1. 15-2 IDEAS THAT SHAPED DARWIN’S THINKING Objectives 1)How did Hutton and Lyell describe geological change? 2)According to Lamarck, how did species evolve? 3)What was Malthus’s theory of population growth?

2.  People during Darwin’s era thought the world was created only a few thousand years ago  People didn’t believe living species or the Earth had ever changed  Scientists were discovering new evidence to disprove common beliefs INTRODUCTION

3. AN ANCIENT, CHANGING EARTH  2 scientists formed important theories based on evidence suggesting that Earth was very old and had changed slowly over time Hutton and Lyell

4. AN ANCIENT, CHANGING EARTH CONT’D  Hutton and Lyell helped scientists recognize that Earth is manly millions of years old Processes that changed Earth in the past are the same processes that operate in the present

5.  Hutton published a detailed hypothesis about the geological forces that have shaped Earth in 1795 HUTTON AND GEOLOGICAL CHANGE

6.  Proposed Layers of rock form very slowly Moved up by forces beneath Earth’s surface Buried Pushed up from the sea floor to form mountain ranges HUTTON AND GEOLOGICAL CHANGE CONT’D

7. Rocks are shaped by a variety of natural forces Rain Wind Heat Cold temperatures Operate extremely slow  Because of this he proposed that Earth had to be much more than a few thousand years old HUTTON AND GEOLOGICAL CHANGE CONT’D

8. LYELL’S PRINCIPLES OF GEOLOGY  Darwin was given a copy of Lyell’s book Principles of Geology shortly before his voyage on the H.M.S. Beagle.  This book inspired Darwin to ask questions If the Earth could change over time, might life change as well? Wouldn’t it have taken many, may years for life to change in the way Lyell suggested? This would only be possible if the Earth were extremely old

9.  What are some ways the Earth has changed over time? BLUE TICKET QUESTION

10. LAMARCK’S EVOLUTION HYPOTHESES  French naturalist  Jean-Baptiste Lamarck  Among the 1 st scientist to recognize Living things have changed over time All species were descended from other species Organisms were somehow adapted to their environment

11. LAMARCK’S EVOLUTION HYPOTHESES  Lamarck proposed Selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime Traits could then be passed on to their offspring Led to change in a species over time

12.  All organisms have an innate tendency toward complexity and perfection Continually changing and acquiring features that help them live more successfully in their environments TENDENCY TOWARD PERFECTION

13. USE AND DISUSE  Organisms could alter the size or shape of particular organs by using their bodies in new ways

14.  Acquired characteristics could be inherited If during its lifetime an animal somehow altered a body structure, then it would pass that change on to its offspring INHERITANCE AND ACQUIRED TRAITS

15.  Lamarck’s hypotheses had flaws He did not know how traits are inherited An organism’s behavior has no effect on its heritable characteristics  He was one of the 1 st to develop a scientific hypothesis of evolution and realize that organisms are adapted to their environments EVALUATING LAMARCK’S HYPOTHESES

16. POPULATION GROWTH  Thomas Malthus Reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

17. POPULATION GROWTH CONT’D This hasn’t happened because humans produce fewer offspring Other organisms Majority of offspring die Only a few offspring succeed in reproducing

18. 15.2 EXIT TICKET