AGE2011S_Notes PDF

Week 1 Lecture 1 Intro to human evolution ☆ Science: systematic critical exporation of mat nature ☆ Theory of Evolution incredibly well supported The Scientific Method ☆ Observations/facts ☆ Hypothesis ☆ Testability (can hypothesis be tested) ☆ Hypothesis tested / rejected ☆ Turns into mo...

Week 1 Lecture 1 Intro to human evolution ☆ Science: systematic critical exporation of mat nature ☆ Theory of Evolution incredibly well supported The Scientific Method ☆ Observations/facts ☆ Hypothesis ☆ Testability (can hypothesis be tested) ☆ Hypothesis tested / rejected ☆ Turns into model = set of repeatedly tested hypotheses ☆ Theory = set of models ☆ Evo acted to create biodiversity ☆ How has it happened? ☆ Time depth difficult but not impossible (rely on indirect evidence) ☆ we are not unique in this How science works ☆ Collective, historical process - most scientists play small roles - Historical/Social context import. ↳ Changes constantly - Not necessarily full picture or history ☆ Only 1 form of rational inquiry, defined by v. specific set of rules - Can only answer certain kinds of questions Lecture 2 History of Evolutionary Thought ☆ Helps us understand many things ☆ Historical roots ☆ focus on the same historical figures (1700 →) ☆ Evo thought much deeper than that w/ roots in antiquity ☆ Begins in non-European spaces ☆ Ancient Greeks, Romans, Chinese, Medieval Islamic scholars, Philosophers & theologians of the Middle Ages Ancient Greece: 800-500 BC ☆ Philosophers began questioning explanations of natural phenomena based  on religious myth ☆ Instead started applying rational thought & reason to understand the world around them (Rationalist approach) ☆ Rationalist approach thought to extend back before Socrates ☆ Aristotle formalized some of these ideas-precursors to evolutionary theory ↳ School of thought used rationality & reason to understand natural world European kingdoms after fall of Western Roman empire ☆ Areas of outer Europe became vulnerable to attacks from Germanic tribes ☆ Previously Roman areas eventually split into over a dozen different kingdoms, eachof which had diff language, history & Culture ☆ Result → significant amount of Greek  scholarship virtually disappeared from circulation in the West (lack of linguistic/ intellectual continuity) ☆ Period starting @ Fall of Roman Empire (476 BCE to 1000 early Middle Ages; to 1500 for all Middle Ages) → Western Europe's Dark Ages. ☆ Dark = no light, e.g no written knowledge ☆ Aristotle's work disappeared from circulation in Western Europe for centuries ☆ Eastern Roman Empire survived attacks. ☆ only here Greek scholarship survived under what eventually became the Byzantine Empire. Islamic empire (Islamic Golden Age 8ᵗʰ-13ᵗʰ Cen) ☆ But eventually the eastern Roman Empire fell to Islamic invaders. ☆ HERE is where we can trace some of the deepest roots of modern evo thought, during the Islamic Golden Age. Transmission of Greek philosophy to Arab world ☆ Arabs came in contact w/ Greek texts, ideas & knowledge that had survived in the Eastern Roman Empire ☆ Prince Khalid (of one of the first Muslim dynasties) spearheaded Movement to translate scientific works from Greek into Arabic ☆ 9ᵗʰ & 10ᵗʰ Cen → process of translation became state-level enterprise be of commitment to scientific & philosophical output ☆ Works of Greek philosophers/ theologians became foundation/ building blocks for the subsequent 1000 yrs of Islamic scholarship ☆ By 9ᵗʰ Cen, writings of Muslim scholars allude to some of the ideas that scientists like Linnaeus & Darwin later dev ☆ 4 major concepts in evo theory 1st appear in the writings of Islamic scholars ☆ Grew & expanded foundations 1ˢᵗ laid by Aristotle ☆ Were later used by Europeans Mineral, plant & animal kingdoms ☆ Most striking sim btwn Greek, Islamic & Western European scholars that come later... ☆ Natural world could be divided into 3 groups-minerals, plants, & animals w/ each 'Kingdom' giving rise to the next ☆ At least 6 Isla mic texts organized living world into these 3 categories & hypothesized their r-ship to each other ☆ Ikhwan Al-Safa (Brethren of Purity): secret Soc of Muslim thinkers in present day Iraq, in 10ᵗʰ Cen, wrote about how the plant Kingdom connected to the mineral Kingdom below it & the animal Kingdom above it Ibn Khaldun ☆ North African ☆ one of the most famous Muslim polymaths of all time ↳ polymath = someone who has a lot of knowledge about diff topics ☆ Muqadimmah (1377):" One should then take a look at the world of creation. It started out from the minerals and progressed, in an ingenious, gradual manner, to plants and animals." - In this work wrote ideas that sound  much like what Darwin said much later, Ind about human evo ☆ Hearkens back Aristotle's Great chain of Being ☆ Similar ideas expressed in works of Al-Beruni, Tusi & Nidhami Arudi i Samarqundi ☆ ideas widely dispersed in Islamic world @ time Linnaeus, Systema Naturae (1735) ☆ Ibn Khaldun's ideas resemble what Linnaeus wrote 400 yrs later: "Natural bodies are divided into three kingdomes [ sic] of nature: viz, the mineral, vegetable and animal kingdoms. Minerals grow, Plants grow and live, Animals grow, live and have feeling." Descent w/ modification ☆ Idea assoc w/ Darwin & theory of evo ☆ Also dev by Muslim scholars to explain observed sim in form ☆ Al Jahiz - present-day Iraq (781-869) - fascinated w/ animals (like Aristotle) - Book of Animals incl. theory that original tetrapod (four-legged) ancestor gave rise to other 4 legged animals - Common ancestor that Gave rise to similar forms Ibn Miskawayh (Al-Fawz Al-Asghar) ☆ 10ᵗʰ Cen Persian Muslim philosopher ☆ Drew on works of Al-Jahiz ☆ Proposed model for relatedness or all things. ☆ Understanding of descent & change w/in descent ☆ Recognizes hierarchy of Animal Kingdon w/ apes & humans on top Struggle for existance ☆ Essential aspect of Darwin's theory of natural selection ☆ Again something we see dev by Muslim scholars ☆ Al-Jahiz noted how stronger animals eat weaker animals & is part of cycle of survival in nature Nasir ad-Din Tusi [AkhlaQ i Nasiri (Nasirean Ethics) ☆ 13ᵗʰ Cen Persian Muslim ☆ Wrote Sim ideas -i. e that  organisms w/ new features have adu over others that allow them to survive & that animals, have the traits they need to survive & live Precursors to the theory of natural selection ☆ Darwin provided mech to explain how descent w/ mod. worked (Nat. Selection) ☆ Nearly 1000 yrs earlier, Al-Jahiz tried to do the same Al-Biruni, Kitab al-Jamahir, 11ᵗʰ Cen ☆ 11ᵗʰ Cen Muslim Astronomer from central Asia (now Turkmenistan & Uzbekistan) ☆ Artificial selection shaped organisms. ☆ Darwin wrote about this 800 yrs later ☆ closer to Lamarc than Darwin's but these ideas still expressed v. early in Islamic world. Al- Jahiz & Ibn Khaldun ☆ skin colour affected by climate/envir among sub-saharan Africans ☆ Environment influenced appearance of various northern African people ☆ (Both proposed these theories) Learning centres in Islamic Golden Age ☆ Ideas were lost when they were conquered by the Mongols , their learning centers were destroyed (incl the central one in Baghdad in 1256) ☆ One survived in Cordoba, Spain ☆ Learning shifted from central to cathedral system → curriculum given to churches & towns (this is due to culture changes imposed by Spain) ☆ Arabic to Spanish dissemination of knowledge ☆ Translators v. important in allowing for this intellectual continuity Timeline of dark ages ☆ Dark ages 4 evo science not true if we take all of Eurasia & North Africa into account ☆ Western world saw role of Islamic scholars as translators & preservers of the works of the Greeks ; not true as they created theories similar to that of modern-day theories ☆ Evo theories of Muslim scholars remain unrecognised in muslim & mod. Western  science. ☆ They laid groundwork for later thinkers Leg Curvier, Lamarck, Lyell) who in turn paved the way for Darwin. 18ᵗʰ & 19ᵗʰ Cen Intellectual Climate ☆ Religion & science were close ↳ Ideology = Theology - Christian Theology... Fixed, unchanging universe - Literal interpretation of the Bible (Genesis) = world origin 4004 BC ☆ Not much space 4 evo thought Philosophy ☆ Typological thinking (tendancy to classify things into types) - Plato's Eidos-'type, essence or idea'  - Naturalism - Linnaean Classification - Nominalists Naturalism ☆ Can place all beings on a scale ☆ World evolved not used by scale implies it ☆ Not a lot of scope 4 variation in this theory ☆ Both simple & complex things exist & are successful Early Muslim Scholarship ☆ Applied temporal aspect to Scala Naturae, supporting notion that species change over time ☆ Evo & all changes in nature under guidance of God Linnean classification ☆ 1758 Systema Naturae (10ᵗʰ edition) ☆ Start of today's bio classification of animals ☆ Binomial Nomenclature (two part latin names) ☆ Kingdom, class, order, genus, species (at the time) ☆ How do you sort variation? Highly typological Nominalists ☆ No types; only indiv. ☆ Grouping mental construct (something people did, not fixed in nature) ☆ Locke, Lamarck, Darwin ☆ Recognised that there is more than one way to divide the world Geology → 2 schools of thought ☆ Catastrophism ☆ Uniformitarianism Catastrophism ☆ Georges Cuvier ☆ French anatomist ☆ Believed in fixity of species ☆ 1817 The Animal Kingdom Distributed According to Its Organisation ☆ Thru geology we see the results of a series of natural disasters ☆ Agassiz-palaeontologist Uniformitarianism ☆ Charles Lyell ☆ 1830 Principles of Geology ☆ 1863 The Antiquity of Man ☆ = the present is the key to the past assume same processes observable today (erosion, uplifting) operated in past. processes of change are slow & gradual big change = long time ↳ small changes over a long time can create a big change Biology ☆ Seeds of evo thought - Preformism - Finalism & Progressionasm - Lamarckianism Preformism ☆ Evo from mini version found in sperm or egg ☆ Implies all of evo was predetermined & it unfolds over time ☆ Embryology & evolution conflated Finalism & Progressionism ☆ Evo is a directed, goal orientated series of charges ☆ Simple → complex ☆ Progress = improvement ☆ Goals = appearance of us; union of us + creator ☆ Pierre Tethard de Chardin (1881-1955) Omega point Lamarckianism ☆ Jean Baptiste Lamarck (1744-1829) ☆ Invertabrate biologist ☆ Coined word biology ☆ Heraclitus "nothing endures but change" ☆ Button - universe constantly in flux ☆ Uni formitarianist-70k-500k old world ☆... 1ˢᵗ reasonable theory of organic evo Lamarck's 4 Components of Evo 1. Organisms adapt to the envir (progressionalism; finalism) 2. Spontaneous generation (Frequents 3. Inner drive for perfection (vitalism) 4. Inheritance of acquired characteristics ☆ Geoffrayism (passive) vs Lamarckianism  (active) Charles Darwin (1809-1882) ☆ Ship Naturalist ☆ 1831- 1836: Voyage of the Beagle ☆ 1859: On the Origin of species by Means of Natural Selection Island biogeography ☆ Darwin examined variation on islands ☆ Islands are specialised natural labs, w/ semi-isolated natural communities ☆ Typically have large no. of endemic species ☆ Geo & other intrinsic factors can have major impact on no. & types of animals/plants on an island ☆ Galapagos islands created as tectonic  plates moves over volcanic hotspot Galapagos Islands ☆ One of the most volcanic places on Earth ☆ Crossroads of 4 major ocean. Currents - marine diversity hotspot ☆ Island 700k → 4. 2Ma (oldest underwater 8m? Plume 90m?) ☆ Geo/Ecological diff (& therefore faunal diff) are closely tied to diff ages of the Islands. ☆ Parallel btwn species morphology. behaviour, geo & adatation ( 'fit") to envir (the foundation of biogeo) Influences... ☆ Lyell's geo... rejected 6 day special creation ☆ Thomas Robert Malthus -political economist & demographer - Many more organisms born that can survive (pop sizes available resources) - ↑ pop size- competition-strong survive Darwin's contribution ☆ Demostrated FACT of evo (& defined it as descent w/ mod.) ☆ Offered explanatory mech (ie natural selection.. survival & mortality KEY to this definition ☆ Natural selection : preservation of favourable Indiv diffs & variations & the destruction of those are injurious ☆ Darwin did NOT coin "survival of the fittest"  (Herbert Spencer did) ↳ term evokes sense of competition for survival ☆ In fact, he argued against it & tied the success of human (& other animal) evo to the evo of compassion Alfred Russel Wallace (1823-1913) ☆ Malay Archipelago: 1848-1862 ☆ 1857: "On the Tendency of Variation to Depart Indefinitely from the Original Type" 5 parts to natural selection ☆ Heredity of most features ☆ Heritable variation in the pop. ☆ Variation leads to diff. rates in survival & reproductive success among variations ☆ Diff survival & reproduction leads to change  in Frequency of characters (pop will diverge from one another) ☆ If process goes on long enough, parent & dougher species can no longer interbreed (e.g they have become too diff) ☆ Environmental context is essential!!! Gradual Evolution ☆ Darwin generally considered to be a gradualist (changes happen slowly & gradually) ☆ Influenced by important go school of thought @ the time (Uniformitarianism) Industrial Melanism ☆ The peppered moth (Biston betularia)  occur in 2 varieties (melanic & non-melanic) ☆ Non-melanic Form virtually invisible against pale-coloured background, vice versa for melanic form. ☆ Diff survival rates under environments of diff colour ☆ Prior to industrial revolution lighter form dom. - a survival adv. against lichen-covered trees ☆ After the industrial rev, more offspring of melanic form survive to reproduce ☆ Relative frequency shift for melanic: 5% → 98% ☆ Process occurred in just 40 gens ☆ Note: in this case nat. selection does not create the forms, but rather edits the pops ☆ Nat selection is 'fine-tuning' pops to their physical envir ☆ Bergmann's Rule: larger animal for warmer envir; smaller animal for colder envir ☆ Allen's Rule: longer limbs for warmer envir; shorter limbs for colder envir ☆ correlate btwn latitude (climate) & body mass/limb length Successes & Major failures... ☆ Freed himself from prevailing Ideologies (eg young Earth, Catastrophism) ☆ Defined evo as descent w/ mod ☆ Supplied this concept w/ a new metaphor ☆ Demonstrated descent w/ mod using the mech of nat selection ☆ BUT... origin of "new" variation? Medelian Genetics ☆ Gregor Mendel (1822-1884) ☆ 1865/6 ☆ "Versuche über Pflanzenhybriden" (Experiments on Plant Hybridization) ☆ Gene = fundamental unit of heredity ☆ Rediscovered in 1900 How does a trait disappear in 1ˢᵗ gen then reappear? ☆ Used pea plants ☆ Examined one trait @ a time ☆ Bred uniform parents ☆ Bred F1 & F2 gens Mendel's Principles of Inheritance ☆ Principle of Segregation - Expressions of traits controlled for by discrete units - Units occur in pairs; offspring inherit one from each parent - Each unit separates into parent sex cell& comes together @ fertilization ☆ Principle of Independent Assortment - Expression of one trait not influenced by expression of another Lucky for Mendel that he chose simple (Mendelian) traits!! ☆ Mendelian traits = governed by alleles @ one locus (discontinuous) ☆ Polygenic traits = influenced by alleles @ more than one locus (continuous) ☆ Linkage (genes inherited together;  exception to indep. assortment) & crossing over (exception to linkage) ☆ Inter-related nature of bio systems... - plecotropy- allele has erect on more than 1 trait - interactions = eg. one allele determine expression of another - epigenetic effects = dev affects gene expression ☆ All results in variation & uniqueness!!! The Modern Evolutionary Synthesis ☆ Merger of Mendelian genetics w/ Darwin's understanding ☆ Model for describing how evo works ☆ Dominant model of bio evo in 30s & 40s ☆ Still forms basis of our understanding of how evo works (but substantial mods/additions) Critical components ☆ Evo results from accumulated mutations & recombination of genetic traits over long periods of time ☆ Nat selection is primary mech by which species change over time ☆ Nat selection acting on pop leads to adaptation of specific envir conditions History of Discovery of DNA ☆ Watson & Crick (1953) ☆ Many things known (cell content constant; mutations; basic molecules In DNA,etc) ☆ Rosalind Franklin: ✗ -ray diffraction photos showing helical structure & precise measurements of DNA crystal ☆ Wilkins: had access to her photos ☆ DNA, PCR (replicating DNA), DNA sequencing ☆ Continental drift/plate tectonics ☆ Evo-devo development (epigenetics, homeobox genes, punctuated equilibrium, heterochrony, etc) ☆ Fossil discoveries (Feathered dinosaurs, bipedal apes, etc) ☆ Horizontal gene transfer ☆ Genetic drift, Hybridization, "Non-Darwinian" evo & more... Week 2 ☆ Descent wt mod (Darwin) ☆ Process by which species of organisms arise from earlier life forms & undergo change over time thru successive gens ☆ change in allele frequencies in pop over time What creates new forms? ☆ Nat selection (NS) 1 evo force (process) that can act to create (or delete) forms when viewed over deep time ☆ So do other evo forces (mutation, gene flow, drift) ☆ Action of evo forces produces organismal diversity How Natural Selection works ☆ must be variation in pop ☆ Trait must be heritable ☆ Some indiv better adapted to envir.Diff in adaptation = diff in survival rates ☆ More importantly diff in reproductive success ☆ Over time pop changes in the frequency of trait; pop has evolved Directional Selection ☆ Selects for an extreme over time (e.g cranial capacity) ☆ At heart of gradualism ☆ Another example is lactose non-persistence Stabilizing (normalizing) selection ☆ selects for average (Favours intermediate) in unchanging envir ☆ ↓ variation as pop stabilises on a particular value ☆ Probably most common form of NS ☆ Many things evolutionarily constrained ☆ Stasis (eg human birth weight) Diversifying (disruptive) selection ☆ Selection favours 2 outcomes ☆ ↑ genetic variation ☆ Branching event ☆ Eg: sexual dimorphism, generalists versus specialists, omnivores versus herbivores Skin colour ☆ UVR = UVA + UVB ☆ Too much is BAD: - Sunburn & DNA damage - Malignant melanoma - Folate (water-soluble vitamin B) destruction ↳ necessary 4 red blood cell production cell division, DNA repair & embryonic dev ☆ Too little UVR is also BAD: - UVB radiation stimulates production of Vit D - Vit D-fat-soluble essential nutrient - Vit D necessary 4 calcium absorption, regulates cell growth - Deficiency → rickets, joint pain, muscle weakness, osteoporosis, high blood pressure - Vit D may protect against cancer, inhibiting growth/ spread of tumours  - Also plays a role in other diseases & disorders Sexual dimorphism in skin colour ☆ During preg & breastfeeding, women's need 4 calcium 2x that of a man ↳ women tend to be lighter than men ☆ Needs more UVB Balancing selection ☆ Balanced polymorphism ☆ Maintains varation in pop due to envir context ☆ Favours heterozygote ☆ Example: sickle cell/hemoglobin in a malarial envir Sexual selection ☆ selection 4 secondary sex characteristics that are non-adaptive ☆ Traits can have reproductive benefit (affect fitness) ☆ Adaptation: change or structure, form, or habits to fit diff conditions which ↑ fitness ☆ Exaptation: process by which a structure that Is adaptive in one way becomes adaptive in another ☆ Spandrel: selectively neutral byproduct of other evo (adaptive) changes Mutation (+ recombination) ☆ Mutation: producer of new genetic variation (allelic change) ☆ Mostly duplication errors (carcinogens, radiation, age, etc ↑ error  rate) ☆ Some portions of genome mutate faster than others ☆ Human genome 6.8B basepairs ☆ Average mutation rate 4 humans 3 mutations/ billion/ year ☆ ~ 300-500 new mutations appear in genome of each indiv every generation (zoya) ☆ Diff types of mutation (point, addition/duplication, deletion, inversion, translocation) can have very diff effects evolutionarily ☆ Recombination. primary mech thru which variation is intro in pop ☆ Rearrangement of DNA sequences by the breakage & rejoining of chromosomes or chromosome segments ☆ Feature of meiosis as genes are regrouped in formation of gametes (sex cells) ☆ Ensures no two daughter cells are identical Genetic Drift ☆ Genetic Drift: random fluctuations in allele frequencies due to chance occurrences ☆ "Neutral evo " ☆ ↓ genetic variation w/in pop/ subspecies (ss) /species (s) (fixation/loss) ☆ Can act to diversify pop/ss /s (↑ genetic variation btwn them) ☆ Diffs are chance effects... particularly powerful in small (isolated) pops. ☆ Founder's Effect: small # founding indiv ☆ Bottleneck effect: +1 gen size smaller Gene flow (hybridization) ☆ Exchange of genetic material brun pop/ss Is ☆ Major factor in distribution of genetic Variation ☆ Acts as evo force if pop/ss/s are not reproductively isolated & are genetically distinct ☆ Can act to homogenise OR diversify pop/ss/s ☆ Can also produce new, hybrid lineages that in circumstances can be more 'fit' than parents ☆ "Reticulate evo" ☆ Hybrid zones (temp or long-term) ↳ hybrids exist in pop & even make own pop in hybrid zones ☆ Migration (perma pop exchange) Vikings & Irish Pop History ☆ Viking invaded Norway (800-1200AD) ☆ Similarity bown midland Irish & Norway/Denmark pop What is a species? ☆ Uniform types of organisms ☆ Classify organisms as belonging to one or other species ☆ Many diff ways of defining species ☆ In practice : species recognised not solely by repro isolation, but by some combo of factors (morphology, genetics, geo proximity, behaviour, & ecology) that together make a species distinct even in the face of gene How ☆ Diff species can look v. similar (Eastern &  Western Meadowlark) ☆ Indiv of same species can look v. diff (dogs) Biological species ☆ Group of actually or potentially interbreeding natural pop units which is repro isolated from other such groups (Mayr 1942, 1963 & Dobzhansky) ☆ Repro community of pops that occupies a specific niche in nature (Mayr 1982) ☆ Animals of diff species can sometimes interbreed ↳ Infertile offspring (mostly) ◦ Horse + donkey = mule ↳ Sometimes produces fertile offspring but geo ranges do not overlap in nature ◦ lion + tiger = tiger/tigon Evolutionary species ☆ Pop or group of pops that shares a common evo fate through time (Simpson 1961) ↳ Homo erectus & Homo sapiens Phylogenetic species ☆ Smallest diagnosable cluster of indiv organisms w/in which there is a parental pattern or ancestry & descent Recognition species ☆ Most inclusive pop of indiv biparental organisms which share a common fertilization system (Paterson, 1985)  ↳ group of organisms who recognize each other as potential mates ☆ + biological species concept = repro species concept Cohesive species ☆ Most inclusive pop of indiv having the potential for phenotypic cohesion thru intrinsic cohesion mech (Templeton, 1989) - genetic drift & selection - gene flow What is a race? ☆ Often people will equate ss w/ races ☆ Ss are bio units below the level of a species ☆ Race is a category ☆ Race is a social construct based on  decisions about how to draw boundaries among people, based on physical/cultural traits ☆ These physical traits r continuous & don't map nearly to racial categories; boundaries r arbitrary Microevolution ☆ Time: generations ☆ Units: below species (demes) ☆ Focus: Process ☆ Discipline: Pop genetics ☆ Fitness: Births/deaths of indiv ☆ Evo: changes in allele frequencies overt ime ☆ Nat set: = indiv selection Macroevolution ☆ Time: millions of years ☆ Units: above species Ivl ☆ Focus: Products (patterns of organic diversity ☆ Discipline: Palaeobiology ☆ Fitness: Births/deaths of species ☆ Evo: changes in pattern of organic diversity thru time ☆ Nat set: = species selection All species live within limits ☆ Envir factors exert selection pressure- influence survival (fitness) of organisms & their offspring ☆ Therefore species are limited in where they can live ☆ Limiters incl: ◦ physiological stress (too much/ little moisture, light, temp, pH, specific nutrients) ◦ competition w/ other species ◦ predation incl. parasites/disease ◦ luck ☆ Tolerance limits of species indicate envir factors beyond which a species cannot survive/ repro Species change through time ☆ Because species live w/in limits, change in species form & numbers (+/-) thru time occurs as organisms are forced to adapt to changing envir ☆ Random change (mutation, drift) & interactions (gene flow) further affect variation w/in a species & its ability to  adapt ☆ One species can change into a single new species (anagenesis) or into ≥2 species (cladogenesis) ☆ Can happen gradually or rapidly ☆ Tempo: phyleric gradualism or punctuated equilibrium How does one species split into 2 (or more)? ☆ Speciation-dev of new species ☆ One important mech of speciation is geo isolation; this type of speciation is called allopatric speciation ☆ Sympatric speciation. when barriers  dividing pops are not physical (eg. behaviour) ☆ once isolation is imposed, species diverge thru selection, genetic drift & other evo means Allopatric speciation ☆ Species becomes geo divided by barrier [continental drift, rifting, change in course of river, fire, etc) ☆ Separate pops are repro isolated from each other ☆ Pops diverge thru neutral evo (drift, mutation) ☆ Nat selection also operates indep in each pop, acting on these divergent groups & causing pops to become uniquely adapted to their own envir ☆ Repro isolation initially imposed by geo  constraints but eventually pups diverge too much resulting in perma barrier (diff genomes, behaviours, etc) ☆ Speciation complete; one species has become 2 or more Sympatric speciation ☆ Speciation w/in a pop ☆ Pops become genetically isolated even though their ranges overlap (diff ecological opportunity) Evolutionary change & speciation via developmental shifts ☆ Small changes in dev/regulatory genes may cause large changes in morphology etc of a species  eg: Hox genes-control dev of body segments eg: Heterochrony-evo acting on timing/rate of dev Extinction ☆ If speciation occurs all the time, there should be more species today than 10 000 yrs ago, & more than there were 10 million yrs ago, right? ☆ NO, because extinction is ubiquitous (which is why speciation is important for maintaining biodiversity) ☆ 99% of all species that have ever existed on Earth have gone extinct ☆ some geological periods are characterised, or dom by extinction (eg. end-Permian, end-Cretaceous) ☆ Mass extinction events Mass extinction ☆ Causes varied & sometimes controversial ☆ End-Permian event resulted in loss 90% of all marine species- global warming may have been the culprit (a lesson?) ☆ End-Cretaceous (K-T) likely caused by asteroid impact. Loss of large proportion of reptiles (esp the dinos) ☆ Causal factors may have been climate change induced by impact: global cooling. Megafauna of Today ☆ Human-induced climate change, habitat change & hunting are continuing to threaten megafauna worldwide - the 6ᵗʰ Mass Extinction? Week 3 Intro to Primates ☆ Classification - How do we classify - Schools of Thought in Classification ☆ Hist of primate classification ☆ Hist of human (racial) classification - Race & racism ☆ What is a Primate? - Mammal traits - Primate traits Classification ☆ Process-ordering organisms into groups based on sim/ r-ships ☆ Product-hierarchy of terms (eg. kingdom, phylum, class, order, family, genes, species) ☆ Related terms - Systematics (study of the diversification of living forms) - Taxonomy (theoretical study of classification -eg. the practice & science of classification) - Phylogeny(evo hist of organisms) - Nomenclature (system of names, terms, & rules for naming in a formal naming system) Hierarchy of terms ☆ Kingdom: Animalia ☆ Phylum: Chordata ☆ Class: Mamalia ☆ Order: Primates ☆ Suborder : Haplorhini ☆ superfamily: Hominoidea ☆ Family: Hominidae ☆ Genus: Homo ☆ Species: H. sapiens ☆ Taxon (taxa): group(s) of organisms recognized as a formal group @ ANY level of a hierarchial classification Rules of nomenclature ☆ International Code of Zoological Nomenclature ☆ 1ˢᵗ name given to an organism is the valid one ☆ Holotype-type specimen, based on original discovery/naming ☆ Binomial nomenclature (eg. scientific name, or 'Latin name' ) - Genus (subgenus) species subspecies - Homo sapiens neanderthalensis  - Australopithecus (Paranthropus) robustus The Concept of Similarity ☆ Analogous traits (Homoplasy) ☆ Homologous traits (Homology) ↳ Primitive (symplesiomorphies) ↳ Derived (apomorphies) ↳ Shared (synapomorphies) ↳ Unique (autapomorphies) Schools of thought in classification ☆ Numerical Taxonomy (Phonetics/ Gradists): importance of all traits; only Sim important (not evo recon ) ; homoplasy can sneak in. ☆ Phylogenetic systematics (Cladistics): importance of derived traits; evo recon (branching pattern) most important; degree  of divergence not important; homologous, monophyletic groups. ☆ Evolutionary systematics: importance of both Sim (but avoid homoplastic traits) & evo recon; both branching pattern & degree of divergence are of concern ☆ Monophyly = single ancestral species gave rise to all species in this clade & to no species in any other clade ☆ Polyphyly = homoplastic groups... sim organisms in group, but doesn't incl. ancestor ( eg. pachyderms) ☆ Paraphyly= group of organisms w/ most recent common ancestor of those organisms plus some (but not all) of that ancestors descendants (eg. reptiles; Anthropoids) ☆ Clade -group of organisms sharing  common ancestry to the exclusion of others (emphasizes molecular divergence) ☆ Grade = group of organisms characterised by a certain level of org and/or adaptation (emphasizes adaptative divergence) History of Primate Classification ☆ Linnaeus: Primate Order (in me 1700s - Systema Naturae) - 4 Subgroups: Homo, Simia, Lemur, Vespertilio ☆ St.George Jackson Mivart (1827-1900) - 2 Suborders: Anthropoidea & Prosimii ☆ Sir Wilfred Le Gros Clark (1895-1971) - recognised that characterization of primates is difficult (v. generalized)  - emphasised evo trends or general tendencies (eg. grades.. common terms like humans, great apes, lesser apes, monkeys, prosimians) ☆ Modern classification - relies on clade-based classification of primates (eg. monophyly) History of human (racial) classification ☆ Linneaus (1788) 10ᵗʰ Ed. Systema Naturae - Homo sapiens ↳ H. sapiens ferrous ↳ H. sapiens americanus ↳ H. sapiens europaeus ↳ H. Sapiens asiaticus ↳ H. sapiens afer ↳ Homo monstrosis!! (6 varieties →  behavioural, cultural, physical attributes) Comte de Buffon (1749) ☆ Replaced "variety" w/ "race" ☆ Based on stature, skin colour, body form, behaviour, etc... ☆ Notion that there was an ideal type ☆ But didn't believe categories (sensu Linneaus) were real ☆ 6 "Races" ↳ Laplander ↳ Tartar ↳ South Asiatic ↳ European ↳ Ethiopian ↳ American John Friedrich Blumenbach (1781) ☆ FOUNDER of physical anthro ☆ Race based on physical traits ☆ But believed divisions were arbitrary ☆ Tried to understand source of phenotypic variation (climate, food, disease, mode of life) ☆ 5 races ↳ Caucasian ↳ Oriental ↳ American Indian ↳ African ↳ Malay ☆ Coined "Caucasian" (defined as beautiful, closest to God, original human from which all other degenerated) ☆ 1ˢᵗ hierarchical (as opposed to go classification) ☆ Work standard reference point for future  discussions of human races Immanuel Kant (1724-1804) ☆ Considered one of the most influential philosophers of the Enlightenment & important moral theorists of modern times ☆ Originator of mod. concepts of race & scientific racism ☆ Races based on colour & climate (which determined temperament incl intellectual ability) ☆ Races are fixed, i.e. lower races don't have capacity for reason, moral perfection, etc ☆ Hierarchy: Europe (white) → Asia (yellow) → Africa (black) → America (red) ☆ latter 2 don't qualify as full people; extended this to Jews as well 1800s ☆ End of monogenism-(degenerate) envir influence; Rise of polygenism- unchangeable, biologically fixed ☆ Diff in physical traits (esp cranial capacities) → separate creations of superior & inferior races; racial "purity" ☆ Move to equate certain races w/ apes/monkeys ☆ Beginning of modern eugenics ☆ Broca (France), physician & anatomist (1824-1880)... Statistical measures. Justification for racism ☆ 1940s.. collections of allele frequencies ☆ 1960s... movement against racial classification (biological reality of variation distinct from racial types) Continuous vs. discontinuous physical trait variation ☆ Discontinuous traits → traits you have or don't have; fall easily into categories (eg. number of fingers, tooth number, etc) ☆ Continuous traits → traits that are part of a spectrum; divisions btwn traits are arbitrary (eg. skin colour, hair texture, height, weight, etc) ☆ Sometimes this range of continuous trait variation is assoc W/ geo... Clinal distribution of traits Race ☆ Bio variation is real ☆ Skin colour & other physical traits are bio  determined; races are not ☆ Race is a category ☆ Human races are not analogous to (bio determined) ss ☆ Race is a social construct based on decisions about how to draw boundaries among people. ☆ These physical traits are continuous & don't map neatly to racial categories; boundaries are arbitrary Racism ☆ Racism is when value judgements are assoc w/ racial categories (ie. one group being better or worse) ☆ house value judgements are often rooted in historical & social hist & norms & are learned behaviours ☆ Racism has deep historical roots Race in SA ☆ How many races are there in SA & what are they? ☆ How does this compare to the USA? ☆ Why do the racial categories differ? ☆ What does that say about diff in history, migration, politics, etc? ☆ What does it mean to be coloured? Atrocities justified using findings of early physical/ biological anthro (using bad science to support racism) incl: ☆ Holocaust (Nazi Germany) ☆ Apartheid (SA) ☆ Slavery (USA) ☆ Sterilization of Mexican-American women  in 1970s ☆ Etc... What is a mammal? ☆ Kingdom: Animalia ☆ Phylum: Chordata ☆ Class: Mammalia Important features of mammals ☆ Homiothermy ☆ Heterodontism ☆ Vivaparous (mostly) ☆ Hair/fur ☆ Internal eardrum ☆ 4-chambered heart ☆ Relatively large cerebrum ☆ Increased parental care What is a primate? ☆ One of the more diverse groups of mammals ☆ 600+ species alive (as many extinct) by IUCN counts ☆ Lots of variation! Primate envir: tropical rainforests (primarily) ☆ ↑ precipitation, bio rich areas ☆ Many primate traits are a direct result of evolving in (and adapting to) this envir Primate morphology ☆ Ancestral Mammalian Traits - generalized mammalian body plan  - retention of clavicle - relatively flexible joints in forelimbs - pentadactyly - generalized hetero dont detition (no highly specialized teeth → widely varied diet) ☆ Shared Derived Traits - grasping hands & feet mobile digits opposable thumbs prehensility - nails instead of claws (+sensitive tactile pads) - post-orbital protection post-orbital bar post-orbital plate post-orbital enclosure Evo trends ☆ Vision more important - post-orbital bar, plate, or enclosure - larger/ more der retina & visual cortex - orbital convergence (binocular, stereoscopic vision) ☆ Olfaction less important - less prognathism - no rhinarium in haplorrhines - smaller olfactory bulbs relative to total brain size ☆ bulla made up of the petrosal bone (ie. bony middle ear) * only synapomorphy UNIQUE to primates ☆ Increasing Brain size & complexity  - larger relative brain: body size than other mammals - Increased complexity of brain (esp. cerebral cortex) Primate behaviour & life history ☆ emphasis on learning ☆ group living ☆ Intelligence important ☆ long-life history stages ☆ strong mother-offspring bonds ☆ more parental investment ☆ kinship important ☆ longer life history stages ↓ ☆ longer periods of growth & dev (& dependence on mothers) after birth  ↓ ☆ more flexible, learned behaviour ↓ ☆ social behaviour & social complexity ☆ Extended life history has an impact on morphology / development - smaller litters (only 2 mamary glands) - long gestation periods - Slow maturation, long life span Advantages of group living ☆ Improved access to food ☆ Protection from predators ☆ Access to mates ☆ Assistance in rearing offspring Social organization ☆ Solitary dispersed (most nocturnal strep sirrhines; orangutans) ☆ Monogamous family group (1 male, 1 female, gibbons, Lemur mongoz, Indriids) ☆ Polyandrous group (1 female, multi-male; Callitrichids) ☆ Multi-male (multi-female) group (most baboons, macaques, etc) ☆ multi-level social system (Hamadryas- type system; fission-fusion chimps) Correlation btwn social org & sexual dimorphism ☆ polygynous mating systems → more Sexual dimorphism ☆ Monogamous mating systems → less sexual dimorphism Sexual dimorphic traits ☆ large body size ☆ large canines ☆ Facial colouring ☆ manes ☆ cheek pads Diet & Tooth morphology ☆ Sharp, high cusps = puncturing, crushing = small animal prey ☆ Cresting blades = shearing = insectivorous & foliverous ☆ Rounded cusps = crushing, grinding = seeds & hard material Diet & Body Size ☆ insectivores & gummivores ☆ frugivores who eat insects ☆ frugivores who eat leaves ☆ gramnivores & folivores Diet & Social System ☆ insectivores: solitary dispersed ☆ frugivores: group-living Primate locomotion ☆ Arboreal quadrupedalism ☆ Terrestrial quadrupedalism ☆ Leaping ☆ Suspension ☆ Bipedalism Aboreal quadrupedalism ☆ most common form of locomotion in primates ☆ walking ☆ slow climbing ☆ claw climbing & clinging ☆ Adaptation on body - Narrow thorax, anteriorly placed scapula - Powerful flexors /extensors (restriction of movement to parasagittal plane) - Long digits - Skeletal changes assoc w/ permanently flexed elbow (triceps leverage/support) - Equal limb lengths - Long tail (usually) Terrestrial quadrupedalism ☆ Reduced tail ☆ Larger bodied than arboreal quadrupeds ☆ Shortened digits for weight bearing ☆ Limbs designed for speed rather than power or complex balancing/stabilizing movements Leaping ☆ Vertical clinging & leaping ☆ shorter forelimbs ☆ long hind limbs ☆ elongated feet/ankles (levers) Suspensory locomotion ☆ Semi-brachiation ☆ Brachiation ☆ Quadrumanous climbing ☆ long digits ☆ long arms ☆ short trunk ☆ extremely flexible, shoulder, dorsally placed scapula Knucklewalking & Fistwalking ☆ Unique to apes ☆ Adaptation of suspensory body plan to life on the ground ☆ Relatively minor skeletal changes in the hand & wrist Bipedalism ☆ Ventral foramen magnum ☆ S-shaped spine ☆ Vertebrae increase in size w/ weight bearing ☆ Mods to pelvis (balance) ☆ Long legs; large femur head angled femora ☆ hallux adducted arched foot feet as levers Comparative postcranial morphology: Intermembral Index ☆ Intermembral index: length of humerus +length of radius length of femur +length of tibia X 100 ☆ higher index = forelimbs longer ☆ lower index = hindlimbs longer ☆ Index close to 100 in quadrupeds ☆ Lower in leapers & bipeds ☆ Higher in brachiators Week 4 The Living Primates ☆ Kingdom: Animalia ☆ Phylum: Chordata ☆ Class: Mammalia ☆ Order: Primates Phenetic (grade-based) classification ☆ Primates ↳ Prosimians (lemurs, lorises, pottos, bush babies & tarsiers) ↳ Anthropoids ( "Higher primates" a.k.a. monkeys & apes) Prosimians ☆ smaller bodies & brains ☆ grooming claws ☆ unfused mandibular symphasis ☆ unfused metopic suture ☆ mostly nocturnal ☆ less social Anthropoids ☆ larger bodies & brains ☆ no grooming claws ☆ fused mandibular symphysis ☆ fused metopic suture ☆ mostly diurnal ☆ more social Cladistic (clade-based) classification ☆ Primates ↳ Strepsirrhines (lemurs, lorises, pottos, bush babies, no tarsiers) ↳ Haplorhines (Monkeys, apes AND tarsiers) Strepsirrhines ☆ rhinarium ☆ split upper lip ☆ tapetum lucidum ☆ post-orbital bar ☆ tooth combs Haplorhines ☆ no rhinarium ☆ continous upper lip ☆ no tapetum lucidum ☆ post-orbital plate or enclosure ☆ no tooth combs Primate Subordinal Taxonomy Strepsirrhines ☆ Suborder: Strepsirrhini ↳ Lemurs, lorises, pottos, angwantibos, bush babies, and aye-ayes Infraorder: Lorisiformes ☆ Lorises, pottos, angwantibos & bush babies ☆ SE Asia (lorises) & Africa ☆ < 1.6kg ☆ nocturnal & arboreal ☆ primitive dental formula (2:1:3:3) ☆ specialized for slow climbing (lorises, porters, angwantibos) ↳ very mobile joints, intermediate Intermembral index, reduced 2ⁿᵈ digit, reduced tails ☆ OR specialized for vertical clinging & leaping (galagos) ↳ powerful hindlimbs, low intermembral index, long tails, enlongated tarsal bones ☆ solitary dispersed social system Infraorder: Lemuriformes ☆ Lemurs: true, dwarf & mouse, sportive & wooly ☆ Madagascar & nearby islands ☆ adaptive radiation ☆ wide variety in body size, diet & social system ☆ derived dental formula ☆ aboreal quadrupedalism ☆ Vertical clinging & leaping Infraorder: Chiromyiformes ☆ Aye-aye ☆ Madagascar ☆ One species: Daubentonia madagascariensis ☆ ~ 2.5kg (world's largest nocturnal primate) ☆ unique rodent-like dentition (only 16 teeth) ☆ arboreal quadrupedalism ☆ specialised adaptation of middle finger ( woodpecker niche) Haplorhines ☆ Suborder: Haplorhini ↳ tarsiers, monkeys & apes Infraorder: Tarsiiformes ☆ tarsiers ☆ SE Asia ☆ 100-150g ☆ arboreal ☆ Insects & animal prey ☆ nocturnal predators (owl niche) ☆ large eyes ☆ head rotates ☆ specialized for vertical clinging & leaping: ↳ powerful hindlimbs  ↳ low invermembral index ↳ fushed tibia & fibula ↳ elongated tarsal bones Infraorder: Simiiformes (Anthropoids) ☆ monkeys & apes ☆ larger bodies ☆ larger & more complex brains ☆ more complex social structure ☆ almost all diurnal (except one) ☆ more visually-oriented ↳ visually oriented ↳ post-orbital enclosure ☆ no grooming claws ☆ no dental combs ☆ fused mandibular symphysis ☆ fused metopic suture  Haplorrhines Tarsiiformes Simiiforms Platyrrhines (P) Catarrhines (C) Superfamily: Cercopithecoidea Superfamily: Hominoidea (American (Afro-Eurasian monkeys) monkeys & apes) Morphological differences btwn platyrrhines & catarrhines Dental formula ☆ Platyrrhines (2:1:3:3) ☆ Catarrhines (2: 1: 2:3) Nostril Orientation ☆ Catarrhines ↳ nostrils closer together ☆ Platyrrhines ↳ nostrils far apart Tympanic structure ☆ P: ring-like ☆ C: tubular Parvorder: Platyrrhini ☆ American monkeys ☆ Central & South America ☆ Families: Cerbidae, Aotidae, Pitheciidae, Atelidae ☆ Examples: marmosets, tamarins, capuchins, squirrel monkeys, night monkeys, sakis, titis, uakaris, howler, spider & wooly monkeys Family: Cerbidae ☆ Capuchins, squirrel monkeys, callitrichids ☆ arboreal quad ☆ diurnal ☆ small 150g → 4kg ☆ variable coloration ☆ mostly fruit/insect eating ☆ 2:1:3:3 dental formula (2:1:3:2 in callitrichids) ☆ 1-2 Offspring (twins in callitrichids) Family: Atelidae ☆ spider, wooly & howler monkeys ☆ arboreal, diurnal ☆ moderate-sized (~5-10kg) ☆ fruit/leaf eaters ☆ polygamous ☆ suspensory locomotion (semi-brachiation... prehensile tails, reduced thumbs, very mobile shoulder joints) Family: Aotiidae ☆ night (owl) monkey ☆ only nocturnal monkey ☆ no colour vision ☆ excellent spatial resolution ☆ small ~ 1kg ☆ monomorphic ☆ pair-bonded ☆ male primary care giver Family: Pitheciidae ☆ titi monkeys, sakis, uakaris ☆ small to medium sized (~1-5kgs) ☆ arboreal, diurnal ☆ long, colourful pelage ☆ fruit & seed eaters ☆ polygamy- uakaris, bearded sakes ☆ monogamy- titis, sakis Parvorder: Catarrhini ☆ Afro-Eurasian monkeys & apes ☆ Africa & Asia ☆ Families: Cercopithecidae, Hylobatidae, Hominidae ☆ Example: baboons, mandrills, macaques, colobines, langurs, gibbons, siamangs, chimpanzees, bonobo's , gorillas, orangutans, humans Cercopithecoids ☆ Tails ☆ Smaller brain size ☆ Blophodont molars ☆ Adapted for quadrupedalism: ↳ ribcage deeper than wide ↳ scapulae more laterally positioned ↳ longer thorax ↳ more stable joints Hominoids ☆ No tails ☆ Larger brain size ☆ Y-5 molars ☆ Adapted for suspensory locomotion: ↳ ribcage wider than deep ↳ scapulae more dorsally positioned  ↳ shorter thorax ↳ more mobile joints Family: Cercopithecidae ☆ Afro-Eurasian Monkeys ☆ Super family: Cercopithecoidea ☆ macaques, baboons, mandrills, guenons, vervets, colobines, snub-nosed monkeys, langurs, doucs ☆ Omnivorous ☆ Adaptable, flexible ☆ Specialised feeding adaptations end. cheek pouches & complex digestive tracts Colobine monkeys ☆ Colobus monkeys (Africa), leaf monkeys & langurs (Asia) ☆ Subfamily of AE monkeys specialized for leaf-eating (folivory) → toxins + cellulose ☆ specialized digestive systems: ↳ long digestive tract ↳ multi-chambered stomach ↳ specialized bacteria ↳ foregut fermentation Simiiformes Platyrrhines Catarrhines Cercopithecoids Hominoids Superfamily:Cercopithecoida Superfamily:Hominoidea Afro-Eurasian monkeys apes (incl humans)  human chimp gorilla orangutan ~6mya gibbon Hominidae ~8 mya Hylobatidae ~12 mya ~15mya Family: Hylobatidae ☆ gibbons & slamangs ☆ Super family: Hominoidea ☆ SE Asia ☆ 4 genera; 13 species ☆ "lesser apes" ☆ smallest ape @ 6kg ☆ briachiation (long arms & fingers, short thumbs) ☆ pair-bonded ☆ monogamous/ monomorphic ☆ territorial Family: Hominidae ☆ "Greater apes" & humans ☆ 4 genera (Pongo, Gorilla, Pan, Homo) ☆ 8 species ☆ Great ape distrib: Africa & SE Asia (Borneo & Sumatra) ☆ Human distrib: Worldwide (but evolved in Africa) Genus: Pongo ☆ Orangutans ☆ Pongo pygmaeus (Borneo; 100k) ☆ Pongo abelii (Sumatra; 13k) ☆ Pongo tapanuliensis (Sumatra; 800) ☆ red/brown hair ☆ far pads (flanges) in males ☆ males 80-90kg; females 33-45kg ☆ quadrumanous climbing/ hanging ☆ fist-walking on gound ☆ solitary social system Genus: Gorilla ☆ Gorillas ☆ Gorilla gorilla (w. gorillas: western lowland & Cross River) ☆ Gorilla beringei (e. gorillas: eastern lowland & mountain) ☆ Equatorial Africa only ☆ blackish hair (some red on head in lowland groups) ☆ males 180kg i females 90kg ☆ knuckle-walking ☆ small groups w/ 1 dominant male Week 5 Genus: Pan ☆ Chimps & bonobos ☆ Pan troglodytes (Eastern & Western chimp) ☆ Pan paniscus (bonobo) ☆ Equatorial Africa only Pan troglodytes ☆ highly variable faces & overall appearance ☆ males 50kg; females 40kg ☆ knuckle-walking ☆ both terrestrial & arboreal (varies by culture) ☆ large communities (50+) ☆ adult male bonds, fluid dominance (size, strength, intelligence) Pan paniscus ☆ highly variable morphologically ☆ knuckle-walking ☆ large communities ☆ matriarchal social structure ☆ strongest bonds btwn females ☆ "Pansexual"- eg. sex part of societal fabric ☆ adept bipeds Homo sapiens ☆ highly variable morphologically ☆ large, variable communities ☆ variable social structure (egalitarian) ☆ sex part of societal fabric ☆ extended life history ☆ distrib globally ☆ habitual bipeds Non-human primates as models for human ancestors ☆ We study primares to better understand them ☆ We also study them to better understand ourselves, how we differ from them (or not) & what our ancestors might have looked/ behaved like ☆ Diff primates make more or less good models for understanding diff aspects of human evolution Documentary- Ape Genius ☆ Culture - Hunting (bush babies + Monkeys) - Swimming - Toolmaking - Fishing for termites ☆ Similarities btwn human & chimp activities - imitation - ask for help - cause & effect - tool-making - mind-reading - language - problem-solving - CO-ordination - mother to child bond - justice - caring for dead ☆ Diff btwn chimps & humans - lack impulse control - cannot team - don't offer encouragement - lack shared commitment to shared goals How do we differ from other primates? ☆ Distrib-African origins, currently worldwide (yet molecularly invariable) ☆ Skin & hair colour/texture ↑ variable ☆ Bipedal locomotion ☆ Reduced canine size, no diastema, no dimorphism-egalitarian social system ☆ Extremely large brains, complexity of tool production & use ☆ Resultant domestication & agriculture ☆ Music, art, maths, etc... ☆ Many traits that we consider special to humans are built on a foundation of traits that are diff in DEGREE BUT NOT KIND from the other primates (reflects primate ancestry) ☆ Traits also reflect the ENVIR OUR ANCESTORS (AT ALL LEVELS) EVOLVED IN & ADAPTED TO Not unique to humans... ☆ Ability to exploit a wide range of envir (generalists) ☆ complex social structures ☆ Tool use & culture ☆ Intelligence (Self-awareness; Theory of mind) ☆ complex communication (language?) Ability to exploit wide range of envir ☆ Important for, but not unique to, humans. ☆ Other primates, baboons, macaques, etc ☆ Other mammals: dogs, rats, etc. ☆ Extremely wide distrib has resulted from (eg. bipedalism) & lead to (eg. ectodermal variability) certain human traits. Complex social structures ☆ Many mammals have complex social structures. ☆ This is esp true among primates, & esp apes. ☆ Other apes known to form power alliances (politic), spread habits (culture) & show empathy & fairness (morality) Tool use & culture ☆ Humans unique in our reliance on tech & dev of complex technological systems Tool use & 'culture' in non-human primates ☆ Tool production & use-capuchin monkeys, orangutans, gorillas, chimps ☆ Variation across pops in forms of tool use & other cultural 'traditions' ☆ Social transmission Capuchin monkeys: ☆ Experiments in captivity ☆ Tool use in wild: - Nut-cracking w/ stone - Throwing branches - Probing w/ stick  - Pounding with oyster shell - Use of branch to strike snake Orangutans: ☆ Sticks: - To extract insects - To extract seeds - For scratching ☆ Leaves: - To drink water - As serviettes - To swat away bees - As gloves - As umbrellas Gorillas: ☆ Walking sticks while crossing water ☆ sticks to test depth of muddy water ☆ Postural support while foraging ☆ Disabling poaching traps Chimpanzees: ☆ Termite-fishing: - Variation in technique (Gombe & Mahale, Tanzania; Assirik, Senegal); Mainly females ☆ Nut-cracking: - Hammer- stone or wood - Anvil = stone or tool - Bossou, Guinea- fav stones, 3ʳᵈ stone as wedge ☆ Leaves to obtain water: - Containers - Sponges ☆ Weapon production: - Senegal- sharpen sticks as spears Variation in other 'cultural traditions' in apes ☆ Nest-building (chimps, gorillas & orangutans) - Mostly arboreal, sometimes re-used - Variation among pops ☆ Plants as medicine ☆ Hunting & meat eating (chimps): - Habitual, cooperative hunting - Mainly males - Variation among study sites ☆ Hand clasp while grooming & leaf-clipping - Meaning differs by region- display; play; sexual solicitation Self awareness ☆ Mirror self-recognition - Great apes - Dolphins, Orcas - Elephant - Magpies, pigeons - Manta rays, cleaner wrasses - Others...? ☆ Theory of Mind - Great apes (maybe simpler) ☆ Chimps react to their reflections in a mirror ☆ Wild chimps show aggressive behaviour & then some curiosity & self-directed behaviour ☆ Captive chimps using a mirror to see parts of their body they can't usually see Symbolic communication ☆ In great apes (& other animals)  - Chimps - Bonobos - Orangutans - Gorillas - Dolphins - Parrots ☆ Apes can understand signs, lexigrams, speech ☆ Kanzi- simple syntax & rudiments of language; invention of novel vocalized words? ☆ Symbolic communication in monkeys? - vervets in Kenya w/ predator-specific alarm calls Does language = cognition? ☆ Humans may be only linguistic species, with symbolic communication as rich and multifunctional as ours. ☆ We don't need language in order to think (eg. pre-verbal children), though it does assist thinking by providing categories & concepts. ☆ Capacities underlying language (eg communication systems w/ rich meaning) exist in other animals. - Hand gestures esp noteworthy in apes- under voluntary control & often learned. ☆ Documented thinking in nonlinguistic creatures argues against importance of language. Continuum of animal cognition most monkeys great apes humans mammals dolphins (incl strep parrots primates) primates) elephants Week 6 Early Primate Evolution ☆ Fossils & the Geologic Time Scale ☆ How do we date fossils? ☆ When/where did primates evolve? ☆ Who were the earliest primates? - Early primate-like mammals - Earliest true primates ☆ Why did primate adaptations evolve? Fossils ☆ Preserved remains or traces of an organism that lived in the past ☆ Most fossils are formed when organisms die & are buried in sediment ☆ Eventually the sediment can harden in some cases to become sedimentary  rock. Kinds of fossils ☆ Petrified- minerals replace organic material in bone/wood/ shell etc. turning these into rock. ☆ Mould- organic material dissolves after burial , leaving a hollow in hardened sediments or mineralised bone ☆ Cast- mould becomes filled w/ minerals that are not a part of the original organism ☆ Trace fossils- a fossil of a footprint, trail, burrow, or other trace of an animal (rather than of the animal itself) ☆ Sometimes whole animals become preserved intact (rare) ☆ Ice/ tar/ amber Why date fossils? ☆ Fossils have little meaning unless placed w/in some context ☆ Age of fossils allows for comparison to other fossil species from same or diff time period ☆ Understanding apes of related fossil species helps piece together the evo history of a group of organisms Geologic Time Scale ☆ This scale divides the time that the earth has existed into 2 eons, 5 eras ☆ Eras are then divided into periods & epochs based on events Pre- Cambrian (4,550 -541 mya) ☆ Began w/ formation of the Earth 4.6 billion  ya ☆ Bacteria appeared 3.5 billion ya, followed by algae & fungi Paleozoic Era (541 - 252 mya) ☆ Divided into 6 periods: Cambrian period- Sponges, snails, clams & worms evolve Ordovician period- 1ˢᵗ fishes evolved & some species become extinct Silurian period- Land plants, insects & spiders appears Devonian period- Amphibians evolve & cone-bearing plants start to appear Carboniferous period- Tropical forests appear & reptiles evolve Permian period- Seed plants become common & insects & reptiles become widespread. Sea animals &  some amphibians begin to disappear Mesozoic Era (252 - 66 mya) ☆ Divided into 3 periods: - Triassic period- Turtles & crocs evolve & dinosaurs appear - Jurassic period- Large dinos roam the world. 1ˢᵗ mammals & birds appear - Cretaceous period- flowering plant appear, mammals, become more common, dinos become extinct Cenozoic Era (66 Ma - present) ☆ Divided into 2 periods: - Tertiary period- 1ˢᵗ primates appear & flowering plants become the most common Paleocene Epoch (66-56 Ma)  Eocene Epoch (56-34 Ma) Oligocene Epoch (34-23 Ma) Miocene Epoch (23-5 Ma) Pliocene Epoch (5-2.6 Ma) - Quaternary period - Direct human ancestors (Homo) evolve & large mammals like woolly mammoths become extinct. Pleistocene (2.6 Ma - 12 ka) Holocene (12 ka - present) The Archaeological Time Scale ☆ Lower (Early) Paleolithic: ~3.3 Ma-30 ka ☆ Middle Paleolithic: ~ 30-40 ka ☆ Upper (Late) Paleolithic: 40-10 ka ☆ Neolithic: 10 ka - ☆ ESA: ~ 3.3 Ma - 200 ka ☆ MSA: ~ 280 - 40 ka ☆ LSA: ~ 40 ka - Three general approaches allow scientists to date geological materials ☆ Relative dating puts geological events in chronological order w/o requiring that a specific numerical age be assigned to each event ☆ Absolute dating attaches a numerical age to geological event; can sometimes reveal precisely when fossil species existed in time ☆ Magnetism in rocks can be used to estimate the age of a fossil site. Based on orientation of the Earth's magnetic field (which has changed thru time) Dating Methods ☆ Relative Dating - Chemical tests - Stratigraphy ☆ Absolute (Numerical) Dating - Isotopic/radiometric dating - Thermoluminescence, Fission track, OSL, ESR - Dendrochronology ☆ Palaeomagnetism Chemical Tests (relative) ☆ Fluorine & Nitrogen Methods - site specific - bones + Fluorine - Flouroapatite - nitrogen-containing amino acids a bone collagen break down as bone fossilizes ☆ Same site, bone w/ low fluorine & high  nitrogen content are recent, & vice versa Strata & stratigraphy (relative) ☆ Strata: horizontal layers of sedimentary & volcanic rocks ☆ The study strata is called stratigraphy ☆ Using a few basic geological principles, it is possible to work out the relative ages of these Strata/ rocks (i.e. what is older vs younger) - original horizontality - original lateral extension - superposition - cross-cutting r-ships - inclusion Principle of faunal succession ☆ Fossils can be useful tools for understanding the relative ages of rocks ☆ Each fossil species reflects a unique period of time in Earth's history ☆ Different fossil species always appear & disappear in the same order & once a fossil species goes extinct, it disappears & cannot reappear in younger rocks Biostratigraphy ☆ Study of the succession of fossils & its application to relative dating ☆ Biostratigraphic units est. by: - 1ˢᵗ appearances (/disappearances) of species (e.g. migrations, extinctions) - changes w/in lineages (e.g. ↑ molar crown height, loss of digits) - or both ☆ Index fossil: a fossil that is useful for dating  & correlating the state in which it is found Index fossils can be used to date rocks/ sediments in diff locations ☆ An index fossil is species that has to be recognizable & must have existed for a (relatively) short period bur over a wide geo range ☆ Because they are often rare, hominin fossils are not usually good index fossils Small mammal example: ☆ European Microtine rodent teeth ☆ Useful because of their abundance ☆ 3.5 Ma appearance of cementum ☆ ~500 ka appearance of 'ever-growing' properties Large mammal example: ☆ Less abundant but appearance/ disappearance & major morphological change in lineages still helpful ☆ Red deer: Double to multipoint antler ~400-250 ka ☆ Trend towards mammoth tooth complexity ☆ Hominin-bearing sites such as Elandsfontein (West Coast) are difficult to date because they are often situated in dune fields (always moving) ☆ Sites have historically been dated on the basis of mammal species that they share w/ radiometrically-dated eastern African localities Absolute dating ☆ Provide chronological estimates of the age of certain geological materials assoc w/ fossils, & even direct age measurements of the fossil material itself ☆ To est. the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed/died ☆ Geologists commonly use isotopic/ radiometric dating methods ☆ Also use other methods (e.g. electron spin resonance) Isotopic / radiometric dating (absolute) ☆ Relies on the decay of naturally occurring radioactive elements, i.e. how much decay since X mineral formed, & therefore how much time has expired Carbon-14 (14C) ☆ half-life (HL) = 5730 yrs ☆ 50k years BP - ~ 200 yrs ago ☆ life 14C/12C = atmosphere ☆ death 14C → 14N ☆ measure 14C/ 12C ☆ Assume constancy of atmosphere; all carbon in sample from atmosphere Potassium-Argon (K-Ar)/Argon-Argon (40Ar / 39Ar) ☆ few 100k years → infinity ☆ HL = 1.3 billion yrs ☆ Rocks heated (volcanic) then cooled; Ar accumulates ☆ 40K → 40Ar & 40Ca ☆ Measure 40Ar / 39K Uranium-series dating ☆ Varies (U-Pb > 1 Ma; U-Th > 500k- recent) ☆ Uranium isotopes → # of daughter isotopes ☆ Daughter isotopes precipitate out & you measure these ☆ More precipitate = longer time ☆ Becoming widely used in SA Fission-track Dating ☆ 10 Ma -10 ka ☆ Spontaneous fission of uranium → 'tracks' ☆ Heat erases tracks ☆ Measure density (time since heating) ☆ Arch; pottery clay, contain Zircon Thermoluminescence ☆ Measures how long ago minerals were heated 100 ka- 50 ya ☆ Irradiation → electrons → crystalline "traps" ☆ Heat / firing empties traps; Measure electron accumulation Optical stimulated luminescence ☆ Measures how long ago minerals were exposed to sunlight ☆ 300 ka- 100 ka ☆ Irradiation → electrons → crystalline "traps" ☆ Exposure to light empties traps; emits signal ☆ Measure electron accumulation ☆ Intensity = time since burial Electron Spin Resonance ☆ 5 Ma - 5 ka ☆ Irradiation → electrons → dental enamel ☆ Measure electron accumulation Dendrochronology ☆ ~10 ka - present ☆ Hot dry fluctuating climates ☆ Ring irregularity Paleomagnetism ☆ Earth is like a gigantic magnet- magnetic north & south pole; magnetic field is everywhere ☆ Small magnetic minerals that occur  naturally in rocks point toward magnetic north when rocks are formed ☆ Because of this, magnetic minerals in rocks are excellent recorders of the orientation, or polarity, of Earth's magnetic field. ☆ Paleomagnetism- Geomagnetic reversal studies ☆ changes in polarity of magnetic rock recorded in rocks polarity columns built by taking ocean cores When/where did primates evolve? ☆ End of Cretaceous, beginning of Paleocene (K-T boundary): extinction of 78% of life forms, incl dinosaurs many new open riches mammalian radiation  Primates initially evolved in Laurasia, later diversified in Africa Primates filled (via adaptive radiation) niches that opened up in tropical forests How do we determine ancient climate? ☆ Global scale → deep sea cores, determine the amount of water locked up in ice, etc. ☆ Paleocene mild (relative to Cretaceous); much warmer than tody (tropical → subtropical forests) ☆ Local → map distribution of ancient coals, desert deposits, tropical soils, salt deposits, glacial material, etc ☆ Distribution then mapped to past positions of continents ☆ Indicator certain → types of rocks form under specific climatic conditions (e.g. coal formation needs abundant rainfall which occurs in tropical rainforests or temperate forests ☆ Map distrib of plants (incl pollen) & animals, esp non-generalists that are sensitive to climate (alligators, palm trees, mangrove swamps, etc) Early primate-like mammals ☆ Plesiadapiforms, e.g. " archaic primates" ☆ Lived in Laurasia ☆ Arboreal quads ☆ Nocturnal w/ visual predation ☆ Dichromatic, limited stereoscopy ☆ Mostly insectivourous; some veg ☆ Dispersed solitary social system ☆ Best known fossil genera: Plesiadapis, Purgatorius, Ignacius, Carpolestes ☆ Similarities to primates primate-like molars (post-protocone fold, moving towards primate-like diet?) grasping hands & feet (initial adaptations to tree-life) ☆ Diff from primates claws no postorbital bar prognathic incisors separte from molars (rodent-like) weak orbital convergence smaller brains than living strepsirrhines L o ris e s , le m u rs , & A m e ric a n T a rs ie rs g a la g e s A E m onkeys m onkeys  m onkeys (ta rs iifo rm e s ) (s tre p s ) (C e rc o p it h e c o id e a ) Apes (P la ty rin in e s ) (H o m o n o id e a ) Eocene (~56-34 Ma) ☆ Slight global warming relative to Paleocene ☆ adaptive radiations of small mammals, including primates ☆ adaptive radiation of "Eurprimates" ("true" primates) ☆ Strepsirrhine radiations ☆ During Early Eocene crocs swam in swamps near North Pole, & palm trees grow in southern Alaska. Much of central Eurasia was warm & humid Earliest 'true' primates ☆ Adapoids & Onomyoids ☆ North America, Europe & Asia ☆ plesiadapiform "primate features" PLUS ☆ "true" primate features nails postorbital bar broader, shorter snouts more orbital convergences enlarged brains petrosal bulla ☆ Strepsirrhine traits unfused frontal bones post-orbital bar rhinarium & split upper lip (?) arboreal quad vertical clinging & leaping Adapoids ☆ North America & Europe ☆ "lemur-like" ☆ larger ☆ ring-like ectotympanic (s) ☆ fused mandibular symphysis (4) ☆ more prognathic (s) ☆ smaller eyes → diurnal? ** diurnal, frugivorous & social? Omomyoids ☆ North America & Asia ☆ "taster-like' ☆ smaller ☆ tubular ectotympanic (H) ☆ unfused mandibular symphysis (5) ☆ less prognathic (H) ☆ larger eyes → nocturnal? ** nocturnal, insectivorous & solitary? Why did primate adaptations evolve? ☆ Tropical rainforests ☆ Characteristics that unite primates direct result of evolving in (& adapting to) this environment ☆ Rainforest strata emergent trees main canopy understory Possible Hypotheses ☆ Arboreal Hypothesis: GE Smith & FW Jones Arboreal lifestyle → primate adaptations ☆ Nocturnal Visual Predation Hypothesis: M Cartmill Orbital convergence most extreme in animals w/ a visual system for detecing prey Insects, nocturnal, terminal branches ☆ Angiosperm Coevo Hypothesis: R Sussman Insects + flowers + fruits + nectar + gums, etc. ☆ Narrow Niche Hypothesis: J Orkin & H Pontzer Not sufficient-other animals (e.g. red squirrels) can do all these things! Confinement to aboreal niche  necessary (loss of morphology attributable to loss of wider behavioural repertoire, e.g. divergent eyes, claws) Stereoscopic vision ☆ Ability to view slightly diff images in 2 eyes (largely overlapping but diff pictures) ☆ Allows organisms to judge distance & have true depth perception ☆ Provides significant advantage in wild ☆ Navigation thru dense tropical rainforest (escape predators, locomon in 3D envir, access food) ☆ Many animals have it to varying degrees (extreme in primates, birds) Evolution of the Simiiformes ☆ 1ˢᵗ monkeys ☆ Evolution of colour vision ☆ Emergence & adaptive radiation of apes ☆ Summary of adaptive radiations, phylogeny, & the origin & evolution of important primate traits ☆ earliest monkeys in late Eocene ☆ monkey radiation in Oligocene (14-23 Ma) ☆ fossil sites in Asia & Africa ☆ Eocene/Oligocene transition MAJOR drop in global temp due to separation of South America & Australia from Antarctica ☆ Global climate during the Late Eocene was warmer than today. ☆ Ice had just begun to form at the South Pole. ☆ India was covered by tropical rainforests, & Warm Temperate forests covered much of Australia ☆ During the Oligocene, ice covered the South Pole but not the North Pole. Warm Temperate forests covered northern Eurasia & North America ☆ Lowered sea levels; pole glaciation ☆ Eocene/Oligocene boundary → streps disappeared from Europe ☆ Late Oligocene → gone from N. America ☆ Migration or extinction? ☆ Beginning of tremendous reduction in # & diversity of streps; confinement to nocturnal niches ☆ Successful radiation of simiiformes (diurnal) Fayum, Egypt ☆ tropical rain forest in late Eocene/ early Oligocene ☆ primate fossils:  Parapithecidae Propliopithecidae Fossil anthropoids / simiformes found at Fayum: ☆ Parapithecids: small body size 2: 1:3:3 dental formula ring-like ectotympanic arboreal vertical clinging & leaping ↳ ancestral monkeys (not a platyrrhine or a catarrhine; ancestral to both) ☆ Propliopithecids: larger body size 2: 1: 2:3 dental formula Y-5 molars  ring-like ectotympanic arboreal quad or leaping ↳ ancestral catarrhines (not hominoids / cercopithecolds; ancestral to both) Fossil Platiyrrhines (American Monkeys) ☆ late Oligocene (~25 Ma) ☆ Bolivia, Colombia, & Argentina ☆ no fossil AM earlier than Oligocene ☆ AM evolved from early monkeys In Africa in Eocene/ Oligocene ☆ AM arrived in South America during Oligocene How did primates reach the New World? ☆ came from either North America or Africa ☆ neither connected to South America during Oligocene ☆ But landmasses "stepping stones" existed due to global temp drop ☆ rafting from Africa? ☆ island hopping from N. America? Evolution of colour vision Trichromatic colour vision ☆ Three visual pigments responsible for human (& primate) colour vision ☆ Each absorbs light from a particular region of the colour spectrum ☆ Wavelengths closely correspond w/ colours human perceive as blue, green & red. ☆ Short wavelength pigment (S)-430 nanometres (nm) ☆ Medium wavelength pigment (M)- 530 nm ☆ Long wavelength pigment (L)- 560 nm ☆ S pigment gene located on chromosome 7 ☆ M & L very similar to each other (differ in 3/ 364 amino acids) & located on X chromosomes ☆ Three pigments = protein + light absorbing compound ☆ Reside in photo receptive nerve cells in the retina (cone cells) ☆ Light absorption by pigment → excitation of cone cell → signal conveyed to brain (I see red!!) Afro-Eurasian monkeys / apes vs. American monkeys ☆ Afro-Eurasian monkeys & apes have full  trichromatic colour vision ☆ American monkeys have polymorphic trichromatic colour vision ☆ 1 gene location (locus) on X chromosome, 3 gene varients (alleles)-M, L, & something in btwn ☆ As a result, AM males see in 2 colours, while some females (ML heterozygote) can see in 3 colours ☆ Probably the ancestral condition, & a precursor to full trichromacy (achieved through gene duplication) Adaptive benefits ☆ Improved colour discrim ☆ Improved foraging efficiency (ID of ripe fruits, new edible leaves) ☆ Predator & poison detection ☆ ID of skin/hair colour diff (sexual selection;  sensing the emotions/ states of others) Why only primates?? ☆ Trichromatic colour vision has not evolved in any other eutherian mammals ☆ Primates have complex neural cell system which likely evolved to improve visual acuity ☆ This may have allowed for the nervous system to process additional input of trichromacy ☆ In combination w/ stereoscopy, trichromatic colour vision is a primate adaptation that provided an immense fitness benefit in a tropical rainforest envir, & has continued to provide benefit to us even as we emerged from that envir & populated the world... ☆ Miocene (25-5 Ma) global warming ☆ rise in sea levels ☆ tropical forests in Europe & Asia ☆ hominoid radiation ☆ Pre-16 Ma → Tropical forests in Africa; Eurasia came together solidly w/ Africa ca. 17 Ma ☆ Post-16 Ma → Major ecological shift in East Africa from forested to more open country; cooler, drier, increased grasslands Catarrhine fossils from Miocene ☆ ancestral catarrhines ☆ ancestral cercopithecoids ☆ ancestral hominoids ☆ all catarrhines 2: 1: 2:3 dental formula tubular ectotympanic Adaptive radiation of hominoids (apes) ☆ ALL had hominoid cranial features: Y-5 pattern on lower molars larger brains no tails ☆ later hominoids also had: adaptations for suspensory locomotion: - high intermembral index - chest broader than deep - no tails - very mobile shoulder joints Early Miocene apes ☆ abundant (14 genera in Africa alone!) ☆ thin molar en met ☆ lightly built, gracile jaws ☆ considerable size variation ☆ arboreal quads Proconsul (20-17 Ma, Kenya) ☆ early hominoid ☆ hominoid dental features but not post cranial features ☆ EXCEPT no tail Middle Miocene apes: ☆ fossil sites in Eurasia (some in Africa) ☆ thick molar enamel ☆ robust mandibles ☆ flaring zygomatic arches ☆ Adaptations to changing climate (drier, more open) & hard foods in that climate (nuts, tough plants) ☆ general quads (some hanging) Sivapithecus (12-8 Ma, India, Turkey) ☆ similar to orangutans: oblong orbits narrow inter-orbital region dish-shaped face Dryopithecus (13-7 Ma, Europe & Asia) ☆ low, rounded molar cusp (frugivore) ☆ Suspensory locomotion Otavipithecus nambiensis (13 Ma, Namibia) ☆ small ape (~ 15kg) ☆ Shows apes were geo widespread in South Late Miocene apes ☆ Apes become extremely rare in the African fossil record by late Miocene ☆ Pockets survive in abundance in S. Asia & China ☆ This is in contrast to monkeys who flourish & increase in numbers during middle/late Miocene Chororapithecus abyssinicus (~ 8.5-8 Ma, Afar Valley, Ethiopia) ☆ gorilla-sized dentition ☆ early dental adaptation to fibrous diet (like gorillas) Ouranopithecus (9 Ma, Greece) ☆ large body size ☆ low, rounded molar cusps ☆ orbits & nasal aperture like gorillas Gigantopithecus (7 Ma, India & Pakistan; also 500 ka, China) ☆ larger than gorilla (300kg?) ☆ large molars ☆ low, flat molar cusps ☆ palaeoproteomic studies ↳ cousin of orangutan Primate adaptive radiations 1. Late Cretaceous- leading to insectivore-like Paleocene Plesiadapiformes 2. Early Eocene- leading to lemur-like & tarsier-like 'true' primates 3. Late Eocene- leading to various primative higher primates 4. Oligocene- leading to diff of monkeys 5. Early Miocene- leading to a variety of apes, w/ ape-like bodies & special adaptations Fossil record for living ape ancestors / relatives ☆ Yuanmoupithecus 7-8 Ma → gibbon ☆ Sivapithecus 12-8 Ma & Gigantopithecus 7 Ma → orangutan ☆ Chororapithecus 10 Ma → gorilla ☆ Pan from Kenya 545-284 ka → Chimpanzee ☆ Bonobo? ☆ How do we know this? Comparing biomolecular data ☆ Diff in whole proteins (Immune diffusion &  electrophoresis) ☆ Diff in specific amino-acid sequences (AA sequencing) ☆ Diff in DNA molecules (DNA hybridization) ☆ Diff in nucleotide sequences of DNA (DNA sequencing) The biomolecular clock ☆ Based on assumption that many (most?) molecular differences btwn taxa are neutral & occur at a relatively constant rate averaged over geological time ☆ Therefore, larger molecular diff = earlier divergence date ☆ Must ultimately be calibrated using fossil record (25 Ma OWM/ ape)  5 2 2 5 8 3 8 absolute 2 date ~ 40 Ma 96-99% similar (full genome ~97) Gorilla Human Chimp Gibbon Orangutan ~8-5 Ma ~10-7 Ma ~13-10 Ma ~20-17 Ma Primate evo trends occurring w/ divergence of new lineages ☆ Increased visual acuity ☆ Reliance on grasping hands & mobile digits (variability by locomotion/niche) ☆ Dietary diff (Heterodontic dentition, becoming specialized in some lineages) ☆ Increase in complexity of brain & behaviour Homo sapiens Insectivore-like Plesiadapiformes  Increasing complexity through time? Origin of primates ☆ Nocturnal visual predation ☆ ↑ orbital convergence (tapetum lucidum?) ☆ Mostly insectivourous (slight move towards fruit/veg) ☆ Unfused mandibular symphasis ☆ middle ear simple (single, undivided cavity) ☆ Dichromatic (nocturnal) ☆ Arboreal clingers & leapers ☆ Dispersed solitary social system (similar to extant nocturnal primates)  S t r e p s ir r h in e s T a r s iifo r m e s P la t y r r h in e s C e r c o p it h e c o id e a H o m in o id e a ◦ n o c tu rn a l ◦ d ic h r o m a t ic in s e c t iv o u r o u s ◦ u n f u s e d s y m p h y s is e tc Haplorrhine divergence ☆ Acquired more complex (divided) middle ear ☆ Visual system changes (lost tapetum; retinal fovea; post-orbital plate or  enclosure)- all increase visual acuity ☆ Diurnal first w/ tarsiers a reversal? Or Omomyoid condition primitive? ☆ Regardless fundamental shift... small diurnal mammals rare in tropical rainforests.. direct competition w/ BIRDS ☆ ↑ visual acuity likely evolved for diurnal visual predation, but subsequently co-opted for visual signalling among individual group members S tre p s ir r h in e sT a rs iifo rm e sP la ty rrh in e sC e rc o p it h e c o id e a H o m in o id e a ◦ n o c tu r n a l  ◦ d ic h ro m a tic in s e c tiv o u ro u s ◦ u n fu s e d s y m p h y s is n o ta p e tu m e tc d iu r n a l? p o s t o r b it a l p la t e Simiformes/Anthropoid divergence ☆ Further improvement in visual acuity (convergence; post-orbital closure; polymorphic trichromacy) ☆ Expanded dietary niche (significant frugivory + fused mandibular symphysis for accessing tougher diets) ☆ Shift to generalised aboreal quad locomotion ☆ Probably evolved gregariousness along w/  diurnal behaviour S tre p s ir r hTin e siifo a rs P rm la ty e rrh s Cin e so p it h e c o id e rc Ho ea m in o id e a ◦ n o c tu r n a l ◦ d ic h ro m a tic d iu r n a l? in s e c tiv o u ro u s p o ly m o r p h ic ◦ u n fu s e d s y m p h y s is t r ic h r o m a t ic e tc fu s e d s y m p h y s is n o ta p e tu m f r u g iv o r y d iu r n a l? p o s t o r b ita l p la te Catarrhine divergence ☆ Evo of full trichromacy (thru gene duplication) & adoption of primary frugivory Hominoid divergence ☆ Continued evo of larger & more variable body sizes (& corres larger brains) ☆ Suspensory & ground dwelling adaptations S t r e p sTirarPrhsla in te Cysrerrm iifo eosp rhcin e it s h eHcoom idin eoa id e a p o s t - c r a n ia l a d a p t a t io n s n o c tu rn a l  ◦ n o c tu rn a l t r ic h r o m a t ic ◦ d ic h r o m a t ic f r u g iv o r y d iu r n a l? in s e c t iv o u r o u s ( p r im a r y ) p o ly m o r p h ic ◦ u n f u s e d s y m p h y s is t r ic h r o m a t ic e tc fu s e d s y m p h y s is n o ta p e tu m f r u g iv o r y d iu r n a l? p o s t o r b it a l p la t e ☆ It is also in postcrania that we 1st see changes in our lineage, suggesting that adaptations for changing habitat use were primary in driving the evolution & diversification of not just the apes but also our earliest ancestors... How do we differ from other primates? ☆ Distrib- African origins, currently worldwide (yet molecularly invariable) ☆ Skin & hair colour/texture highly variable ☆ Bipedal locomotion ☆ Reduced canine size, no diastema, no dimorphism-egalitarian social system ☆ Extremely large brains, complexity of tool production & use ☆ Resultant domestication & agriculture ☆ Music, art, maths, etc... Week 7 The australopiths & other early hominins ☆ Hist of discovery of the earliest hominins ☆ Early hominin morphology & phylogeny ☆ The evo of bipedalism ☆ Hair loss & its significance ☆ Earliest evidence for tool use What is a hominin? Chimps Bonobos Humans Gorillas ~ 6-7 Ma ☆ All mod humans & their ancestors ☆ Bipedal apes (facultative; habitual; obligate) ☆ Only 1 living species - Homo sapiens - but many extinct species ☆ Family Hominidae (humans + great apes + ancestors), Subfamily Homininae( humans + African apes + ancestors), Tribe Hominini (vs Gorillini & Panini) ☆ Early hominins lived in Africa ☆ Later hominins (Homo) migrated across old World (Afro-Eurasia) Hominins NOT members of our genus ~6 – 1 million years ago (Ma) Earliest  ☆ Sahelanthropus tchadensis ☆ Orrorin tugenensis ☆ Ardipithecus kadabba ☆ Ardipithecus ramidus "gracile" australopiths ☆ Australopithecus anamensis ☆ Australopithecus bahrelghazali ☆ Australopithecus afarensis ☆ Australopithecus garhi ☆ Australopithecus africanus ☆ Australopithecus sediba "robust" australopiths ☆ Paranthropus aethiopicus ☆ Paranthropus robustus ☆ Paranthropus boisei ☆ Kenyanthropus platyops Members of our genus Homo ~2.5 Ma to the present Clearly defined species  ☆ Homo habilis ☆ Homo erectus ☆ Homo neanderthalensis ☆ Homo naledi ☆ Homo floresiensis ☆ Homo sapiens ☆ Homo rudolfensis Geo varients or transitional species ☆ Homo ergaster ☆ Homo heidelbergensis ☆ Homo antecessor ☆ Homo rhodesiensis ☆ Taung "place of lions" - 130km N of Kimberley - most SW site on continent yielding early hominins - Raymond Dart ☆ Australopithecus africanus (SA ape) - The "Taung child"  - 2. 5-2.0 Ma (Faunal) - Human-like neuroanatomy - Semi-arid climate - Bird-of-prey accumulation Intellectual revolution about human origins? ☆ New human-ape genus ☆ 1ˢᵗ truly ancient hominin fossil in Africa ☆ Worldwide community ready to find missing link ☆ But... Asia & Piltdown Man (1912/1953) ☆ Human-like morphology due to paedomorphosis? Sterkfontein ☆ Australopithecus africanus (Mrs Ples) - Sts 5 - 600+ fossil homonin species  - Mostly A. africanus (also 1 early Homo, "Little Foot", possible teeth from robust) - members 1- 6 (U-Pb & U-Th) (deeper → shallower) M2: 2. 8- 2.6 Ma M4: 2.6-2.0 Ma M5: 2. 0- 1. 7 Ma - Transition to open grasslands/ aridity ~ 2.5/ 2.0 Ma - M5 Scavenge site? Bone cut marks, Olduwan tools East African Sites ☆ Ethiopia, Kenya, Tanzania, Malawi + Chad ☆ Olduvai Gorge, Tanzania - Fossil deposits "discovered" by Wilhelm Kattwinkel (1911) - Louis & Mary Leakey  1ˢᵗ finds (1935) Zinj (1959) ◦ OH 5 ◦ 1.75 Ma - Australopiths 1.8-1.7Ma (Beds I & II) (also OH7 1964) Lake margin deposits; swamp & marshland near lake, wooded away ☆ Hadar, Middle Awash, Ethiopia - 3.4-2.9 Ma; Paleoenvironment lake margin - Early 70's - combined geo & palaeontological surveys - ~ 250 specimens; min. 35 indiv (since... 100s more; 3-4-2.9Ma; IHO) - Australopithecus afarensis "Lucy" A.L. 288-1 1973 3.2 Ma - Afar depression  Badlands at confluence of E. Africa, Red Sea & Gulf of Aden Rift systems - E. African Rift Valley Lake & river deposits K-Ar; Ar-Ar Tectonic activity sparse veg + rainfall = erosion Friable - SA Limestone cave breccias Faunal; U-Pb, U-Th; paleomag Predator/ scavenger/ wash-in Warped Earliest (ape-like) hominins (~7-4.4 Ma) ☆ bipedal (facultative (optional)/habitual?) ☆ small brained ☆ Mix of ape-like & hominin-like traits ☆ ↑ly variable inter-specifically Sahelanthropus tchadensis (6-7 Ma) ☆ Toros- Menalla, Chad (Sahel desert) ☆ 2500 km W of Rift Valley ☆ VIP: Michel Brunet ☆ Mixture of primitive & derived traits - Chimp-like: posterior cranium - Hominin-like: face, cranial base, molars ☆ Mosaic envir ☆ Gallery forest, savannah, grassland ☆ Extensive aquatic habitat ☆ "Tournai" ☆ 6 specimens-mostly teeth bits + 1 complete skull ☆ Molar enamel- thicker than Pan & Ardipithecus, thinner than australopiths & Homo Orrorin tugenensis (~ 6 Ma) ☆ Tagen Hills Baringo, Kenya ☆ Orrorin = original man ☆ forests shrinking. Part of general Miocene warming/drying trend. Prior to savannah expansion. ☆ VIPs: Brigitte Senut, Martin Pickford ☆ Direct evidence 4 biped (very human - like femur ☆ small teeth; thick enamel Ardi. Kadabba & Ardi. ramidus (5.8-4.4 Ma) ☆ Aram is, Middle Awash, Ethiopia ☆ Ramidus = root ☆ Wet, closed habitats? (challenged) ☆ VIPS: Yohannes Haile-Selassie; Tim White. ☆ Hominin- like: evidence 4 biped; Incisiform  canines ☆ Ape-like: thin tooth enamel; large canines; muscled, locking elbow ☆ small brain (300-350 cc) ☆ advanced facultative biped (biped on ground, quad in trees ☆ pelvis & feet "mosaic" - btwn a biped & quad ☆ Omniverous ☆ ↓ canine dimorphism (bonobo-like?) "Gracile" australopiths (~4.2-2 Ma) ☆ Body - biped (advanced Facultative/ habitual; also hair loss, dark skin, sweating, etc.) - maintain climbing ability early on - ape- like dev & life hist - small bodies (chimp-sized) - pronounced dimorphism (chimp-like,  males (40- 45kg), females (30-35kg) - ape-like social org ☆ Brain/neurocranium - chimp-sized cranial capacity (slightly larger in some), ✗3 of Miocene apes - brain: body size slightly larger than ape - brain encephalization high compared to other mammals - beginnings of neural reorg (eg. temporal lobe expansions) in some - pneumatised skull bones > thru time ☆ Face - large, prognath Faces (varies interspecifically) - large posterior teeth - enamel thick → thin thru time - reduced canines & incisors (more egalitarian social structure) Australopithecus anamensis (4.2-3.8 Ma) ☆ Kanapoi & Allia Bay, Kenya ☆ Anam = lake (lake margin envir) ☆ > 100 fossils ; > 20 indiv ☆ VIPs: Meave Leakey, Carol Ward Distinguishing features ☆ Mixture of primitive & derived features... ☆ Thicker tooth enamel & larger broader molars than Ardi. ramidus ☆ larger canines relative to later taxa ☆ Homo- like features of tibia & humerus ☆ powerful tree-climbing arms ☆ heavier (47-55kg) & more dimorphic than later hominins ☆ Ancestral to Aus. afarensis? Australopithecus afarensis (3.8-3.0 Ma) ☆ Hadar, Laetoli, Dikika (possibly others) ☆ Important people: Donald Johanson, Mary Leakey, Bill Kimbel, Zeresenay Alemseged ☆ Hadar, Ethiopia - "Lucy" - A. L. 288-1 - 3.2 Ma - "The First Family" Distinguishing features ☆ Variable body size (30-40kg) & stature (1-1.7m) ☆ Small brain @ 380-500cc ☆ Powerful masticatory apparatus ☆ Large anterior teeth; small diastema ☆ Retain some ape-like post-cranial  characteristics ☆ Pelvis retains some ape-like features (obstetrics) ☆ Long arms, curved fingers & toes (powerful climbers)... Still facultative habitual bipeds ☆ More than one species? Anagenetic change from A. anamensis? Laetoli footprints (Site G, ~ 3.6 Ma) ☆ Grasslands savanna/bush; semiarid (no crocs, hippos, etc.) Aus. bahrelghazali (3.5-30 Ma) ☆ Important person: Michel Brunet ☆ Only 1 specimen... KT12/H1 (found in 1996) ☆ Bhar el Ghazel, Chad ☆ Extends early homs 2500km W of Rift  Valley ☆ Sim to A. afarensis (some people think it is) Kenyanthropus platyops (3.5 Ma) ☆ platyops ="flat face" ☆ Only one specimen... KNM-WT 40000 ☆ Nachukui Formation, W Turkana, Kenya ☆ Important person: Meave Leakey (ML) ☆ Derived facial features; smaller molars ☆ Linked to later Homo? (esp. Homo rudolfensis) ☆ ML suggests all aus might be side branch Aus. prometheus ☆ 3.67 Ma? Maybe younger? ☆ Sterkfontein, SA ☆ Only one specimen- "Little foot"- StW 573 ☆ 90% complete ☆ Important person: Ron Clarke ☆ Foot bones found in bags at Wits; subsequent care search revealed skeleton. ☆ Aus. prometheus (name favoured by discoverer). Others think its an early Aus. africanus ☆ Advanced facultative biped. Aus. Africanus (3.2 -2.0 Ma) ☆ Historically longest known early hominin species ☆ SA (Sterkfontein, Taung, Makapansgat, Gladysvale) ☆ Important people: Raymond Dart. Robert Broom, Philip Tobias, Ron Clarke, Mirriam Tawane ☆ "Mrs. Ples" - Sts 5 (Sterkfontein, SA) ☆ Taung child (Taung, SA) Distinguishing features ☆ Cranium is more human-like (generalised) ☆ ↑ brain: body size (430-520 cc) ☆ Neural reorg (↑ in areas of communication & consciousness) ☆ No sagittal crest; ↓ posterior temporal is ☆ ↓ in anterior dentition; no diastema ☆ Shorter arms than Aus. afarensis; gracile. ☆ Members 3 & 4 (3.0-26 Ma) - oldest definitive Aus. africanus - ca. 30 specimens - Fluctuating climate - Subtropical forest, bush & savanna - Makapansgat Osteodontokeratic culture & the "killer ape" theory ☆ Makapansgat non-hominin vertebrates artificially fractured, preferentially preserved ☆ Hominins responsible? ☆ Teeth as saws, long bones as clubs, horns as spears, etc ☆.. driving force for later (now discredited)" Killer-ape" Theory... i.e. war & interpersonal aggression driving force behind human evo ☆ Experiments w/ living animals (baboon carcasses & predators) ☆ Accumulation by carnivore scavenger, probably hyaena ☆ Start of modern TAPHONOMY ☆ Bob Brain ☆ Proportions of non-local indivs among the fossil specimens determined by strontium isotope ratios (87Sr/ 86Sr) ☆ Aus. africanus patrilocal (like chimps, many humans, & bonobos; unlike gorillas) Aus. garhi (2.5 Ma) ☆ Bouri, Middle Awash, Ethiopia ☆ Garhi = surprise ☆ Only 1 indiv... Cranial + postcranial fragments ☆ Lake margin envir ☆ Important person: Yohannes Haile-Selassie ☆ Possible assoc w/ lithics?? ☆ Evidence of food processing (cut & hammerstone marks) Aus. sediba (1.977 Ma) ☆ Malapa, SA ☆ Sediba = well, spring (mix of fauna you might find at watering hole) ☆ Aus w/ Homo-like traits ☆ Important people: Matthew Berger, Lee Berger, Job Kibii ☆ brain size 430 cc ☆ Homo-like teeth ☆ Aus-like neuro cranium ☆ Mosaic post cranium (long arms, small body, Homo-like from waist down, mosaic feet) ☆ Ancestral to Homo?? "Robust" australopiths... genus Paranthropus (~ 2.5- 1.2 Ma) ☆ similar to "gracile" aus (biped, ape-like dev, chimp-sized brain/body) ☆ BUT suite of cranial & dental changes signifying adaptation to harder, tougher diets (huge molar teeth; flat faces; bony saggital crests; flaring cheek bones) Paranthropus robustus (1.8-1.2Ma) ☆ SA (Kromdraai, Swartkrans, Drimolen, Gondolin??) ☆ Important people: Raymond Dart, Robert Broom, Job Kibii, Stephanie Baker, Nomawethu Hlazo, Palesa Madupe... Distinguishing features ☆ Larger brain capacity (~ 530 cc) ☆ Heavy chewing adaptations for advanced vertical force ☆ Classically "robust" teeth (small incisors & canines; huge molars); no diastema ☆ Stature apx. 110-132am; 32-40kg Kromdraai