Session 18: Episode 5(3) Genomics, our African genesis and family tree

Transcription

1 Session 18: Episode 5(3) Genomics, our African genesis and family tree William P. Hall President Kororoit Institute Proponents and Supporters Assoc., Inc. - william-hall@bigpond.com Access my research papers from Google Citations

2 Tonight To this point I have summarized a vast array of evidence about the physical evidence for reconstructing hominin history leading to domination of the world by Homo sapiens (ourselves). In tonight s session I begin to reconstruct the evolutionary circumstances that led humans to diverge from their close primate relatives to become something so completely new that our capacity to dominate our physical and biological environment has grown to the point where we are on the way to consuming the entire planetary biosphere. How and why did the divergence begin? How has this shaped who we are today and are likely to become? An Evolutionary Hypothesis: - Our First Five Million Years or How Did We Get Here? Life in the primeval forest The end of Eden and adapting to a hard life in a drier world with fewer trees What can we learn about early hominins from chimpanzees and capuchin monkeys Cultural versus hereditary transmission of technological knowledge Where hominins have gone beyond chimpanzees and capuchins.

3 An evolutionary hypothesis 3 How and why did our ancestors 5 mya not greatly different from today s chimpanzees and bonobos become us? Evolution cannot anticipate the future (or can it?) The success of a lineage or species depends on it occupying and maintain an ecological niche where it can out-compete other contenders for the resources available in that ecological space. Evolution of populations is driven by constant arms-races with other pops contending for those resources. Individuals must access enough resources to survive and reproduce subsequent generations also able to access adequate resources. Genetically determined anatomical, physiological, and behavioral adaptations are all involved in maintaining access to the necessary ecological space for population survival. Two aspects of hominid biology are particularly important to maintaining the successful continuity of an evolutionary lineage life history system of heredity Hypothesis: blind evolution put us in a place where we began to consciously anticipate the future

4 System of heredity 4 The heredity of a species/population is knowledge transmitted from one generation to the next that determines its capacity to occupy and survive in an ecological niche Genetic inheritance: my PhD thesis focused on the role of genetic systems in managing hereditary knowledge genetic system = aspects molecular genetics, cytogenetics, and population biology that determine evolutionary plasticity, etc. These aspects are themselves subject to evolution via natural selection Cultural inheritance: survival knowledge helping to determine the capacity for occupying and surviving an in ecological niche may also be culturally transmitted cultural system = aspects of neurobiology, behavior, and population biology affecting adaptability are also subject to selection System of heredity = genetic system + cultural system Hypothesis is that natural selection led humans to evolve increasingly powerful cultural systems that now gives us conscious control over our evolution including ability to anticipate

5 Primates in the Garden of Eden

6 Primate life in the primeval tropical forests 6 Ancestral great ape was a clambering tree dweller probably able to walk along the tops of branches Grasping hands & feet Binocular vision Lived social in persistent groups Primarily frugivorus Used hands to access hidden/ protected food items May have used resources from ground Large size minimized predation risk In most seasons could forage in trees or on the ground with little effort for readily available fruits, herbs, nuts, insects and the occasional small mammal prey Probably slept in trees, and if on the ground during the day they encountered one of the few large carnivores hunting in the forest, e.g., leopards (Boesch 1991), they could easily escape up a tree Biology was probably similar to today s chimpanzees (with bonobos) our closest living relatives who continue to live in the Primeval Eden

7 CLCA life history strategy 7 Life History: Gestation >8 months; infant (preweaning) mortality <40%; weaning 4-7 years; puberty at 6-10 years; female reproduction at years (postponed); interbirth interval <5 years; year-round breeding; maximum lifespan years; no menopause. Behavior contributing to system of heredity: more females than males disperse; polygamous mating system; possessive male mating strategy; exerted female mate choice; male dominance; paternal care and paternal protection present; conjugal families within semi-cohesive communities; opportunistic male mating strategy; rape absent; positive correlation of male rank and copulation rate, high -male mating success (100-81%). Other behaviors: sexual adornments of adult males present; mediumsize testes; medium copulatory frequency; exchange of favors for sexual access present; moderately hostile intergroup encounters (limited amount of lethal intergroup violence); multi-male groups present. Subsistence: group foraging; fission-fusion social groups, cultural diversity (behavioral traditions) present, simple tools used for extractive foraging; nest building present Anatomical: moderate sexual dimorphism in body weight and canine size.

8 Chimpanzees and bonobos suggest that our common ancestor used and made simple tools click picture for video click picture for video Making thick and thin probes to fish for ants Clubs and a thrown rock deter/kill a leopard click picture for video Videos from Bossou 8 Chimps learn hammer and anvil Breaking into a beehive

9 Other chimp tools Types 9 Spears used to kill & extract small mammalian prey hiding in tree holes Digging sticks used to harvest roots & tubers Mashers large pestles used to mash hearts of palm trees Sponges used to extract drinking water from tree holes Cultural and ecological distribution Culturally transmitted knowledge: tools used vary by location from none to many Savanna chimpanzees have most extensive tool kits

10 Bonobos and chimps show their intelligence in the lab 10 Intelligence Mechanical: chimps show capacity to make & use a variety of tools Social: show significant tolerance & can cooperate on tasks Linguistic: both learn more than 250 word lexigrams use in 2-3 word phrases click picture for video Bonobos don t use tools in the wild but it is clear that they could if they needed to! Kanzi is one smart ape! watch extraordinary documentary Natural history Nova the last great ape

11 The destruction of our ancestors Eden forced us onto a divergent path that led us to dominate Earth s resources

12 Plate tectonics 1 the splitting of domes lifted by plumes 12 Wood & Guth (2013)

13 Plate tectonics 2 Eden destroyed Rising mountains on either side of rift block rain Cause increasing aridity & seasonality Wood & Guth (2013) 13

14 Exposed to global cooling and growing rifts E African hominins adapted to a hard life with fewer trees 14 Uplifted mountains E and W of the rifts increasingly block rains from either direction Gradual aridification progressively changes vegetation structure Moist closed forest Open forest Grassy woodland Savanna Open grassy scrubland Desert Increased seasonality Gradual replacement of fruits by nuts & underground storage organs (Envisat)

15 Hominin evolution and environmental variability over the past 7 million years Alternative responses to variability Genetic adaptation (change) Genetic adaptation (versatility) Cultural change Cultural accumulation 15 Potts Hominin evolution in settings of strong environmental variability. Quaternary Science Reviews 73, 1-13 Potts & Faith Alternating high and low climate variability: The context of natural selection and speciation in Plio- Pleistocene hominin evolution. Journal of Human Evolution - DOI: /j.jhevol

16 Impacts of environmental change and variability in E African Rift (Olduvai, etc.) between 3.0 and 1.5 mya 16 Long periods (lasting ky each) of magnified moist-arid variability occurred between 3.0 and 1.5 mya. Possible modes of adaptation Fail to track (= extinction) Track with adaptive change (shift niche) Become more versatile (expand niche) Limits to genetic adaptation Slow & ponderous (intergenerational) Do one thing or the other not both Cultural adaptation Fast (intragenerational) Group-based phenomenon cultural knowledge pertains to group not particular individuals Potts, R Environmental and behavioral evidence pertaining to the evolution of early Homo. Current Anthropology 53(S6), S229-S317. Group knowledge easily lost (dependent on intergenerational knowledge transfer, in turn dependent on genetically determined capacities, group size, structure, and dynamics) Culturally transmitted knowledge relating to tool-making and use was grade-shifting Savanna ape inherited limited capacity to transmit cultural knowledge and existing culture of simple tool-making and use from CLCA

17 Finding enough food to make a living 17 Optimizing dietary quantity and quality Modes of acquisition/foraging in a deterioriating Eden require increasing knowledge Random picking (if it looks, smells, & tastes good, eat it) Genetics determines informs goodness (looks, smells, & taste) Targeted picking (know what is in season and where to find it) Long life, good memory of time and landscape, cognitive mapping of world Too much for trial-error learning major benefit from cultural knowledge Extractive foraging (know where edibles hide & how to extract them) Innovation and ability to imagine the invisible Tool assisted extraction & processing (find & make inedible edible) Using levers and hammers to extend and empower the physical body Putting things together to make complex tools and processes Understanding causation Extending cognition Mapping the territory Imagining where food might be hidden & how to access it Retaining & sharing know how Increase cognitive capacity to manage more/more complex knowledge

18 Surviving to reproduce 18 Forest-dwelling chimpanzee-human last common ancestor (CLCA) Primarily frugivorous with some tool-based extractive foraging Fission-fusion social structure, some transfer of cultural knowledge High selfishness, limited cooperation in defense and hunting Savanna apes as extractive foragers & scavengers Edible plant resources more widely scattered and harder to find New kinds of resources needed Roots, tubers and nuts Meats New dangers Big cats Hyenas Wild dogs Selection pressures Imagine where food might be hidden Retain & transfer cultural knowledge Increase memory & cognitive capacity (Tattersall 2012)

19 Cooperative defense and scavenging of carnivore kills cached in trees gave early hominins increased access to meat on the savanna Savanna offers limited resource of edible plant foods but a rich supply of grass-eating herbivore meat (most food found on the ground) Chimpanzee social defence against leopards is uncoordinated mobbing with clubs - Might be enough to deter leopard from returning to tree cache - Wouldn t stop a pride of lions or mob of hyenas on ground Simple requisites for grade shift to aggressive scavenging on the ground Coordinated & cooperative defense and offense using effective deterrence Oldowan butchering tools for cutting skin & ligaments 19 Hominins using haak en steek branches as tools (Guthrie 2007): a. for driving big cats away from their prey. b. The simple conversion of a thorn branch into a "megathorn" lance for active hunting.

20 Cognitive advances enable grade shifting revolutions in cultural and organizational cognition 20 Accelerating change in extending human cognition > 5 million years ago social defence cooperative foraging & hunting knowledge-based autopoietic groups ~ 2.0 mya - linguistically coordinated activities around campfires to share group knowledge (mime, dancing, singing, story-telling, myth, ritual) ~ 200 thousand years ago mnemonic songlines apply ritual & method of loci to landscapes to build & retain cultural memories ~ 12 kya mnemonic guilds & monumental architectures enable husbandry, settlement, farming & economic specialization ~ 7 kya tokens & writing enable bureaucratic cities & states ~ 600 years ago communications, coordination & rise of chartered companies ~ 100 ya instant communication & rise of transnationals ~ Now emergence of global brains & global cognition Expanding role of cultural knowledge will be explored in further sessions

21 Knowledge-based revolutions in material technology cause grade shifts in the ecological nature of the human species 21 Accelerating change in our material technologies: > 5 million years ago - Tool Making: sticks and stone tools plus fire (~ 1 mya) extend human reach, diet and digestion ~ 11 thousand years ago - Agricultural Revolution: Ropes and digging implements control and manage water and non human organic metabolism ~ 560 years ago Printing enables Reformation & Scientific Revolution ~ 2.5 ca - Industrial Revolution: extends/replaces human and animal muscle power with inorganic mechanical power ~ 50 years ago - Microelectronics Revolution: extends human cognitive capabilities with computers ~ 5 years ago - Cyborg Revolution: convergence of human and machine cognition with smartphones (today) and neural prosthetics (tomorrow)

22 Repeating the experiment in a New World Was the emergence of human cognition a rare chance event or is it a potentially repeatable outcome of normal evolutionary processes?

23 Repeating the experiment in a New World ~ 40 mya 23 The common ancestor of primates in both worlds ran along the interconnected highways of the tree canopy Moderate sized omnivore, with grasping hands & feet Ready supply of fruits, flowers, grubs & succulent leaves Stays in trees to avoid the predators of ground and air

24 Platyrrhine ancestor colonized New World mya 24 Could raft across narrower Atlantic in 1-2 weeks Hystricomorph rodents colonized around same time

25 25 Another expulsion from the Garden of Eden Brueghel & Rubens knew them in 1615

26 Introducing smart monkeys from the New World Many people see capuchins as smart pets 2½ ( ) 4 ( ) kg Life-span years 26 click picture for video Detail from "Students encounter an organ-grinder monkey on campus with man holding Times-Picayune box, Rice University," Rice University,

27 Will the real capuchin stand up! A knowledgable capuchin prepares its own meal using a very heavy stone hammer and a log as an anvil (see other video for the full sequence behind the picture) click picture for video 27

28 Just how smart are capuchins? Clip documented by a series of publications by Westergaard and colleagues from independently repeated by other labs click picture for video 28

29 The capuchin s knowledge-based nut-cracking industry Steps in the industrial process 1. Select ripe nut 2. Peel 3. Dry in sun for several days 4. Select appropriate anvil site 5. Find & transport suitable hammer stone(s) to anvil site 6. select suitably dry nut(s) 7. transport nuts to anvil site 8. place nut in suitable anvil pit 9. strike nut with hammer to crack (60-70 blows may be required!!) 10. eat nut & possibly share with young scroungers learning the process click picture for video 29

30 Other technologies reported in the scientific literature Capuchins in primeval forests not seen to use any tools 30 Other tool uses seen in various scrubland cultures Defensive: Bombarding jaguars and people with rocks and boulders from cliff-tops Bashing snakes with sticks (too small to fight off leopards) Hunting: spearing lizards & small mammals in holes with sharp sticks Mining: using stone picks to extract more suitable stone from hillsides Cultivating: using stones and sticks as hoes and shovels to dig up edible roots & tubers Communication: females in oestrous throw stones towards desirable males to attract attention Different groups use different tools

31 Forging a hard life in a barren landscape Amazonia Thorn scrub Atlantic forest 31 Caatinga and Cerrado Short rainy seasons (~ 2 months) Hot almost entirely rainless dry seasons Thorn scrubs and savanna

32 Genetic proliferation in & after last glaciation Sapajus Atlantic forest Cebus Amazonia } The tool users all live in Caatinga and Cerrado and are very recent derivatives now

33 Adversity is the mother of intelligence and invention Encephalization quotients of some primtes Sapajus

34 Semi-terrestrial capuchins are also being selected for bipedalism click picture for video 34 Carrying two nuts and a hammer to an anvil site

35 Could these monkeys rule the world with human grade cognition if it were not for humans? Encephalization quotient equivalent to hominins ~ 4-3 mya May have less symbolic and mechanical intelligence than chimps/bonobos No ape other than humans shows as much understanding of its tools or manages as complex an industrial process as do Sapajus Clear evidence for cultural sharing and transmission of sophisticated survival knowledge 35

36 What do you think? Virgil has the nuts, Vulcan has the knife click picture for video 36

37 Next session explores how apes became human with the control of fire and the development of language In the next session I explore the selective processes and technological innovations that helped carnivorous savanna apes become recognizably human and set them on a still accelerating path of technological and cultural evolution In this process culture begins to replace genetics as the major mechanism for transmitting adaptive knowledge With increasingly effective tools and increasingly better means of sharing knowledge in processes of teaching and learning, these early humans became versatile enough to spread through most of the rest of Africa and Eurasia as H. erectus, heidelbergensis, and perhaps other genetically distinct species 37 Becoming human Using, keeping & making fire Language revolution and the emergence of archaic humans Language and the emergence of groups as higher order autopoietic systems Homo sapiens dispersal out of Africa Considering the pace of technological change