what sustains life on earth? solar energy, the cycling of matter, and gravity sustain the earth’s...

What Sustains Life on Earth?What Sustains Life on Earth?

Solar energy, Solar energy, the cycling of the cycling of matter, and matter, and gravity sustain gravity sustain the earth’s life.the earth’s life.

Figure 3-7Figure 3-7

The Carbon CycleThe Carbon Cycle


The Nitrogen CycleThe Nitrogen Cycle

The Phosphorus CycleThe Phosphorus Cycle

Populations, Communities, and Populations, Communities, and EcosystemsEcosystems

Members of a same species interact in Members of a same species interact in groups called groups called populationspopulations..Populations of different species living and Populations of different species living and interacting in an area form a interacting in an area form a communitycommunity..A community interacting with its physical A community interacting with its physical environment of matter and energy is an environment of matter and energy is an ecosystemecosystem..

Ecosystems consist of nonliving (Ecosystems consist of nonliving (abioticabiotic) ) and living (and living (bioticbiotic) components. These ) components. These factors determine what life can exist in an factors determine what life can exist in an ecosystem.ecosystem.


Factors That Limit Population Factors That Limit Population GrowthGrowth

Availability of matter and energy resources Availability of matter and energy resources can limit the number of organisms in a can limit the number of organisms in a population (population (zone of tolerancezone of tolerance))


Trophic Levels and Trophic Levels and Laws of ThermodynamicsLaws of Thermodynamics

First Law of ThermodynamicsFirst Law of Thermodynamics– Energy cannot be created or destroyed; it can Energy cannot be created or destroyed; it can

change from one form to anotherchange from one form to anotherEx: organisms cannot create energy they need to Ex: organisms cannot create energy they need to survive- they must capture it from another sourcesurvive- they must capture it from another source

– Focus is on quantityFocus is on quantity

Second Law of ThermodynamicsSecond Law of Thermodynamics– When energy is converted from one form to When energy is converted from one form to

another, some of it is degraded to heatanother, some of it is degraded to heatHeat is highly entropic (disorganized)Heat is highly entropic (disorganized)

– Focus is on qualityFocus is on quality

Producers: Basic Source of All Producers: Basic Source of All FoodFood

Most Most producersproducers capture sunlight to produce capture sunlight to produce carbohydrates by carbohydrates by photosynthesisphotosynthesis::

ChemosynthesisChemosynthesis::– Some organisms such as deep ocean bacteria draw Some organisms such as deep ocean bacteria draw

energy from hydrothermal vents and produce energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (Hcarbohydrates from hydrogen sulfide (H22S) gas .S) gas .

Consumers: Eating and Recycling Consumers: Eating and Recycling to Surviveto Survive

ConsumersConsumers ( (heterotrophsheterotrophs) get their food by ) get their food by eating or breaking down all or parts of other eating or breaking down all or parts of other organisms or their remains.organisms or their remains.– HerbivoresHerbivores

Primary consumers that eat producersPrimary consumers that eat producers– CarnivoresCarnivores

Primary consumers eat primary consumersPrimary consumers eat primary consumersThird and higher level consumers: carnivores that eat Third and higher level consumers: carnivores that eat carnivores.carnivores.

– OmnivoresOmnivoresFeed on both plant and animals.Feed on both plant and animals.

– ScavengersScavengersFeed on dead leftovers, lazy hunters.Feed on dead leftovers, lazy hunters.

AerobicAerobic and and AnaerobicAnaerobic Respiration: Getting Energy for Respiration: Getting Energy for

SurvivalSurvivalOrganisms break down carbohydrates and other organic Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need.compounds in their cells to obtain the energy they need.This is usually done through This is usually done through aerobic (cellular) aerobic (cellular) respirationrespiration..– The opposite of photosynthesisThe opposite of photosynthesis

Aerobic and Anaerobic Aerobic and Anaerobic Respiration: Getting Energy for Respiration: Getting Energy for

SurvivalSurvivalAnaerobic respiration or fermentationAnaerobic respiration or fermentation::– Some decomposers get energy by breaking Some decomposers get energy by breaking

down glucose (or other organic compounds) in down glucose (or other organic compounds) in the the absence of oxygenabsence of oxygen..

– The end products vary based on the chemical The end products vary based on the chemical reaction:reaction:

Methane gasMethane gasEthyl alcoholEthyl alcoholAcetic acidAcetic acidHydrogen sulfideHydrogen sulfide

Decomposers and DetrivoresDecomposers and Detrivores

– DecomposersDecomposers: Recycle nutrients in ecosystems.: Recycle nutrients in ecosystems.Bacteria and fungiBacteria and fungi

– DetrivoresDetrivores: Insects or other scavengers that feed on wastes : Insects or other scavengers that feed on wastes or dead bodies.or dead bodies. Figure 3-13Figure 3-13

ENERGY FLOW IN ECOSYSTEMSENERGY FLOW IN ECOSYSTEMS

Food chainsFood chains and and webswebs show how show how eaters, the eaten, eaters, the eaten, and the and the decomposed are decomposed are connected to one connected to one another in an another in an ecosystem.ecosystem.


Energy Flow in an Ecosystem: Energy Flow in an Ecosystem: Losing Energy in Food Chains Losing Energy in Food Chains

and Websand WebsEcological Ecological efficiencyefficiency: : percentage of percentage of useable energy useable energy transferred as transferred as biomass from biomass from one trophic level one trophic level to the next. to the next. Energy lost as Energy lost as heat.heat.


Productivity of Producers: Productivity of Producers: The Rate Is CrucialThe Rate Is Crucial

• Net primary productionNet primary production (NPP) (NPP) Energy captured Energy captured

through through photosynthesis minus photosynthesis minus the energy respired the energy respired by the producers. by the producers. The energy respired The energy respired is the energy used for is the energy used for survival and stored survival and stored as biomass.as biomass.

What are nature’s three most productive and What are nature’s three most productive and three least productive systems?three least productive systems?


Biomass PyramidBiomass PyramidBiomassBiomass – amount of living matter – amount of living matter

BIODIVERSITYBIODIVERSITY


Why Should We Care About Why Should We Care About Biodiversity? Biodiversity?

Biodiversity – Biodiversity – the variety of different species, the variety of different species, variety of ecosystems, and genetic variability variety of ecosystems, and genetic variability within each species.within each species.Biodiversity provides us with:Biodiversity provides us with:– Natural Resources (food water, wood, energy, and Natural Resources (food water, wood, energy, and

medicines)medicines)– Natural Services (air and water purification, soil Natural Services (air and water purification, soil

fertility, waste disposal, pest control)fertility, waste disposal, pest control)– Aesthetic pleasureAesthetic pleasure

Ecosystem ServicesEcosystem ServicesProvisions – Provisions – ecosystems provide goods humans can use (lumber, ecosystems provide goods humans can use (lumber, food crops, medicinal plants, natural rubber, furs, pharmaceutical drugs)food crops, medicinal plants, natural rubber, furs, pharmaceutical drugs)

Regulating Services – Regulating Services – ecosystems regulate nutrient and ecosystems regulate nutrient and hydrological cycles (a lot of carbon is removed from atmosphere by hydrological cycles (a lot of carbon is removed from atmosphere by rainforests and oceans)rainforests and oceans)

Support Systems – Support Systems – pollination of food crops, natural pest control pollination of food crops, natural pest control services, filter pathogens and chemicals from waterservices, filter pathogens and chemicals from water

Cultural Services – intellectual and aesthetic Cultural Services – intellectual and aesthetic satisfactionsatisfactionResilience – Resilience – rate at which an ecosystem returns to its original state rate at which an ecosystem returns to its original state after a disturbance (higher genetic diversity usually means higher after a disturbance (higher genetic diversity usually means higher resilience)resilience)

EVOLUTION, NATURAL EVOLUTION, NATURAL SELECTION, AND ADAPTATIONSELECTION, AND ADAPTATION

Biological evolution by Biological evolution by natural selectionnatural selection involves the change in a population’s involves the change in a population’s genetic makeup through successive genetic makeup through successive generations.generations.– genetic variabilitygenetic variability– MutationsMutations: random changes in the structure or : random changes in the structure or

number of DNA molecules in a cell that can number of DNA molecules in a cell that can be be inheritedinherited by offspring. by offspring.

Natural Selection and Adaptation: Natural Selection and Adaptation: Leaving More Offspring With Leaving More Offspring With

Beneficial TraitsBeneficial TraitsThree conditions are necessary for biological Three conditions are necessary for biological evolution:evolution:– Genetic variabilityGenetic variability, traits must be heritable, trait , traits must be heritable, trait

must lead to must lead to differential reproductiondifferential reproduction. .

An An adaptive traitadaptive trait is any heritable trait that is any heritable trait that enables an organism to survive through enables an organism to survive through natural selection and reproduce better under natural selection and reproduce better under prevailing environmental conditions.prevailing environmental conditions.

Coevolution: A Biological Arms Coevolution: A Biological Arms RaceRace

CoevolutionCoevolution - Interacting species can - Interacting species can engage in a back and forth genetic contest engage in a back and forth genetic contest in which each gains a temporary genetic in which each gains a temporary genetic advantage over the other.advantage over the other.– This often happens between predators and prey This often happens between predators and prey

species.species.

ECOLOGICAL NICHES AND ECOLOGICAL NICHES AND ADAPTATIONADAPTATION

Each species in an ecosystem has a Each species in an ecosystem has a nicheniche or a or a specific rolespecific role or way of life. or way of life.– Fundamental nicheFundamental niche: the full potential range of : the full potential range of

physical, chemical, and biological conditions and physical, chemical, and biological conditions and resources a species could theoretically use.resources a species could theoretically use.

– Realized nicheRealized niche: to survive and avoid : to survive and avoid competition, a species usually occupies only competition, a species usually occupies only part of its fundamental niche.part of its fundamental niche.

Generalist and Specialist Species: Generalist and Specialist Species: Broad and Narrow NichesBroad and Narrow Niches

GeneralistGeneralist species tolerate species tolerate a wide range of a wide range of conditions.conditions.SpecialistSpecialist species can species can only tolerate a only tolerate a narrow range of narrow range of conditions.conditions.


SPECIATION, EXTINCTION, AND SPECIATION, EXTINCTION, AND BIODIVERSITYBIODIVERSITY

SpeciationSpeciation: A new species can arise when : A new species can arise when member of a population become isolated member of a population become isolated for a long period of time.for a long period of time.– Genetic makeup changes, preventing them Genetic makeup changes, preventing them

from producing fertile offspring with the from producing fertile offspring with the original population if reunited.original population if reunited.

Geographic IsolationGeographic Isolation

……can lead to reproductive isolation, can lead to reproductive isolation, divergence of gene pools and speciation.divergence of gene pools and speciation.


Species Diversity and Niche Species Diversity and Niche Structure: Different Species Structure: Different Species

Playing Different RolesPlaying Different RolesBiological communities differ in the types and Biological communities differ in the types and numbers of species they contain and the numbers of species they contain and the ecological roles those species play.ecological roles those species play.– Species diversitySpecies diversity: the number of different : the number of different

species it contains (species it contains (species richnessspecies richness) combined ) combined with the abundance of individuals within each of with the abundance of individuals within each of those species (those species (species evennessspecies evenness).).

TYPES OF SPECIESTYPES OF SPECIES

NativeNative: those that : those that normally live and normally live and thrive in a particular thrive in a particular community.community.

Nonnative speciesNonnative species: : those that migrate, those that migrate, deliberately or deliberately or accidentally accidentally introduced into a introduced into a community.community.

Indicator SpeciesIndicator Species: : Biological Smoke AlarmsBiological Smoke Alarms

Species that serve as early warnings of Species that serve as early warnings of damage to a community or an ecosystem.damage to a community or an ecosystem.They have such narrow zones of tolerance They have such narrow zones of tolerance that when they have “issues” it is a sign that when they have “issues” it is a sign that something is different from optimum.that something is different from optimum.– Presence or absence of trout species Presence or absence of trout species

because they are sensitive to temperature because they are sensitive to temperature and oxygen levels.and oxygen levels.

Keystone Species: Major PlayersKeystone Species: Major Players

Keystone speciesKeystone species help determine the help determine the types and numbers of other species in a types and numbers of other species in a community thereby helping to sustain it.community thereby helping to sustain it.

Figures 7-4 and 7-5Figures 7-4 and 7-5

Foundation Species: Foundation Species: Other Major PlayersOther Major Players

Expansion of keystone species category.Expansion of keystone species category.Foundation species can create and Foundation species can create and enhance habitats that can benefit other enhance habitats that can benefit other species in a community.species in a community.– Wolves in YellowstoneWolves in Yellowstone– Elephants push over, break, or uproot trees, Elephants push over, break, or uproot trees,

creating forest openings promoting grass creating forest openings promoting grass growth for other species to utilize.growth for other species to utilize.

SPECIES INTERACTIONS: SPECIES INTERACTIONS: COMPETITION AND COMPETITION AND

PREDATIONPREDATIONSpecies called Species called predatorspredators feed on other feed on other species called species called preyprey..Organisms use their senses their senses to Organisms use their senses their senses to locate objects and prey and to attract locate objects and prey and to attract pollinators and mates.pollinators and mates.Some predators are fast enough to catch their Some predators are fast enough to catch their prey, some hide and lie in wait, and some prey, some hide and lie in wait, and some inject chemicals to paralyze their prey.inject chemicals to paralyze their prey.

SPECIES INTERACTIONS: SPECIES INTERACTIONS: PARASITISM, MUTUALISM, AND PARASITISM, MUTUALISM, AND

COMMENSALIMCOMMENSALIMParasitism (+and -)Parasitism (+and -) occurs when one occurs when one species feeds on part of another organism.species feeds on part of another organism.In In mutualism (+ and +)mutualism (+ and +), two species , two species interact in a way that benefits both.interact in a way that benefits both.Commensalism (+ and o)Commensalism (+ and o) is an interaction is an interaction that benefits one species but has little, if that benefits one species but has little, if any, effect on the other species.any, effect on the other species.

Parasitism (+ and -): Sponging Parasitism (+ and -): Sponging Off of OthersOff of Others

Although parasites can harm their hosts, Although parasites can harm their hosts, they can promote community biodiversity.they can promote community biodiversity.– Some parasites live in host (micororganisms, Some parasites live in host (micororganisms,

tapeworms).tapeworms).– Some parasites live outside host (fleas, ticks, Some parasites live outside host (fleas, ticks,

mistletoe plants, sea lampreys).mistletoe plants, sea lampreys).– Some have little contact with host (dump-Some have little contact with host (dump-

nesting birds like cowbirds, some duck nesting birds like cowbirds, some duck species)species)

Commensalism (+ and o): Using Commensalism (+ and o): Using without Harmingwithout Harming

Some species Some species interact in a interact in a way that helps way that helps one species one species but has little or but has little or no effect on the no effect on the other.other.


CompetitionCompetition (- and -) (- and -)In competition they both theoretically loose. A In competition they both theoretically loose. A community interaction where there is a fight for food, community interaction where there is a fight for food, territory, or mates. Energy is lost by both in the territory, or mates. Energy is lost by both in the struggle. struggle. InterspecificInterspecific and and IntraspecificIntraspecific competition. competition.

Competition Reduction Competition Reduction Strategy:Strategy:

Resource PartitioningResource Partitioning

Each species minimizes Each species minimizes competition with the others competition with the others for food by spending at for food by spending at least half its feeding time least half its feeding time in a distinct portion of the in a distinct portion of the spruce tree and by spruce tree and by consuming somewhat consuming somewhat different insect species.different insect species.

Specialized Feeding NichesSpecialized Feeding Niches

Resource partitioning reduces Resource partitioning reduces competition and allows sharing of limited competition and allows sharing of limited resources.resources.


Ecotones on LandEcotones on Land

Shares many of the Shares many of the species and species and characteristics of both characteristics of both ecosystemsecosystemsMay also include May also include unique conditions that unique conditions that support distinctive support distinctive plant and animal plant and animal speciesspecies

Terrestrial-to-Aquatic-System Terrestrial-to-Aquatic-System EcotoneEcotone

Shares many of the Shares many of the species and species and characteristics of both characteristics of both ecosystemsecosystemsMay also include May also include unique conditions that unique conditions that support distinctive support distinctive plant and animal plant and animal speciesspecies

POPULATION DYNAMICS AND POPULATION DYNAMICS AND CARRYING CAPACITYCARRYING CAPACITY

Most populations live in clumps although other Most populations live in clumps although other patterns occur based on resource distribution.patterns occur based on resource distribution.


Exponential and Logistic Exponential and Logistic Population Growth: J-Curves and Population Growth: J-Curves and

S-CurvesS-CurvesPopulations Populations grow rapidly with grow rapidly with ample ample resources, but resources, but as resources as resources become limited, become limited, its growth rate its growth rate slows and levels slows and levels off.off.


Reproductive PatternsReproductive Patterns

r-selected species r-selected species tend to be opportunists tend to be opportunists (generalist) while (generalist) while K-selected species K-selected species tend to tend to be competitors (specialist).be competitors (specialist).


SPECIES EXTINCTIONSPECIES EXTINCTION

Species can become extinct: Species can become extinct: – LocallyLocally: A species is no longer found in an : A species is no longer found in an

area it once inhabited but is still found area it once inhabited but is still found elsewhere in the world.elsewhere in the world.

– EcologicallyEcologically: Occurs when so few members : Occurs when so few members of a species are left they no longer play its of a species are left they no longer play its ecological role.ecological role.

– Globally (biologically)Globally (biologically): Species is no longer : Species is no longer found on the earth.found on the earth.

Global ExtinctionGlobal Extinction

Some animals have become prematurely Some animals have become prematurely extinct because of human activities.extinct because of human activities.


Endangered and Threatened Endangered and Threatened Species: Ecological Smoke Species: Ecological Smoke

AlarmsAlarms

Endangered speciesEndangered species: so few individual : so few individual survivors that it could soon become extinct.survivors that it could soon become extinct.Threatened speciesThreatened species: still abundant in its : still abundant in its natural range but is likely to become natural range but is likely to become endangered in the near future.endangered in the near future.


Some species Some species have have characteristics characteristics that make them that make them vulnerable to vulnerable to ecological and ecological and biological biological extinctionextinction..

SPECIES SPECIES EXTINCTIONEXTINCTION


SPECIES EXTINCTIONSPECIES EXTINCTIONScientists use measurements and models to Scientists use measurements and models to estimate extinction rates.estimate extinction rates.– The The International Union for the Conservation of Nature International Union for the Conservation of Nature

and Natural Resources and Natural Resources (IUCN) publishes an annual (IUCN) publishes an annual Red ListRed List, listing the world’s threatened species., listing the world’s threatened species.

– The 2004 Red List contains 15,589 species at risk for The 2004 Red List contains 15,589 species at risk for extinction.extinction.

– For the United States – For the United States – US Fish and Wildlife Dep. US Fish and Wildlife Dep. Lists / Delists species and enforces protection.Lists / Delists species and enforces protection.


HABITAT LOSS, DEGRADATION, HABITAT LOSS, DEGRADATION, AND FRAGMENTATIONAND FRAGMENTATION

Conservation biologists summarize the most Conservation biologists summarize the most important causes of premature extinction as important causes of premature extinction as ““HIPPCOHIPPCO”: ”: – HHabitat destruction, degradation, and fragmentationabitat destruction, degradation, and fragmentation– IInvasive speciesnvasive species– PPopulation growth (Human)opulation growth (Human)– PPollutionollution– CClimate Changelimate Change– OOverharvestverharvest


The greatest threat to a species is the loss, The greatest threat to a species is the loss, degradation, and fragmentation of where it lives.degradation, and fragmentation of where it lives.



Reduction in Reduction in ranges of four ranges of four wildlife species, wildlife species, mostly due to mostly due to habitat loss habitat loss and and overharvest.overharvest.


Case Study: Case Study: A Disturbing Message from the A Disturbing Message from the

BirdsBirdsThe majority of the The majority of the world’s bird species world’s bird species are found in South are found in South America.America.– Threatened with Threatened with

habitat loss and habitat loss and invasive species.invasive species.


INVASIVE SPECIESINVASIVE SPECIESA nonnative species that A nonnative species that dominates or outcompetes dominates or outcompetes native species. native species. Some are Some are good, just not in the good, just not in the nonnative area. They can nonnative area. They can provide us with food, provide us with food, medicine, and other medicine, and other benefits but a few can wipe benefits but a few can wipe out native species, disrupt out native species, disrupt ecosystems, and cause ecosystems, and cause large economic losses.large economic losses.

Kudzu vine was introduced in Kudzu vine was introduced in the southeastern U.S. to the southeastern U.S. to control erosion. It has taken control erosion. It has taken over native species habitats.over native species habitats.

Figure 11-AFigure 11-A

INVASIVE SPECIESINVASIVE SPECIES

US spent $1.2 billion in 2007US spent $1.2 billion in 2007Globally $1.4 trillionGlobally $1.4 trillion


CowbirdCowbird

INVASIVE SPECIESINVASIVE SPECIES

The Argentina fire The Argentina fire ant was introduced ant was introduced to Mobile, Alabama to Mobile, Alabama in 1932 from South in 1932 from South America.America.– Most probably from Most probably from

ships.ships.– No natural No natural

predators.predators.


Introduced Species: Rabbits in Introduced Species: Rabbits in AustraliaAustralia

Introduced into Australia from England in Introduced into Australia from England in 18591859No natural enemies – rabbit population No natural enemies – rabbit population explodedexplodedOverabundant herbivore population Overabundant herbivore population devastated natural vegetation (see Fig. 4-devastated natural vegetation (see Fig. 4-11 in text).11 in text).Using disease as control measure – why Using disease as control measure – why will this procedure fail in the long-term?will this procedure fail in the long-term?

Zebra MusselsZebra Mussels

Water HyacinthsWater Hyacinths

Fig. 11-13, p. 236

• Climate similar to habitat of invader

• Absence of predators on invading species

• Early successional systems

• Low diversity of native species

• Absence of fire

• Disturbed by human activities

Characteristics ofSuccessful

Invader Species

• High reproductive rate, short generation time (r-selected species)

• Pioneer species

• Long lived

• High dispersal rate

• Release growth-inhibiting chemicals into soil

• Generalists

• High genetic variability

Characteristics ofEcosystems Vulnerable

to Invader Species

PollutionPollutionEach year pesticides:Each year pesticides:– Kill about 1/5Kill about 1/5thth of the of the

U.S. honeybee U.S. honeybee colonies.colonies.

– 67 million birds.67 million birds.– 6 -14 million fish.6 -14 million fish.– Threaten 1/5Threaten 1/5thth of the of the

U.S.’s endangered U.S.’s endangered and threatened and threatened species.species.

Example of Example of biomagnificationbiomagnification of DDT in an aquatic food of DDT in an aquatic food chain.chain.


Effects of climate change on Effects of climate change on Biodiversity: Biodiversity:

Winners and LosersWinners and LosersPossible effects of Possible effects of climate change on climate change on the geographic the geographic range of beech range of beech trees based on trees based on ecological ecological evidence and evidence and computer models.computer models.

OVEREXPLOITATIONOVEREXPLOITATION

PoachingPoaching - Some protected species are - Some protected species are killed for their valuable parts or are sold live killed for their valuable parts or are sold live to collectors.to collectors.Killing predators and pests that bother us or Killing predators and pests that bother us or cause economic losses threatens some cause economic losses threatens some species with premature extinction.species with premature extinction.Legal and illegal trade in wildlife species Legal and illegal trade in wildlife species used as pets or for decorative purposes used as pets or for decorative purposes threatens some species with extinction.threatens some species with extinction.

OVEREXPLOITATIONOVEREXPLOITATION

Rhinoceros are Rhinoceros are often killed for their often killed for their horns and sold horns and sold illegally on the illegally on the black market for black market for decorative and decorative and medicinal medicinal purposes.purposes.


Case Study: Case Study: The U.S. Endangered Species ActThe U.S. Endangered Species Act

One of the world’s most far-reaching and One of the world’s most far-reaching and controversial environmental laws is the controversial environmental laws is the 1973 1973 U.S. Endangered Species ActU.S. Endangered Species Act ( (ESAESA).).– ESA forbids federal agencies (besides defense ESA forbids federal agencies (besides defense

department) to carry out / fund projects that would department) to carry out / fund projects that would jeopardize an endangered species.jeopardize an endangered species.

– ESA makes it illegal for Americans to engage in ESA makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect commerce associated with or hunt / kill / collect endangered or threatened species.endangered or threatened species.

PROTECTING WILD SPECIES: PROTECTING WILD SPECIES: LEGAL AND ECONOMIC LEGAL AND ECONOMIC

APPROACHESAPPROACHESInternational treaties have helped reduce the International treaties have helped reduce the international trade of endangered and international trade of endangered and threatened species, but enforcement is difficult.threatened species, but enforcement is difficult.– One of the most powerful is the 1975 One of the most powerful is the 1975 Convention Convention

on International Trade of Endangered Specieson International Trade of Endangered Species ((CITESCITES).).

Signed by 169 countries, lists 900 species that cannot be Signed by 169 countries, lists 900 species that cannot be commercially traded.commercially traded.

International International Biodiversity HotspotsBiodiversity Hotspots

60% of the biodiversity is located on just 1.4% of the Earth’s land surface.

RECONCILIATION ECOLOGYRECONCILIATION ECOLOGY

Reconciliation ecologyReconciliation ecology involves finding ways involves finding ways to share places we dominate with other to share places we dominate with other species.species.– Replacing monoculture grasses with native Replacing monoculture grasses with native

species.species.– Maintaining habitats for insect eating bats can Maintaining habitats for insect eating bats can

keep down unwanted insects.keep down unwanted insects.– Reduction and elimination of pesticides to protect Reduction and elimination of pesticides to protect

non-target organisms (such as vital insect non-target organisms (such as vital insect pollinators).pollinators).

AQUATIC BIODIVERSITYAQUATIC BIODIVERSITYWe know fairly little about the biodiversity of We know fairly little about the biodiversity of the world’s marine and freshwater systems.the world’s marine and freshwater systems.– The greatest marine biodiversity occurs in coral The greatest marine biodiversity occurs in coral

reefs, estuaries and the deep ocean floor.reefs, estuaries and the deep ocean floor.– Biodiversity is higher near the coast and surface Biodiversity is higher near the coast and surface

because of habitat and food source variety.because of habitat and food source variety.

The world’s marine and freshwater systems The world’s marine and freshwater systems provide important ecological and economic provide important ecological and economic services.services.

Population Growth and PollutionPopulation Growth and Pollution

Each year plastic Each year plastic items dumped items dumped from ships and left from ships and left as litter on as litter on beaches threaten beaches threaten marine life.marine life.


Overfishing and Extinction: Overfishing and Extinction: Gone Fishing, Fish GoneGone Fishing, Fish Gone

About 75% of the world’s commercially About 75% of the world’s commercially valuable marine fish species are over fished valuable marine fish species are over fished or fished near their sustainable limits.or fished near their sustainable limits.– Big fish are becoming scarce.Big fish are becoming scarce.– Smaller fish are next.Smaller fish are next.– We throw away 30% of the fish we catch.We throw away 30% of the fish we catch.– We needlessly kill sea mammals and birds.We needlessly kill sea mammals and birds.

Fig. 12-A, p. 255

Fish farming in cage

Trawler fishing

Spotter airplane

Sonar

Trawl flapTrawl lines

Purse-seine fishing

Trawl bagFish school

Drift-net fishingLong line fishing

Lines with hooks

Fish caught by gills

Deep sea aquaculture cage

Float Buoy

Why is it Difficult to Protect Why is it Difficult to Protect Aquatic Biodiversity?Aquatic Biodiversity?

Rapid increasing human impacts, the Rapid increasing human impacts, the invisibility of problems, citizen unawareness, invisibility of problems, citizen unawareness, and lack of legal jurisdiction hinder protection and lack of legal jurisdiction hinder protection of aquatic biodiversity.of aquatic biodiversity.– Human ecological footprint is expanding.Human ecological footprint is expanding.– Much of the damage to oceans is not visible to Much of the damage to oceans is not visible to

most people.most people.– Many people incorrectly view the oceans as an Many people incorrectly view the oceans as an

inexhaustible resource.inexhaustible resource.

PROTECTING AND SUSTAINING PROTECTING AND SUSTAINING MARINE BIODIVERSITYMARINE BIODIVERSITY

Laws, international treaties, and education Laws, international treaties, and education can help reduce the premature extinction can help reduce the premature extinction of marine species.of marine species.Since 1989 the U.S. government has Since 1989 the U.S. government has required offshore shrimp trawlers to use required offshore shrimp trawlers to use turtle exclusion devices (T.E.D.s).turtle exclusion devices (T.E.D.s).– Sea turtle tourism brings in almost three times Sea turtle tourism brings in almost three times

as much money as the sale of turtle products.as much money as the sale of turtle products.

PROTECTING AND SUSTAINING PROTECTING AND SUSTAINING MARINE BIODIVERSITYMARINE BIODIVERSITY

Fully protected marine reserves make up Fully protected marine reserves make up less than 0.3% of the world’s ocean area.less than 0.3% of the world’s ocean area.– Studies show that fish populations double, size Studies show that fish populations double, size

grows by almost a third, reproduction triples and grows by almost a third, reproduction triples and species diversity increases by almost one fourth.species diversity increases by almost one fourth.

Some communities work together to develop Some communities work together to develop integrated plans for managing their coastal integrated plans for managing their coastal areas.areas.

Fig. 12-7, p. 261

SolutionsManaging Fisheries

Fishery Regulations

Set catch limits well below the maximum sustainable yield

Improve monitoring and enforcement of regulationsEconomic Approaches

Sharply reduce or eliminate fishing subsidies

Charge fees for harvesting fish and shellfish from publicly owned offshore waters

Certify sustainable fisheriesProtected Areas

Establish no-fishing areas

Establish more marine protected areas

Rely more on integrated coastal managementConsumer Information

Label sustainably harvested fish

Publicize overfished and threatened species

Bycatch

Use wide-meshed nets to allow escape of smaller fish

Use net escape devices for sea birds and sea turtles

Ban throwing edible and marketable fish back into the seaAquaculture

Restrict coastal locations for fish farms

Control pollution more strictly

Depend more on herbivorous fish species

Nonnative Invasions

Kill organisms in ship ballast water

Filter organisms from ship ballast water

Dump ballast water far at sea and replace with deep-sea water

what sustains life on earth? solar energy, the cycling of matter, and gravity sustain the earth’s...

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