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LS LSAF Chapter 6

Adaptations over time

TermDefinition
species a group of creatures with similar characteristics that can reproduce fertile offspring
evolution change in hereditary features over time
natural selection organisms with traits best suited to their environment are more likely to survive and reproduce
variation an inherited trait that makes an individual different from other members of the species
adaptation any variation that makes a creature better suited to its environment
gradualism model that describes the slow, continuous process by which one species changes to another
punctuated equilibrium model that describes the evolution of new species through the mutation in a few, select genes over a short period of time
sedimentary rock layers of sand, silt, clay or mud compact to form new rock; sometimes containing fossils
radioactive element gives off a steady stream of radiation and subatomic particles; changing into a new element
embryology the earliest growth stages of an organism
homologous similar in origin and structure
vestigial physical structures that don't seem to have a function
primates mammals with opposable thumbs, binocular vision, and flexible shoulders to allow arm rotation
hominids human-like primates which walked upright; having a larger brain than most other primates of their time; 4-6 million years ago
Australopithecus "Lucy" fossil found in Africa in 1974. Features smaller brain, upright gait. Upheld as evidence for evolution of modern humans - 3.2 million years old
Homo habilis Fossils found in Africa in 1960's. Features larger brain, erect posture, and buried with primitive tools nearby - 1.5 million years old.
Homo erectus Once considered a creature adapted from Homo habilis; the historical significance of this specimen is now in question.
Homo sapien Modern day humans are considered part of this genus/species.
neanderthals Thought to be an off-shoot of modern day humans. Lived in family groups; had advanced tools; short heavy bodies with thick bones, small chins, and heavy browridge. Disappear from fossil record ~300,000 years ago.
cro-magnon Skeletons almost identical to modern humans, but much shorter. Lived in caves, left behind stone carvings and wall paintings, and buried their dead. Disappeared ~10,000 years ago.
Created by: MrGross