ExtinctionExtinction

ExtinctionExtinction

The Definition and CausesThe Definition and Causes

What is Extinction?What is Extinction?

Extinction occurs when the last existing Extinction occurs when the last existing member of a given species diesmember of a given species dies In other words…there aren’t any more left!In other words…there aren’t any more left!

It is a scientific certainty when there are It is a scientific certainty when there are not any surviving individuals left to not any surviving individuals left to reproducereproduce

Functional ExtinctionFunctional Extinction Only a handful of individuals are leftOnly a handful of individuals are left Odds of reproduction are slimOdds of reproduction are slim

Causes of ExtinctionCauses of Extinction

Genetics and DemographicsGenetics and Demographics Small populations = increased riskSmall populations = increased risk MutationsMutations

• Causes a flux in natural selectionCauses a flux in natural selection• Beneficial genetic traits are overruledBeneficial genetic traits are overruled

Loss of Genetic DiversityLoss of Genetic Diversity• Shallow gene pools promote massive inbreedingShallow gene pools promote massive inbreeding

Causes Con’t.Causes Con’t.

Habitat DegradationHabitat Degradation One of the most influentialOne of the most influential Has many causesHas many causes Some due to humansSome due to humans Some due to other factorsSome due to other factors

Habitat DegradationHabitat Degradation

ToxicityToxicity Kills off species directly through food/waterKills off species directly through food/water Indirectly via sterilizationIndirectly via sterilization Can occur in short spans (a single generation)Can occur in short spans (a single generation) Can occur over several generationsCan occur over several generations

• Increasing toxicityIncreasing toxicity• Increasing competition for habitat resourcesIncreasing competition for habitat resources

Habitat DegradationHabitat Degradation

Destruction of HabitatDestruction of Habitat ““Save the Rainforests!”Save the Rainforests!” Elimination of living spaceElimination of living space Change in habitatChange in habitat

• Rainforest to pasture landsRainforest to pasture lands Leads to diminishing resourcesLeads to diminishing resources

• Increases competitionIncreases competition Can be caused by natural processesCan be caused by natural processes

• Volcanoes, floods, drought, etc…Volcanoes, floods, drought, etc…

Causes Con’t.Causes Con’t.

PredationPredation CompetitionCompetition DiseaseDisease

CoextinctionCoextinction Mass ExtinctionMass Extinction Planned ExtinctionPlanned Extinction

PredationPredation

Introduction of predatorsIntroduction of predators Invasive alien speciesInvasive alien species Transported by humansTransported by humans

• Cattle, rats, zebra muscles, etc…Cattle, rats, zebra muscles, etc…• Sometimes on purpose, sometimes notSometimes on purpose, sometimes not

Can eat other speciesCan eat other species Eat food sourcesEat food sources Introduce diseasesIntroduce diseases

CoextinctionCoextinction

The loss of one species leads to the loss The loss of one species leads to the loss of anotherof another

Chain of extinctionChain of extinction Can be caused by small impacts in the Can be caused by small impacts in the

beginningbeginning A predator looses its food sourceA predator looses its food source Affected by interconnectedness in natureAffected by interconnectedness in nature

Mass ExtinctionMass Extinction

Aka: an extinction eventAka: an extinction event A sharp decrease in the number of A sharp decrease in the number of

species on Earth in a short period of timespecies on Earth in a short period of time Coincides with a sharp drop in speciationCoincides with a sharp drop in speciation

The process by which new biological species The process by which new biological species arisearise

There have been at least 5There have been at least 5 Last one was 65M years agoLast one was 65M years ago

Mass Extinction DiagramMass Extinction Diagram

Mass ExtinctionMass Extinction

Nearly 2/3rds (or more) of all animal Nearly 2/3rds (or more) of all animal species that ever existed on the planet are species that ever existed on the planet are now gone. now gone.

• With contemporary extinction being attributed to With contemporary extinction being attributed to HUMAN activity. HUMAN activity.

Numerous factors go into the extinction of Numerous factors go into the extinction of a specific species.a specific species.

• Though all point the finger to climate change.Though all point the finger to climate change.

Mass ExtinctionMass Extinction

Began about three-million years ago Began about three-million years ago (Continental Glaciations).(Continental Glaciations).

Hypotheses for initial extinction:Hypotheses for initial extinction:• Sea level depletion vs. Temperature decreaseSea level depletion vs. Temperature decrease

Though these hypotheses aren’t mutually Though these hypotheses aren’t mutually exclusive, they may have conspired exclusive, they may have conspired together. together.

Mass Extinctions Mass Extinctions

1.1. Cretaceous-Tertiary Extinction (65). Cretaceous-Tertiary Extinction (65).

2.2. End Triassic Extinction (200). End Triassic Extinction (200).

3.3. Permian Triassic ExtinctionPermian Triassic Extinction (250). (250).

4.4. Late Devonian Extinction (364). Late Devonian Extinction (364).

5.5. Ordovician-Silurian ExtinctionOrdovician-Silurian Extinction (440). (440).

(#= millions of years ago)(#= millions of years ago)

Planned ExtinctionPlanned Extinction

Human controlledHuman controlled Thought of to help humansThought of to help humans Deadly virusesDeadly viruses

SmallpoxSmallpox• Extinct in the wildExtinct in the wild

PolioPolio• Near extinct (only in small parts of the world)Near extinct (only in small parts of the world)

Natural Causes of Natural Causes of ExtinctionExtinction

Climatic Heating and CoolingClimatic Heating and Cooling

Changes in Sea Level or CurrentsChanges in Sea Level or Currents

www.johnstonsarchive.net/spaceart/cylmaps.html www.johnstonsarchive.net/spaceart/cylmaps.html

AsteroidsAsteroids

Causes complete Causes complete devastationdevastation

Flattening and crater at Flattening and crater at

or around impact site-or around impact site-hundreds of miles widehundreds of miles wide

Reverberations felt around Reverberations felt around the worldthe world

Cosmic RadiationCosmic Radiation

www.iit.edu/~ipro313s/home.html www.iit.edu/~ipro313s/home.html

Acid RainAcid Rain

Kills acid intolerant Kills acid intolerant

speciesspecies

Disease/EpidemicsDisease/EpidemicsDisease/EpidemicsDisease/Epidemics

Can wipe out entire Can wipe out entire speciesspecies

Frog with fungus Frog with fungus diseasedisease

Killing frogs and other Killing frogs and other amphibiansamphibians

Spread of Invasive SpeciesSpread of Invasive Species

Natural factors usually occur at a slower rate and therefore cause a low extinction rate. Human activities occur at a faster rate and cause higher extinction rates. Human activities are mostly responsible for the present extinction rates.

http://www.gov.mb.ca/conservation/sustain/extinct.pdf

Human Causes of Extinction

Top Human Causes of Extinction:

Increased human population

Destruction/Fragmentation of habitat

Pollution

Climate change/Global warming

Extinctions caused by humans are generally considered to be a recent phenomena. HOWEVER:

•In Australia—earliest humans: 64,000 years ago

extinction—30,000-60,000 years ago

•In the Americas—80% of large animals became extinct around the same time as first human presence there

Based on these, and other studies done by The international Union for Conservation of Nature and Natural Resources (IUCN), human induced extinctions are not necessarily a new phenomena. However, extinction by humans today is becoming much more rapid.

The rapid loss of species today is estimated by some experts to be between 100 and 1,000 times higher than the natural extinction rate, while others estimate rates as high as 1,000-11,000 times higher.

Habitat Degradation

Habitat loss and degradation affect 86% of all threatened birds, 86% of mammals and 88% of threatened amphibians

Climate change/Global Warming

John W. Williams from UW-Madison suggests that changes in regions such as the Peruvian Andes, portions of the Himalayas and southern Australia could have a profound impact on indigenous plants and animals

Williams and his research partners used computer models to estimate how various parts of the world would be affected by regional changes consistent with the IPCC's climate models.

Their findings indicated that “By the end of the 21st century, large portions of the Earth’s surface may experience climates not found at present and some 2th century climates may disappear.”

Their studies also suggest isolated climates such as the Peruvian Andes could change drastically enough to lead to species extinctions.

The climate change might also create new climates, providing new opportunities for other species to thrive, Williams said.

Regions where novel climates are expected to form in tropical and subtropical regions include the western Sahara, southeastern U.S. and eastern India.

Extinction HotspotsExtinction Hotspots

Where and what are hotspots?Where and what are hotspots? ““The concept of biodiversity hotspots was The concept of biodiversity hotspots was

penned by British ecologist Norman Myers in penned by British ecologist Norman Myers in 1988 as a means to address the dilemma of 1988 as a means to address the dilemma of identifying the areas most important for identifying the areas most important for preserving species.” (national geographic) preserving species.” (national geographic)

Hotspots are included in 6 continents excluding Hotspots are included in 6 continents excluding Antarctica. Antarctica.

Hotspots are heavily distributed along shore Hotspots are heavily distributed along shore lines and near the equator. lines and near the equator.

Hotspots are effected by many factors Hotspots are effected by many factors includingincluding LoggingLogging Agriculture Agriculture Hunting Hunting Climate changeClimate change GovernmentGovernment

Hotspots can be added and removed from Hotspots can be added and removed from the classification of “hotspot” by what the classification of “hotspot” by what recovery or lack of prevention is taking recovery or lack of prevention is taking place in each area.place in each area.

What is required to be considered a What is required to be considered a hotspothotspot

““The region must support at least 1,500 The region must support at least 1,500 plant species found nowhere else in the plant species found nowhere else in the world, and it must have lost at least 70 world, and it must have lost at least 70 percent of its original habitat.” percent of its original habitat.”

Interactive mapsInteractive maps

http://www.biodiversityhotspots.org/xp/Hothttp://www.biodiversityhotspots.org/xp/Hotspots/home/interactive_map.xmlspots/home/interactive_map.xml

http://www.zeroextinction.org/pointmapper/http://www.zeroextinction.org/pointmapper/azefiles/index.htmlazefiles/index.html

What is Biodiversity?What is Biodiversity? Biodiversity is the variation of taxonomic life Biodiversity is the variation of taxonomic life

forms for a given biome or ecosystemforms for a given biome or ecosystem Boosts Ecosystem productivityBoosts Ecosystem productivity Measure of the health of a biological systemMeasure of the health of a biological system

Benefits of BiodiversityBenefits of Biodiversity

Food and drinkFood and drink MedicinesMedicines Industrial materialsIndustrial materials Ecological servicesEcological services Leisurely, cultural, and Leisurely, cultural, and aesthetic valuesaesthetic values

Causes of Biodiversity LossCauses of Biodiversity Loss

PollutionPollution Loss of tropical forestLoss of tropical forest Spread of urban areasSpread of urban areas WarfareWarfare Large dam constructionLarge dam construction Road buildingRoad building TourismTourism Loss of traditional Loss of traditional

lifestyleslifestyles

Consequences of Biodiversity LossConsequences of Biodiversity Loss Loss of foodLoss of food Decrease in biomassDecrease in biomass Collapse of food webCollapse of food web Loss of keystone speciesLoss of keystone species Reduction of ecosystem Reduction of ecosystem

efficiency and community efficiency and community productivityproductivity

Loss of medicinal suppliesLoss of medicinal supplies Increased vulnerability of Increased vulnerability of

species to disease and species to disease and predationpredation

CropsCropsMonoculture of crops lets the yield Monoculture of crops lets the yield become susceptible to pests or viruses become susceptible to pests or viruses 75% of crop varieties are extinct 75% of crop varieties are extinct Due to the spread of modern agriculture Due to the spread of modern agriculture

Tropical Forest CuttingTropical Forest Cutting Cover 13% of EarthCover 13% of Earth Home to 50% of all known plant and animal Home to 50% of all known plant and animal

speciesspecies FAO reports 15.4 million hectares are FAO reports 15.4 million hectares are

destroyed annuallydestroyed annually

The Convention on Biological The Convention on Biological DiversityDiversity

Mission StatementMission Statement

““The objectives of this convention are the The objectives of this convention are the conservation of biological diversity, sustainable conservation of biological diversity, sustainable use of its components and the fair and equitable use of its components and the fair and equitable

sharing of the benefits arising out of the sharing of the benefits arising out of the utilization of genetic resources.”utilization of genetic resources.”

Since it was adopted at the Earth Summit in Rio de Janeiro in 1992, Since it was adopted at the Earth Summit in Rio de Janeiro in 1992, 189 countries have signed and implemented it. The United States 189 countries have signed and implemented it. The United States signed it in 1993 but has yet to put it into action still todaysigned it in 1993 but has yet to put it into action still today

The Convention on Biological The Convention on Biological DiversityDiversity

2010 Biodiversity Target2010 Biodiversity Target

Members adopted a plan to significantly reduce the present Members adopted a plan to significantly reduce the present rate of biodiversity loss at the global, regional and rate of biodiversity loss at the global, regional and national level by the year 2010.national level by the year 2010.

References References Ceballos, G., and Ehrlich, P., 2002, Mammal Population Losses and the Extinction Ceballos, G., and Ehrlich, P., 2002, Mammal Population Losses and the Extinction

Crisis: Crisis: Science, v. 296, p. 904-908.Science, v. 296, p. 904-908. Fahrig, L., 2002, Effect of Habitat Fragmentation on the Extinction Threshold: A Fahrig, L., 2002, Effect of Habitat Fragmentation on the Extinction Threshold: A Synthesis: Ecological Applications, v. 12, p. 346-353.Synthesis: Ecological Applications, v. 12, p. 346-353. Gittleman, J., The Risk of Extinction—What you don’t know will hurt you: Science, v. Gittleman, J., The Risk of Extinction—What you don’t know will hurt you: Science, v.

291. 291. Petcchey, O.L., and Gaston, K.J., Extinction and the loss of functional diversity: They Petcchey, O.L., and Gaston, K.J., Extinction and the loss of functional diversity: They

Royal Royal Society, p. 1721-1727. Society, p. 1721-1727. Rutledge, D., Lepczyk, C., Xie, J., Liu, J., 2001, Spatiotemporal Dynamics of Rutledge, D., Lepczyk, C., Xie, J., Liu, J., 2001, Spatiotemporal Dynamics of

EndangeredEndangered Species Hotspots in the United States: Conservation Biology, v. 15, p. 475- 487.Species Hotspots in the United States: Conservation Biology, v. 15, p. 475- 487. Kent, Holsinger. "The Causes of Extinction." 27 Aug. 2005. 12 Mar. 2007 Kent, Holsinger. "The Causes of Extinction." 27 Aug. 2005. 12 Mar. 2007

<http://darwin.eeb.uconn.edu/eeb310/lecture-notes/extinctions/node3.html>. <http://darwin.eeb.uconn.edu/eeb310/lecture-notes/extinctions/node3.html>. Madeley, J., Warnock, K., 1995, Biodiversity: A Matter of Extinction: The challenge of Madeley, J., Warnock, K., 1995, Biodiversity: A Matter of Extinction: The challenge of

protecting the South’s biological heritage <http://www.panos.org.uk/pdf/reports/ protecting the South’s biological heritage <http://www.panos.org.uk/pdf/reports/ biodiversity.pdf>.biodiversity.pdf>.

Trombulak, Stpehen C., et. Al. 2004, Principles of Conservation Biology: RecommendedTrombulak, Stpehen C., et. Al. 2004, Principles of Conservation Biology: Recommended Guidelines for Conservation Literacy from the Education Committee of the Society forGuidelines for Conservation Literacy from the Education Committee of the Society for Bald Eagle. US Fish and Wildlife Service <http://www.fws.gov/endangered/i/b/msab0h.html>.Bald Eagle. US Fish and Wildlife Service <http://www.fws.gov/endangered/i/b/msab0h.html>. Conservation Biology: Conservation Biology Conservation Biology: Conservation Biology

<http://www.conbio.org/Resources/Education/conservation_literacy_english.pdf>.<http://www.conbio.org/Resources/Education/conservation_literacy_english.pdf>. Extinction. Lecture by Bruce Walsh at University of Arizona, 1995. Extinction. Lecture by Bruce Walsh at University of Arizona, 1995. <http://nitro.biosci.arizona.edu/courses/EEB105/lectures/extinction/extinction.html>.<http://nitro.biosci.arizona.edu/courses/EEB105/lectures/extinction/extinction.html>.

References References Trombulak, Stpehen C., et. Al. 2004, Principles of Conservation Trombulak, Stpehen C., et. Al. 2004, Principles of Conservation Biology: RecommendedBiology: RecommendedGuidelines for Conservation Literacy from the Education Guidelines for Conservation Literacy from the Education Committee of the Society forCommittee of the Society forBald Eagle. US Fish and Wildlife Service Bald Eagle. US Fish and Wildlife Service <http://www.fws.gov/endangered/i/b/msab0h.html>.<http://www.fws.gov/endangered/i/b/msab0h.html>.Conservation Biology: Conservation Biology Conservation Biology: Conservation Biology <http://www.conbio.org/Resources/Education/conservation_literac<http://www.conbio.org/Resources/Education/conservation_literacy_english.pdf>.y_english.pdf>.Extinction. Lecture by Bruce Walsh at University of Arizona, Extinction. Lecture by Bruce Walsh at University of Arizona, 1995. 1995. <http://nitro.biosci.arizona.edu/courses/EEB105/lectures/<http://nitro.biosci.arizona.edu/courses/EEB105/lectures/extinction/extinction.html>.extinction/extinction.html>.