The First Americans. Exploring the Origin of Humans in the Americas

Transcription

1 The First Americans Exploring the Origin of Humans in the Americas

2 Or--The First Americans? Exploring the Origin of Humans in the Americas

3 Course Outline Lecture 1 Background & Human Evolution Lecture 2 The Indigenous People of America Lecture 3 Migration Routes to America Lecture 4 Out of Africa Theory & Europe at LGM Lecture 5 The Clovis Culture in America Lecture 6 Origins of the Pre-Clovis People

4 Background Outline Lecture 1 Human Evolution Out of Africa Theory Basic DNA Analysis Timeline of Migration Based on DNA Analysis Effect of Climate on Human Migration

5 Terminology Time will be a very important factor in these lectures We are familiar with BC and AD Now in political correct terminology BCE and CE Scientists express the age of artifacts or human remains in different but very precise terminology The media reports frequently misquote scientific findings

6 Terminology I ll use Years Before Present most often That term is abbreviated YBP It doesn t mean years before now It means years before 1950 Why?

7 Why? Radiocarbon dating is used to date most organic artifacts and human remains from the past Dates obtained from measuring the amount of C14 are not true measures of time

8 Why? Present means 1950 That s because radiocarbon dating began in 1950 We won t worry about the 66 years we need to add to get to present time. Example: 20,000 RC years= 24,000 Years Before Present

9 Human Evolution A quick summary of the descent of Homo Sapiens from earlier human-like ancestors Starting 4 million years ago

10 Australopithecus 4M YBP Homo erectus 1.5M YBP Homo heidelbergensis 800K-300K YBP Neanderthal 400K -30K YBP Denisovan?-40K YBP? Homo sapiens 200K YBP- Present

11 Tool Technology Homo erectus Homo heidelbergensis Neanderthal Bone Homo sapiens

12 Several Species Migrated Homo erectus migrated out of Africa and populated much of the Old World No evidence he made it to Americas But Homo erectus had maritime capability Homo heidelbergensis migrated out of Africa Neanderthals & Denisovans migrated Homo sapiens populated all lands except Antarctic

13 Migrations

14 Kow Swamp People Homo erectus tools found east of Borneo Kow Swamp People from Victoria, Australia Appear to be Homo erectus vs Homo Sapiens Their remains are dated to 10,000 YBP At that time Homo sapiens (Aboriginal People) had been in Australia 50,000+ years Possibly Modern Humans and Homo erectus lived in Australia at the same time

15 Occupation Meant Watercraft 50,000+ YBP

16 Migrations Out of Africa

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18 Basic DNA Science

19 Sex Education When mommy and daddy got together Daddy contributed sperm cell with an X- and Y- chromosome Mommy contributed egg cell with two X- chromosomes When the two cells combined an X-chromosome from mommy paired with either an X or Y-chromosome from daddy XX produces a female and XY produces a male

20 Chromosome 23 The Sex Chromosome Each Egg cell has one of the mother s two X chromosomes

21 Sex Education In addition, the combined sperm and egg cell have 22 other pairs of chromosomes that combine. How those chromosomes combine determines the other traits an infant will inherit. Example: inherit mother s red hair or fathers black hair.

22 How Do Chromosomes Work? Chromosomes are packages of protein arrayed in a double helix (spiral) of molecules Those protein chains are called DNA

23 DNA What is it? DNA=Deoxyribonucleic acid

24 Genes and Alleles A gene is a section of DNA that provides the biological code to determine a physical trait Example: the portion of the DNA that determines eye color An Allele is one of the various forms of a gene Example: the variant for blue eyes Specific genes can have a number of alleles (variations)

25 1. Nucleolus 2. Nucleus 3. Ribosome (dots) 4. Vesicle 5. Rough Reticulum 6. Golgi body 7. Cytoskeleton 8. Smooth Reticulum 9. Mitochondrion 10. Vacuole 11. Cytosol 12. Lysosome 13. Centrosome 14. Cell Membrane Animal Cell

26 Mitochondrial DNA Mitochondria are the components of cells that produces chemical energy for the cells At reproduction only the mitochondria of the mother are passed on to the offspring Mitochondria contain separate and distinct DNA

27 Human Genome The human genome consists of the entire DNA sequence obtained from the 23 pairs of chromosomes. The genome contains 3 billion base pairs of the four proteins (adenine, thymine, guanine, cytosine) Human genomes vary by about 0.1% among individual humans. Human and chimpanzee genomes differ by about 4%

28 Changes in DNA Various factors can change the coding in DNA Radiations such as ultraviolet light Chemical exposure Spontaneous changes within the chromosome Naturally occurring DNA damage These changes are called Mutations

29 Human Genome is Evolving Human DNA has changed over the millennia Mutated genes are passed down to succeeding generations Scientists can look for specific mutated genes or clusters of such mutated genes and trace ancestry this way If a person has a specific cluster of mutated genes Those genes were inherited from the ancestor who first had the mutation

30 Haplotype & Haplogroup A cluster of genes that are likely to be inherited from one parent Individuals sharing the same haplotype are categorized as belonging to a haplogroup (they share a common ancestor) For our purpose (tracing ancestry) we focus on haplotypes contained in The y chromosome inherited from fathers The mitochondrial DNA inherited from mothers

31 Y Chromosome Ancestry Fred 1 Haplogroup Mutation Fred 1 Haplotype Fred 1 Haplogroup Fred 1a Haplotype Fred 1a Haplogroup

32 PARENTS GRANDPARENTS GREATGRANDPARENTS X4/5 Y1 X9 Y1 X4 X5 SON X Y1 X1/7/10 Y1 X1/7/10 X1 X7/107 X1 Y2 X7 X10 DAU. X1 X X2/12 or X3/8/13 X2 /12or X3/8/13 X2/12 X3/8/13 X2/12 Y3 X3 X8/13 X11 Y3 X2 X12 X3 Y4 X8 X13

33 Mitochondrial DNA Ancestry Wilma 1 Haplogroup Mutation Wilma 1 Haplotype Wilma 1 Haplogroup Wilma 1a Haplotype Wilma 1a Haplogroup

34 Distribution of Haplogroups In populations living today

35 Now we can apply this science to determine where humans first emerged and trace our descent back to the dawn of the human race This is the basis for the Out of Africa Theory currently held by most anthropologists

36 Genetic Adam and Eve Chromosomal & mitochondrial genes mutate at predictable rates (0.003 per generation for chromosomal DNA) Genetic scientists examine how the human genome varies in populations from different regions They identify Haplogroups to distinguish these different populations Using the mutation rate, they project backward in time to when a specific haplogroup emerged

37 Genetic Adam and Eve Using genes specific to the Y chromosome genetic scientists postulate where and when the most recent common paternal ancestor of all people living today lived Likewise, using genes specific to mitochondrial DNA they postulate where and when the most recent common maternal ancestor lived

38 Genetic Adam and Eve Haplogroups

39 Genetic Adam and Eve Our most recent Y-chromosomal ancestor (Adam) lived about 120,000 to 300,000 YBP Various models give different time estimates Our most recent mitochondrial DNA ancestor (Eve) lived about 140,000 to 200,000 YBP

40 Biblical vs Genetic Genesis Lived about 10,000 YBP Lived about 200,000 YBP

41 Haplogroups

42 Typical Map of haplogroup migration N1c1 originated in Southern Siberia 12,000 YBP

43 Time 26,500 YBP to 3,000 YBP

44 60,000 to 40,000 YBP Mitochondrial DNA

45 Kostenki Man Skeletal remains found near Voronezh, Russia Dated to 37,000YBP Has DNA very similar to modern Europeans Genome has small percentage of Neanderthal DNA as do humans today dating to an event about 54,000 YBP Mitochondrial DNA is U haplogroup Y DNA is C haplogroup

46 Siberian Femur Thighbone found near the Irtyush River, near the settlement of Ust'-Ishim, Siberia Dated to 45,000YBP This sample used to determine the date of inbreeding between Homo Sapiens and Neanderthals Event was 52,000-68,000 YBP

47 Siberian Femur Black Sea Locations of the two Oldest Homo Sapiens remains subjected to DNA testing

48 Distribution of Haplogroups In populations living today

49 Much Later Migrations

50 Migration into the Pacific Islands BC speakers of Austronesian languages spread through Pacific islands starting out from Taiwan into Micronesia and on to Melanesia. Polynesian ancestors settled in Samoa around 800 BC, colonized the central Society Islands between AD. Dispersed to New Zealand, Hawaii and Easter Island and other locations AD.

51 Environmental Factors How cycles of Ice Ages affected human migration

52 Temperature History Average Annual Temperature Deduced from Antarctic Ice Core Samples

53 Old World & New World Glaciers

54 Northern Hemisphere During the Ice Age The continents of the northern hemisphere were more affected by glaciations than the southern ones, which generally remained mostly tropical and subtropical, though more humid during ice ages. The coldest regions of the world became arctic deserts. However, the great hot deserts of North Africa and Western North America today were mostly vast grasslands with large permanent lakes and abundant large game animals during the Pleistocene ice ages

55 Sea Levels During Human Migration

56 Bridges Connected Continents

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58 Atlantic Shore During Last Ice Age

59 Southeast Asia & Australia During Ice Age

60 There Were Roadblocks

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62 North America

63 Europe

64 Life During the Last Glacial Maximum

65 Life During the Last Glacial Maximum People were hunter-gatherers Lived in small bands united primarily by kinship Used stone tipped or bone tipped lances Had some maritime capability Wore clothes fashioned from animal hides Were artistic, religious, liked personal adornment Lived in harsh conditions in the Northern Hemisphere arctic and subarctic climate Those are the people who came to settle the Americas

66 Next Lecture American Indigenous People Native Americans, First Nation People, Los Indios Today The Indigenous people at their peak prior to 1492 Indigenous people today Ancestry via DNA Ancestry via Linguistics Ancestry via Cultural Clues

67 Questions & Comments