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115 Cards in this Set
- Front
- Back
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Homologies |
Similar structure or characteristics that are acquired from a common ancestor . |
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Homologous structure |
Similar in fundamental structure,position and development. But....different functions e.g paradactyl limb |
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Divergent(adaptive) evolution or Divergence |
Show evidence of evolution and similarities traced to a common ancestor. E.g Habitat and mode of life changed the structures |
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Analogous structure |
Similarly functioned structure in different organism because they evolved in similar environments(not from common ancestors) e.g bat and Butterfly wings |
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Biological evolution |
Genetic changes in a population (of a living organism) that are inherited over successive generations. Due to natural selection eventual lead to the formation of a new species |
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Macro evolution |
Development of new life form or species from earlier life forms over many generations(extended geological period) I.e involves speciation Usually can’t be seen happening in current time |
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Micro evolution |
Change occluding not at a level of species. That’s not over a long period of time . I.e small changes in gene pool |
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Phylogeny |
Scientific study of evolutionary relationships among species |
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Phylogenetics |
The study of evolutionary relationships among organisms which have been discover through evolutionary lines of evidence |
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Phylogenetic tree |
Show evolutionary relationships over time. Usually Comprised of stasis, lineage splitting and adaptive radiation |
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Cladogebesis |
Is an evolutionary splitting event where a parent species splits into 2 distinct species (forming a clade) That live at the same time |
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Clade |
Life-form groups consist of common ancestor and it’s descendants- representing single branch on tree of life |
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Anagenesis |
Ancestral species gradually accumulate change over time. Until, species is sufficiently different enough from it’s origin. Lineage in phylogenetic tree doesn’t split. Ancestor does not exist at same time |
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Evolution vs natural selection |
Evolution must involve a significant gain of genetic information. So that the common ancestor dies out. Whilst, natural or artificial selection always has a loss in vigour i.e only suitable for current conditions |
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Punctuated Equilibrium |
Theory by Stephen J Gould and Niles Eldredge explain long period fossil record unchanged and absence of “missing links” Species is In equilibrium untill rapid change “punctuated “ (interrupted) their existence |
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Gradualism |
Darwin’s model of slow gradual change in a species |
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Natural selection |
Seen as a “mechanism of evolution” were nature selects fittest individuals for survival (best suited individuals adapt to and environment pass on favourable hereditary trait) Occurs in populations not individuals |
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Artificial selection |
Deliberately breed plant or animal to acquire desired characteristics- human is selective pressure I.e new individuals not necessarily best suited for survival |
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Selective breeding(unnatural selection ) |
Specific organism with specific trait is bread with organisms of same characteristics- to eventually form desirable trait E.g farmers/ breeders |
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Steps of Natural selection |
1)Overpopulation, 2)Variation must be hereditary in individuals , 3)Changes in environment, 4)Selection occurs(Best suitable individuals reproduce) others die out If evolutionary .. 5)All individual in population have trait 6) Numerous changes (eventually lead to new species)
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Selective pressure |
Certain environmental factors exert pressure and trigger Natural selections e.g food competition , temperature change ect. |
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Examples of Artificial selection Animals and agriculture |
Canis lupus( grey wolf)- Canis Lupus familiaris( Domestic dogs) Brassica oleracea(wild mustard) - turnip, cabbage, broccoli... by out breeding |
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Inbreeding |
Cross closely related individuals to maintains desired trait( increase homozygosity- identical alleles brought together more frequently ) |
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Out breeding |
Cross unrelated individuals( different strains, populations ect ) to introduce new or stronger traits. Offspring are genetically different ( Promotes heterozygosity-alleles are different ) |
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Formation of a new species ( mechanism of evolution) |
Natural selection, gene flow , genetic drift and Polyploidy( type of reproductive isolation ) |
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Species |
A group of organism that can interbreed to produce viable (fertile) offspring |
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Speciation |
The evolutionary process whereby new species form- E.g the formation of a species increases range of organisms on earth and biodiversity |
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Extinction |
the permanent loss of a species ( results in decreases in biodiversity on earth ) |
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Population |
A group of organisms that live in a particular place at a particular time with the ability to freely interbreed. I.e same species share gene pool but they can be free gene flow between populations |
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Gene pool |
Total number of allele in all the reproductive individuals in a particular population |
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Gene flow |
The exchange of alleles between populations E.g migration and seed dispersal constitute Im(in) or En(exit)-migration |
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Reproductive isolation |
Isolation prevent ancestral and new species interbreeding Can be geographical separated(allopatric) or occupy same area (sympatric) |
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Summary of speciation |
1)Variation in a population 2)Evolution by Natural selection-“Adaptation to the niche” 3)Reproductive isolation prevents interbreed 4)New species formed |
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Types Variation |
Continuous variation and discontinuous variation |
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Continuous variation |
Range of Phenotypes for same characteristics. Usually polygenic characteristics ( more allele = more possible combos) |
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Discontinuous Variation |
Phenotypes fit into seperate characteristics- no intermediate form Usually only single pair of allele occur(fewer possible combo) E.g HBO blood groups, tongue roll ect |
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Mechanism of variation |
Genetic Recombination Mutations( gene or chromosomal) -Variation is essential because environment selects best adapted from the variation |
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Mutation |
Change in at-least one nucleotide base, usually due to the presence of mutagens - only Gonad and Gamete mutation inherited |
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Fixed mutation |
Once all organism of a population have new good allele |
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Chromosomal mutation |
Chromosome structure or chromosome number change
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Polysomy |
Chromosome number more than normal diploid number |
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Polyploidy |
Occurrence of multiple sets of chromosome- often in plants e.g tetraploid Duran wheat |
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Genetic drift |
Random changes in the frequency of characteristics in a population. I.e role of chance Important in very small population. More influential than Natural selection |
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Types of mutations( by effect) |
Beneficial, Harmfully, Neutral |
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Contrast finches from Galapagos island to mainland finches |
Island - Darwin saw approximately 13 different species [Each diff. Beak and food source ] + diff. To mainland Mainland(1000s km away) - All seed eaters belonging to 1 species |
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How did variation occour in Galapagos finches? |
1)Ancestral species( relatively few) arrive on floating trunk(drift wood) . Due to strong current. 2) little competition and lots of empty niches 3) mutations occurred as they multiplied( Variation in Pop.) 4) On Each island different trait considered beneficial mutation-Due to unique environment. 5)Finch with beneficial trait reproduce most successful. So, trait multiplies 6) mutations occouring constantly allows for the formation of new species - that fill a variety of niches (E.g beak size differs for function)
Nb.Absence of other birds- (confirm Darwin’s theory- species change as environment change) Finches Can’t interbreed cross islands or with mainland species
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Pros and cons of In breading |
Pro -Predictable offspring -undesirable trait can be isolated( often recessive gene) Con - offspring low resistance to disease - high mortality rate and abnormality -loss of Vigour(heterozygosity) -gene pool gets smaller(possible extinction) - recessive genetic disease prevalent |
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Human and animal example of inbreeding |
Cheetah- Game reserve. Population genetically isolated. Increase misaligned jaws prevalence( less effective hunting) - inbreeding can either reinforce or eliminate trait Human- Presence of double recessive (e.g Tay-Sachs or haemophilia ) occurs Due to small population, geographic isolation,royalty ect
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Bottle neck effect |
A Sudden decrease in population causes a decrease in the gene pool Causes a decrease in variation. Often inbreeding happens afterwards-which further lowers variation Causes: Humans(hunting), Natural disasters, disease ect |
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Pros and cons of Outbreeding |
Pros -Genetic variation, new trait introduced, bigger gene pool - increase hybrid vigor -reintroduce lost traits Cons - typical traits lost - New races develop( loss of seperate racial breed) -less predictable offspring |
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Animal examples of Outbreeding |
Bonsmara cattle Breed 2 vulnerable cattle breed in subtropical RSA. So out-breeding had to occour. Afrikaner ( irregular birth, poor meat quality, late sexual maturity) Herelord & shorthorn(unable to adapt to climate, susceptible to tick related disease) Bonsmara(Good meat and milk produced, regular birth, more disease resistant) Bons(Prof. Jon Bonsma) Mara(research farm used in Limpopo) |
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Founder effect |
Loss of genetic variation when a new population is formed from a number of individuals moving to a new area Nb=gene pool of new pop. contains genes of founder members |
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Examples of founders effect |
-Afrikaans population(40 Dutch family 1652) Brought Huntington’s cholera -Cheetah(likely due to catastrophic event)- |
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Fecundity |
Ability to produce healthy offspring |
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Convergent evolution |
Many unrelated organism independently develop adaptation for similar environment . Think analogous structures |
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Divergent evolution |
Single common ancestor gave rise to a variety of different, but related organisms Think homologous structures |
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Mechanism(types) of speciation |
Geographic(allopatric) and Sympatric |
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Allopatric speciation |
New species originated from ancestral species -now separated by geographical barrier. Often followed by , Reproductive Isolation. |
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Reproductive isolation |
No gene flow occurs. New mutation in each population lead to new allele forming and different gene pools.
Since environmental pressure different in each area. Natural selection occur independently. Population Become Genetically different, Can’t interbreed( seperate species) |
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Example of allopatric speciation c |
Galapagos finches(On different islands) In different niches . Remember- No need to fly since successful in differing niches.
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Cambrian Explosion |
Every phylum suddenly existed. (All complex life appeared) Can’t be gradualism. That’s why they came up with punctuated equilibrium |
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Adaptive radiation |
Burst of divergence from single lineage-giving rise to many species to fill niches E.g Galapagos finches or protea in RSA AUS & SA Usually allopatric speciation Nb. Those who can experience adaptive radiation usually start with an unusual characteristic |
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Sympatric speciation |
New species arise from ancestral species in same geographical area- Thereby, Experience reproductive isolation suddenly. |
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Short examples of sympatric speciation |
Polyploidy in plant( not evolutionary though)- can’t form matching homologous pairs Hybrid species formation - In plants sometimes hybrid produces fertile offspring that is isolated( Not common in nature) |
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Cichlids(of lake Malawi) as an example of rapid sympatric speciation |
Same lake with different selective pressures 1)Habitat specific selection- sandy(bottom) vs rocky( sides) 2)Food specific selection- few common ancestors ate great variety. Increase in pop. Lead to increase in interspecific comp. Develop specific food source niche(filled empty ones.) 3)Sexual specific selection- Original random mutate -bright color - proved beneficial( female liked them)
Nb. New species occur in same geographical area- No geographical barrier for reproductive isolation |
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Types of Reproductive Isolating mechanism( prevent gene flow) |
Prezygotic ( occurs before fertilisation to prevent mating and/or fertilisation ) Postzygotic( occur after fertilisation and cause abnormal development of zygote-no viable offspring) |
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Prezygotic strategies of reproductive isolation |
Temporal- Breed at diff. Times E.g Nocturnal vs diurnal animal E.g Rana Boylii (Feb) & Rana Aurora(April) Behavioural- Courtship ritual species- specific I.e only species recognise(so save energy no mistake mate) E.g Dogs and wolves courtship display differ Mechanical- different plant in different adaptation (structure and colour scheme for pollinator)
E.g wind vs insect pollinated plants vs bird Insect pollinated plant release pheromones to atract Bird pollinates usually un scented and beak shaped Reproductive- e.g mating calls(roar,hum,sing) or colour change indicating maturity |
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Post zygotic examples of reproductive isolation |
Hybrid isolation Development of sterile offspring e.g mule show hybrid vigour(stronger than parents) - Faster than donkey and hardier than a horse |
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Classification of hominids |
Class- Mammalia Order- Primate Super family-Hominodea Family -Hominidae( other is hylobatidae) Sub Family- Hominae (other is ponginae) Tribe- Hominini( other is gorillini) Species- Homo(other is pan) Other grate apes -Pongo- Orangatan -Gorilla- Gorrila -Pan-chimp
Extra - Hylobates-gibbon |
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Hominids |
All members of family hominidae (great ape and human) - some say not great apes only fossil ancestor |
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Hominins |
Refer to Human and fossil ancestors ( hominini tribe without chimps) - this context hominids are bipedal animal infossil record show mix of ape an human features |
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Anatomical Similarity between great African ape and humans |
-Opposable thumb day is the the rèqqq pul( power grip but only human have done motor grip) - 2 hands on each 5 finger + same with feet and toes - long arms rotate freely at shoulder joint ( all direction movement) -Flat nails -No tail - sexual dimorphism - eyes have cones(and rods) so colour vision is possible |
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Anatomical differences between African ape and humans |
Quadrupedal vs bipedal Vertebral column: C shaped vs s shaped Feet: Flat vs arched Pelvis: Narrow long vs short wide Forman magnum: at back of skull vs closer to front Brain: Small undeveloped vs larger developed Prognathism: High vs reduced Jaw strength(zygomatic arch) : high vs reduced Canines; prominent vs small,same size as other |
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Anthropology |
The study of the origin and social relationships of human kind |
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Paleoanthropology |
The study of human evolution by study fossils of humans and artifacts |
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Evidence of common ancestor for hominids |
Fossil evidence(bipedalism, brain size, Crainial & Brow ridge, prognathism, dentition and palate shape ) Genetic evidence( mtDNA and Chromosomal DNA comparison of living Hominds) Archaeological Evidence:tools(Oldowan, Acheulian, mousterian and recent) |
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Primate subdivision |
Lemur, lorises,tarsier, New world primate(platyrrhini), humans , African ape and old wold primates(catarrhini) |
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Arboreal |
Living in trees |
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Palaeontology |
The study of plans and animal fossils |
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Archaeology |
The study of artefacts left behind by early human populations |
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Hominid sequence |
Ardipithecus ramidus (5.8-4mya) Australopithecus (4.5-1.4mya) e.g laetoli footprint(3.3mya) Paranthropus Robustus(aprox 4mya) Australopithecus Africanus(3-2mya) E.g Taung Child and Mrs Ples Australopithecus afarensis (3.5mya) Australopithecus prometheus Australopithecus sediba(2-1.7mya) Homo habillis(2.2-1.6mya) Homo ergaster(2-1.4mya) e.g Tarkana boy Homo erectus(1.8-0.3mya) Homo heidelbergensis(700-200kya) Home neanderthalensis(230-30kya)= not direct to man Homo naledi(about 300kya) =not directly relate to man Homo sapiens(200kya-now) Sometime make us sapien sapien
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Ardipithecus ramidus |
Ape like everything -probably bipedal(still opposable toe) Changed depending on climb or walk 1993- Afar valley |
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Australopithecus |
Gracile and robust(Paranthropus robustus) Form First bipedal primates (non opposable toe and tenth humanish)- laetoli footprints show this Not common ancestor as develop simultaneously to homo genius |
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Australopithecus africanus |
1924-Taung child(3-4yr child skull) Raymond Dart, taung, NW of Kimberly 1947-Mrs Ples(Complete adult skull + Varius bones) Robert Broom, Sterkfonteon caves Most plant-less meet |
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Australopithecus afarensis |
1974-Lucy, Fossilised female skeleton(pelvis) Face, limbs ape-like but show bipedalism Donald johanson, Hadar afar region of Afar Valley |
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Australopithecus Prometheus |
1994- Ankle foot bones by Ron Clark 1997- found rest still excavate now Hand similar to modern human and bipedal Sterkfontein caves |
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Australopithecus sediba |
2008- lee Berger and Matthew find mother and boy(Karabo) 1st new hominid species since mrs Ples(announce 2010) Most complete hominid fossil so far- Consider transition fossils - A africanus and h sapien Can Finally walk for long distance(pelvis like humans) Prof Berger...Think Australopithecus could be related to homo |
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Difference homo and Australopithecus genus’s besides obvious ones |
Homo brain- enlarged for language and use tools Homo skull- more human like less prominent brow ridge and flat face |
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Homo habillis |
Lived with Australopithecine(2.2-1.6mya) Discovered in 1960( smaller body then Australopithecines) Consider 1st use stone tools- larger brain so could use hands |
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Homo erectus |
Closer to modern human than ape-man(1.8-0.3mya) 1st to use fire(larger Brain) large body like humans Face still slightly ape-like(brow ridge and jaw) Out of Africa model- 1st exodus Most complete- Tarkana boy(1.5mya), lake Tarkana-sometimes called homo ergaster Pekeng man(0.4mya) China Java man (0.7mya) Java, Indonesia |
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Homo neanderthelensis |
230- 30kya 1856 Neander valley Germany discovered Brain larger than Homo sapiens but limited development - buried dead Prominent brow ridge and big nose |
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Homo sapiens |
200kya-now make tools from bone and stone( bow, fish hook( Life in tents and formed community Animal Migration followers and domesticate + cultivate land Jewellery and body paint Bury the dead |
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Homo Naledi |
Found 2015 by cavers Probably in-burial site- difficult getting in Not directly related to humans extinct side branch Found in dinaledi chamber(limestone caves) About 1500 specimen and 15 individuals |
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Homo heidlbergensis |
700-200kya Often referred to as archaic homo sapien 1st species to group hunt and build simple wood+ rock dwelling Taller than modern man , brain slightly smaller |
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The SAN the world oldest extant people |
mtDNa show greatestbgenetic diversity Suggested direct descendent if homo sapien before the migration Taken of ancestral land by African and European population I’m unfavourable condition now 100k left in Southern Africa (RSA,BW,Namibia ,Angola) |
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Interdependence on Hominid skills |
Scientist differ explain how bipedalism, fire making, tool making , culture and brain capacity link Difficult to distinguish which happened first. So, interdependent(Essential to each other ) Bipedalism- need tool skills to actually hunt event though see prey Develop complex tool kit- hunt kill larger prey(more protein). Better for brain development Increase brain capacity depend on improved diet- bigger brain =more like to get skills for fire making or tools to hunt Develop fire making skills- greater range of food(Growth and development follow) Hunting- require language and communication |
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Out of Africa hypothesis |
Homo sapien originate in Africa 200kya and migrate relatively recently (50kya) 1st Exodus- Homo erectus left Africa 1.8mya establish population in Europe , Asia and Indonesia 2nd Exodus- 50kya Homo sapien also left Africa to out compete each life form they came up against. ( high level technical skill, better environmentally adapted )
Early Homo sapiens when to Africa and Asia to outcompete homo erectus |
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Multi regional Hypothesis |
Homo Erectus left Africa & simultaneously across the world gave rise to Homo sapiens( parralel evolution) Denosovan(Asia) Neanderthols(Europe) Homo Erectus in both Both model supported by genetic and fossil evidence |
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Evidence of African origin for all humans |
Genetic links(DNA) - Chromosomal- similar to great apes and great apes in Africa (rarely tested because degrades) - Mitochondrial- simpler time analyse fewer genes code for about 13 proteins Only received from mum( only nuclei of a sperm enter ova) Compare different population for extent of variation( logic most variation=more time to mutate) Mitochondrial eve- use expected rate of mutation /year, to find out lived 200-150mya (support out of Africa ) -Y chromosome- Only inherited by males no crossing over and exchange material. So, Pedigree form on male line , Lead to Y chromosome Adam Was fossil record (largest collection of hominid fossils in africa) -Great Rift Valley(Kenya,Ethiopia, Tanzania) Deep split in river due to shift in tectonic plate (valley divided in to western and eastern section) Largest lake on content- probably attract lots of animal and hominids Since 1993 Leaker family- contribute a lot work their -Cradle of human kind(richest source hominid fossils globally) 1/3 of works holiday fossils 1998 - Prof Philip Tobias campaign- Unesco world heritage site Consists of 13 fossil sites- Sterkfontein caves most known |
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Cradle of human kind |
Back (Definition) |
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Great Rift Valley |
Back (Definition) |
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Hominid fossils in SA |
Taung, NC- A africanus( Raymond Dart and Philip Tobias) Blombos,WC- h sapien , Art and complex hunting kit Pinnacle Point, Mosael bay, WC- earliest use of fire and ochre artifacts Klassie River caves, EC- h sapien burriel Florid bad, FS- h heidelbergensis skull Border cave, KZN- h sapien, tools and marked bones (Raymand Dart) Makapansgat,LP- a afrikanus & h sapien(Raymond Dart) Langaaban,WC- h sapien,” Eve’s footprints “ |
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Dr Robert broom(1866-1951) |
Mrs Ples( a africanus) in Sterkfontein cave 1947 & Australopithecus fossil around |
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Prof Raymond Dart(1893-1988) |
Taung Child(small a. Africanus skull) in 1924 |
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Proff Philip Tobias(1925-2012) |
Valuable research In Sterkfontein Caves and identified homo habillis with Louis leaky in Olduvai Gorge |
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Proff Ronald Clark(1944-) |
Discover little foot( a prometheus) in Sterkfontein cave -1994 |
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Dr Andre Kruger (1938-2010 |
Discover complete scull female a robustus near Sterkfontein in 1994 |
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Evolutionary trend in hominids |
Quadrupedal- bipedal Decrease -Cranial and brow ridge size -Size of teeth -Prognathism Increase -Brain capacity -Dexterity (skill in performing tasks especially with hands) |
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Swaartkrans |
First site show 2 specie lives in same are at same time A robustus and h erectus found Bob Brian discover- evidence controlled use of fire(1mya) |
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Resistance ( in terms of evolution in present times) |
Ability of an organism to reproduce in the presence of chemical which would normally limit growth or cause their death |
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Evolution in present time |
Evolution usually Takes place over centuries and can be difficult to observe. But, in organism that multiply rapidly( bacteria, virus and some insect and birds ) = possible) |
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Types of evolution in present tie |
Resistant to insecticides in insects - DDT is selective pressure( variation through random mutate)- used to control and exterminate mosquitoes Resistant to antibiotics in bacteria
Drug resistant TB bacteria - MDR TB( resist 2 AB) and XDR TB(resist all AB, must use chemotherapy but only cure 50%) - That’s why DOTS( directly observed treatment short course) was invented |
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Evidence pronates close common ancestor |
Arboreal- common ancestor probably lived in trees - kept clavicle( stabilise shoulder and allow weight when hanging) - opposable thumbs for grasping enlarged complex brain relative to body size - complex social behavior- usually extended care - Eyes face forward and reduced snout- rely on stereoscopic vision not smell Large percentage of shared DNA - have full trichromatic vision |
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Adaption |
Procces by which an organism becomes better suited to its environment |
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Clad a gram |
Branching diagram showing classification relationship between spieces |
