MIDTERM REVIEW

~Chapter 1: History of Human Origins~

• Anthropology: the study of humans, close relatives, and ancestors
• Archaeology: the study of fossils
• physical/biological anthropology: study of human biological variation and evolution
• linguistic anthropology: the study of languages
• palaeoanthropology: concerned with fossil hominids
• Age of enlightenment: an intellectual and philosophical movement that dominated Europe roughly from the mid-1600s to early 1800s
• before age of enlightenment, all views about humans and the world were based on the BIble
• Irish Archbishop, James Ussher (1650s): believed and preached the idea that the world was created in 4004 BC (just over 6020 years ago) by GOD.
• fixity of species: all life forms were created by God and have not evolved since

~The enlightment~

• Humanism: ethics should be based on logic, empathy, and reason
• Liberalism: value of individual human life and individual freedom
• Rationalism: knowledge gained through logic and rational thought
• Empiricism: knowledge comes from experience and observation

~Scientific revolution~

• free speech: individuals are free to develop hypotheses but other are free to criticize any hypotheses
• peer review: researchers review each others’ hypotheses
• empirical testing and standards of evidence: hypotheses are tested against data from the natural world
• Recognition of inherent biases: methodologies were developed to avoid such problems
• early naturalists were becoming familiar with the great variety of organisms that actually existed across the world and that lifeforms changed over time
  • the main task was to understand what was causing all this variety
  • butterflies → there are 20,000 known species
  • spiders → almost 50,000 species
  • beetles → almost 400,000
• John Ray: became aware of the wide variety of animals and plants, developed the concepts of species (taken from specific) and genus (taken from general)
• Carl Linnaeus: created the system of naming plants and animals → called the binomial system
• binomial system: each plant and animal is given a genus name followed by a specific names, both names being in Latin
• Domain → Kingdom → Phylum → Class → Family → Genus → Species
• biological definition of species: group of organisms distinguished from other groups of organisms by their ability to successfully reproduce viable offspring
  • so a group of organisms can be differentiated by their ability to give birth to viable offspring
• different breeds of domesticated animals are NOT the same as different species
  • different breeds can showcase variability within a species/group but a new species does not emerge in an individual’s lifetime
  • since the beginning of domestication:
  • dogs: 340 breeds have been created
  • goats: 200 breeds
  • horses: 350 breeds
  • cattle: 800 breeds
  • sheep: 1000 breeds
• scholars of geology and palaeontology noticed that bibilicaal framework did not align with what they were encountering in the natural world
  • earth had to be more than 6000 years old
  • lifeforms also seem to have changed
  • layers of different types of sediments had been accumulating for so long that they had turned to rock and in many places was kilometres thick
  • all types of different fossils stacked in these geologic strata showed that in terms of the history of life on earth, change was the only constant
• James Hutton(1700s): Scottish geologist, realized that the processes going on today’s were the same ones that had always been forming the earth’s surface → slow disposition and erosion by wind, water, and gravity → formed “Law of Uniformitarianism”
• Law of Uniformitarianism: the present is the key to the past → geologically ancient conditions were the same as or uniform to those of today
• Charles Lyell(1835): argued that the earth was at least 300M years old according to geological and paleontological evidence
  • the church did oppose this idea but the evidence was too compelling to dismiss
• Georges Cuvier: “Founding father of Palaeontology” → didn’t believe in evolution but in 1813, he proposed that there were cyclical creations and destructions of life forms by global extinction events such as deluges
• In 1856, workmen were quarrying limestone near Feldhofer Cave in the Neander Valley in West Germany → they found the skeleton of a person, although peculiar looking, in very old deposits
• Johann Fuhlrott & Hermann Schaaffhausen: first people to examine Feldhofer Skeleton and recognized that remains were not form a modern human and suggested it was from an extinct human species
• Jacques de Boucher de Perthes(1840s): french amateur archeologist, discovered flint axes associated with bones of extinct animals in ancient river gravel deposits
  • obvious implication was that people had been around much longer than what was thought
  • few people accepted his claim at the time and argues the object was not human-made
• George Buffon: “Species adapt slightly to new conditions” → recognized regional variations within species → suggested that the earth was in fact older than 6k yrs since the cooling rate of iron would make earth 75k yrs old

~Chapter takeaways~

• earth was most definitely older than 6000 years
• lifeforms change with time
• some species no longer exist
• there is great variation within and between species
• Humans have been around a lot longer that than the bible says

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~Evolutionary Theory~

• a change in allele frequency in a population from one generation to the next
• allele: specific form of a gene
• gene: portion of DNA that determines a certain trait
• population: an interbreeding group of organisms
• Gene pool: all the different genes and their various expressions (alleles) that exist in the DNA of a species or population
• Genotype: genetic makeup of an individual (can refer to their entire genetic makeup or alleles found at specific gene locations)
• Phenotype: the physical expression of an individual’s genotype
• Jean-Baptiste Lamarck(1774-1829): proposed his theory of the transmutation of species, the first fully formed theory of evolution
  • believed that living things evolved in a continuously upward direction, from dead matter, through simple to more complex forms, towards human “perfection”
  • basically the first to figure out an explanation for the variation in life throughout earth’s history
• epigenetics: some traits can be developed within a lifespan and passed on to offspring
• Charles Darwin(1809-1882): voyage of the HMS Beagle (1832-1836) → determined that evolution occurs through natural selection. developed ideas as to how organisms evolved as he was closely working and examining them on his trip
• Galapagos Islands: 15 species of finches → each lived in a different/specific region (ground vs trees) → had various diets (fruits, insects, cactus, or seed) // all had different beaks and according darwin that was because of their varying diets
• Tortoises: wetter more lush habitats with round
• Natural Selection: requirements → variation in populations, inheritance of traits, selective pressures, more offspring than can be supported
  • mutation creates variation
  • unfavourable mutations selected against
  • reproduction and mutation
  • favourable mutations more likely to survive
  • and reproduce
• Six fundamental premises of natural selection: 1. more offspring are produced by a species than can be supported by naturally available food sources. 2. within any one species, there exists a significant amount of biological genetic variability. 3. individuals with advantageous traits will have an edge over other members of their species in terms of their ability to survive longer. 4. individuals with traits that increase their chance of living longer are more likely to reach the age of maturity (environmental conditions/circumstances select certain traits). 5. traits that are advantageous under current environmental conditions will tend to be passed on. 6. speciation will occur
• Speciation: accumulated changes result in a new species
• Thomas Malthus: “animal population tend to increase exponentially while food supplies remain stable”
• Survival of the Fittest: fitness in evolutionary biology means the ability of an organism to pass on its genetic material to its offspring. Biological or “Darwinian” fitness is being able to live long enough to reproduce and keep the population or species alive
  • individuals with advantageous traits will have an edge over other members of their species in terms of their ability to survive longer
• Microevolution: happens on a small scale (within a single population) → results in subspecies
• Macroevolution: happens over a long period of time, involves significant genetic change, and results in species that cannot interbreed (squirrels & beavers//gorillas & chimpanzees)
• The traditional view of Speciation: distance causes the different populations to fail to continue to interbreed and very slowly diverge into a new species
• Phyletic Gradualism: slow and gradual accumulation of difference which is a part of the evolutionary process and explains microevolution
• Mutations: add variation, can be neutral or can produce a trait that is selected for or against
• The basic notion of natural selection → the gene pool changes over generations because certain genes give individual an advantage and thus become more common
• Factors that act upon variability in allele frequencies
  • mutation
  • non-random mating
  • migration or gene flow
  • random genetic drift
• Inbreeding: mating individuals that are genetically closely related
  • increased chance of offspring will inherit 2 recessive alleles for a dangerous traits
  • sickle cell anemia, hemophilia
• Natural selection = Reproductive success NOT health, happiness, and longevity

~sexual selection~

• Positive Assortive Mating: tendency to select mates of a similar phenotype as your own
• Negative Assortive Mating: tendency to select mates of a different phenotype from your own

~inheritance of traits~

• Gregor Mendel(1822-1884): conducted research on plant hybridization, mainly peas to help understand genetics

  • Selection + Mendel Genetics = The modern Synthesis

• Genetic Drift: change in the frequency of an existing gene variant in a population due to random sampling of organisms → the alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces

• Alleles: different versions of a specific trait

• Homozygous dominant: having 2 of the dominant form of an allele

• Heterozygous: having 1 dominant and 1 recessive gene

• Monohybrid: crossing 2 plants that differ in only one characteristic

• Dihybrid: crosses where parent plants differed in 2 different characteristics

• Mendel’s Principles: segregation(offspring inherit one discrete factor for a trait from each parent), dominance + recessiveness (some expressions of a specific trait were dominant over others), independent assortment (different traits were not inherited together, passed on from generation to generation as independent units)

• Fossil records: odds are small that individual will die in the right place for it be perfectly preserved (matter of luck), is a poor reflection of all the organisms that have lived

• Punctuated Equilibrium: results in macroevolution and proposes that change happens suddenly over short periods of time followed by a long period of no change at all

• Anagenesis: when all members of species are together in a contained environment

• Cladog

• </p>

• ____

• enesis: species occurring as separate populations that can be subject to different selective pressures and is most common way that evolution occurs (population splits up and lives in different regions )

• James Watson and Francis crick: discover double helix DNA

• Gene: set sequence of base pairs (out of a whole DNA sequence) that codes for a specific protein

• Mitosis: somatic cell replication (1 somatic cell divides into 2)

• Meiosis: sex cell replication (carries only half the chromosomes → 23)

• Two components to the evolutionary process: creation of genetic variability in individuals + external factors that act upon individuals’ genetic variability

  </p>

• *Evolution is not a theory → its a demonstrable fact*

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~Primates~

• we are primates so studying other living primates will inform us about the stages of our own evolutionary history
• many of the processes (like natural selection and sexual selection) that are acting on modern primate species are likely working in similar ways to when they played a role in our own emergence

~primate phylogeny~

• DOMAIN (EUKARYA) → KINGDOM (ANIMALIA) → PHYLUM (CHORDATA) → CLASS (MAMMALIA) → ORDER (PRIMATES)

~primate characteristics~

• lot of variation, but there are 8 traits shared by all primates

  1. Prehensile hands - capable of grasping, opposable 1st and 2nd digits
  2. Flat nails
  3. forward facing eyes → stereoscopic vision (predators have a blind zone)

~Arboreal Hypothesis (Wood-Jones and Elliot-Smith → 1920s)~

• Argues that these traits may be adaptations to:

  1. enable safe leaping from branch to branch and grasping of fruits, leaves, or insects with great precision
  2. accurately see and judge distances when leaping from branch to branch and seeing small insects for food
  3. allow the private to grab branches more securely and pick up food more easily
  4. Generalized body plan
  • most species have a specialized body plan for their lifestyle and environment
  • are highly versatile and adaptable
  • capable of developing a wide range of behaviours, accessing a wide range of food types, and living in a wide range of habitats
  • allows them to have different locomotor behaviours
  • example: vertical clinging and leaping, arboreal quadrupedalism, brachiation, terrestrial quadrupedalism, knuckle-walking, bipedalism facilitative/habitual/oligate
  1. Generalized teeth
  • dentition is adapted directly to diet and/or defence
  • incisors, canines, premolars/bicuspids, and molars
  1. reduced olfactory systems
  2. enclosed bony eye orbit
  • protects eyes from physical damage
  1. large encephalization quotient
  • an increase in brain or neocortex size relative to body size, size of lower brain area, and/or evolutionary time
  • Encephalization Quotient (EQ): measure of relative brain size and is often used to convey how small or large a species brain is compared to that of other species similar body size

• Squirrels, however, don’t have forward facing eyes, prehensile digits, and instead have claws → plus they leap in trees

~Visual Predation Hypothesis (Cartmill 1970s)~

• forward-facing eyes, grapsing hands, are better explained as adaptions for catching prey like insects and smaller animals
• other predators like owls and cats also have forwad-facing and grapsing abilities

~Primate evolution~

• humans are simply the current tip of a growing branch on a complex tree that reflects a long history of evolution that includes some important and consistent trends
• humans have an immediate hominin ancestor
• Adaptive radiation: reflects many years of evolution, relatively rapid in evolutionary terms and usually follows major environmental change or changes in configuration of the continents → these present new ecosystems to species
• Rapid speciation: (divergent evolution) within a lineage to fill different ecological niches also usually follow a major change in environmental cirumstances
  • explosion in the diversity of flowering plants following the appearance of insect pollinators
  • flowering plants firs appeared around 15 MYA but were not common or abundant for many millions of years because they only relied on unreliable mechanisms like the wind to spread their pollen
  • insect pollinators appread 100MYA
  • there’s 400k species of flowers
  • explosion of mammals after the dinosaurs went extinct
  • mammals appeared 200 MYA → dinosaurs died 65 MYA → by 45 MYA, mammal diversity reached the level we see today → 5500 species belonging to 153 families in 29 different orders
• Parallel evolution: independent evolution of similar traits in different species - starting from a kind of similar, but very distant ancestor
  • implies that two or more lineages have changed in similar ways, so that the evolved descendants are as similar to each other as their ancestors were
  • us and dolphins share a common ancestors who had a brain
  • however, last common ancestor was a tiny mammal with a little brain so we have evolved independently of each other and are the result of parallel evolution
• homologous traits: traits that are similar to one another due to shared ancestory
  • as species adapt and evolve over time, these traits may change in appearance and function, but they still share the structure, genetics, or embryonic structure of their common ancestor
• convergent evolution: different organisms independently evolve similar traits
  • analogous traits have similar function and superficial resemblance but have different origins
  • wings of a fly, moth, and a bird are analogous because they developed independently as adaptations to a common function - flying
• first primates appeared sometime around 70 mya
• earth looked different due to the continental drift
• oldest confirmed primate fossils found so far come from eastasia, but there are some likely primate fossils that are older - some from morroco and some from North America
• primates never made it to Australia even though it eventually moved up very close to the islands of SE Asia where primates had long been living
• world was much warmer and more humid than today: most of the world was covered by tropical forest and in fact grasses didn’t evolve until 65 mya
• primate ancestor was likely arboreal but lacked the basic primate traits: they had lateral-facing eyes, claws, and their hands and feet were not prehensile
• between 80 mya and 10 mya there havebeen five major stages in primate evolution
• these followed major adaptive radiation events during which previous primate species moved into new regions and underwent major changes to adapt to those new regions and new lineages developed

1. First radiation in the late Cretaceous (80-65 MYA):
   • appearance of first primates from common ancestor
   • slight divergence from insectivore ancestor
   • tooth shape indicates broadening of the diet
2. second radiation in the Paleocene (65-55 MYA):
   • grasping hands
   • nails instead of claws
   • vision beings to dominate over smell
   • 2 major lines: lemur-like and tarsier- like forms
3. third radiation in the Early or Mid-eocene (55-45 MYA):
   • primitive monkeys appear
   • increased arborela quadrupedalism
   • larger brain and increased reliance on vision
4. fourth radiation in Late Oligocene/Early Miocene (30-20MYA):
   • split into two main groups: monkeys and primitive apes
   • difference in diet: monkeys eat leaves, early apes eat fruit
   • all sit arboreal

fifth radiation in the late Miocene (after 17 MYA):

• appearance of first true apes
• large, barrel-like torso
• limbs designed for hand-over-hand climbing

some terrestrial adaptions

~Primate taxonomy~

• ORDER → PRIMATES → STREPSIRRINI + HAPLORRHINI
• suborder of primates that includes the lemuriform primates which consists of the lemurs of Madagascar, galagos (bushbabies), and pottos from Africa, and the lorises from India and SE Asia (NOT MONKEYS OR APES)

~Strepsirrini~

• primarily tree-dwellers
• havelonger snout that usually ends in a moist nose, indicating a well-developed sense of smell
• larger proportion of the brain devoted to the sense of smell than the sense of vision
• Traits of Strepsirrini: unusual dental tooth comb, laterally flaring talus, and grooming claw on the second digit of their feet

~Haplorrhini~

• Dry-nosed primates
• divided into two infraorders:
  • Tarsiiformes: the tarsiers
  • Anthropoidea: all monkeys and all apes
• Anthropoids: divided up into two parvorders
  • Platyrrhini: all the new world monkeys found in south and central America
  • includes 5 fams
• Catarrhini: all old word monkeys and apes (in Africa, Asia, and Europe)
  • includes two superfamilies
  • Cercopithecoidea: all old world monkeys
  • Hominoidea: all apes and humans (just 26 species)
• New world monkeys: flat, widely spaced nostrils, prehensile tails, three molars (36 teeth), mostly arboreal, frugivorous
  • 2 incisors, 1 canine, 3 premolars, 3 molars (2.1.3.3) → NW MONKEYS
  • 2 incisors, 1 canine, 2 premolars, 3 molars (2.1.2.3) → HUMANS
• Old World Monkeys: downward pointing, closely spaced nostrils, sitting pads, two premolars (32 teeth), omnivorous
• Prehensile tails: present in NWM // not present in OWM
• Greater size range in OWM than NWM
• Greater degree of sexual dimorphism in OWM
• Superfamily Hominoidea has two families:
  • Hylobatidae: Gibbons - the lesser apes
  • 18 species found in SE Asia
  • range in size from 4 to 14 KG
  • live in rain forest canopies and eat mostly leaves and fruit, sometimes insects
  • very vocal and tend to form monogamous pairs
  • especially adapted to brachiation with long arms, short legs, curved fingers, and short thumbs
  • Hominidae: Great Apes and humans
  • four living genera with 8 species
    • 3 of orangutans
    • 2 of gorilla (lowland vs mountain)
    • One species of us - homo sapiens
  • Apes: brachiation, larger brain, broader chest, bigger shoulder joints, no tail, can walk on two legs
  • Monkeys: leap, smaller brain, narrower chest, smaller shoulder joints, tail, mostly walk on all fours

~Primate social behaviour~

• Three F’s → Food, Fighting, Fornication
• reproduction → access to mates
• reproductive asymmetry: difference in reproductive potential between males and females
• females:
  • once pregnant, cannot get pregnant again for the duration of the gestation period
  • primate infants are dependent on their mothers for a good amount of time - extends minimum time between pregnancies: interbirth intervals
  • can only have a limited number of babies over her lifetime and generally only 1 at a time
  • chimpanzee and bonobo interbirth intervals are 3-6 yrs
  • each female can have a max of 6 babies with average number being 4 or 5
• Males:
  • can have many babies with many females at the same time and throughout life
  • although average number of babies any one male fathers will be the same as the average number of babies the females have
  • individual males can do their best to father more that the average - but, at the expense of other male’s reproductive success
• females - mate choice is very important
  • competition occurs to grab female attention
• species with male-male competition for access to females tends to have increased sexual dimorphism
• sexual selection pressure - females tending to choose larger males to mate with
• natural selection - being larger can provide individual males with a range of advantages over smaller males
• the degree of sexual dimorphism is much lower or non-existent in small species and those that tend to be monogamous - like these common marmoset from brazil
• complicating factor in primate behaviour is cycles in female reproductive physiology
• non-human females are not sexually receptive all the time → only ovulating at certain times
  • orangutans → 29 days
  • gorillas → 30 days
  • chimpanzees → 37 days
  • Estrus: period of fertility and sexual reception
  • cycles not linked to seasons of the year which means not all females will be ovulating at the same time

~anatomical signals~

• sexual swelling: at the time ovulation, female rump will change colour (become bright red) and their external genialia will swell up
  • has evolved independently at least 3 times in different primate species
• Pheromones: scents that signal their receptiveness and fertility
  • females in estrus give off powerful pheromones
  • in humans, it is reduced, while both men and women produce phermones, our detection of these signals is not conscious
  • humans and vervet monkeys are the only primates to have concealed ovulation → females show no physical signs of ovulation

~access to food~

• food sharing is not a significant part of primate interaction and only occurs under certain conditions and between closely related individuals
• every ape and monkey for themselves, however, females and children may depend on the males
• intra-group competition for food is seen to be more important than inter-group competition
  • younger, weaker, less aggressive individuals can often have trouble getting access to food because the larger, stronger, more aggressive individuals will tend to push them out when food is encountered
• matrilineal clusters: female formed groups where mothers, sisters, aunts, nieces, etc. socialize more strongly and share amongst themselves
  • are competitive units that defend food patches against other group members - especially the larger, more aggressive males

~Avoiding predtors~

• although larger groups have more eyes, ears, and noses to detect predators more easily, they also make the most amount of noise that attracts them
• smaller groups may not be able to detect as often and not get as much food, but they don’t attract as often either
• lemurs in madagascar: more to eat at ground level but also an easy target for predators
• smaller groups avaoid group foraging more than larger groups because of increased danger of not detecting approaching predators → also find less food

~social systems~

• social systems: structures of primate social interaction
• female social systems: evolved behavioural strategies for balancing their various adaptive demands: finding food; predator avoidance, selecting mates, and rearing offspring
• male social systems: evolved strategies to maximize their access to food and females

~orangutans practice solitary living~

• females and children maintain individual territories, while individual males maintain adjacent territories
• these territories ae maintained with scent markings and vocalizations
• only time males and females come together is when a female is in estrus and the pheromones she gives off attract males from the surrounding forest
• once she becomes pregnant the males head off again to each of their territories
• monogamy: a male and female live in an exclusive pair bond for an extended period of time
  • true monogamy is nonexistent among such primates
• social monogamy: pair remains together and shares in rearing young, though these offspring may sometimes be fathered by another male and he may have fathered young with other females
• reproductive monogamy: a pair stay together and mate only with each other, this system is extremely rare, if it exists
• polygamy: multiple bondings
  • one-male polygyny: multi-female/single-male groupings
  • infanticide: a dominant male may kill offspring of previously dominant male
  • females must decide whether to mate with a new dominant since infanticide can occur → when a new dominant male replaces the previous one, he’s not guaranteed to have the cooperation of the females
  • mountain gorillas: one male groups make up half the the social groupings, females can move freely between different groups
  • dominant “silverback” male attached to a group of females views other adult males with fear and anxiety, because position as the dominant male is always tentative and can be very short-term
  • adult males that don’t attached themselves to a group are called “extragroup males” and form bachelor groups (da players)
    • may attack the dominant males attached to a group
    • often hang around on in the forest on the fringe of the groups and females will sometimes mate with them in secret
  • multi-male polygyny: multi-female/multi-male groups
  • there will still be a dominant male who will try to maintain access to the majority of the females or obtain the majority of mating events
  • several dominant males compete for a “priority of access”
    • results in a dominance hierarchy - a ranking of the dominant males, with the dominant or alpha male, at the top - it’s not an all or none competition
  • polyandry: 1 female and multiple males
  • several males will bond together to help raise the offspring of a single female
  • some of the smallest species, like marmosets and tamarins, have evolved to sometimes use this system and sometimes practice socially monogamy
  • this complexity may have been a major factor in the development of our large brains

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~Emergence of Hominins~

• any member of the “tribe” Hominini
  • FAMILY: HOMINIDAE
  • ORDER: PRIMATES
• Hominid: apes and all ape ancestors, including hominins
• Hominin: lineage leading to humans, all ancestors since the split with Pan
• all our earliest ncestors first evolved from some distant ape ancestor in Africa
• hominin fossils older than 2M yrs have all been found in Africa
• 2 main regions where researchers have the most luck finding remains of early hominins
  • EAST AFRICA
  • SOUTH AFRICA
  • has to do with geology of these area to preserve fossils, not that fossils only lived here
  • here are specific area in these regions that are particularly rich in hominin skeletal remains
• all hominins remains found in South Africa have been discovered in caves
  • Taung, where the taung child crania was discovered in 1925
  • Serkfontein, Kromdraai, and Swartkrans - archaeologists started working at these sites in the 1930s and 1940s
  • Malapa is a very recent discovery, found in 2008
  • UNESCO world heritage site called: “the cradle of mankind”
• Dolinas: vertical caves, formed by slow dissolving of the limestone or dolomite bedrock
  • relatively soft sedimentary rock which is easily eroded by rain and running water, but are also composed of calcium carbonate, which react with rainwater to easily dissolve away
  • small crevices forms on the surface through mechanical erosion and chemical dissolution
  • grow larger and deeper over 100 of k or M of years
  • after millions of years, they often become large cavities with only a small opening visible at the ground surface
  • make natural sediment traps and slowly fill up with dirt and rocs that fall in, are blown in, get washed into the hole
  • animals occasionally fall in and die, and their bones become part of the deposits
  • possibly happened to hominins from time to time
  • were used as dens by hyenas (would drag their meals)
  • campsites by humans (evident from tools)
  • slowly, sediments build up and the bones of animals and hominins become incorporated into the deposits
  • water percolating through the deposits cements them together with calcium carbonate and turns them into a new type of rock called breccia
• Sterkfontein: 20m of breccia dating to 3.5mya at the bottom and 200 kya at the top, rock quarrying began here in the 1890s and archaeological excavations in 1936, researchers have found 700 hominin bones and bone fragments
  • Little foot → Australopithecus sp. was found in 90s but because the breccia made it so difficult to remove the bones, they were only announced as open for research in the last few years
• Malapa: discovered in 2008

~East Africa’s rift valley~

• 6000 km long fault line formed by movement of tectonic plates
• nubian and somalian plates are slowly moving away from each other resulting in the slumping of the thick deposits between them
• this exposes huge sections of sediments that have been filling the fault and building for Millions of years - some places are 100m thick and date to 20M+ years
• the fault is a logical place for rivers to form and the rivers cutting down into these ancient deposits has exposed fossils form various time periods
• fossils of very early apes species like Ekembo are found in the rift
• Ekembo is an early ape (Hominoid) genus found in 17-20MYO sediments from the Miocene Epoch
• remains of early hominin species that date to the last 5MY are present
  • lived along the rivers/lakes, hunted/gathered wild animals and plants
• when a hominin died, its remains were sometimes rapidly covered by river/lake sediments
• East Africa: no dolinas found here, geology is different here, focus on the rivers and lakes, red sea is part of the same system
• East African Sites: Olduvai gorge, laetoli (very famous near Tanzania), west Turkana, Kobi fora, and Kada hona and Hadar (Ethiopia)

~Northern Tanzania~

• Olduvai Gorge: is a relatively small lake, has expanded and retracted over 100k yrs, is very dry and scrubby now, stone tools were discovered here. Louis and Marie Leakey didn’t find anything here for 30 yrs but eventually made an important discovery of hominins
• Laetoli: famous for 3.7M yr old footprint, theory is that an eruption occurred and all the animals and hominins were walking away from it, the hominin footprints got preserved as it rained and the ash hardened

~Northern Kenya~

• Koobi Fora: footprints were found here by a money bank river, could be from a homo erectus and were 2M yrs younger
• West Turkana: stone tools dating to 3.3M yr old were found here, if the dating is right then they could be the oldest artifact in the world

~Ethiopia~

• Kada Gona: stone tools were found here dated to 2.6M yr old, if dating is right, they could be the oldest tools found
• Hadar: bones are often heavily fragmented

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