Ch 11 Becoming Human Flashcards
(32 cards)
Homo sapiens
The species name for modern humans.
Taxon (pl. taxa)
A unit of biological classification into which related organisms are classified. Taxa are arranged in a hierarchical rank from kingdom down to species, where members of a specific taxon typically share certain morphological characteristics.
Mammals
Warm-blooded vertebrates belonging to the taxonomic class Mammalia that have mammary glands, hair/fur, three middle ear bones, and one lower jawbone.
Primates
The highest order of mammals, comprised of about 400 different living species who share a number of features including opposable digits and binocular vision.
Hominoids
Members of the superfamily Hominoidea that includes apes and humans.
Hominins
Members of the taxonomic tribe Hominini that includes modern humans and our upright-walking ancestors.
Cranium
The part of the skull that covers the brain.
Prehensile
The ability to grasp objects.
Opposable digit
A digit (either the thumb, big toe, or both) that is able to touch all the other digits on the same appendage.
Precision grip
A type of grip involving the tips of the thumb and finger, used by primates (to varying extents) for precise manipulation of objects of various sizes.
Power grip
A type of grip involving the palm and the fingers, used by primates (to varying extents) for moving and manipulating objects. The power grip generates more force due to the significant use of the palm.
Bipedalism
Using two legs for walking upright.
Genus (pl. genera)
A taxonomic rank above species and below family. Modern humans belong to the genus Homo.
Foramen magnum
The hole in the base of the skull through which the spinal cord passes. A more centralised foramen magnum indicates bipedal locomotion.
Biped
An individual that moves on two legs (upright-walking).
Arboreal
Living in or amongst trees.
Cerebrum
The largest part of the brain, which comprises two-thirds of the brain’s entire weight and is responsible for a large range of vital functions including sensory processing, motor control, and visual and spatial learning.
Sagittal crest
A ridge of hard bone running lengthwise (front to back) along the top of the skull. A pronounced sagittal crest indicates strong jaw muscles.
Arm to leg ratio
The ratio of arm length to leg length. Tree-dwelling hominids have longer arms and shorter legs, or a larger arm to leg ratio.
Inference
Conclusions or assumptions reached by analysing and extrapolating from evidence.
Transitional fossil
A fossil that shows traits that are common
to both its ancestral group and its descendant group. They are particularly important when the descendant species is physically very distinct from the ancestral species, such that the transitional fossil can help demonstrate evolutionary changes between the two.
Interbreeding
Refers to the mating between different species (e.g. between Homo sapiens and other closely related species such as Neanderthals and Denisovans). Also known as crossbreeding.
Multiregional hypothesis
A model for the geographical spread of Homo sapiens which suggests that separate human populations evolved independently from earlier hominins that had spread throughout Eurasia and experienced gene flow. Also known as the regional continuity model.
Out of Africa hypothesis
A model for the geographical spread of Homo sapiens which suggests that humans first developed and evolved in Africa before migrating outwards and expanding their colonies, replacing the earlier hominins that had spread prior. Also known as the African replacement model.
