Human Evolution Flashcards
define evolution
a slow and continuous process whereby complex forms of life have emerged from simpler forms through millions of years
define vestigial organs
those organs that have ceased to be of any use to the possessor but still persist generation after generation in a reduced form
ex: wisdom teeth, vermiform appendix, pinna
facts of “theory of natural selection”
- overproduction
- struggle for existence
- variation
- survival of the fittest
struggle for existence
individuals multiply in a geometric ratio whereas space and food remain almost constant
competition may be intraspecific or interspecific
variation in Darwinism
struggle for existence among organisms has compelled them to adapt themselves according to the conditions so that they can utilize natural resources and survive successfully . this causes differences
without variation, no evolution
define speciation
origin of new species by gradual modification
homo sapiens/ modern man belongs to which order
Primates, along with monkeys and apes
changes required for going from ape-like form to human form
- bipedal locomotion and freeing forelimbs from ground
- increase in crainial capacity
- reduction in size of canines due to omnivorous feeding habits
- loss of jaw power
- development of chin
- increase in heigh
- erect posture by development of lumbar curve
different stages of human ancestors during evolution
- ramapithecus
- australopithecus
- homo habilis
- homo erectus
- neandrathals
- cro-magnon
- homo sapiens
ramapithecus
walked erect on hind feet
only few teeth
australopithecus
small statured
120 cm tall
450-600 cubic cm cranial capacity
walked nearly straight
vertebral column had lumbar curve and broad pelvis
teeth were man like
simian gap between incissors and canines was absent
had prognathous (protruding face), chin absent
homo habilis
150 cm tall
cranial capacity: 680-735 cubic cm
showed bipedal locomotion
large head
less protruding face
body covered in air
small canines
homo erectus
150 cm
cranial capacity: 800-1125 cubic cm
first to hunt animals and use fire
walked fully upright
bowl shaped pelvis
neandrathal man
160 cm tall
cranial capacity: 1450 cubic cm
absolute bipedalism
large head
broad flat and sloping forehead
prominent brow ridges
almost no chin
less body hair
cro-mgnon
180 cm tall
cranial capacity: 1450-1600 cubic cm
large skull
broad face
rounded forehead
prominent chin
lacked eyebrow ridges
less hairy
face was orthognathous (straight and strong jawed)