Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Rotating locomotion in living systems wikipedia , lookup
Sexual selection wikipedia , lookup
Natural selection wikipedia , lookup
Theistic evolution wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Vestigiality wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Inclusive fitness wikipedia , lookup
Paleontology wikipedia , lookup
Darwin’s Theory of Evolution (Chapter 15) Evolution ! change over time • Theory ! a well supported, testable explanation of events that occurs in the natural world Darwin’s Journey • Traveled on the HMS Beagle starting in 1831 • His detailed drawings and observations helped him piece together his ideas on why life is so diverse • Observations o Plants and animals were well suited for the environment that they lived in o Some animals are widely distributed while others are only found in certain areas o Some living animals resembled fossils of animals from long ago o Some fossils did not resemble any living organism • Galapagos Islands o Each island has a different climate o Giant Tortoises found on each island were different o Several types of small birds were found on each island but they all had different sized beaks • On Darwin’s journey home he began to wonder if all the different animals on the islands were once the same species Ideas before Darwin • James Hutton ! proposed that the geological forces that shape Earth’s surface occur very slowly o Rocks are moved by forces under Earth’s surface • Charles Lyell ! the same geological forces that occurred long ago are continuing today • Jean-Baptiste Lamarck ! the use or disuse of certain features are passed on to offspring o Giraffes have long necks because their parents stretched their necks • Thomas Malthus ! if human population continues to grow unchecked, we will run out of room and food On the Origin of Species by Means of Natural Selection • The natural variation found in populations are important o Artificial selection ! humans select the traits in animals or plants they want the next generation to have " Hairless Chihuahua • Populations change as natural selection acts on its individuals o Struggle for existence ! members of each species compete with each other for food, water, mates and shelter " Organisms have more offspring than can survive " The ability of an organism to survive and reproduce in it’s environment is called fitness • Adaptations are inherited characteristics that increase an organism’s fitness o Natural selection ! organisms that are best suited for survival in an environment will reproduce more and pass their advantageous traits on to their offspring o Sexual Selection ! one sex chooses a mate based on behavior or appearance • All living species have descended from other species over time! descent with modification • All living things descended from a common ancestor Evidence for evolution • Fossil record ! shows that life on earth has changed over time • Animals living in different areas with similar climate have similar features !biogeography • Homologous body structures o Structures that come from a common ancestor but are different in the adult form o Vestigial structures ! the remains of structures that are no longer used " Pelvic bone in whales • Analogous body structures o Structures that are similar in distantly related organisms due to similar environmental pressures " Wings in butterflies and birds • Similarities in embryological development