CHAPTER 9

• Bees


  Play a key role in pollination
• European honeybees pollinate 71% of vegetable and fruit crops
• Commercial beekeepers truck hives to farms to pollinate different crops
• Colony Collapse Disorder


  All bees abandon a colony
• Since 2014, U.S. beekeepers have been losing 30–40% of their stock every season
• Species extinction


  • Species are becoming extinct 1,000–10,000 times faster than the historical rate
• Human-related causes of extinction

  • Habitat loss
  • Climate change
  • Ocean acidification
• Extinction


  Extinction of many species in a short period of time
• Past causes of mass extinctions most likely involved global changes in environmental conditions
• Human population has destroyed and degraded habitats
• Extinction rates have risen recently
• Current extinction rate is 1,000 times higher than natural background rate
• Rate of extinction and threats to ecosystem services likely to rise sharply in the next 50–100 years due to harmful human impacts
• Biodiversity hotspots


  Places where extinction rates projected to be much higher than average
• Biologically diverse environments are being eliminated or fragmented
• Jigsaw activity


  1. Break up into groups

  2. Access HHMI Interactive Timeline of the earth's major extinctions

  3. Summarize assigned extinction event and the geologic era that came before it

  4. Share findings with the class
• Endangered species


  So few individuals that the species could soon become extinct
• Threatened species


  Still enough individuals to survive but numbers declining, may soon be endangered
• Regionally extinct


  In areas a species is normally found
• Functionally extinct


  Point where interactions with other species are lost or greatly diminished
• Reasons to avoid hastening the extinction of wild species: they provide valuable ecosystem and economic services, it can take millions of years for nature to recover from large-scale extinctions, many people believe species have a right to exist regardless of their usefulness to humans
• Orangutans


  • Only about 119,000 remain in the wild
  • Tropical forest habitat being cleared to grow palm oil
  • They are illegally smuggled and sold
  • Lowest birth rate of all animals
  • May disappear within two decades without urgent protective action
• Reasons species provide value

  • Pollination, pest control, and oxygen production
  • Food crops, wood for fuel, paper from trees, and ecotourism
  • Bioprospectors search for species that can be used to make medicinal drugs
• Extinction can hinder speciation
• Many people believe species have an intrinsic right to exist
• Greatest threats to species (acronym HIPPCO)

  • Habitat loss, degradation, and fragmentation
  • Invasive (nonnative) species
  • Population and resource use growth
  • Pollution
  • Climate change
  • Overexploitation
• Habitat destruction, degradation, and fragmentation

  • Caused by roads, logging, crops, and urban development
  • Barriers limit species ability to disperse and colonize areas, locate food and mates
• Many species introductions are beneficial
• Nonnative species


  • May have no natural predators, competitors, parasites, or pathogens
  • Can crowd out native species, viewed as harmful, invasive species
• Kudzu vine


  1. Imported from Japan in the 1930s to help control soil erosion

  2. Spreads rapidly, taking over land

  3. Very difficult to kill

  4. Common fungus can kill Kudzu vine

  5. Potential benefits: medicinal and nutritional uses, potential uses as paper, biofuel
• Wild boar invasions


  1. Introduced to the United States in early 1900s, privately owned hunting reserves

  2. Some escaped, some released into the wild

  3. Wild boars multiplied rapidly, with populations in 36 states

  4. Prefer forests but can live anywhere, eat almost anything, do not have enough natural predators to control population
• Burmese python, African python, and boa constrictor in Florida are altering food webs and ecosystem services
• Controlling invasive species


  1. Prevention is the best way to limit the harmful effects

  2. Research programs to identify invaders

  3. Track invasive species with ground surveys and satellite observations

  4. Establish international treaties banning transfer between countries

  5. Public education about releasing exotic pets and plants
• Human population growth and rising resource use per person is degrading wildlife habitat
• Pollution can cause bioaccumulation and extinctions of species not directly affected
• Climate change will accelerate the sixth extinction, leading to major loss of diversity and ecosystem services
• Pollution can cause bioaccumulation and extinctions of species not directly affected by pollution
• European honeybee population has been cut in half over the past 50 years
• Possible reasons for honeybee decline

  • Parasites
  • Viruses
  • Pesticide use
  • Stress from transportation and overwork
  • Poor nutrition from pollinating single crops
• Poaching and smuggling of protected animals is driven by organized crime due to huge profits