Biology Chapters 12 - 14 Earth’s Geologic History Evolution (Darwin’s Theory) Classification System (Linneaus)

Earth’s Geologic Timeline Earth was formed 4.5 billion years ago Prokaryotic cells were the first life on Earth Eukaryotic cells (with nucleus) formed 1.5 billion years ago Fossils indicate that evolution takes place gradually Fossils are old bones, traces of dead animals, & footprints

Darwin’s Origin of the Species Species come from common ancestors Theory of Evolution states species change over time (they evolve) Natural Selection is the mechanism of the Theory of Evolution The environment selects what organisms will survive and reproduce Darwin did his research on the Galapagos Islands

Natural Selection Can cause the spread of adaptations through a population The process of organisms with well suited traits reproduce at a greater rate Natural Selection can not occur without genetic variation in species The process by which a species becomes better suited is called adaptation Scarcity of resources results in competition

Classification of Organisms Developed by Carolus Linnaeus Taxonomy is a system of grouping organisms Kingdom is the largest group (most inclusive) Species is the smallest group (least inclusive) Scientific names must have two Latin words Example: Homo sapien (common name: humans)

Taxonomic Groups 7 levels K Kingdom largest group (6 Kingdoms) P Phylum (chordata-vertebrates, invertebrates) C Class (molluscs, arthropods, mammals, etc) O Order (smaller groups with characteristics) F Family (smaller groups yet) G Genus (smaller groups yet) S Species (individual groups of organisms that naturally breed in the wild)

Binomial Nomenclature Humans are given the name Homo sapien Bi (two) – Nomenclature (names) First name is the Genus Second name is the species