Extinction

• What prehistoric animals were once living in the Philippines?

  Stegodon and rhinoceroses
• Where were the fossils of Stegodon and rhinoceroses found in the Philippines?

  In Cagayan Valley, Panay Island, Agusan Valley, and Taguig City
• What does the presence of these fossils indicate about the Philippines' geographical history?

  That some islands were once connected to mainland Asia via a land bridge
• During which period did these animals migrate to the Philippines?

  During the last Ice Age
• What happened to Stegodon and rhinoceroses in the Philippines?

  They have long disappeared
• What is extinction?


  It is a process in which a species ceases to exist
• When does extinction typically occur?

  When the death rate is higher than the birth rate
• What happens once an organism becomes extinct?

  The organism is lost forever
• How is extinction related to evolution?

  Extinction is a vital part of evolution
• What drives the process of natural selection?

  Organisms with characteristics well suited to the environment are selected
• What can lead to extinction in organisms?

  Failure to adapt to a changing environment or compete effectively
• What percentage of organisms that ever lived have gone extinct?

  99%
• What does the statistic that only one in a hundred species survives today imply?

  That the vast majority of species that ever existed are now extinct
• What are the main causes of extinction in species?

  • Higher death rate than birth rate
  • Inability to adapt to environmental changes
  • Failure to produce healthy offspring
  • Inability to compete with other organisms