Evolution A fundamental theme in all of biology

Charles Darwin (1809 - 1882) British naturalist Theological & ______ training Father was a surgeon 1830’s: naturalist on the ______ Traveled around the globe Observed and collected nature Afterward, conducted ___________ with domestic animals In 1959, published: “On the origin of species by means of ________________” Said Natural Selection was the ________ of evolution “Survival of the fittest” Alfred Russel ______ also described natural selection

Darwin’s rationale for natural selection: 1) All species produce _______ offspring High reproductive _________ 2) Resources (food, shelter) are ________ Causes a ________ for survival Intraspecific competition 3) Individuals of a population differ somewhat Genetic variation 4) Individuals with “_______” traits compete better Are more likely to contribute to next generation

Google: The Darwin Awards Adaptation: a trait that increases _______ Increases the __________ of: Good health Successful breeding Passing adaptive traits to the next generation Darwinian fitness: Successful passing of ______ to next generation Google: The Darwin Awards “Commemorate those who improve our gene pool by removing themselves from it.”

Physical evidence for _____-evolution: Gradual changes over ________ time 1) Fossils Bones, shells, footprints, droppings, etc. Occur in _______________ strata Deeper = _______ Grand Canyon exposes strata >1 billion years old

Transitional fossils show gradual ______ over time E.g., horse evolution: 55 - 45 mya 33 - 29 mya 17 - 11 mya present mya = millions of years ago

_________________ structures Inherited from a _______ ancestor 2) Comparative Anatomy _________________ structures Inherited from a _______ ancestor E.g., forelimbs of all mammals have the same bones: Human: grasping Cat: pouncing Whale: swimming Bat: flying Conclusion: the common ancestor of mammals had these bones

Size and function very _______ Results from ______ over time Vestigial structures Size and function very _______ Results from ______ over time E.g., tail (coccyx) in humans: Hind limbs of certain snakes:

3) Embryological development Similar organisms have similar __________ stages E.g., early vertebrate embryos: Become typical of their type at the ________ stage

4) Universality of the genetic code Genetic code of all organisms is based on the same 4 nucleotides Suggests the first organism was a common ancestor to all

Two types of evolution: 1) __________ evolution One species becomes two (or more) over time Usually results from geographic ____________ E.g., the Ratite (large, flightless) birds: Southern continents were once joined (________) ___ ancestral species occupied the whole area After southern continents split up: Ostrich (Africa) Rhea (S. America) Emu (Australia)

2) ____________ evolution Parallel evolution of a similar adaptation Not inherited from a common ancestor E.g., fins of penguins and whales Common ancestor of birds and whales was a ______ Fins are adaptations to similar ____________ Referred to as _________ structures