Bio Anth Exam 2

Common ancestor

A species from which two or more different species evolved

Linnaean system of classification

A system used to organize living things into hierarchical categories

Linnaean levels

Kingdom Phylum Class Order Family Genus Species

Human kingdom

Animalia

Human phylum

Chordata

Human class

Mammalia

Human order

Primate

Human family

Hominidae

Human genus

Homo

Human species

Homo sapiens

Primates include

Lemurs lorises tarsiers monkeys apes humans

Primate trait grasping hands

Hands capable of holding objects using opposable thumbs

Primate trait opposable thumb

A thumb that can touch the other fingers to grasp

Primate trait large brain

Brain size large relative to body size

Primate trait forward facing eyes

Eyes positioned in front of the face allowing depth perception

Primate trait reliance on vision

Primates rely more on sight than smell

Primate trait weak smell

Primates have smaller olfactory systems than many mammals

Primate trait nails instead of claws

Flat nails replace claws on fingers and toes

Primate trait social behavior

Primates often live and interact in groups

Cladogram

A diagram showing evolutionary relationships between organisms

Osteology

The study of bones

Anatomical position

Standing upright facing forward arms at sides palms forward

Sagittal plane

Divides the body into left and right halves

Frontal plane

Divides the body into front and back halves

Transverse plane

Divides the body into upper and lower halves

Cranial skeleton

The bones of the skull

Postcranial skeleton

All bones of the body except the skull

Superior

Toward the head or above

Inferior

Toward the feet or below

Anterior

Toward the front of the body

Posterior

Toward the back of the body

Medial

Toward the midline of the body

Lateral

Away from the midline of the body

Proximal

Closer to the trunk of the body

Distal

Farther from the trunk of the body

Hominin

Humans and extinct species more closely related to humans than chimpanzees

Key hominin traits

Bipedal locomotion and reduced canine teeth

Bipedalism

Walking on two legs

Foramen magnum

Hole in the skull where the spinal cord connects to the brain

Foramen magnum in bipeds

Located underneath the skull

Foramen magnum in quadrupeds

Located toward the back of the skull

Biped pelvis

Short and bowl shaped

Quadruped pelvis

Long and narrow

Human finger bones

Straighter phalanges

Ape finger bones

Curved phalanges adapted for climbing

Human rib cage

Barrel shaped

Ape rib cage

Cone shaped

Human femur

Angled inward to support upright walking

Human arm length

Shorter relative to legs

Ape arm length

Longer relative to legs

Human foot

Arched with aligned toes for walking

Human spine

S shaped curvature

Early hominins

Earliest members of the human lineage about 6 to 4 million years ago

Early hominin traits

Possible bipedalism reduced canine teeth ape like bodies

Early hominin examples

Sahelanthropus Orrorin Ardipithecus

Australopithecus

Early bipedal hominins with small brains

Australopithecus time period

About 4 to 2 million years ago

Australopithecus traits

Bipedalism small brain climbing ability small body

Australopithecus examples

Australopithecus anamensis Australopithecus afarensis Australopithecus africanus Australopithecus sediba

Paranthropus

Hominins with very large teeth and strong chewing muscles

Paranthropus time period

About 2.5 to 1 million years ago

Paranthropus traits

Large molars powerful jaws sagittal crest

Homo genus

Human lineage with larger brains and tool use

Homo first appearance

About 2.5 million years ago

Homo traits

Larger brains smaller teeth tool use human like body proportions

Homo examples

Homo habilis Homo erectus Homo heidelbergensis Homo neanderthalensis Ho