Created by C. Ippolito May 2005 Chapter 15 Darwin’s Theory of Evolution The Puzzle of Life’s Diversity (pp ) Ideas That Shaped Darwin’s Thinking (pp ) Darwin Presents His Case (pp )

Created by C. Ippolito May 2005 Chapter 15 Section 1 The Puzzle of Life’s Diversity Objectives: Describe Charles Darwin’s contribution to science. Describe the pattern Darwin observed among the organisms of the Galapagos Islands.

Created by C. Ippolito May 2005 Evolution Scientific explanation for the diversity of life Scientific explanation for the diversity of life Evolution is the process by which modern organisms have descended from ancient organisms. Evolution is the process by which modern organisms have descended from ancient organisms.

Created by C. Ippolito May 2005 Voyage of the Beagle Voyage of the Beagle HMS Beagle left England in 1831 to Chart the coast line of So. America for the Royal Navy HMS Beagle left England in 1831 to Chart the coast line of So. America for the Royal Navy Darwin served as naturalist Darwin served as naturalist Collected evidence that led him to propose a revolutionary hypothesis of how life changes over time. Collected evidence that led him to propose a revolutionary hypothesis of how life changes over time.

Created by C. Ippolito May 2005 Darwin’s Observations Patterns of Diversity Patterns of Diversity regions had similar environments regions had similar environments life forms were very different life forms were very different Living Organisms and Fossils Living Organisms and Fossils some fossils resembled modern organisms some fossils resembled modern organisms other fossils were completely different other fossils were completely different Galapagos Islands Galapagos Islands each island had different tortoises each island had different tortoisestortoises shells changed with source of food shells changed with source of food each island had different finches each island had different finchesfinches beaks changed with source of food beaks changed with source of food

Created by C. Ippolito May 2005

Created by C. Ippolito May 2005 Chapter 15 Section 2 Ideas That Shaped Darwin’s Thinking Objectives: Describe how Hutton and Lyell described geological change. Describe how Lamarck explained the evolution of species. Describe Malthus’ theory of population growth

Created by C. Ippolito May 2005 An Ancient, Changing Earth James Hutton James Hutton Theory of Uniformitarianism Theory of UniformitarianismUniformitarianism forces acting on the Earth today (wind & water erosion) are the same as those that changed the Earth in the past forces acting on the Earth today (wind & water erosion) are the same as those that changed the Earth in the past Charles Lyell Charles Lyell Principles of Geology Principles of Geology canyons and mountains formed over time by the millions of years result of same forces canyons and mountains formed over time by the millions of years result of same forces

Created by C. Ippolito May 2005 Lamarck’s Evolution Hypothesis Tendency Toward Perfection Tendency Toward Perfection organisms strive to be more complex and more perfect organisms strive to be more complex and more perfect Use and Disuse Use and Disuse organisms alter size and shape of parts by use organisms alter size and shape of parts by use more use – larger – more important more use – larger – more important less use – smaller – less important less use – smaller – less important Inheritance of Acquired Traits Inheritance of Acquired Traits changes during life time passed to offspring changes during life time passed to offspring

Created by C. Ippolito May 2005 Population Growth Malthus published a paper of the growth of human populations Malthus published a paper of the growth of human populations Malthus people reproduce as a geometric function people reproduce as a geometric function 1 x 2 = 2 x 3 = 6 x 4 = 24 x 5 = x 2 = 2 x 3 = 6 x 4 = 24 x 5 = 120 plants reproduce as an arithmetic function plants reproduce as an arithmetic function = = = = = = = = 15 More humans are produced than can be feed More humans are produced than can be feed controlled by controlled by famine famine disease disease war war

Created by C. Ippolito May 2005 Chapter 15 Section 3 Darwin Presents His Case Objectives: Describe how natural variations are used in artificial selection. Describe the relationship between natural selection and a species’ fitness. Describe the evidence that supports Darwin’s Theory of Evolution.

Created by C. Ippolito May 2005 On the Origin of Species 1836 – – years gathering evidence to support idea 23 years gathering evidence to support idea 1858 Alfred Wallace in Malaysia 1858 Alfred Wallace in Malaysia sends essay summarizing thoughts on how species change sends essay summarizing thoughts on how species change 1859 “On the Origin of Species” published by Charles Darwin proposing the Theory of Natural Selection 1859 “On the Origin of Species” published by Charles Darwin proposing the Theory of Natural Selection

Created by C. Ippolito May 2005 Inherited Variation and Artificial Selection Plant and animal breeders use heritable variation to improve crops and livestock Plant and animal breeders use heritable variation to improve crops and livestock Artificial Selection Artificial Selection Natural variations chosen by breeders to alter characteristics of domestic plants and animals Natural variations chosen by breeders to alter characteristics of domestic plants and animals

Created by C. Ippolito May 2005 Evolution by Natural Selection Struggle for Existence Struggle for Existence Species compete for food, living space Species compete for food, living space Survival of the Fittest Survival of the Fittest Fitness Fitness Ability to survive and reproduce in an environment Ability to survive and reproduce in an environment Adaptation Adaptation inherited characteristic that increase chances of survival inherited characteristic that increase chances of survival Anatomical – porcupine’s quills – antelope’s speed Anatomical – porcupine’s quills – antelope’s speed Physiological – seal’s blood holds more O 2 Physiological – seal’s blood holds more O 2 Behavioral – live or hunt in groups Behavioral – live or hunt in groups Over time inherited characteristics of a population change increasing a species’ fitness in a particular environment Over time inherited characteristics of a population change increasing a species’ fitness in a particular environment

Created by C. Ippolito May 2005 Evidence for Evolution Fossil Record Fossil Record Comparative Anatomy Comparative Anatomy Homologous Structures Homologous Structures Vestigial Organs Vestigial Organs Comparative Embryology Comparative Embryology Comparative Biochemistry Comparative Biochemistry

Created by C. Ippolito May 2005 Fossil Record Comparing fossils in layers of rock Comparing fossils in layers of rock Simple fossils in older layers Simple fossils in older layers More complex fossils in younger layers More complex fossils in younger layers

Created by C. Ippolito May 2005 Homologous Structures Similar form, similar origin, different function Similar form, similar origin, different function Points to common ancestry Points to common ancestry

Created by C. Ippolito May 2005 Vestigial Organs Traces of homologous organs that have vital roles in other species but no long affect survival in current species Traces of homologous organs that have vital roles in other species but no long affect survival in current species

Created by C. Ippolito May 2005 Comparative Embryology Similar organisms develop in similar ways follow the same sequence of development or developmental pattern Similar organisms develop in similar ways follow the same sequence of development or developmental pattern

Created by C. Ippolito May 2005 Comparative Biochemistry Similar organisms use similar substances Similar organisms use similar substances DNA function in all the same DNA function in all the same Protein structures point to descent with modification Protein structures point to descent with modification