Unit 3: Lecture 3 Recent Distribution patterns, dispersal & centers of origin

Unit 3: Lecture 3Recent Distribution patterns, dispersal & centers of origin

1. How many genera disappear during 5 Mass extinctions? How did this contribute to development of new species?

Cenozoic Eon – recent history • Tertiary Period - 65-1.64 MYA • Quaternary Period - 1.64-present MYA • Pleistocene • 1.65 mya – 10,000ya • Holocene – 10,000 years ago

2. What happened during the Tertiary Period, 65-1.64 MYA • A 10 km diameter asteroid hit the north coast of the present-day Yucatan (the impact created a sharp sediment boundary between the Cretaceous and the Tertiary periods called the K-T boundary). • about 75% of the previously existing plant and animal species disappeared. • No species of land animal weighing more than about 55 pounds survived into the Tertiary. • Set the stage for the Cenozoic “age of the mammals”

3. What types of animal were present in theTertiary Period? • Saber tooth tiger • brontotherium • Camels, hippos in western US • Horses in North America • Mastodons in IL

4. Describe the Quaternary Period, 1.64-present MYA • During this period four Ice Ages, separated by warmer interglacial periods, covered the northern land areas. • ice y advanced and retreated, climate zones and mammal faunas moved across the continents via the Bering region and Panama Isthmus. • giant representatives of nearly every order of mammals, kangaroo and lemur, to deer, beaver, and mammoth

5. What are the 2 subdivisions of the Quaternary Period? • two epochs; • Pleistocene (two mya to ten thousand years ya) • Holocene (ten thousand years ago to the present day).

6.What theories explain the loss of pleistocene mammals? • Evidence for hunting – • human association with extinction – mastodon tusks show increase in birth rate prior to extinction. • Linguistics show pattern of human distribution • Human access to areas where death occurs • Disease

Pleistocene extinction con’t • Climate change - 2006 report exonerates humans from slaughtering the large mammals. • mammoths and horses became extinct, • wapiti, bison and moose survived and thrived, • suggesting that the faunal change was a function of ecological change rather than human-induced "overkill

7. What evidence do we have of Pleistocene Megafauna Extinctions? • Human Migration to The New World • data: excavation and dating • Caves • geneticslinguistics • [Beringian Migration] (Alternatives) (Alternatives) • Overkill [Martin 1973] (text)

8. Describe the impact of the pleistocene extinctions in the midwest US. • Midwest, US • Pleiostocene extinctions – impact on the midwest

Midwest evidence • Mastodon remains • Lincoln – mammoth tooth

9. What are the La Brea Tar pits? Where located? What do you find there? • La Brea tar pit: http://www.tarpits.org/

10. What was the global pattern of Megafauna extinction? • Compare this graph to human migration patterns

11. Describe the Holocene epoch - 10,000 years • To observe a Holocene environment, - look around • the time since the end of the last major glacial epoch, or "ice age." • has been a relatively warm period in between ice ages. • Another name for the Holocene that is sometimes used is the Anthropogene, the "Age of Man."

12. What has been the Human distribution pattern? • 150 mya Africa….. 10-11 New world vs 40-90 Old world

Out of africa • Homo sapiens archaic 400 - 130 Ka Homo neanderthalinsis? 300 - 30 Ka Africa spread Europe

Human migration

13. What is the significance of the Bering land bridge? • Bering land bridge

14. Describe primate characteristics? • Evolutionary Trends • Bipedalism vs. arboreal • Size: early Australopithecenes chimp-sized • Cranial Capacity: three-fold increase • Neotony[.]Birth Canal: infant cranium too large • Parental Care: born helpless • Dietary Specialization: tooth size & shape, enamel

15. Describe changes in brain size in hominids. • Massive increase in brain size – language, reasoning – (cerebrum)

16. Describe Human adaptations to dispersal • Hominid Adaptations to dispersal • Wood – all primates • Stone tools: 2.5 Mya Ethiopia • Fire: probably H. erectus 1.8 Ma - 300 Ka • Clothing: H. sapiens • Domestic animals

17. Name5 other Primates • Family Hominidae (great apes and humans) • Genus Gorilla(gorillas) • Species Gorilla beringei(eastern gorilla) • Species Gorilla gorilla(western gorilla) • Subspecies Gorilla gorilla gorilla(western lowland gorilla) • Genus Homo(humans) • Species Homo sapiens(human) • Genus Pan(chimpanzees) • Species Pan paniscus(bonobo) • Species Pan troglodytes(chimpanzee) • Genus Pongo(orangutan) • Species Pongo abelii(Sumatran orangutan) • Species Pongo pygmaeus(Bornean orangutan)

18. Describe changes in primates over the past 100 million years. • Primate history • Characteristics • Skulls

19. What are the criteria for Cain’s Centers of Origin • Location of greatest number of species (taxa) • Location of greatest concentration of individuals (dominance) • Location of primitive and closely-related forms • Location of largest individuals • Location of greatest productivity and stability • Center of lines of migration radiating from a location • Location of greatest breadth of habitats (least dependence on rare habitat) • Center of lines of clonal variation radiating from location • Geographical affinity (all southern hemisphere) • Greatest number of overlapping distributions

20. Centers of origin – sea snakes • Restricted by temperature 20 oC • Cenozoic origin • Distributions overlap with nearest relatives (Elapidae, cobras) • Australian-New Guinea origin • Highest diversity (30 sp.) • Location of closest relatives • Most primitive genus in New Guinea

Sea snake centers of origin • Sea snake distribution

21. How does Historical Biogeography support COO theories? • rigorous logic and hypothesis testing • rigorous phylogenetic systematics • use of area cladograms • emphasis on fossil data • Darters example

Darters con’t • Darter center of origin & distribution pattern • Compare cladogram w/ distribution

22. Write a paragraph comparing continents & dispersal trends in mammals. • Mammal family distribution & similarity

23. Write a paragraph comparing continents & dispersal trends in flowering plants. • Plant families and similarity – dispersal

24. Write a paragraph comparing continents & dispersal trends in red & jack pines. • Red pine dispersal at end of ice ages in US.

References: • http://geo.arizona.edu/Antevs/ecol438/lect11.html • Mastodon: http://www.beringia.com/images/Teichmann/MASTODON.JPG • Mammoth teeth • http://www.museum.state.il.us/exhibits/larson/images/mmpr_m3_small.gif • Similodon: http://www.netbiologen.dk/zoologi/images/st6a.jpg • Pleistocene glaciation: http://images.encarta.msn.com/xrefmedia/aencmed/targets/maps/map/T041365A.gif • Man: http://pratyeka.org/prokudin-gorskii/a-sart-old-man-1911.jpg • La brea tar pits: http://www.stonecover.com/albums/TarPits/DSC_6659.highlight.jpg • http://www.walkinginla.com/2002/Oct27/10_27_02.html • Bering:http://www.foreignlands.org/Geographical_/Arctica/BeringBridge/a_BeringLandBridge.jpg

Unit 3: Lecture 3 Recent Distribution patterns, dispersal & centers of origin