Final Flashcards
(82 cards)
what is Mosaic Evolution?
when rate of evolution varies
defining characteristic of hominin evolution
bipedal locomotion
how far back did the earliest known ancestors live?
6 million years ago
three explanations for bipedalism?
- carrying and manipulating objects (tools/food/infants)
- predator avoidance (standing up to see further)
- energy efficient travel
(moderation of heat stress, saves 50% of daily calories)
current ideas on where hominins first lived?
forest/woodlands
mixed landscapes
savannah
position of foramen magnum in humans compared to chimps?
towards the center for humans
further back for chimps
mechanics of Bipedalism?
four
pelvis is short back to front
long legs relative to body and arms
foot with double arch
foramen magnum position
where was the earliest hominin found? how old was it?
Chad, 6 million years
name of the first hominin?
sahelanthropus tchadensis
basic information of tchadensis?
features (3) , characteristics that suggest bipedalism (2) , habitat (1)
- jaw and teeth resemble an ape
- ape sized brain
- non-protruding face
- base of skull + thigh bone suggests bipedalism
- habitat is forest land, near a lake
who discovered the first hominin skull? what was its name?
Michel Brunet, Toumai
after tchadensis, what species is next? where is it found? how old is it?
Ardipithecus ramidus, found in Ethiopia, 4.4 mya
basic information of ardipithecus?
habitat, bipedal characteristics, interesting characteristics (2)?
- wooded habitat
- femur and pelvis indicate bipedalism
- long arms and large hands
- grasping feet - opposable big toe
named Ardipithecus ramidus? what did it tell us?
Ardi, gave insight on last common ancestor of chimps and humans
how many species in the australopith gene?
nine
australopith general characteristics?
how does it move, brain and teeth size
- bipedal
- small brain
- large premolars and molars
oldest australopithecus species?
australopithecus anamensis
what species comes after a. anamensis?
a. afarensis
date range of a. afarensis?
3.9 - 3.0 mya
where were a. afarensis bones found?
two places
Afar, Ethiopia and Tanzania, Laetoli
physical characteristics of a. afarensis?
four
short legs, sexual dimorphism, curved phalanges, had a hyoid like an apes
Laetoli footprints?
1,000s were found perserved in volcanic ash. footprints included animals’ and at least two hominids who were bipedal
special A. afarensis and why? where was it found?
Lucy, special because her skeleton is very complete, found in Hadar, Ethiopia
younger special A. afarensis and importance? where was it found?
Selam, three year old, found in Ethiopia, important because it is a mostly complete female infant