lec 33- hominin evolution Flashcards
what is the oldest clade of primates?
prosimians (tarsiers and lemurs, lorises, pottos Galagos)
what are prosimians also known as?
pre monkeys
what are the characteristics of prosimians?
Nails instead of claws, binocular vision and grasping hands
during what time period did ancient apes give rise to the present day clades of apes?
Miocene (planet of the apes 23-5 Ma)
what continents are ape fossils found on and where do surviving apes live today?
-fossils found in Europe, Africa, and SE Asia
-surviving gibbons and orangutans in Asia, chimps and gorillas in Africa, and no surviving apes in Europe
what was the largest ape that ever lived?
Gigantopithecus, fossils found during miocene
how many species are there of gorillas chimps and orangutans?
2
what clade are humans most closely related to?
the chimpanzee clade
what is pedomorphosis?
the retention or keeping of juvenile features in sexually mature adults
what are hominins?
hominins are all fossil non-ape pre-humans and modern humans
what do all humans and all hominins have that is similar?
-32 teeth in the same position in the skull and jaw
-canin in hominins is much reduced compared to apes
why is linear evolution of humans wrong?
because many hominins lived at the same time, around 2 Ma
what is the newly discovered hominins species and its characteristics?
Homo naledi, 300,000 yo, showed a mix of advanced (upright stature, reduced brows) and primitive traits (small, brain curved fingers)
what is the hobbit hominin called?
homo floresiensis, 1 m tall, lived until 60,000 years ago, lived on Flores island Indonesia
what time period did the Australopithecines live and where did they live?
4-2 Ma, Africa
what are the two types of Australopithecines?
gracile and robust
who found out that australopithecines had small brains and were bipedal?
Mary Leaky, they were small brained with massive jaws and large teeth
What were Lucy’s (3.2 Ma) characteristics which made her a transitional fossil?
had arboreal (climbing) and bipedal (walking and running) adaptations
did Ardipithecus ramidus (4.4 Ma) have early bipedal characteristics?
yes, was able to climb and walk like lucy
how did drought potentially promote bipedalism?
drought increased the area of the savannah (open grasslands with few trees) in Africa around the time of the hominin evolution, causing adaptations to more open areas
what is the advantages of bipedalism?
upright stance frees hands for tool manufacture and use, carrying food, tools, babies, also many reduce sun exposure
from what habitat to the other did Africa undergo in the late Miocene?
from the lush forests to the savannah
what is the earliest homo?
homo habilis (handy man) lived during 2.4-1.5 Ma
what is the skull 1470 controversy?
Richard Leaky found a hominin skull similar to homo habilis but had distinct different features making it believed to be a different species. originally lived during 2.8 Ma but now it is considered to live 2.4 Ma
what were the characteristics of homo erectus?
efficient walkers and runners with enlarged brains
do homos have the largest brains relative to body mass?
yes
does brain volume increase over the years in human evolution from Australopithecus to homo?
yes
what drove increased brain size in Homo?
social evolution (speech)
did bipedalism come before large brains?
yes
when was the earliest migration out of Africa done by homo erectus?
1.8 Ma
