Macroevolution

Question 1

the origin and extinction of new taxonomic groups.

It can happen gradually, or slowly.

Answer 1

Macroevolution

Question 2

The two major processes of macroevolution

Answer 2

Speciation

Extinction

Question 3

A modern understanding of speciation begins 100 years after Darwin, when Ernst Mayr, and others, developed a scientific theory of speciation based upon

Extinction took even longer

Answer 3

Genetic and Ecological Processes

Question 4

Species are groups of actually or potentially interbreeding individuals that can mate and produce fertile offspring

A species is the smallest set of organisms that share a common ancestor, and can be distinguished from other such sets

Answer 4

Biological Species Concept

Phylogenetic Species Concept

Question 5

Species are collections of living organisms that have certain morphological and biochemical traits in common.

Answer 5

Morphological Species Concept

Question 6

This idea was promoted by Ernst Mayr, an evolutionary biologist who worked on birds.

It is excellent, conceptually, because it defines species objectively, based upon the capabilities of the organisms in question.

Answer 6

BIiological Species Concept

Question 7

In principle, this applies to most species, but in many cases, it is simply impossible to test whether two species have the potential to interbreed.

Fossil species, species which do not reproduce in the lab or zoo (the vast majority), and asexual species are sticky issues.

Answer 7

Biological species concept

Question 8

This is what most taxonomists actually use to classify specimens and describe species.

It is expedient-it can be applied to dead specimens, and even to fossils.

Answer 8

Morphological Species Concept

Question 9

It has many disadvantages.

It is subjective.
Cryptic species, which look identical to humans but are in fact reproductively isolated, are problematic.
Species with morphological variation, and complex life histories, pose problems.

Answer 9

Morphological Species Concept

Question 10

This concept emphasizes the species as a lineage on the tree of life.

It is, at least in theory, objective, because it defines lineages as the smallest set of organisms that share a common ancestor-though in practice, that common ancestor is always dead, and its existence must be inferred.

Answer 10

Phylogenetic Species Concept

Question 11

the origin of new species. With extinction, it is one of two keystone processes of macroevolution
It is one of two cornerstone processes of macroevolution.

It takes _____ for species to originate

Answer 11

Speciation

Reproductive Isolation

Question 12

If this reproductive isolation continues long enough, speciation occurs. One, or several, new species originate from isolated populations of the parent species.

Answer 12

As we shall see, this is frequently the result of a geographic barrier, although it may be the result of a chromosomal change or habitat preference.

Question 13

This type of species live in the same place. Without some mechanism preventing allele and gene exchange among sympatric species, distinct species would be impossible.

Answer 13

Sympatric Species

Instead, we would see a continuum of variation from one form of life to another, and many forms of life would not be possible, because interbreeding with different forms would produce non-viable combinations of traits

Question 14

Barriers to allele flow are called …

They allow sympatric species to exist and to maintain distinct sets of characters and adaptations.

Answer 14

Isolation Mechanisms

Question 15

Without isolation mechanisms, closely related species would hybridize: allele flow and recombination would eventually transform them into a single, polymorphic species.

Answer 15

Isolation mechanisms are responsible for the origin of species, and they maintain the integrity of species

Question 16

Isolation mechanisms prevent mating, so that gametes of sympatric species never form hybrid zygotes.

Answer 16

Prezygotic Isolation mechanisms

Question 17

Isolation mechanisms that act after a mating has occurred, to prevent fertilization or to prevent potential hybrids from passing on their genes.

Answer 17

Postzygotic Isolation Mechanisms

Question 18

The 5 prezygotic isolation mechanisms

Answer 18

Habitat Isolation
Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Gametes Die

Question 19

occurs because sympatric species never meet due to differences in their habitat preference.

Answer 19

Habitat Isolation

Question 20

What type of isolation?

Sympatric species of spadefoot toads (Scaphiopus) seldom meet because they prefer different soil types.

Answer 20

Habitat Isolation

Question 21

Type of isolation?

Many species of closely-related parasites, such as bird lice, never meet because they live and mate on different hosts.

Answer 21

Habitat Isolation

Question 22

Isolation that occurs because species mate at different times

Answer 22

Temporal Isolation

Question 23

Type of isolation
The American Toad (Bufo americanus) and the Fowler’s Toad (Bufo fowleri) have been mated in laboratory settings, but mating does not happen in the wild because the American Toad mates early in the summer, and the Fowler’s Toad mates in late summer.

Answer 23

Temporal Isolation

Question 24

isolation mechanisms that include differences in courtship behavior, differences in chemical signals or vocalizations, and differences in color or morphology that allow individuals to recognize their own species.
They are a very common mechanism keeping closely-related sympatric animals from interbreeding

Answer 24

Behavioral/Ethological Isolation

Question 25

Birds are very visually-oriented creatures, with extensive behavioral repertoires. Visual recognition is thought to play a key role in mate recognition for most species.
Gulls normally mate only with their own species.

NOTE. The point of this experiment is to demonstrate the existence of an isolation mechanism by artificially removing it

Answer 25

Artificial hybridization can be induced by cross-fostering herring gulls and lesser black-backed gulls. Members of each species “imprint” on archetypes of their own species as juveniles. If eggs are switched, they imprint on the wrong species, and hybridize. Thus, the isolation mechanism is behavioral.

Question 26

occurs because the sexual organs of closely-related sympatric species are incompatible: they do not fit together.
This is thought to be an important isolation mechanism in arthropods, particularly insects and millipedes.

Answer 26

Mechanical Isolation

Question 27

The adeagus (closest thing there is to a penis) of various Drosophila species is an example of

Answer 27

Mechanical Isolation

Question 28

Gametes are frequently very specialized cells, which can only perform well in the reproductive tract of the opposite sex of the same species.
In many angiosperms, for instance, pollen transferred to the stigma of another species will not germinate, or if they do, will not form a pollen tube.

Answer 28

Gametic Mortality

Question 29

Some species that do not ordinarily interbreed occasionally do so. Frequently, the progeny of these interspecific matings die at some point during their development.

Answer 29

Hybrid Inviability

Question 30

Ex: Hybrids between the frogs Rana pipiens and Rana sylvatica do not survive more than a day or so

Answer 30

Hybrid Inviability

Question 31

occurs when the hybrid of an interspecific mating is unable to reproduce.
Examples: Mules are the hybrid of a horse and a donkey, they do not form normal sperm

Answer 31

Hybrid Sterility

Question 32

Hybrids between Drosophila melanogaster and D. pseudoobscura exhibit what type of post-zygotic isolation?

Answer 32

Hybrid sterility

Question 33

If interspecific hybrids do survive, they often have very low fitness, this effectively keeps them from spreading genes from one of their parent species to the other parent species

Answer 33

Low Hybrid Fitness

Question 34

Dog-Wolf hybrids are perfectly viable, but they are considered to be unsuitable pets in most areas.
Wild wolf populations do not accept hybrids, they are killed on sight.

Answer 34

Low Hybrid Fitness

Question 35

Speciation that involves a geographic barrier

Answer 35

Allopatric Speciation

Question 36

Speciation that does not involve a geographic barrier

Answer 36

Sympatric Speciation

Question 37

involves a geographic barrier that physically isolates populations of a species and blocks gene flow.
Once isolated, allopatric populations (living in different places) accumulate genetic differences due to

Answer 37

Natural Selection, Sexual Selection, Genetic Drift, New Mutations

Question 38

If the Geographic Barrier is Removed, the Two Species May:

Answer 38

1) meld together by allele flow and recombination to once again form a single species.
2) remain reproductively isolated

Question 39

The new species that results when geographic barriers are removed and they meld together by allele flow and recombination

Answer 39

Incipient Species

Question 40

Its fate depends upon whether isolation mechanisms have evolved during the period of isolation

Answer 40

Incipient Species

These isolation mechanisms may be premating or postmating.

Question 41

Premating isolation mechanisms may evolve in incipient species that have postmating isolation, to reduce the probability of incorrect matings and the subsequent loss of fitness.

Answer 41

!

Question 42

Two closely-related species of antelope squirrels live on opposite sides of the grand canyon. On the South rim is

on the North rim is Ammospermophlus leucurus

Answer 42

Ammospermophilus harrisi

Question 43

Have species(Birds) that can cross the grand canyon diverged into different species on opposite sides?

Answer 43

No.

Question 44

a black bird with a crest of feathers, it is highly variable in behavior and appearance throughout its range.
Each semi-isolated population has its own appearance.

A “double” invasion probably occurred in Tasmania over the course of the past few thousand years.

Answer 44

The Drongo

Question 45

This species is widespread on the Australian continent. Tasmania has a slightly differentiated population of this bird.

Answer 45

Acanthiza pusilla

Question 46

Another, reproductively isolated species, that is even more differentiated from Australian Drongos in appearance and morphology also inhabits Tasmania

Answer 46

A. ewingi

Question 47

During the last ice age, when sea level was lower, Tasmania was part of an island, this is probably when the ancestors of A. ewingi invaded the island. Eventually they evolved reproductive isolation from their Australian counterparts.

Answer 47

When A. pusilla re-invaded the island more recently, the two species were able to co-exist because they are reproductively isolated.

Question 48

Nobody knows for sure how long allopatric speciation takes, and it depends upon the group.
McCune and Lovejoy, based on a study of reproductive isolation in 40 pairs of allopatric fishes which were each other’s closest relative, estimated that, for fishes, it takes between

Answer 48

.8 and 2.4 million years for reproductive isolation to evolve.

Question 49

Central America has only been an effective reproductive barrier to marine creatures for 3 million years. In that time, pairs of species of _______ have evolved on opposite sides of the isthmus

Answer 49

Snapping Shrimp

Question 50

Hurt and Hedrick conducted interesting studies of incipient allopatric speciation in the Sonoran topminnows

Based on molecular evidence, these two species/subspecies have been isolated for between one and two million years in different river drainages in Arizona

Answer 50

Poeciliopsis sonorensis and Poeciliopsis occidentalis

Question 51

Hurt and Hendrick found that males of each species prefer to mate with females of their own species, but given no choice, they will hybridize, rather than not mate.

Answer 51

Poeciliopsis sonorensis and Poeciliopsis occidentalis

Question 52

What type of fitness did the hybrids of Poeciliopsis sonorensis and Poeciliopsis occidentalis have, especially when a hybrid was crossed with an original species?

Answer 52

Reduced hybrids

Question 53

For this species, hybrids demonstrated brood sizes that were smaller, and there was an unusual, male-biased sex ratio for these crosses. Particularly occurred when a hybrid was crossed with an original species

Answer 53

Poeciliopsis sonorensis and Poeciliopsis occidentalis

Question 54

This phenomenon-where the products of matings between the original species and hybrids with another species have especially low fitness, is called

It is a relatively common phenomenon in poztzygotic isolation scenarios

Answer 54

Hybrid breakdown

Question 55

Are Poeciliopsis sonorensis and Poeciliopsis occidentalis separate species?

Answer 55

Clearly, the answer is subjective. In this case, if the populations were to mix together, the process of reinforcement would probably complete the job….so probably yes.

Question 56

natural selection on females of incipient species pairs in cases where there are postzygotic isolating mechanisms, to avoid mating with males of the wrong species.

Any trait that causes them to avoid mating with the wrong species becomes common, because the cost of producing unfit offspring is avoided

Answer 56

Reinforcement

Question 57

It is not usually observed in males, for the reason that females generally invest more in any given reproductive effort and have more to loose.

Answer 57

Reinforcement

Question 58

Example-Coyne and Orr documented that Drosophila species pairs, such as _____ and ________ avoid interspecific matings, when they are captured from the parts of their range where these species overlap, but they do not avoid hybridization if they are captured from the parts of their range where there is no overlap between species.

Answer 58

D. pseudoobscura and D. persimilis

Question 59

speciation that results from intrinsic factors, such as chromosomal changes and nonrandom mating.

Species become genetically isolated even though their ranges overlap

Answer 59

Sympatric Speciation

Question 60

Name the mechanisms of sympatric speciation (2)

Answer 60

Polyploidy

Nonrandom Mating

Question 61

Disorders of meiosis cause the accidental formation of gametes that are 2N rather than N. Self-fertilization, or any other union of two of these 2N gametes produces a zygote that is 4N

Answer 61

Poloyploidy

Question 62

The chromosome number has doubled, instantaneously producing a potential new species.
This process is called

Answer 62

autopolyploidy

Question 63

Gametes of two species meet and form a hybrid.

Usually the hybrid is sterile, but sometimes it is not.

Answer 63

Interspecific Hybridization

Question 64

What is produced from interspecific Hybridization, which is usually infertile (the chromosomes can not pair during meiosis), but may reproduce asexually?

If the chromosomes double by a disorder of mitosis, and these cells go on to form germ-line tissue, it produces a potentially sexual species.

Answer 64

Allopolyploid

Question 65

These mechanisms are probably common in plants, but rare or absent in animals.

Why?

Answer 65

Interspecific Hybridiztion, Allopolyploidy

Plants are frequently capable of self-fertilization, and some can survive with double the normal number of chromosomes, and most can propogate asexually.

Question 66

Plants have no real germ line-somatic tissue, can give rise to meiotic tissue under a variety of circumstances-thus, an asexual species is likely to have individuals that have spontaneously doubled their chromosome number, and are forming gametes.

Answer 66

!

Question 67

Wheat is doubly autopolyploid, the product of an interspecific hybridization, then a doubling of chromosomes, then another interspecific hybridization, then another doubling of chromosomes, to produce a fertile hexaploid.

Yellow bananas are a sterile allopolyploid, the product of two interspecific hybridization events.

Answer 67

! (look at diagram for wheat)

Question 68

Many species of parasites mate on or nearby the host. A shift to a new species of host therefore reproductively isolates the parasites exploiting the different species of hosts.

Answer 68

Host Shift (Nonrandom Mating)

Question 69

The best studied example of host shift occurs in the

Answer 69

apple maggot

Question 70

Apple trees are not native to the US, they were introduced here in the nineteenth century.
Following their introduction, the hawthorn maggot began to feed on apples.
The flies cue in to the smell of their original host, so apple and hawthorn maggots are now reproductively isolated: and considered to be different species.

Answer 70

!

Question 71

Speciation is not always clear-cut, there are many examples of SOME populations being reproductively isolated, while OTHERS are able to interbreed. This is sometimes called

Answer 71

Parapatry

Question 72

A well known example involves California garter snakes, Thamnophilus sp..
Each population of land snakes is able to interbreed with the populations closest to it, but not with more distant populations. In some cases, however, a distant population has come back around to encounter a distantly related population. In these cases, they do not interbreed.

Answer 72

Parapatry

Question 73

A similar relationship exists for water populations. Some water snakes can even interbreed with the local land snakes

Answer 73

Parapatry

Question 74

A “family tree” describing how species are related. The branching pattern of different groups of organisms is caused by repeated cladogenesis.

Answer 74

Phylogeny

Question 75

is the study of phylogeny

Answer 75

Systematics

Question 76

Is the process of describing and naming organisms. Our modern process of taxonomy is based on phylogeny, so an understanding of phylogenetic relationships-names reflect relatedness

Answer 76

Taxonomy

Question 77

Every species has a place in the taxonomic hierarchy

Answer 77

!

Question 78

It is worth noting that systemetists form new rankings, such as infraorder, subphylum, etc., whenever they need to.
A more modern approach is to define groups on the tree of life based upon branching points.
This avoids the confusion of exactly what constitutes an order, etc.

Answer 78

!

Question 79

the origin of lineages, is the formation of a new branch on the tree of life. Speciation is the mechanism for it

Answer 79

Cladogenesis

Question 80

promotes biological diversity by increasing the number of species

Answer 80

Cladogenesis

Question 81

Extinctions pare down the number of species present on the planet, and thus, a lineage, such as mammals, with thousands of species, originally started as a single species.

Answer 81

!

Question 82

The branching pattern that gave rise to a group of taxa can be inferred from a variety of types of evidence.
These include:

Answer 82

• Morphological, biochemical, behavioral, and genetic features
• DNA sequence information
• The fossil record
• Biogeography

Question 83

Shared morphological, biochemical, genetic, or behavioral characters that were passed down from a common ancestor are called

The most reliable in constructing a phylogeny for a group of organisms.

Answer 83

Homologies

Question 84

A character state is _ in two species when it is inherited by both from a common ancestor.

Answer 84

Homologous

Question 85

infers the pattern of phylogeny based on homologies. Groups are constructed based on shared characteristics inherited from a common ancestor, that no other group has.

The most widely accepted school of systematics today

Answer 85

Cladistics

Question 86

For any group of taxa, a pattern of loss and acquisition of characters, and the subsequent passing-down of these traits to descendent species, can be mapped on a tree called a

Answer 86

Cladogram

Question 87

The cladogram with the fewest number of transitions and reversals (parsimony), or

the one with the most likely series of transitions, is chosen as the best-supported phylogeny.

Answer 87

Parsimony

Maximum Likelihood

Question 88

An evolutionary novelty for a group

An evolutionarily primitive state

Answer 88

Apomorphy

Pleisomorphy

Question 89

a novel (derived) trait that a group has inherited because the common ancestor of that group had a novel characteristic and passed it on

Answer 89

Synapomorphy

Question 90

an evolutionarily primitive trait that a group has inherited because the common ancestor of that group had inherited the primitive condition, unchanged, from an earlier group.

Answer 90

Synplesiomorphy

Question 91

Note that these terms are relative-a synplesiomorphy for one group may be a synapomorphy from the larger group it came from.

Answer 91

!

Question 92

The wings of bees of the families andrenidae and Halictidae have basal veins, it is straight in adrenidae and curved in halictidae. It is a chief distinguishing feature between them that has remained constant during the long evolution o these groups. What is this an example of?

Answer 92

Synapomorphy

Question 93

If a character has evolved more than once, if possessed by two species but not present in the common ancestor, it is called a

Answer 93

Homoplasy

Question 94

One form of homoplasy that is quite common because different species are often subject to similar selective pressures.

Answer 94

Convergent Evolution

Question 95

Homoplasy, when mistaken for homology, can obscure the pattern of evolutionary history.

Answer 95

!

Question 96

The labrum/food channel etc. of flies is an example of

Answer 96

Homoplasy NOT homology

Question 97

A major force in macroevolution

Answer 97

Extinction

Question 98

Species do not last forever…the mean expected lifespan of a marine bivalve is about

and the mean expected lifespan of a terrestrial mammal might be about a tenth that

Answer 98

14 million

Question 99

As some species originate, they inevitably drive other species

Answer 99

Extinct

Question 100

Extinctions pave the way for….

Answer 100

Speciation

Question 101

a wave of speciation that occurs as a new habitat is colonized by a lineage, or in the wake of the extinctIon of another lineage.

Answer 101

Adaptive Radiation

Question 102

An adaptive radiation of mammals followed the extinction of the dinosaurs.

An adaptive radiation of dinosaurs followed the extinction of the land crocodiles and mammal-like reptiles that preceded them.

Answer 102

!!

Question 103

At all times in history, groups of organisms have a

Answer 103

Background Extinction Rate

Question 104

Extinction rates are much higher than background rates for a short period of time, the history of life on Earth is riddled with these periods

Answer 104

Mass-Extinctions

Question 105

5 Extinctions over the last 500 million years

Answer 105

1) The Late Devonian
2) Mid-Ordovician
3) Permian-Triassic
4) Late Triassic
5) Cretaceous-Paleogene.`

Question 106

One of the best-understood mass-extinctions occurred at the end of the Mesozoic era, at the boundary between the Cretaceous Period and the Neogene period.

Every species of non-avian dinosaur was driven extinct, as well as pterosaurs, mosasaurs, plesiosaurs, the ammonoid and belemnoid molluscs, rudist bivalves, and quite a few other taxa as well.

Answer 106

The Cretaceous-Paleogene Mass Extinction

Question 107

What percent of species was eliminated over an interval of 1,000 years during the Cretaceous-Paleogene Mass Extinction

Answer 107

50%

Question 108

The scientific consensus, at the moment, is that one or several impact events are responsible for the extinction-though a severe marine regression at the time, and climate change induced by a period of intense vulcanism, may have played a role, rendering the biosphere much more susceptible to mass extinctions resulting from an impact.

Answer 108

The Cretaceous-Paleogene Mass Extinction

Question 109

Since the development of agriculture, 10,000 years ago, humans have modified an increasing proportion of the Earth’s resources for our own purposes.
Humans impact has caused extinction rates to be 10 to 1000 times greater than any time in the last 100,000 years.

Answer 109

!

Question 110

For example-one estimate for the recent background extinction rate for birds is one species extinction per

Answer 110

400 years

Question 111

If only the background extinction rate affected the number of bird species, no more than a couple of extinctions should have occurred in the past 800 years.
Scientists estimate that the actual loss during this time period lies somewhere between

Answer 111

200 and 2,000

We have set in motion a mass extinction, one of the largest, that will not culminate until thousands of years from now.

Question 112

The human population passed __ billion in the year 2012, and is growing at a rate of almost ___ per year (down from a maximum of over 2% per year).

Answer 112

7 billion

1.1%

Question 113

Worldwide, more than __% of all land area is used for farms or permanent pastures. Much of the rest is grazed or logged on a regular basis.

Answer 113

35%

Question 114

From ___ to ____& of Global Net Primary Productivity now goes to serve human needs

Answer 114

35-45%

Question 115

In aquatic ecosystems as well, an increasing amount of productivity is harvested by humans. Nearly every major fishery in the Northern Hemisphere has showed strain from overharvesting, and many have collapsed.

Answer 115

!

Question 116

The 4 Major Sources of Anthropogenic Extinction

Answer 116

Habitat Destruction and Habitat Fragmentation
Habitat Change and Disruption of Ecosystem Processes
Introduction of Exotics
Overexploitation

Question 117

Most of the grasslands and forests of the Northern Hemisphere were destroyed by the end of the nineteenth century.

Answer 117

Habitat Destruction and Fragmentation

Question 118

The grasslands of the southern hemisphere are now vanishing, and tropical forests are disappearing at a rate of about ___% per year

Answer 118

2%

Question 119

This type of destruction has become the norm for most biological communities, as the human population expands our economic needs require resources from more and more land.

Answer 119

Habitat Destruction and Fragmentation

Question 120

The remaining habitat is often broken into many small fragments, which are separated by large areas of land under cultivation or other human uses, effectively reducing a single “continent” into many “islands”.

Answer 120

Habitat Destruction and Habitat Fragmentation

Question 121

Essentially, every habitat fragment becomes a biological “island” (analogous to continental shelf islands, rather than the oceanic kind).
As in the Mac Arthur Wilson model (see your textbook), the smaller the island, the ______ (larger/smaller) the population of any given species it can support

Answer 121

Smaller

Question 122

Small populations are at much greater risk of extinction due to random events, such as weather, disasters, and natural fluctuations in their population.

Answer 122

Fragmented Habitats Support Smaller Populations

Question 123

Additionally, smaller populations support less ____________, which could lead to the fixation of harmful alleles and the ultimate extinction of the population (for very small fragments), or simply inhibit their ability to evolve in response to changing conditions

Answer 123

Genetic Variation

Question 124

Fire, certain types of grazing, and other forces fundamentally important to the ecology of organisms, are altered when a habitat is broken into fragments.

Answer 124

Fragmented Habitats Frequently Lack Critical Ecosystem Processes

Question 125

For instance, places where human habitation borders nature preserves frequently have weedy plants, fire is controlled, domestic cats and dogs escape and prey on native wildlife, and human noise and activity disturb the behavior of certain animals.

For certain species, this can be critical to their ability to survive

Answer 125

Edge Effects

Question 126

The edge habitats have different effects on different species.
Some large mammals, such as ___ and _____ reach much higher densities in edge habitats because they are able to take advantage of human resources (garbage), and return to the safety of the preserve.

Answer 126

Coyotes and Racoons

Question 127

Taking this a step farther,raccoons in the US, and red foxes in England, have even penetrated urban areas to become part of the city, reaching high densities.

Answer 127

Raccoons and Red Foxes

Question 128

Other mammal species cannot tolerate edge environments, ___ and ______ do not like humans and cannot live on the edge (in cases where they try, very bad things might happen.

Answer 128

Wolves and mountain lions

Question 129

A species native to the United States.
It is a brood parasite, evicting the eggs of other species to replace them with its own.
They preferedge habitats. Now that forests are fragmented, there are few safe areas from them, and forest interior species such as bluebirds are suffering a major loss of fitness in some areas.

Answer 129

Cowbirds

Question 130

Surviving areas of natural habitat often change because humans have fundamentally altered natural ecosystem processes.

Answer 130

Habitat Change and Disruption of Ecosystem

Question 131

There are probably about 25, 000 species of orchids worldwide, and they are being lost faster than they can be classified.
Orchids are typically tightly coevolved in _______ relationships with other species, and the loss of any of these relationships can lead to extinction.

Answer 131

Mutualistic

Question 132

A very diverse group of orchids that occupy a wide variety of habitats in the Northern Hemisphere. They are in decline even in protected areas, such as Indiana Dunes.

Answer 132

Lady’s Slipper Orchids

Question 133

Human activities have altered their ecosystems.

Ladys’ slippers need a mutualistic fungus to germinate and grow for the first few years

Answer 133

Airborne nitrogen compounds (mostly from automobiles) effectively “fertilize” vast areas of ground and may put the mutualistic fungi at an ecological disadvantage.

Question 134

Also, the widespread application of pesticides, the human tendency to groom and “clean up” areas of open sand and fallen wood, and the arrival of honeybees, have disrupted the ecology of pollination for orchids

Answer 134

Lady’s Slipper Orchids and Habitat Change/Disruption of Ecosystem

Question 135

Salmon species have experienced dramatic declines over the past few decades due to a variety of factors, many of which result from human habitat modification.
Hydroelectric dams have resulted in increased juvenile mortality and made many habitats inaccessible to migrating salmon.

Answer 135

Pacific Salmon

Additionally, human logging and agriculture has silted and modified many of their upstream habitats, causing a drop in recruitment

Question 136

Human activities are creating the worldwide faunal interchange.
This is an uncontrolled experiment in community ecology, with the potential result of a massive loss of gamma diversity worldwide caused by the loss of endemic species.

Answer 136

Introduction of Exotics

Question 137

Most exotic species that arrive on new continents do not spread or establish themselves, but the ones that do often succeed spectacularly, causing change to native ecosystems that results in many extinctions.

Answer 137

Introduction of Exotics

Question 138

discovered in Lake St. Claire near Detroit. It was introduced to the Great Lakes from the Caspian Sea, probably in the ballast water from a cargo ship, sometime around 1985

They have since spread throughout the Great Lakes region and throughout the Mississippi and Ohio River valleys.

Answer 138

Zebra Mussels

Question 139

It forms dense clusters of individuals, and can clog the water intakes of electrical power stations, water stations, and other industrial facilities.
A very effective competitor. Extinction of native bivalves will almost certainly result from this introduction.

Answer 139

Zebra Mussels

Question 140

incredibly effective filter feeders. They actually make the water much clearer, but alter native communities of organisms in the process. In the Hudson River, phytoplankton biomass decreased 85% after these invaded, zooplankton decreased 70% as a result.

Answer 140

Zebra Mussels

Question 141

was introduced to Guam in the late 1940s, probably by hitching a ride in the wheel well of a plane.
Since that time, it has literally eaten most of the endemic birds of Guam to extinction.
Since there are no other native snakes in Guam (other than a blind, burrowing species), the bird fauna there evolved no natural defenses

Answer 141

Boiga Irregularis

Question 142

competition and predation keep it in check, but the simpler ecosystem of Guam has allowed it to increase in numbers to up to 20 individuals per square acre of jungle (among the highest ever recorded for a snake).
It also causes other problems in Guam, including numerous power outages resulting from large numbers of snakes resting on power lines.

Answer 142

Boiga Irregularis

Question 143

Cow-this huge sirenian mammal lived in the reached a length of 26 feet and could way seven thousand pounds or more. It existed on a diet of kelp, and could not dive or swim quickly.
It was delicious, and was hunted to extinction by sailors within 30 years of its discovery

Answer 143

Stellar’s Sea Cow

Overexploitation

Question 144

What makes a species vulnerable to extinction? (5)

Answer 144

Endemism
Rarity
Small Population Size
Ecological Specialization
Beauty/Usefulness to Humans/Competitor with Humans

Question 145

Species that are restricted to a particular, small area, are more vulnerable to extinction

Answer 145

Endemism

Question 146

not the same thing as endeminsm, endemics can be very common in the restricted area where they do occur.
“Naturally rare” species have low population densities, but may be widely distributed and have respectable population sizes.

Answer 146

Rarity

Question 147

We do not completely understand the ecological factors that make some species “naturally rare”, but when a common species gradually becomes rare, it is often a prelude to ____
“Naturally rare” species can be a challenge to conservation, because they are difficult to monitor and it is very difficult to ensure that sufficient habitat is set aside for them.

Answer 147

Extinction

Question 148

Renders a species very vulnerable to extinction, through reduced genetic variation via genetic drift, the potential for inbreeding depression, and demographic stochasticity caused by random ecological disasters.

Answer 148

Small Population Size

Question 149

more prone to extinction because there are only a few ways they can ‘fit themselves into” an ecosystem. They must have certain interspecific relationships in order to feed, obtain mates, have places to live, or maintain competitive superiority. The loss of other species in the community, or habitat change due to human activity, can change these factors, and render a formerly successful species vulnerable to extinction.

Answer 149

Ecological Specialists

ecological specialization

Question 150

Humans-Humans have a way of killing all the pretty things, harvesting all the useful things, and hunting to extinction everything that could be perceived as a competitor.

Answer 150

Useful to Humans or a Competitor of Humans

Question 151

fishermen in San Francisco Bay Area are prone to despising the ________, despite its important place in the ecosystem of the California Coast, because of its perceived status as a competitor. This is an example of

Answer 151

California Sea Otter

Useful to Humans or Competitor to humans

Question 152

Crocodiles kill pets. Rattlesnakes, despite their critical role in ecosystems, are often despised in the Southwestern United States.
They are protected now, however, they were nearly hunted to extinction for their pelts. Species that cross the paths of humans sometimes suffer for it.

Answer 152

Useful to humans or a competitor to humans

Question 153

Any conservation plan that does not take human economics into account is prone to failure. It is very difficult to set aside a habitat and protect it from all human activity.
The closest we have ever come are on military bases and nuclear test sites (the conservation effect was unintentional at first), and some private organizations (Nature Conservancy) buy natural land and simply fence it off.

Answer 153

Even these exceptional preserves have neighbors, and are occasionally eyed by developers and government reclassification.
The vast majority of preserves must balance the needs of human ecotourists, indigenous peoples, neighbors, and government budget considerations against conservation goals.