15-2: Ideas that Shaped Darwin’s Thinking Biology 2

Darwin was influenced by other scientists during his travels – Especially those studying the history of Earth Europeans believed: Earth was thousands of years old Plant and animals had not changed Earth’s featured were created by BIG events Introduction

1795: James Hutton published paper about geology shaping Earth Layers of rock form very slowly Rocks are moved up from beneath Earth surface, pushed down or pushing up from ocean floor – Forms rocks, mountains and valleys Hutton and Geological Change

Rocks, mountains and valleys are shaped by rain, wind, heat and cold temperatures These are formed VERY slowly (over millions of years) Hutton proposed that Earth has to be millions of years old Hutton and Geological Change

1830: Charles Lyell publishes Principles of Geology Scientists have to explain events based on what can be SEEN or STUDIED Volcanoes still erupt, erosion still carves out canyons just like millions of years ago Lyell’s Principles of Geology

Lyell helped explain how geological features can be built up or torn down over millions of years Helped Darwin understand: – If they Earth could (and does) change, why not living things? – Because the Earth takes millions of years to change, so must living things Lyell’s Principles of Geology

1809: Jean-Baptiste Lamarck published paper on “evolution” Tendency Toward Perfection – Tend to try to be complex and perfect – Continually changing to help them live better in their environment – Example: because birds WANTED to fly, their wings got bigger and better for flying Lamarck’s Evolution Hypotheses

Use and Disuse – Because living organisms want to be perfect, they could change the size/shape of organs – Example: bird-like animals used their front limbs to try to fly, so they transformed into wings If a bird doesn’t use their wings, they would get smaller and disappear Lamarck’s Evolution Hypotheses

Inheritance of Acquired Traits – Thought that characteristics living organisms gained could be passed to offspring – Example: if you lifted weights your whole life, your children would have bigger muscles too Lamarck’s Evolution Hypotheses

1798: Thomas Malthus published a book about population growth Said that if human populations grow without limits that there would not be enough food or shelter for everyone – War, Famine, and Disease control populations Population Growth