Presentation on theme: "Clues About Evolution Chapter 6, Section 2. Support for Evolution Fossils –Remains or traces of organisms found in sedimentary rock. –Provide an incomplete."— Presentation transcript:
Clues About Evolution Chapter 6, Section 2
Support for Evolution Fossils –Remains or traces of organisms found in sedimentary rock. –Provide an incomplete record of changes that have occurred in organisms and in the climate.
Support for Evolution Fossils –Dating a fossil: Relative Dating –Gives an estimated date based on ages of rock layers above and below the fossil. Radioactive Dating –Gives an exact date by comparing the amount of radioactive element in a rock with the amount of the stable element.
Support for Evolution Embryology –Study of the development of embryos (earliest stage of a life form). Example: –All vertebrates at some point have both gills and a tail.
Support for Evolution Homologous Structures: –Structures that are similar in structure and origin (and sometimes function). Example: –Human arm, bat wing, and a dolphin flipper.
Support for Evolution Vestigial Structures –Structures that appear to have no function. Examples: –Appendix, pelvic bones of snakes and whales.
Support for Evolution DNA –Similarities in DNA can suggest similar ancestry.
Support for Evolution Direct Observations: –Antibiotic resistant, selective breeding