Human fossil record Flashcards
what are the hominin genus we need to know
ardipithecus, australopithecus and homo
ardipithecus
very early hominin, lived 4.4 mya, exihibits both ape and non-ape like features
features of ardipithecus
ape-like teeth, narrower molar teeth capped with thin enamel, size of modern chimps, sexual dimorphism
environment of ardipithecus
lived in shady forests rather than the savannah
austtalopitthecus
primitive hominin, lived 4-2mya
what fossil provides evidence of australopithecus
lucy (australopithecus afarensis), dated as 3.2 mya
what are the two australopithecus
australopithecus afarensis and australopithecus africanus
australopithecus afarensis
3.9-2.9 mya, found in africa
features of australopithecus afarensis
slender build, reduced canines and molars but larger teeth than humans, small brain, projecting face, human femur and pelvis
where australopithecus afarensis exclusively bipedal
the anatomy of the hnds feet and shoulder joints favour tree climbing, toe bones and finger allow to efficientluy grasp branches
australopithecus africanus
2-3mya, thought to have been a direct ancestor of modern huumans
how does australopithecus africanus compare to australopithecus afarensis
more human like cranium, permitting a larger brain and human like facial features
what are the different homos
homo habillis, homo erectus, homo heidelbergensis, homo neandethalensis, homo spaiens, homo denisovans, homo floresiensis
homo habilis
2.4 mya, found in africa, first to use tools
homo erectus
2mya - 300,000ya, fossils in and out of africa
behavioural features of homo erectus
controlled use of fire, elaborate stone tools, make noise, buried their dead
structural featurees of homo erectus
protruding jaw, marked brow ridge
homo heidelbergensis
400,000-40,000 ya, intermediate between homo erectus and homo sapiens, fossils ffound in and out of africa
homo neanderthallensis
120,000-35,000 ya, existed and interbreed with homospaiens
behavioural features ooof neanderthals
crafted fine tools and jewellery, wore clothes, music, carnivorous
structural features of neanderthals
large brains, strongly built, wide skull, sloping forehead and heavy brow ridge
theories on why neanderthals became extinct
unable to compete with homo spaiens or wiped out by disease
how long have homo sapiens existed
in africa since 175,000 ya
homo florensis
18,000 ya, overlaps with homo spaiens and evolved from homo erectus
homo denisovans
40,000 ya, closely related to neanderthals
what was the fossil that provided evidence of denisovans
bone fragments and associated artefacts discovered in siberia in 2010, mitochondrial dna was extracted from a single bone and sequenced
how is africa the cradle of humanity
no prehuman hominins or australopithecine fossils have been found outside africa
what do all the fossils that have been found of hominins share in common
are very few and are incomplete
why does the fossilisation of hominins rarely occur
fossilisation iis a rare event, hominins dont live in places where fossilisation occurs, hominins have behaviours that make dossilisation unlikely and homins have not been around for long, species only live for a short period of time
what are the two reasons for an incomplete fossil record
complete fossil of an incomplete specimen and incomplete fossil of a complete specimen
complete fossil of an incomplete specimen
specimen may have been subject to movement/washed away before fossilisation has occured
incomplete fossil of a complete specimen
the whole individual may have been fossilised but then subjected to earth movements or erosion
how is the fossil record incomplete
because we lack the fossils to complete the story of hominin evolution, fossils are still out there but havent been discovered yet
why is the evolution of humans still unknown
different palentologists may interpret the same evidence in different ways. the hominin evolutionary tree is highly branched and subject to change when new hominin fossils are discovered
what evidence shows that homo spaiens and neanderthals interbreed
nuclear DNA studies show that 1-4% of the human genome is identical to DNA found in neanderthals. neanderthal fossil contained a sigificant amount of human DNA not found in other naeanderthal populations
what is the fossil that established homo denisova
bone fragments found in siberia 2010, dated as 40,000 yo
homo luzonesis
a relatively small bodied hominin ancestor 50,000-70,000ya
what fossil provided evidence of homo luzonesis
2007 fossil found in the northern parts of luzon, dated as 67,000 ya
