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Extinction: Bad Genes or Bad Luck?

Rodriquez Ring-necked Parakeet. Extinction: Bad Genes or Bad Luck?. Defined- the complete death of a taxon. Not to be confused with gradual evolutionary change that leads to the creation of a new species. Which is termed as Anagenesis. First. Remain. Species A. Unchanged. Speciation.

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Extinction: Bad Genes or Bad Luck?

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  1. Rodriquez Ring-necked Parakeet Extinction: Bad Genes or Bad Luck? Defined- the complete death of a taxon Not to be confused with gradual evolutionary change that leads to the creation of a new species Which is termed as Anagenesis

  2. First Remain Species A Unchanged Speciation Species B Second Species A Species C Third Anagenesis Species A Possible “Fates” Over Time for Species A Species A Species D

  3. Forth Death Rate Species A Exceeds Birth Rate Gene Flow Fifth Species A Hybridization Possible “Fates” Over Time for Species A Extinction by demographic failure Extinction by Genetic Swamping Species X Species X’

  4. Ash Meadows Killifish Extinction as a Natural Process Life as we define it has existed on earth for ~ 4 billion years Possibly as many as 4 million species on earth today Estimated that 50 billion species have lived on earth Thus, less than 1 in 1,000 species that have lived on earth are alive today!

  5. Polar Bears in a “stand-off” posture Characteristics of Extinction-Prone Species 1. Low reproduction rate

  6. Everglades Kite- eats only apple snails 2. Species with specialized feeding habits

  7. Giant Panda- eats only bamboo shoots

  8. Koalas- eat only leaves from certain species of eucalyptus tree

  9. Black-footed ferret- eats mostly prairie dogs and pocket gophers

  10. 3. Species that feed at high trophic levels, such as, Bengal Tiger or

  11. Jaguar

  12. 4. Species that are large in size such as the rhinoceros or

  13. African elephant

  14. 5. Limited or specialized nesting or breeding area, such as Kirtland’s Warbler which breed only in burned over jack-pine forest stands in Michingan, Minnesota and Canada

  15. 6. Found only in one place or region, such as the elephant seal from the Pacific Coast or...

  16. Unique island forms such as the Hawaiian Honey-creepers including the O-O complex

  17. 7. Species with fixed migratory patterns, including Whooping Cranes

  18. Gray Whale migration route

  19. Timber Wolf 8. Species that are purported to prey on livestock or people Coyote

  20. American Alligator

  21. 9. Unique behavioral patterns, such as Key Deer and ….

  22. Social Facilitation in Passenger Pigeons

  23. Population Size

  24. 10. Species with poor dispersal or colonizing potential Such as flightless birds, including the Dodo

  25. Or island forms such the Aye-Aye

  26. 11. Species such as frugivores and nectivores that exploit unreliable resources Complex of Hawaiian Honeycreepers

  27. 12. Species that cannot tolerate habitat disturbance such as forest interior bird species Kentucky Warbler of Eastern North America deciduous forests

  28. Kiwii Multiple Factors Specialized feeding habits Low reproductive potential Unique island form Poor dispersal potential Can’t tolerate disturbance Found in only one place or region

  29. Deterministic Processes and Decline to Extinction Stresses that affect populations in direct, detrimental ways by Increasing mortality And/or decreasing reproduction

  30. Deterministic Processes and Decline to Extinction 1. Direct killing Great Auk- killed for meat and oil

  31. 2. Introduced predators such as rats, cats and mongoose Hooded Warbler- ground nesting songbird in the eastern United States

  32. Guam Flycatcher Brown Tree-snake 3. Exotic predators introduced accidently 12/14 bird species 2/3 bat species 6 lizard species Native of southeast Asia, Philippines, Indonesia Arrived on Guam accidently, probably in a shipment of fruit

  33. 4. Introduced species “out-competing” native species for resources, thus driving them to extinction. Galapagos Rice Rat

  34. Hawaiian Honeycreepers- many driven to extinction by introduced avian malaria 5. Introduced species as vectors for disease

  35. 6. Genetic swamping Mallard- drake

  36. Mallard Hen

  37. Mallard “Group”

  38. Mallard Mexican Duck Black Duck Mottled Duck

  39. 7. Habitat Disruption

  40. Historic Whooping Crane Migratory Stop-over site

  41. Midwest Farming Practices

  42. Brown-headed Cowbird A brood parasite formerly confined to the Great Plains in association with Buffalo Herds Female Male Brood Parasitism: laying eggs in the nest of another species

  43. Female Cowbird laying an egg in a vireo nest

  44. Brown-headed Cowbird Distribution

  45. Habitat Fragmentation The breaking up of contiguous tracts of habitat into smaller, not-connected patches Accomplished in a variety of ways including; Results in creation of patches that are below the minimum area needed for survival and reproduction Concept of “Species Area Curves”- the illusive figure 5.8 page 49

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