Puzzle of Life’s Diversity

1. Puzzle of Life’s Diversity

2. Puzzle of Life’s Diversity • Evolution • Change over time / the process by which modern organisms have descended from ancient organisms • Scientific Theory • A well-supported testable explanation of phenomena that have occurred in the natural world

3. Charles Darwin • British scientist • Born 2/12/1809 – same day as Abraham Lincoln • Completed college and joined the crew of the HMS Beagle in 1831 • Made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changed over time. • This body of work became known as: • The Theory of Evolution • Wrote book On The Origin of Species

4. Voyage of HMS Beagle

5. Darwin’s Observations • Enormous # of species inhabit the earth • Plants and animals seem remarkably well suited to whatever environment they inhabit • Saw a variety of ways in which organisms survive and product offspring • Also studies fossils • Preserved remains of ancient organisms • Some fossils were like organisms still living – others similar but somewhat different

6. Darwin’s Observations • Galapagos Islands • Close together / different climates / different habitats • Observed Finches / Beaks • Observed Tortoises / varied from island to island • Shapes of shells differed depending on habitat • Observed that characteristics of may animals and plants varied noticeably among different islands • Wondered if these animals had been originally from the same species but changed due to their environment after becoming isolated

7. Darwin’s Observations • Was influenced by many different scientists of the time such as: • James Hutton – 1785 • Thomas Malthus – 1798 • Jean-Baptiste Lamarck – 1809 • Charles Lyell – 1833 • Alfred Wallace - 1858

8. James Hutton - 1785 • Proposed that the earth is shaped by geological forces that took place over extremely long periods of time • Estimates that the earth was millions of years old • Not thousands

9. Thomas Malthus - 1798 • Wrote Essay on the Principle of Population • Predicted that human populations will grow faster than the space & food supplies needed to sustain it

10. Jean-Baptiste Lamarck - 1809 • Published his hypothesis of the inheritance of acquired traits • First to propose a mechanism explaining how organisms change over time • Thought that species changed over time and were descended from other species • Proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime

11. Charles Darwin • Theory of Evolution • Artificial Selection • Struggle for Existence • Fitness / Adaptation • Survival of the Fittest • Natural Selection • Descent with modification • Common descent • Geographic distribution • Homologous Structures • Vestigial Organs

12. Charles Lyell - 1833 • Wrote Principles of Geology • Explained that processes occurring now have shaped the earth’s geological features over long periods of time

13. Alfred Wallace - 1858 • Corresponded with Darwin • Speculated that evolution by natural selection might be based on the distribution of plants & animals

14. Darwin Presents His Case • Published his book • On the Origin of Species • Variation • Artificial Selection • Natural Selection • Struggle for Existence • Survival of the Fittest • Adaptation • Descent with Modification

15. Evolutionary Evidence • Fossils • Distribution of Living / Extinct Organisms

16. Evolutionary Evidence • Homologous Structures

17. Evolutionary Evidence • Vestigial Organs

18. Evolutionary Evidence • Similarity in Embryos

19. Summary of Darwin’s Theory • Individual organisms vary – some in inherited • Organisms produce more offspring than can survive • Organisms compete for resources • Each organism has different advantages and disadvantages in their struggle for existence • Species alive today are descended with modification from ancestral species