BiodiversityBiodiversityChapters 5 and 11 and not in exact

order

Striking gold in Costa RicaStriking gold in Costa Rica• Golden toads were

discovered in 1964, in Monteverde, Chile

• The mountainous cloud forest has a perfect climate for amphibians

• Unfortunately, they became extinct within 25 years – Due to global

warming’s drying effect on the forest

Central Case: Saving the Siberian tiger

Central Case: Saving the Siberian tiger

• The largest cat in the world• The Russian Far East mountains

house the last remaining tigers• Nearly became extinct due to

hunting, poaching and habitat destruction

• International conservation groups saved the species from extinction

– Research, education, zoos, and captive breeding programs

Evolution: the source of Earth’s biodiversity

Evolution: the source of Earth’s biodiversity

• Biological evolution = genetic change in populations of organisms across generations

• May be random or directed by natural selection– Natural Selection = the process by

which traits that enhance survival and reproduction are passed on more frequently to future generations than those that do not

New Species arise from old speciesNew Species arise from old species

• It alters the genetic makeup of a population

• It is important for understanding antibiotic and pesticide resistance, agricultural issues, production, medicines, etc.

• Organisms adapt to their environment and change over time

Natural selection shapes organismsNatural selection shapes organisms• In 1858, Darwin and Wallace both proposed

natural selection as the mechanism of evolution– Organisms face a constant struggle to

survive and reproduce– Organisms tend to produce more offspring

than can survive– Individuals of a species vary in their

characteristics due to genes and the environment

– Some individuals are better suited to their environment and will survive and pass their genes on in their offspring

Genetic variationGenetic variation

• Adaptive Trait (Adaptation) = a trait that promotes reproductive success

• Mutations = accidental changes in DNA that may be passed on to the next generation– Non-lethal mutations provide the genetic variation on

which natural selection acts

• Sexual reproduction also leads to variation

Natural selection acts on genetic variation

Natural selection acts on genetic variation

• Directional selection = drives a feature in one direction

• Stabilizing selection = produces intermediate traits, preserving the status quo

• Disruptive selection = traits diverge in two or more directions

If the environment changes, a trait may no longer be adaptive

Evidence of natural selection is everywhere

Evidence of natural selection is everywhere

• It is evident in every adaptation of every organism

• Evident in bacteria and fruit flies in laboratories

• Selective breeding of animals

Artificial selectionArtificial selection

• Artificial Selection = the process of selection conducted under human direction– For example, artificial selection has led to the

great variety of dog breeds

Evolution generates biodiversityEvolution generates biodiversity• Biological Diversity = An area’s sum total of all

organisms – The diversity of species – Their genes – Their populations– Their communities

• Species = a population or group of populations whose members share characteristics and can freely breed with one another and produce fertile offspring

• Population = a group of individuals of a species that live in the same area

Speciation produces new types of organismsSpeciation produces new types of organisms• The process of generating

new species

– A single species can generate multiple species

• Allopatric speciation = species formation due to physical separation of populations

– Can be separated by glaciers, rivers, mountains

– The main mode of species creation

Another type of speciationAnother type of speciation

• Sympatric speciation = species form from populations that become reproductively isolated within the same area– Feed in different areas, mate in different seasons– Hybridization between two species

– Mutations

Speciation results in diverse life forms

Speciation results in diverse life forms• Speciation generates complex patterns of diversity

above the species level• Phylogenetic trees (Cladograms) = Represents the

history of species divergence– Scientists can trace when certain traits evolved– Show relationships between species

ExtinctionExtinction

• Species generally evolve from simple to complex and small to big, but the opposite can occur, and some even disappear

• Extinction = the disappearance of a species from Earth

– Occurs when a species cannot adapt quickly enough to a changing environment

– Speciation and extinction affect species numbers

Extinction is a natural processExtinction is a natural process

• Extinction is irreversible: once a species is lost, it is lost forever

• Humans profoundly affect rates of extinction

Some species are more vulnerable to extinction

Some species are more vulnerable to extinction

• Extinction occurs when the environment changes too rapidly for natural selection to keep up

• Endemic species = a species only exists in a certain, specialized area– Very susceptible to extinction– These species usually have small populations

• Many other factors also cause extinction– Severe weather– New species– Specialized species

Earth has had several mass extinctions

Earth has had several mass extinctions

• Background extinction rate = extinction usually occurs one species at a time

• Mass extinction events = five events in Earth’s history that killed off massive numbers of species at once– 50-95% of all species went extinct at one time

• Humans are causing the sixth mass extinction event– Resource depletion– Population growth– Development

Biodiversity losses and species extinction

Biodiversity losses and species extinction

• Extinction = occurs when the last member of a species dies and the species ceases to exist

• Extirpation (local extinction) = the disappearance of a particular population from a given area, but not the entire species globally– Can lead to extinction

• Mass depletion =occurs when the rate of extinction is greater than usual background rate

• Commercial extinction =too few to make it worth catching and sell

Extinction is a natural processExtinction 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

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

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

People have hunted species to extinction for millennia

Extinctions followed human arrival on islands and continents

Current extinction rates are higher than normal

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

Ecology is studied at several levelsEcology is studied at several levels

• Ecology and evolution are tightly intertwined

• Biosphere = the total living things on Earth and the areas they inhabit

• Ecosystem = communities and the nonliving material and forces they interact with

• Community = interacting species that live in the same area

Levels of ecological organizationLevels of ecological organization

• Population ecology = investigates the quantitative dynamics of how individuals within a species interact

• Community ecology = focuses on interactions among species

• Ecosystem ecology = studies living and nonliving components of systems to reveal patterns– Nutrient and energy flows

Organismal ecology: habitatOrganismal ecology: habitat• Habitat = the environment in which an organism

lives

– Includes living and nonliving elements

– Scale-dependent: from square meters to miles

• Habitat use = each organism thrives in certain habitats, but not in others

• Habitat selection = the process by which organisms actively select habitats in which to live

– Availability and quality of habitat are crucial to an organism’s well-being

– Human developments conflict with this process

Organismal ecology: nicheOrganismal ecology: niche• Niche = an organism’s use of resources and its

functional role in a community– Habitat use, food selection, role in energy and

nutrient flow– Interactions with other individuals

• Specialists = species with narrow niches and very specific requirements– Extremely good at what they do, but vulnerable

to change• Generalists = species with broad niches that can

use a wide array of habitats and resources– Able to live in many different places

Population characteristics

Population characteristics

• All populations show characteristics that help scientists predict their future dynamics

• Population size = the number of individual organisms present at a given time– Numbers can increase,

decrease, cycle or remain the same

Population characteristicsPopulation characteristics

• Population density = the number of individuals within a population per unit area– High densities make it easier to find mates, but

increase competition, and vulnerability to predation

– Low densities make it harder to find mates, but individuals enjoy plentiful resources and space

Population characteristicsPopulation characteristics• Population distribution

(dispersion) = spatial arrangement of organisms within an area – Random – haphazardly

located individuals, with no pattern

– Uniform – individuals are evenly spaced due to territoriality

– Clumped – arranged according to availability of resources• Most common in

nature

Birth and death ratesBirth and death rates

• Crude birth/death rates = rates per 1000 individuals

• Survivorship curves = the likelihood of death varies with age – Type I: More deaths at

older ages– Type II: Equal number

of deaths at all ages– Type III: More deaths

at young ages

Four factors of population changeFour factors of population change

• Natality = births within the population • Mortality = deaths within the population• Immigration = arrival of individuals from outside

the population • Emigration = departure of individuals from the

population• Growth rate formula =

– (Crude birth rate + immigration rate) - (Crude death rate + emigration rate) = Growth rate

Exponential population growthExponential population growth

• Steady growth rates cause exponential population growth– Something increases by

a fixed percent– Graphed as a J-shaped

curve• Exponential growth cannot

be sustained indefinitely– It occurs in nature with a

small population and ideal conditions

Limiting factors restrain growthLimiting factors restrain growth

• Limiting factors = physical, chemical and biological characteristics that restrain population growth– Water, space, food, predators, and disease

• Environmental resistance = All limiting factors taken together

Carrying capacityCarrying capacity

• Carrying capacity = the maximum population size of a species that its environment can sustain

– An S-shaped logistic growth curve

– Limiting factors slow and stop exponential growth

• Carrying capacity changes

Humans have raised their carrying capacity by decreasing the carrying capacity for other species

Perfect logistic curves aren’t often found

Perfect logistic curves aren’t often found

Population density affects limiting factors

Population density affects limiting factors

• Density-dependent factors = limiting factors whose influence is affected by population density– Increased risk of predation and competition for mates

occurs with increased density

• Density-independent factors = limiting factors whose influence is not affected by population density – Events such as floods, fires, and landslides

Biotic potential and reproductive strategies vary

Biotic potential and reproductive strategies vary

• Biotic potential = the ability of an organism to produce offspring

• K-selected species = animals with long gestation periods and few offspring – Have a low biotic potential– Stabilize at or near carrying capacity– Good competitors

• r-selected species = animals which reproduce quickly– Have a high biotic potential– Little parental care

K-selected vs. r-selected speciesK-selected vs. r-selected species

Population changes affect communitiesPopulation changes affect communities

• As population in one species declines, other species may appear

• Human development now displaces other species and threatens biodiversity– As Monteverde dried out, species from lower, drier

habitats appeared– But, species from the cloud-forest habitats disappeared

Challenges to protecting biodiversityChallenges to protecting biodiversity

• Social and economic factors affect species and communities– Nature is viewed as an obstacle to development– Nature is viewed as only a source of resources– Human population growth pressures biodiversity

Preserving biodiversityPreserving biodiversity• Natural parks and protected areas help

preserve biodiversity– Often, they are underfunded– Ecotourism brings jobs and money to

developing areas

Biodiversity encompasses several levels

Biodiversity encompasses several levels

• Humans are reducing Earth’s diversity of life

• Biodiversity – sum total of all organisms in an area– Split into three specific levels:

• Species diversity

• Genetic diversity

• Ecosystem diversity

Species diversitySpecies 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

The taxonomy of speciesThe taxonomy of species• Taxonomists = scientists

who classify species– Physical appearance and

genetics determines a species

– Genera = related species are grouped together

– Families = groups of genera

• Every species has a two-part scientific name: genus and species

Subspecies: the level below a speciesSubspecies: the level below a species• Subspecies = populations of species that occur in

different areas and differ slightly from each other– Divergence stops short of separating the species– Subspecies are denoted with a third part of the

scientific name

Siberian tiger = Panthera tigris altaica

Bengal tiger = Panthera tigris tigris

Genetic diversityGenetic 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 diversityEcosystem 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

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

Insects outnumber all other species

Measuring biodiversity is not easyMeasuring 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 distributedBiodiversity 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

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 loss is more than extinction

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 causesBiodiversity 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 lossHabitat 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

Habitat alteration has occurred in every biome

Particularly in tropical rainforests, savannas, and tropical dry forests

Invasive species cause biodiversity loss

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 lossPollution 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

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

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

Warming has been the greatest in the Arctic

The polar bear is being considered for the endangered species list

It isn’t currently on list and may not make the list because part of the ESA, endangered species act, is habitat protection. For polar bears this would mean protecting sea ice from melting-or reduction in global warming.

Biodiversity loss has a variety of causes

Biodiversity loss has a variety of causes

Biodiversity provides free ecosystem services

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 helps maintain ecosystem function

• Biodiversity increases the stability and resilience of communities and ecosystems – Decreased biodiversity reduces a natural system’s

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 securityBiodiversity enhances food security

• Genetic diversity within crops is enormously valuable

– Turkey’s 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 sourcesSome potential new food sources

Organisms provide drugs and medicines

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

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 naturePeople 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?

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 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 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 biogeographyIsland 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 island’s species richness based on the island’s size and distance from the mainland

Species richness results from island size and distance

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 curveThe 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 speciesSmall “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

Should conservation focus on endangered species?

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

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 controversialThe 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

Other countries have their own version of the ESA

• Species at Risk Act (2002) = Canada’s 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 biodiversityProtecting 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 biodiversityProtecting 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 speciesUmbrella 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 Fund’s panda bear

• Some organizations are moving beyond the single species approach to focus on whole landscapes

International conservation effortsInternational 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 biodiversity’s

benefits– By 2007, 188 nations had signed on– Iraq, Somalia, the Vatican, and the U.S. did not

join

Biodiversity hotspotsBiodiversity 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

There are 34 global biodiversity hotspots

2.3% of the planet’s land surface contains 50% of the world’s plant species and 42% of all terrestrial vertebrate species

Community- based conservationCommunity- 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 strategiesInnovative economic strategies

• Debt-for-nature swap = a conservation organization pays off a portion of a developing country’s 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

ConclusionConclusion

• 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 biodiversity’s benefits

• Science can help save species, preserve habitats, restore populations, and keep natural ecosystems intact