evolution, extinction, maintaining biodiversity chapter 5

Evolution, Extinction, Maintaining Biodiversity Chapter 5

Key Concepts Ecology and populations Human effects on biodiversity Importance of biodiversity How human activities affect wildlife Management of wildlife

Ecology Study of how organisms interact with one another and with their nonliving environment Sustainable ecosystems have a balance and resilience in these relationships between the organisms and the environment in a way that perpetuates the system without depleting the resources

Setting up the hierarchy Cell organism (prokaryote, eukaryotic, species, asexual, sexual) Population- all individuals of a species in an area genetic diversity: size age distrib density genetic composition Habitat-location, address Niche-function or role in ecosystem community-populations interacting in area ecosystem-community of diff species interacting w one another & with their nonliving env of matter & energy biome biosphere

Population dynamics respond to Environmental stress Changes in environmental conditions

ecosystems mosaic of vegetation patches 1-can lead to edges or boundaries 2-ecotones

Fig. 9.2, p. 199 Clumped (elephants) Uniform (creosote bush) Random (dandelions) Dispersion: spatial pattern

Biotic potential Capacity for growth If a population is at biotic potential, it is probably colonizing new areas Intrinsic rate of increase (r ) is the rate of growth, reproductive rate, if there were unlimited resources

Growth factors Favorable environmental conditions High fecundity Generalized niche Adequate food supply Suitable habitat Ability to compete for resources Ability to protect from predation and diseases or parasites Able to migrate Able to adapt to environmental change

Environmental resistances Unfavorable abiotic factors Low reproductive rate Specialized niche Inadequate food supply Poor or unsuitable habitat Too much competition Unable to protect against predation and disease Unable to live in other habitats Inability to adapt to environmental change

Major Characteristics of a population Size: N number of individuals Density: number of individuals per unit space Dispersion: spatial pattern Age distribution

Environmental resistances Unfavorable abiotic factors Low reproductive rate Specialized niche Inadequate food supply Poor or unsuitable habitat Too much competition Unable to protect against predation and disease Unable to live in other habitats Inability to adapt to environmental change

Carrying capacity No population can grow indefinitely Environmental resistances limit population growth Carrying capacity (K) of a population is the result of environmental resistances on biotic potential or the population size that can be sustained indefinitely in a given area

Opportunistic vs. Equilibrium Species R selected species small bodied Mature rapidly Highly fecund Numerous offspring No parental care Short lived opportunistic K selected species Larger Slow maturation (yrs) Low fecundity Few offspring Require parental care Live long equilibrium

Carrying Capacity dN = rN and dN= rN(K-N) dT dT K

Exponential growth If there are few resource limitations, then exponential growth could occur A small population doubles slowly and then as the numbers increase the doubling rate decreases resulting in a J shaped curve

Logistic growth Exponential population growth is decreased with the population encounters environmental resistance (no food, no suitable habitat, competition and so on) After a sharp increase, the growth decreases resulting in an S shaped curve

Fig. 9.4, p. 201 Time (t) Population size (N) K Exponential GrowthLogistic Growth Exponential and Logistic growth

Fig. 9.5, p. 201 2.0 1.5 1.0.5 Number of sheep (millions) 180018251850187519001925 Year Logistic growth

Density Independent Factors on population growth Affect populations size regardless of population density Floods Fires Hurricanes Unseasonable weather Habitat destruction pesticides

Density dependent Factors on population growth Competition for resources Predation Parasitism disease

Fig. 9.6, p. 201 2,000 1,500 Number of reindeer 19101920193019401950 Year 1,000 500 Exponential growth followed by population crash

Types of population fluctuations Stable Irruptive (explosive) Irregular (no known pattern or etiology) Cyclic (boom and bust)

Fig. 9.7, p. 202 Number of individuals Time Irruptive Stable Cyclic Irregular Types of population fluctuations

Biodiversity encompasses several levels Humans are reducing Earths diversity of life Biodiversity sum total of all organisms in an area Split into three specific levels: Species diversity Genetic diversity Ecosystem diversity

Species diversity Species Diversity = the number or variety of species in the world or in a particular region Richness = the number of species Evenness or relative abundance = extent to which numbers of individuals of different species are equal or skewed Speciation generates new species and adds to species richness Extinction reduces species richness

Genetic diversity Encompasses the differences in DNA among individuals within species and populations The raw material for adaptation to local conditions Populations with higher genetic diversity can survive They can cope with environmental change Populations with low genetic diversity are vulnerable To environmental change Disease Inbreeding depression = genetically similar parents mate and produce inferior offspring

Ecosystem diversity Ecosystem diversity = the number and variety of ecosystems Also encompasses differing communities and habitats Rapid vegetation change and varying landscapes within an ecosystem promote higher levels of biodiversity

Some groups contain more species than others Species are not evenly distributed among taxonomic groups Insects predominate over all other life-forms 40% of all insects are beetles Groups accumulate species by Adaptive radiation Allopatric speciation Low rates of extinction

Insects outnumber all other species

Measuring biodiversity is not easy Out of the estimated 3 - 100 million species on Earth, only 1.7 - 2 million species have been successfully catalogued Very difficult to identify species Many remote spots on Earth remain unexplored Small organisms are easily overlooked Many species look identical until thoroughly examined Entomologist Terry Erwin found 163 beetle species specialized on one tree species

Biodiversity is unevenly distributed Living things are distributed unevenly across Earth Latitudinal gradient = species richness increases towards the equator Canada has 30 - 100 species of breeding birds, while Costa Rica has more than 600 species

Latitudinal gradient has many causes Climate stability, high plant productivity, and no glaciation Tropical biomes support more species and show more species evenness Diverse habitats increase species diversity Human disturbance can increase habitat diversity But only at the local level

Biodiversity losses and species extinction Extinction = occurs when the last member of a species dies and the species ceases to exist Extirpation = the disappearance of a particular population from a given area, but not the entire species globally Can lead to extinction

Extinction is a natural process Paleontologists estimate 99% of all species that ever lived are now extinct Background rate of extinction = natural extinctions for a variety of reasons 1 extinction per 1 to 10 million species for mammals and marine species 1 species out of 1,000 mammal and marine species would go extinct every 1,000 to 10,000 years

Earth has experienced five mass extinctions In the past 440 million years, mass extinctions have eliminated at least 50% of all species After every mass extinction the biodiversity returned to or exceeded its original state

The current mass extinction is human caused During this Quaternary period, we may lose more than half of all species Hundreds of human-induced species extinctions, and multitudes of others, teeter on the brink of extinction The current global extinction rate is 100 to 1,000 times greater than the background rate This rate will increase tenfold in future decades due to human population growth and resource consumption

People have hunted species to extinction for millennia Extinctions followed human arrival on islands and continents

Current extinction rates are higher than normal The Red List = an updated list of species facing high risks of extinctions 23% of mammal species 12% of bird species 31 - 86% of all other species Since 1970, 58 fish species, 9 bird species, and 1 mammal species has gone extinct In the U.S., in the last 500 years, 236 animal and 17 plant species are confirmed extinct Actual numbers are undoubtedly higher

Biodiversity loss is more than extinction Decreasing numbers are accompanied by smaller species geographic ranges Genetic, ecosystem, and species diversity are being lost. The Living Planet Index summarizes trends in populations Between 1970 and 2003, the Index fell by 30%

Biodiversity loss has many causes Reasons for biodiversity losses are multifaceted, complex, and hard to determine Factors may interact synergistically Four primary causes of population decline are: Habitat alteration Invasive species Pollution Overharvesting Global climate change now is the fifth cause

Habitat alteration causes biodiversity loss The greatest cause of biodiversity loss Farming simplifies communities Grazing modifies the grassland structure and species composition Clearing forests removes resources organisms need Hydroelectric dams turn rivers into reservoirs upstream Urbanization and suburban sprawl reduce natural communities A few species (i.e., pigeons, rats) benefit from changing habitats

Habitat alteration has occurred in every biome Particularly in tropical rainforests, savannas, and tropical dry forests

Invasive species cause biodiversity loss Introduction of non-native species to new environments Accidental: zebra mussels Deliberate: food crops Island species are especially vulnerable Invaders have no natural predators, competitors, or parasites Cost billions of dollars in economic damage

Pollution causes biodiversity loss Harms organisms in many ways Air pollution degrades forest ecosystems Water pollution adversely affects fish and amphibians Agricultural runoff harms terrestrial and aquatic species The effects of oil and chemical spills on wildlife are dramatic and well known The damage to wildlife and ecosystems caused by pollution can be severe But it tends to be less than the damage caused by habitat alteration or invasive species

Overharvesting causes biodiversity loss Vulnerable species are large, few in number, long-lived, and have few young (K-selected species) The Siberian tiger is hunted without rules and regulations The early 1990s saw increased poaching because of powerful economic incentives Many other species affected: Atlantic gray whale, sharks, gorillas Today the oceans contain only 10% of the large animals they once did

Climate change causes biodiversity loss Emissions of greenhouse gases warms temperatures Modifies global weather patterns and increases the frequency of extreme weather events Increases stress on populations and forces organisms to shift their geographic ranges Most animals and plants will not be able to cope

Warming has been the greatest in the Arctic The polar bear is being considered for the endangered species list

Biodiversity loss has a variety of causes

Biodiversity provides free ecosystem services Provides food, shelter, fuel Purifies air and water, and detoxifies wastes Stabilizes climate, moderates floods, droughts, wind, temperature Generates and renews soil fertility and cycles nutrients Pollinates plants and controls pests and disease Maintains genetic resources Provides cultural and aesthetic benefits Allows us to adapt to change The annual value of just 17 ecosystem services = $16 - 54 trillion per year

Biodiversity helps maintain ecosystem function Biodiversity increases the stability and resilience of communities and ecosystems Decreased biodiversity reduces a natural systems ability to function and provide services to our society The loss of a species affects ecosystems differently If the species can be functionally replaced by others, it may make little difference Extinction of a keystone species may cause other species to decline or disappear To keep every cog and wheel is the first precaution of intelligent tinkering (Aldo Leopold)

Biodiversity enhances food security Genetic diversity within crops is enormously valuable Turkeys wheat crops received $50 billion worth of disease resistance from wild wheat Wild strains provide disease resistance and have the ability to grow back year after year without being replanted New potential food crops are waiting to be used Serendipity berry produces a sweetener 3,000 times sweeter than sugar

Some potential new food sources

Organisms provide drugs and medicines Each year pharmaceutical products owing their origin to wild species generate up to $150 billion in sales The rosy periwinkle produces compounds that treat Hodgkin's disease and leukemia

Biodiversity generates economic benefits People like to experience protected natural areas, creating economic opportunities for residents, particularly in developing countries Costa Rica: rainforests Australia: Great Barrier Reef Belize: reefs, caves, and rainforests A powerful incentive to preserve natural areas and reduce impacts on the landscape and on native species But, too many visitors to natural areas can degrade the outdoor experience and disturb wildlife

People value and seek out nature Biophilia = connections that humans subconsciously seek with life Our affinity for parks and wildlife Keeping of pets High value of real estate with views of natural lands Nature deficit disorder = alienation from the natural environment May be behind the emotional and physical problems of the young

Do we have ethical obligations to other species? Humans are part of nature and need resources to survive But, we also have conscious reasoning ability and can control our actions Our ethics have developed from our intelligence and our ability to make choices Many people feel that other organisms have intrinsic value and an inherent right to exist

Conservation biology responds to biodiversity loss Conservation biology = devoted to understanding the factors that influence the loss, protection, and restoration of biodiversity Arose as scientists became alarmed at the degradation of natural systems An applied and goal- oriented science

Conservation scientists work at multiple levels Conservation biologists integrate evolution and extinction with ecology and environmental systems Design, test, and implement ways to mitigate human impacts Conservation geneticists = study genetic attributes of organisms to infer the status of their population Minimum viable population = how small a population can become before it runs into problems Metapopulations = a network of subpopulations Small populations are most vulnerable to extinction and need special attention

Island biogeography Equilibrium theory of island biogeography = explains how species come to be distributed among oceanic islands Also applies to habitat islands patches of one habitat type isolated within a sea of others Explains how the number of species on an island results from an equilibrium between immigration and extirpation Predicts an islands species richness based on the islands size and distance from the mainland

Species richness results from island size and distance Fewer species colonize an island far from the mainland Large islands have higher immigration rates Large islands have lower extinction rates

The species-area curve Large islands contain more species than small islands They are easier to find and have lower extinction rates They possess more habitats

Small islands of forest rapidly lose species Forests are fragmented by roads and logging Small forest fragments lose diversity fastest Starting with large species Fragmentation is one of the prime threats to biodiversity

Formation of the earths early crust and atmosphere Small organic molecules form in the seas Large organic molecules (biopolymers) form in the seas First protocells form in the seas Single-cell prokaryotes form in the seas Single-cell eukaryotes form in the seas Variety of multicellular organisms form, first in the seas and later on land Biological Evolution (3.7 billion years) Fig. 5.2, p. 103 Chemical Evolution (1 billion years)

What factors contribute to speciation? Why would an organism be needed? function What could lead to new niches? Structure

cyanobacters May use CO2 from atmosphere or water Can convert EMS energy to chemical energy Created pollution crisis due to production of O2 Contributed to the rise of aerobic prokaryotes

eukaryotes Fossil evidence 1.2 bya some O2 in atmosphere was converted by solar energy to O3 now protected from UV green plants near surface water 780 mya first plants fossil evidence on land

Fossils present but rare Evolution and expansion of life Fossils become abundant Plants invade the land Age of reptiles Age of mammals Insects and amphibians invade the land Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Origin of life (3.63.8 billion years ago)

Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Gray Fox Arctic Fox Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward and separates Southern population Northern population Early fox population Fig. 5.8, p. 113 Allopatric speciation

Sympatric Speciation A new species forms within the same spatial and temporal location as the original species; There is no geographic isolation or difference in diurnal or seasonal patterns Changes in niche availability can lead to sympatric speciation Co-evolution can lead to sympatric speciation Need for resource partitioning can lead to sympatric speciation

What is required to maintain a species?

Maintaining reproductive isolation to remain a species Prezygotic barriers: prevent zygote from forming postzygotic barriers: prevent new species from occurring

Prezygotic barriers Habitat isolation: live in different habitats dont encounter others Behavioral isolation: mating/courtship rituals, songs, other signals Temporal isolation: different mating times diurnal, seasonal, or annual differences Mechanical isolation: anatomically incompatible Gametic isolation: gametes may not meet or cannot fuse

Postzygotic Barriers Reduced hybrid variability: genetic incompatibility may abort development of zygote Reduced hybrid fertility: if hybrid offspring is vigorous, hybrid is sterile-meiosis cant produce gametes Hybrid breakdown: 1 st generation hybrid viable and fertile, 2 nd generation feeble or sterile

microevolution dev of genetic variability in population heritable traits; gene pool alleles 4-mutations: exposure of DNA to ext agents radioactivity, X rays, natural and hman made chem. Mutagens random mistakes DNA copied or when reproduces most mutations harmful few are beneficial bene if: give offspring better chances for survival under existing env conditions and when conditions change mutations random and unpredictable, source of totally new genetic raw material (alleles) and are rare events

selection artificial selection: we choose traits and we selectively breed (dog types) natural selection some indiv of pop have genetically based traits that increase their chances of survival and their ability to produce offspring must be natural variability in pop trait must be heritable trait must lead to differential reproduction (leave more offspring) allele becomes more common in successive pop called adaptation or adaptive trait

When is selection likely to occur? when change in env conditions occurs pop can adapt through nat select or migrate if poss to better conditions or become extinct example: peppered moth in England soot on tree trunks birds eat if not blend in

3 types of natural selection directional natural selection: changing env conditions cause allele freq to shift so individual w traits at end of normal range become more common than midrange forms stabilizing natural selection : favor indivi in mid curve average; works best if env changes little and most member of pop are adapted to env diversifying natural selection : occurs when env cond favor individuals at extremes of curve ;eliminate indeterminate traits ; pop may be split into two groups

Directional selection changing env conditions cause allele freq to shift so individual w traits at end of normal range become more common than midrange forms eg peppered moths, genetic resistance to pesticides or to antibiotics

Natural selection New averagePrevious average Number of individuals Coloration of snails Proportion of light-colored snails in population increases Number of individuals Snail coloration best adapted to conditions Average Coloration of snails Average shifts Directional Natural Selection

stabilizing natural selection favor indivi in mid curve -average works best if env changes little and most member of pop are adapted to env

Coloration of snails Light snails eliminated Dark snails eliminated Number of individuals Coloration of snails Snails with extreme coloration are eliminated Number of individuals Average remains the same, but the number of individuals with intermediate coloration increases Natural selection Stabilizing Natural Selection

diversifying natural selection occurs when env cond favor individuals at extremes of curve eliminate indeterminate traits pop may be split into two groups

Number of individuals with light and dark coloration increases, and the number with intermediate coloration decreases Coloration of snails Number of individuals Snails with light and dark colors dominate Coloration of snails Number of individuals Light coloration is favored Dark coloration is favored Intermediate-colored snails are selected against Natural selection Diversifying Natural Selection

Coevolution interactions between species results in micro evol of each of pop

ecological niche: function include range of tolerance for physical and chemical factors types and amts of resources it uses how interacts w other living and nonliving components role it plays in energy flow adaptative traits reflect niche traits enable population to survive and reproduce effectively under given set environmental conditions

niche significance prevent from becoming prematurely extinct assess environmental changes we make in terrestrial and aquatic systems

fundamental niche vs realized niche Fundamental niche is what it could be in the best of all circumstances Realized niche is what it is with limitations that are present

what limits adaptation? traits have to be present to start w even if beneficial heritable trait present the population ability to adapt can be limited by its reproductive capacity don't just eliminate rest of population so that trait can show-usually most of population still around in gene pool

evolution misconceptions fitness is reprod potential not strongest there is no grand plan for perfection

divergent evolution speciation: geographic isolation - allopatric speciation no geographic isolation: sympatric speciation for either next step is reproductive isolation

Why Should We Care About Biodiversity? Instrumental value Intrinsic value Value of Nature InstrumentalIntrinsic Utilitarian Nonutilitarian (human centered) (species or ecosystem centered) Goods Ecological services Information Option Recreation Existence Aesthetic Bequest

biodiversity: speciation - extinction extinction followed by period of recovery that are characterized by adaptive radiation new species evolve to fill new or vacated ecological roles or niches in changed environments 5 mya years to rebuild biological diversity

Ordovician: 50% of animal families, including many trilobites Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites. Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites. Triassic: 35% of animal families, including many reptiles and marine mollusks. Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including many foraminiferans and mollusks. Current extinction crisis caused by human activities. Many species are expected to become extinct within the next 50100 years. Species and families experiencing mass extinction Bar width represents relative number of living species Extinction Millions of years ago PeriodEra Paleozoic Mesozoic Cenozoic Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Today 65 180 250 345 500 Extinction

Human Impacts on Biodiversity Food supply and demand Freshwater supply and demand Forest product supply and demand Climate change Biodiversity loss Habitat change Changes in transpiration and albedo Loss of crop genetic diversity Reduced resistance to change Loss and fragmentation of habitat CO 2 emission Habitat change and fragmentation of habitat Changes in precipitation and temperature Water availability Water use and pollution and soil nutrient loss CO 2, CH 4, N 2 O emissions Erosion, pollution, and changes in water flow Loss and fragmentation of habitat Loss and fragmentation of habitat Deforestation Changes in water supply and temperature Changes in water supply and temperature Fig. 22.2, p. 551

Increasing Biodiversity Physically diverse habitat Moderate environmental disturbance Small variations in conditions Middle stages of ecological succession

Decreasing Biodiversity Environmental stress Large environmental disturbance Extreme environmental conditions Severe limiting factors Introduction of alien species Geographic isolation

US Diversity 67% Secure or apparently secure 1% Other 16%Vulnerable 8%Imperiled 7%Criticallyimperiled 1% Probably extinct

Strategies for Protecting Biodiversity Species approach Ecosystem approach The Species Approach The Ecosystem Approach Goal Protect species from premature extinction Strategies Identify endangered species Protect their critical habitats Tactics Legally protect endangered species Manage habitat Propagate endangered species in captivity Reintroduce species into suitable habitats Goal Protect populations of species in their natural habitats Strategy Preserve sufficient areas of habitats in different biomes and aquatic systems Tactics Protect habitat areas through private purchase or government action Eliminate or reduce populations of alien species from protected areas Manage protected areas to sustain native species Restore degraded ecosystems

Species Extinction Local extinction Ecological extinction Biological extinction

mass depletion extinction rate higher than normal but not high enough to consider it mass extinct

Endangered and Threatened Species Endangered species: any species that is in danger of extinction throughout all or a significant portion of its range Threatened (vulnerable species) any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range Rare: a species where the population is declining to dangerously low numbers but still has enough members to maintain or increase its population Florida manatee Northern spotted owl (threatened) Gray wolfFlorida panther Bannerman's turaco (Africa)

Extinction Risks Factors: population size, habitat, and genetics Population viability analysis Minimum viable population Minimum dynamic area Characteristics of extinction-prone species

Extinction Rates Background (natural) rate of extinction Mass extinction Adaptive radiations Number of families of marine animals Geological Periods Millions of years ago Mass extinctions 800 600 400 200 0 570505438360286208144650 Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Tertiary Quaternary ? 4082452 Fig. 22.10, p. 558

Causes of Depletion of Wild Species Human population growth Failure to value the environment or ecological services Increasing per capita resource use Increasing use of Earths primary productivity poverty

Causes of Premature Extinction of Wild Species Habitat degradation Introduction of non-native species Overfishing Habitatloss Habitat degradation Introducingnonnativespecies Commercial hunting and poaching Sale of exotic pets and decorative plants Predator and pest control Pollution Climate change Basic Causes Population growthPopulation growth Rising resource useRising resource use No environmental accountingNo environmental accounting PovertyPoverty Fig. 22.13, p. 564

Should conservation focus on endangered species? Endangered Species Act (1973) (ESA) = forbids the government and private citizens from taking actions that destroy endangered species or their habitats To prevent extinction Stabilize declining populations Enable populations to recover As of 2007, the U.S. had 1,312 species listed as endangered or threatened

Despite opposition, the ESA has had successes Peregrine falcons, brown pelicans, bald eagles, and others have recovered and are no longer listed Intensive management has stabilized other species The red-cockaded woodpecker 40% of declining populations are now stable These successes occur despite underfunding of the U.S. Fish and Wildlife Service and the National Marine Fisheries Service In recent years, political forces have attempted to weaken the ESA

The ESA is controversial Many Americans support protection of endangered species Opponents feel that the ESA values endangered organisms more than the livelihood of people Private land use will be restricted if an endangered species is present Shoot, shovel, and shut up = landowners conceal the presence of endangered species on their land But, the ESA has stopped few development projects Habitat conservation plans and safe harbor agreements = landowners can harm species if they improve habitat for the species in other places

Other countries have their own version of the ESA Species at Risk Act (2002) = Canadas endangered species law Stresses cooperation between landowners and provincial governments Criticized as being too weak Other nations laws are not enforced The Wildlife Conservation Society has to help pay for Russians to enforce their own anti-poaching laws

Protecting biodiversity Captive breeding individuals are bred and raised with the intent of reintroducing them into the wild Zoos and botanical gardens Some reintroductions are controversial Ranchers opposed the reintroduction of wolves to Yellowstone National Park Some habitat is so fragmented, a species cannot survive

Protecting biodiversity Cloning a technique to create more individuals and save species from extinction Most biologists agree that these efforts are not adequate to recreate the lost biodiversity Ample habitat and protection in the wild are needed to save species

Umbrella species Conservation biologists use particular species as tools to conserve communities and ecosystems Protecting the habitat of these umbrella species helps protect less-charismatic animals that would not have generated public interest Flagship species large and charismatic species used as spearheads for biodiversity conservation The World Wildlife Funds panda bear Some organizations are moving beyond the single species approach to focus on whole landscapes

International conservation efforts UN Convention on International Trade in Endangered Species of Wild Fauna and Flora (1973) (CITES) protects endangered species by banning international transport of their body parts Convention on Biological Diversity (1992) Seeks to conserve biodiversity Use biodiversity in a sustainable manner Ensure the fair distribution of biodiversitys benefits By 2007, 188 nations had signed on Iraq, Somalia, the Vatican, and the U.S. did not join

Biodiversity hotspots Biodiversity hotspots prioritizes regions most important globally for biodiversity Support a great number of endemic species = species found nowhere else in the world The area must have at least 1.500 endemic plant species (0.5% of the world total) It must have lost 70% of its habitat due to human impact

There are 34 global biodiversity hotspots 2.3% of the planets land surface contains 50% of the worlds plant species and 42% of all terrestrial vertebrate species

Community- based conservation Protecting habitats makes good sense, but this affects people living in and near these areas Community-based conservation = conservation biologists actively engage local people in protecting land and wildlife Protecting land deprives people access to resources But, it can guarantee that these resources will not be used up or sold to foreign corporations and can instead be sustainably managed Many projects have succeeded But, others have not, due mainly to funding problems

Innovative economic strategies Debt-for-nature swap = a conservation organization pays off a portion of a developing countrys international debt In exchange for a promise by the country to set aside reserves Fund environmental education, and Better manage protected areas Conservation concession = conservation organizations pay nations to conserve, and not sell, resources

Solutions: Protecting Wild Species from Depletion and Extinction Bioinformatics International treaties: CITES National Laws: Lacey Act Endangered species Act Habitat conservation plans Wildlife refuges and protected areas Zoos, bontanical gardens, and gene banks

Conclusion Loss of biodiversity will result in a mass extinction Primary causes of biodiversity loss are: Habitat alteration, invasive species, pollution, overharvesting of biotic resources, and climate change Human society cannot function without biodiversitys benefits Science can help save species, preserve habitats, restore populations, and keep natural ecosystems intact

evolution, extinction, maintaining biodiversity chapter 5

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