 Darwin wrote up his observations and conclusions (including evidence) in a book, but waited 10 years to publish it  ________________ independently arrived at the same conclusions and sent him an essay to read  Known as the father of biogeography  Darwin published ____________________the next year, on ___________________________

 ________________ : an individual’s adaptation to the environment as measured by its relative genetic contribution to future generations  Descent with modification happens when: _________________________________________ _________________________________________

 500 years ago, Leonardo da Vinci questioned the existence of __________________________________  Prevailing belief: deposited by an ancient flood  Rocks composed of cake-like layers; some contained shells while others did not  Considered it to be similar to spring flooding of rivers and the deposition of silt on riverbeds  If layers had been deposited over time, vertical sequence of fossils would be a fossil record of past life

 By the 1700s, fossils were accepted as remains or impressions of organisms that lived in the past  Fossil: from translation of Latin word meaning __________________________  Interpretation of fossils often influenced by cultural beliefs

 Most fossils are remains of __________________ ________________________________________  Trace fossils are indirect evidence obtained from impressions  Example: tracks  ___________ are fossilized feces Why are fossils hard parts instead of soft matter?

 The ________________ process is very slow  Begins when an organism dies and is covered in ash or sediment  Water infiltrates the remains, and metal ions or other inorganic molecules replace the organic ones in bones or other hard tissues  Soft tissues often decay  The pressure increases from additional sediment deposited on top.

 Pressure + mineralization = transformation of the remains into stony fossils  Fossilization is favored when remains are ___________________ and remain ____________  These conditions are rare; therefore, fossils are rare  Also must remain undisturbed  Scavengers and erosion often make this difficult…

 Sediment particles (including silt, sand, volcanic ash, and other particles) settle and become compressed  Over time, the layers of sedimentary rock form in varying thickness  ___________________ : the formation of layered sedimentary rock  The layers and their chemical/physical properties provide context for the fossils found within them

Figure 16.10, page 247

 Currently more than 250,000 species of fossils  Fossil record will ___________ be complete  Unlikely that a fossil of each species that has ever lived will be found  Favors species with hard parts, dense populations with wide distribution, and that persisted a long time  ________________ (line of descent) of organisms that were remote or lived for brief periods of geologic time are less likely to be represented

 Fossil dating became more accurate with the discovery of radioisotope decay  ________________ : a form of an element with an unstable nucleus that decays and becomes other elements  Decay not influenced by environmental factors; serves as a predictable and constant clock  Used to date fossils and rocks  More recent fossils may be dated using their ratio of carbon isotopes (carbon dating)

 Early geologists counted backward through layers of sedimentary rock to observe transitions in the fossil sequence around the world  Similar transitions were observed in different locations around the world  These became the basis for divisions in the ___________________________

 A chronology of the Earth’s history  Boundaries for major intervals can be determined by transitions in the fossil record  Major divisions can be correlated with macroevolutionary events  Includes dates obtained by radiometric dating  _____________________ : major patterns, trends, and rates of change among lineages

Geologic time clock Figure 16.13, page 249

Figure 16.12, page 249

 Model suggests that all continents were part of a large supercontinent called _______________  Eventually split and drifted apart  Gondwana: southern supercontinent  Jigsaw-like fit between the Atlantic Ocean coastlines of South America and Africa  Helped explain why the same fossils appear in sedimentary rocks on both sides of the ocean  This theory is called plate tectonics

 Movements of Earth’s tectonic plates on outer layer of rock rafted land masses to new positions  Movements had profound impacts on the directions of life’s evolution  Evidence for plate tectonics theory  Distribution of global land masses  Global fossil distribution  Magnetic rocks found in different places around the world  Seafloor spreading from mid-oceanic ridges (fissures)

Figure 16.13, page 249

d 66 myac 152 myab 237 myaa 420 myae 14 mya

We now know that continents collide, split, and move vast distances over the surface of the Earth. Continental drift (plate tectonics) influences life and evolutionary forces on land and in the oceans

 ________________ _______________ is the study of body forms and structures of major groups of organisms, such as vertebrates and plants  Similarities between species may indicate evidence of descent from a common ancestor  _____________ _____________ : similar body parts shared among related organisms  The structures may be used differently, but the same genes direct their development

 In time, isolated populations begin diverging genetically  Over time, differences appear in body form  This macroevolutionary process is called ________________________________  In spite of changes in form, a careful examination reveals common heritage

 Example: the four-legged ancestry of land vertebrates  Divergences led to the major vertebrate groups  Divergence seen in the five-toed limb  The same five-toed limb has been modified into a human arm, an elephant foot, or bird wing  Although they differ in use, size, and shape, they retain the same structure and positioning of bony elements

Figure 16.16, page 252

Certain bones were lost over time Example: digits numbered 1-5 Bones of forearms: colored in orange and pink Stem reptile (a cotylosaur)

pterosaur Figure 16.16, page 252

3 2 1 chicken Figure 16.16, page 252

3 2 penguin Figure 16.16, page 252

porpoise

Figure 16.16, page bat

Figure 16.16, page human

Figure 16.16, page elephant

 Similar body parts are NOT always homologous and do not always share a common lineage  They may have evolved independently in separate lineages  _______________________ look alike in different lineages but did not evolve in a shared ancestor  ____________________________: evolution of similar body parts in different lineages

 Example: ______________________________  All act in flight but examination of their structure reveals that they are not homologous  Unique adaptation for flight are evidence that wing surfaces in bats, birds, and insects are analogous

Figure 16.17, page 253