1. Molecular Composition
**organic compounds; C, N, O, and H
**raw materials->chemical transformation->energy (ATP); 4 aspects: 1.nutrition2.respiration(nutrients->energy)3.synthesis4.growth(to increase size & repair damage)
3. Cellular Composition
**smallest living unit; reproduce; one or many...; identical or specialized...
**equilibrium; narrow range: chemical composition, physical conditions; independent of external environment
**requires detection; animals' nervous system and motility->pronounced responsiveness
6. Growth & Reproduction
**via genetic material of cells (DNA); pass through characteristics life cycle (egg->immature stage->mature adult)
7. Change via Evolution
**genetic change over time via many means (genetic variation, heritable, natural selection (variation->higher fitness->more reproduction), 3.5 billion years of life on earth, DIVERSITY); modern evidence (fossils, biogeography, selective breeding); homologies (morphology, molecular, developmental); provides the best scientific explanation for the diversity of life and thus the origin of the human species, does not provide an explanation for how life first began.