what group form a clade?

crocodiles, nonavian dinosaurs, and birds

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

rank the following taxonomic groups into a hierarchy, from the most inclusive group at the top of the most specific group at the bottom

domain kingdom phylum class order family

As the image shows, mass extinction have had the greatest influence on Earth's history because

enormous adaptive radiation can occur after mass extinction

select all of the following that are names of Domains of life.

eukarya archaea bacteria

mass extinction

event in which many types of living things become extinct at the same time

puncuated equilibrium

evolution happens in spurts rather than being steady

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

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

The ___ model of speciation proposes that evolution proceeds in small, incremental changes over many generations

gradualism

small, incremental changes over numerous generations is the model of speciation described by Darwin and is known as

gradualism

what may be causing a current sixth mass extinction on earth at a rate of about 20 to 200 extinctions per million species a year.

humans

select the most accurate statement about gradualism and the fossil record

in species that evolved gradually, fossils of transitional forms may still remain hidden or may have been destroyed

ancestral characters

inherited attributes that resemble those of the ancestor of a group

taxon

is a group at any rank

cladistics

is a phylogenetic system that defines groups by distinguishing between ancestral and derived characters

hybrid

is the offspring of individuals from two different species

taxonomy

is the science of describing, naming, and classifying species

phylogenetics

is the study of evolutionary relationships among species

macroevolution

large-scale evolutionary changes that take place over long periods of time

organisms have changed overtime; new species have appeared while other species have gone extinct. This is a description of

macroevolution

the disappearance of a great number of species over a relatively short expanse of time is called ___ extinction

mass

postzygotic reproductive isolation

may keep the species separate by selecting against the hybrid offspring, effectively preventing genetic exchange between the populations

impact theory

meteorites or comes have crashed to earth, producing huge debris clouds that blocked sunlight and triggered extinctions in a deadly chain reactions

extinction

occurs when all members of a species have died

the study of evolutionary relationships among species is called

phylogenetics

___ are evolutionary trees that are used by biologists to represent hypothesized relationships among species of groups.

phylogenies

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 condition called ___ occurs when the number of sets of chromosomes increases

polyploid

___ reproductive barriers occur after fertilization and reduce the fitness of the hybrid.

postzygotic

assuming fertilization occurs during a mating between two different species, viable and fertile offspring are prevented by ___ barriers

postzygotic

a ___ reproductive barrier affects the ability of two species to combine gametes and form a zygote.

prezygotic

background extinction rate

results from the steady, gradual loss of species due to normal evolutionary processes

a cladogram is a treelike diagram that shows hypothesized evolutionary relationships among organisms based on

shared derived characteristics

allopatric and sympatric are types of ___ in which populations genetically diverge and reproductive barriers arise

speciation

the formation of a new species is called

speciation

two different models of ___ are gradualism and punctuated equilibrium

speciation

when two populations no longer share the same gene pool, then ___ has occurred

speciation

Biologists group distinct types of organisms into ___, which may also be defined as a group of interbreeding organisms

species

the type of speciation that occurs when populations diverge genetically while living in the same physical area is called ___ speciation

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

in the hierarchical classification system, a group at any rank is called a

taxon

systematic, the study of classification, incorporates two interrelated specialties, which are

taxonomy and phylogenetics

speciation

the formation of new species occurs when some members of a population can no longer successfully interbreed with the rest of the group

systematics

the study of classification, therefore incorporates two interrelated specialties: taxonomy and phylogenetics

gradualism

the theory that evolution occurs slowly but steadily

cladogram

treelike diagram built using shared derived characteristics