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How did the diversity of life originate? Through the process of Evolution.

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Presentation on theme: "How did the diversity of life originate? Through the process of Evolution."— Presentation transcript:

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2 How did the diversity of life originate? Through the process of Evolution

3 Evolution The processes that have transformed life on earth from its beginnings to today's diversity. Evolution is the most pervasive principle in biology.

4 Theory vs theory Theory Hypothesis supported repeatedly by data. Makes testable predictions theory Layperson’s definition. Confused with hypothesis in Science

5 Examples of Theory Cell Theory Big Bang Theory Atomic Theory Theory of Gravity Theory of Evolution

6 Evolution Has itself "evolved" or changed over time. Illustrates “Science as a Process”

7 Overview: Endless Forms Most Beautiful A new era of biology began in 1859 when Charles Darwin published The Origin of Species The Origin of Species focused biologists’ attention on the great diversity of organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

8 Darwin noted that current species are descendants of ancestral species Evolution can be defined by Darwin’s phrase descent with modification Evolution can be viewed as both a pattern and a process Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

9 The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species To understand why Darwin’s ideas were revolutionary, we must examine them in relation to other Western ideas about Earth and its life Charles Darwin Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

10 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

11 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

12 Greek Philosophers 1. Plato - Organisms are already perfectly adapted to their environments. 2. Aristotle - Organisms arranged on a “scale of life” from simple to complex.

13 Result No evolution. Life is already perfect and doesn’t need to change. All the rungs on life's "ladder" are already occupied.

14 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

15 Fixed Species Concept The creator had designed each and every species for a particular purpose. Carolus Linnaeus interpreted organismal adaptations as evidence that the Creator had designed each species for a specific purpose Linnaeus was the founder of taxonomy, the branch of biology concerned with classifying organisms

16 Result No evolution. Created the viewpoint that all species could be identified and named (Taxonomy). A major factor in the Linnaeus classification system.

17 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

18 Catastrophism Georges Cuvier ( ). Attempted to relate fossils to current life.

19 Paleontology, the study of fossils, was largely developed by French scientist Georges Cuvier Cuvier advocated catastrophism, speculating that each boundary between strata represents a catastrophe Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

20 Catastrophism Fossils were the remains of species lost due to catastrophe. No new species originated; species could only be lost over time. Result - No evolution.

21 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

22 Geologists James Hutton and Charles Lyell perceived that changes in Earth’s surface can result from slow continuous actions still operating today Lyell’s principle of uniformitarianism states that the mechanisms of change are constant over time This view strongly influenced Darwin’s thinking Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

23 James Hutton Gradualism Profound change is the cumulative product of slow, but continuous processes.

24 Result Changes on the earth were gradual, not catastrophic.

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26 The study of fossils helped to lay the groundwork for Darwin’s ideas Fossils are remains or traces of organisms from the past, usually found in sedimentary rock, which appears in layers or strata

27 Fig Younger stratum with more recent fossils Layers of deposited sediment Older stratum with older fossils

28 Charles Lyell Incorporated Hutton’s gradualism into a theory called Uniformitarianism.

29 Uniformitarianism Geological processes have operated at the same rate over the Earth’s history. Result - The Earth must be VERY old. (much older than 6000 years of the fixed species concept). Idea that slow and subtle processes can cause substantial change.

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31 Pre-Darwinian Views 1. Greeks 2. Fixed Species 3. Catastophism 4. Hutton and Lyell 5. Lamarck

32 Jean Baptiste Lamarck Published theory in Theory - Life changed from simple to complex over time.

33 Lamark Fossils were the remains of past life forms. Evolution did occur.

34 Lamarck’s Hypothesis of Evolution Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics The mechanisms he proposed are unsupported by evidence Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

35 Lamark Mechanisms 1. Use and Disuse - – Body parts used to survive become larger and stronger. – Body parts not used to survive deteriorate. 2. Acquired Characteristics – Modifications acquired by use/disuse were passed on to offspring.

36 Problem No knowledge of genetics. Acquired traits are not transmitted offspring.

37 Lamarck’s Credits Did suggest correctly the role of fossils in evolution. Did suggest that adaptation to the environment is a primary product of evolution.

38 Another important figure

39 Thomas Malthus Essay on human population growth in Disease, famine, homelessness, and war are inescapable because human populations grow faster than food supplies. Darwin read Malthus.

40 Next time…. Charles Darwin and Natural Selection


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