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Species extinction lecture 2016-17
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- 2. Core Case Study:Where have AllCore Case Study: Where have All The Honeybees Gone?The Honeybees Gone? Bees play a key role in pollinationBees play a key role in pollination Globally, about 1/3 of food supply comesGlobally, about 1/3 of food supply comes from insect-pollinated plantsfrom insect-pollinated plants Currently, agriculture depends heavily onCurrently, agriculture depends heavily on a single species of beea single species of bee Suffering from Colony Collapse DisorderSuffering from Colony Collapse Disorder Each year, 30-50% ofEach year, 30-50% of colonies in Europe andcolonies in Europe and the U.S.the U.S.
- 3. ExtinctionExtinction Background extinctionBackgroundextinction – typical low rate of– typical low rate of extinctionextinction 0.0001% of species per year0.0001% of species per year Mass extinctionMass extinction – significant rise above– significant rise above background levelbackground level 25 – 95% of species25 – 95% of species 5 historically5 historically Currently 6Currently 6thth ??
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- 5. Effects of Humanson BiodiversityEffects of Humans on Biodiversity Biodiversity = speciation – extinctionBiodiversity = speciation – extinction Scientific consensus – human activities areScientific consensus – human activities are decreasing the earth’s biodiversitydecreasing the earth’s biodiversity Extinction now 100 – 10,000X background rateExtinction now 100 – 10,000X background rate Maybe half of existing species extinct by 2100Maybe half of existing species extinct by 2100
- 7. Case Study: ThePassenger Pigeon -Case Study: The Passenger Pigeon - Gone ForeverGone Forever Once most numerousOnce most numerous bird on earthbird on earth 1858 – Passenger1858 – Passenger Pigeon hunting becamePigeon hunting became big businessbig business By 1900 – extinct fromBy 1900 – extinct from over-harvest andover-harvest and habitat losshabitat loss
- 8. SPECIES EXTINCTIONSPECIES EXTINCTION Species can become extinct:Species can become extinct: LocallyLocally – species no longer found in area it once– species no longer found in area it once inhabited, but found elsewhere in worldinhabited, but found elsewhere in world EcologicallyEcologically – when so few members of a– when so few members of a species left, no longer play ecological rolespecies left, no longer play ecological role Biologically (globally)Biologically (globally) – species no longer– species no longer found on earthfound on earth
- 9. Global ExtinctionGlobal Extinction Some animals have become prematurelySome animals have become prematurely extinct because of human activitiesextinct because of human activities
- 10. Endangered and ThreatenedSpecies:Endangered and Threatened Species: Ecological Smoke AlarmsEcological Smoke Alarms Endangered speciesEndangered species – so few individual– so few individual survivors that it could soon become extinctsurvivors that it could soon become extinct Threatened speciesThreatened species – still present in its– still present in its natural range but is likely to becomenatural range but is likely to become endangered in the near futureendangered in the near future
- 11. Fig. 11-3, p.224 Grizzly bear Kirkland’s warbler Knowlton cactus Florida manatee African elephant Utah prairie dog Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger
- 12. Fig. 11-3, p.224 Hawksbill sea turtle Giant panda Black-footed ferret Whooping crane Northern spotted owl Blue whale Mountain gorilla Florida panther California condor Black rhinoceros
- 13. Some speciesSomespecies have traits thathave traits that make themmake them vulnerable tovulnerable to ecological andecological and biologicalbiological extinctionextinction SPECIESSPECIES EXTINCTIONEXTINCTION
- 14. SPECIES EXTINCTIONSPECIES EXTINCTION Scientists use measurements and models toScientists use measurements and models to estimate extinction ratesestimate extinction rates The International Union for the Conservation ofThe International Union for the Conservation of Nature (IUCN) – annualNature (IUCN) – annual Red ListRed List – lists the– lists the world’s threatened speciesworld’s threatened species The 2015 Red List contains 23,250 speciesThe 2015 Red List contains 23,250 species threatened with extinctionthreatened with extinction The IUCN Red List: Guiding Conservation for 50 Years The IUCN Red List: A Barometer of Life
- 15. SPECIES EXTINCTIONSPECIES EXTINCTION Percentage of various species typesPercentage of various species types threatened with premature extinction fromthreatened with premature extinction from human activitieshuman activities
- 16. IMPORTANCE OF WILDSPECIESIMPORTANCE OF WILD SPECIES We should not cause the prematureWe should not cause the premature extinction of species because of theextinction of species because of the economic and ecological services theyeconomic and ecological services they provide – medicine, food, genes, ecotourism,provide – medicine, food, genes, ecotourism, etc. –etc. – instrumental valueinstrumental value Some believe that each wild species has anSome believe that each wild species has an inherent right to exist – ethical –inherent right to exist – ethical – intrinsicintrinsic valuevalue
Editor's Notes
- #12 Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger.
- #13 Figure 11.3 Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger.