Charles Darwin II | Biology

<!DOCTYPE html> <html lang="en" dir="ltr"> <head>  <meta http-equiv="X-UA-Compatible" content="ie=edge"> <meta charset="utf-8"> <base href="https://www.visionlearning.com"> <title>Charles Darwin II | Biology | Visionlearning</title> <link rel="canonical" href="https://www.visionlearning.com/en/library/biology/2/charles-darwin-ii/111"> <meta name="description" content="Learn about the specific mechanisms that drive natural selection and how Darwin came to understand them. It also the events that influenced his thinking on change within a species."> <meta name="keywords" content="Darwin's theory of evolution, evolution by natural selection, what is a species, how does evolution work, influences on Darwin"> <meta name="viewport" content="width=device-width, initial-scale=1.0, shrink-to-fit=no"> <meta name="msvalidate.01" content="D8E20F39AD48052260032E56DE409970"> <script type="application/ld+json"> { "@context": "http://schema.org/", "@type": "Article", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://visionlearning.com/en/library/biology/2/charles-darwin-ii/111" }, "name": "Charles Darwin II", "headline": "Charles Darwin II: Natural selection", "author": { "@type": "Person", "name": "Alfred L. Rosenberger, Ph.D." }, "datePublished": "2004-02-12 08:45:30", "dateModified": "2017-02-12T08:30:00+05:00", "image": { "@type": "ImageObject", "url": "/img/library/moduleImages/featured_image_111-23061209063155.jpg", "width": 696, "height": 464 }, "publisher": { "@type": "Organization", "name": "Visionlearning, Inc.", "logo": { "@type": "ImageObject", "url": "http://visionlearning.com/images/logo.png", "width": 278, "height": 60 } }, "description": "The second in a series discussing the work of Charles Darwin, this module takes a deeper look into the processes that led to Darwin's theory of natural selection and examines specific mechanisms that drive evolutionary change. Key points on which the idea of natural selection rests are outlined. Examples from Darwin's personal life shed light on his thinking about change within a species and the struggle for existence.", "keywords": "Darwin's theory of evolution, evolution by natural selection, what is a species, how does evolution work, influences on Darwin", "inLanguage": { "@type": "Language", "name": "English", "alternateName": "en" }, "copyrightHolder": { "@type": "Organization", "name": "Visionlearning, Inc." }, "copyrightYear": "2004"} </script> <meta property="og:url" content="https://visionlearning.com/en/library/biology/2/charles-darwin-ii/111"> <meta property="og:title" content="Charles Darwin II | Biology | Visionlearning" /> <meta property="og:type" content="website"> <meta property="og:site_name" content="Visionlearning"> <meta property="og:description" content="Learn about the specific mechanisms that drive natural selection and how Darwin came to understand them. 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aria-controls="acc-panel-hazards" aria-expanded="false"> <span class="accordion__button__label"> Hazards </span> </button> <div class="accordion__panel" id="acc-panel-hazards" data-accordion="panel" aria-labelledby="acc-button-hazards" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/earth-science/6/natural-hazards-and-risk/288">Natural Hazards and Risk</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-history" data-accordion="button" aria-controls="acc-panel-earth-history" aria-expanded="false"> <span class="accordion__button__label"> Earth History </span> </button> <div class="accordion__panel" id="acc-panel-earth-history" data-accordion="panel" aria-labelledby="acc-button-earth-history" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/earth-science/6/extinction/295">Extinction</a></li> <li><a href="/en/library/earth-science/6/mass-extinctions/294">Mass Extinctions</a></li> </ul> </div> </div> </div> <button 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<li><a href="/en/library/environmental-science/61/ecosystem-services/279">Ecosystem Services</a></li> <li><a href="/en/library/environmental-science/61/population-biology/287">Population Biology</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-cycles" data-accordion="button" aria-controls="acc-panel-earth-cycles" aria-expanded="false"> <span class="accordion__button__label"> Earth Cycles </span> </button> <div class="accordion__panel" id="acc-panel-earth-cycles" data-accordion="panel" aria-labelledby="acc-button-earth-cycles" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/the-nitrogen-cycle/98">The Nitrogen Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-carbon-cycle/95">The Carbon Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-phosphorus-cycle/197">The Phosphorus Cycle</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/environmental-science/61/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-general-science" data-accordion="button" aria-controls="acc-panel-general-science" aria-expanded="false"> <span class="accordion__button__label"> General Science </span> </button> <div class="accordion__panel" id="acc-panel-general-science" data-accordion="panel" aria-labelledby="acc-button-general-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-methods" data-accordion="button" aria-controls="acc-panel-methods" aria-expanded="false"> <span class="accordion__button__label"> Methods </span> </button> <div class="accordion__panel" id="acc-panel-methods" data-accordion="panel" aria-labelledby="acc-button-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-scientific-method/45">The Scientific Method</a></li> </ul> </div> <button class="accordion__button" id="acc-button-measurement" data-accordion="button" aria-controls="acc-panel-measurement" aria-expanded="false"> <span class="accordion__button__label"> Measurement </span> </button> <div class="accordion__panel" id="acc-panel-measurement" data-accordion="panel" aria-labelledby="acc-button-measurement" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-metric-system/47">The Metric System</a></li> </ul> </div> <button class="accordion__button" id="acc-button-physical-properties" data-accordion="button" aria-controls="acc-panel-physical-properties" aria-expanded="false"> <span class="accordion__button__label"> Physical Properties </span> </button> <div class="accordion__panel" id="acc-panel-physical-properties" data-accordion="panel" aria-labelledby="acc-button-physical-properties" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/temperature/48">Temperature</a></li> <li><a href="/en/library/general-science/3/density-and-buoyancy/37">Density and Buoyancy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-math-in-science" data-accordion="button" aria-controls="acc-panel-math-in-science" aria-expanded="false"> <span class="accordion__button__label"> Math in Science </span> </button> <div class="accordion__panel" id="acc-panel-math-in-science" data-accordion="panel" aria-labelledby="acc-button-math-in-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-equations" data-accordion="button" aria-controls="acc-panel-equations" aria-expanded="false"> <span class="accordion__button__label"> Equations </span> </button> <div class="accordion__panel" id="acc-panel-equations" data-accordion="panel" aria-labelledby="acc-button-equations" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/unit-conversion/144">Unit Conversion</a></li> <li><a href="/en/library/math-in-science/62/linear-equations/194">Linear Equations</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-i/206">Exponential Equations I</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-ii/210">Exponential Equations II</a></li> <li><a href="/en/library/math-in-science/62/scientific-notation/250">Scientific Notation</a></li> <li><a href="/en/library/math-in-science/62/measurement/257">Measurement</a></li> </ul> </div> <button class="accordion__button" id="acc-button-statistics" data-accordion="button" aria-controls="acc-panel-statistics" aria-expanded="false"> <span class="accordion__button__label"> Statistics </span> </button> <div class="accordion__panel" id="acc-panel-statistics" data-accordion="panel" aria-labelledby="acc-button-statistics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/introduction-to-descriptive-statistics/218">Introduction to Descriptive Statistics</a></li> <li><a href="/en/library/math-in-science/62/introduction-to-inferential-statistics/224">Introduction to Inferential Statistics</a></li> <li><a href="/en/library/math-in-science/62/statistical-techniques/239">Statistical Techniques</a></li> </ul> </div> <button class="accordion__button" id="acc-button-trigonometric-functions" data-accordion="button" aria-controls="acc-panel-trigonometric-functions" aria-expanded="false"> <span class="accordion__button__label"> Trigonometric Functions </span> </button> <div class="accordion__panel" id="acc-panel-trigonometric-functions" data-accordion="panel" aria-labelledby="acc-button-trigonometric-functions" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/wave-mathematics/131">Wave Mathematics</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-physics" data-accordion="button" aria-controls="acc-panel-physics" aria-expanded="false"> <span class="accordion__button__label"> Physics </span> </button> <div class="accordion__panel" id="acc-panel-physics" data-accordion="panel" aria-labelledby="acc-button-physics" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-light-and-optics" data-accordion="button" aria-controls="acc-panel-light-and-optics" aria-expanded="false"> <span class="accordion__button__label"> Light and Optics </span> </button> <div class="accordion__panel" id="acc-panel-light-and-optics" data-accordion="panel" aria-labelledby="acc-button-light-and-optics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/the-nature-of-light/132">The Nature of Light</a></li> <li><a href="/en/library/physics/24/electromagnetism-and-light/138">Electromagnetism and Light</a></li> </ul> </div> <button class="accordion__button" id="acc-button-mechanics" data-accordion="button" aria-controls="acc-panel-mechanics" aria-expanded="false"> <span class="accordion__button__label"> Mechanics </span> </button> <div class="accordion__panel" id="acc-panel-mechanics" data-accordion="panel" aria-labelledby="acc-button-mechanics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/defining-energy/199">Defining Energy</a></li> <li><a href="/en/library/physics/24/waves-and-wave-motion/102">Waves and Wave Motion</a></li> <li><a href="/en/library/physics/24/gravity/118">Gravity</a></li> <li><a href="/en/library/physics/24/thermodynamics-i/200">Thermodynamics I</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-process-of-science" data-accordion="button" aria-controls="acc-panel-process-of-science" aria-expanded="false"> <span class="accordion__button__label"> Process of Science </span> </button> <div class="accordion__panel" id="acc-panel-process-of-science" data-accordion="panel" aria-labelledby="acc-button-process-of-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-introduction" data-accordion="button" aria-controls="acc-panel-introduction" aria-expanded="false"> <span class="accordion__button__label"> Introduction </span> </button> <div class="accordion__panel" id="acc-panel-introduction" data-accordion="panel" aria-labelledby="acc-button-introduction" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-process-of-science/176">The Process of Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-the-culture-of-science" data-accordion="button" aria-controls="acc-panel-the-culture-of-science" aria-expanded="false"> <span class="accordion__button__label"> The Culture of Science </span> </button> <div class="accordion__panel" id="acc-panel-the-culture-of-science" data-accordion="panel" aria-labelledby="acc-button-the-culture-of-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-nature-of-scientific-knowledge/185">The Nature of Scientific Knowledge</a></li> <li><a href="/en/library/process-of-science/49/scientists-and-the-scientific-community/172">Scientists and the Scientific Community</a></li> <li><a href="/en/library/process-of-science/49/scientific-ethics/161">Scientific Ethics</a></li> <li><a href="/en/library/process-of-science/49/scientific-institutions-and-societies/162">Scientific Institutions and Societies</a></li> </ul> </div> <button class="accordion__button" id="acc-button-ideas-in-science" data-accordion="button" aria-controls="acc-panel-ideas-in-science" aria-expanded="false"> <span class="accordion__button__label"> Ideas in Science </span> </button> <div class="accordion__panel" id="acc-panel-ideas-in-science" data-accordion="panel" aria-labelledby="acc-button-ideas-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/theories-hypotheses-and-laws/177">Theories, Hypotheses, and Laws</a></li> <li><a href="/en/library/process-of-science/49/scientific-controversy/181">Scientific Controversy</a></li> <li><a href="/en/library/process-of-science/49/creativity-in-science/182">Creativity in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-research-methods" data-accordion="button" aria-controls="acc-panel-research-methods" aria-expanded="false"> <span class="accordion__button__label"> Research Methods </span> </button> <div class="accordion__panel" id="acc-panel-research-methods" data-accordion="panel" aria-labelledby="acc-button-research-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-practice-of-science/148">The Practice of Science</a></li> <li><a href="/en/library/process-of-science/49/experimentation-in-scientific-research/150">Experimentation in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/description-in-scientific-research/151">Description in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/comparison-in-scientific-research/152">Comparison in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/modeling-in-scientific-research/153">Modeling in Scientific Research</a></li> </ul> </div> <button class="accordion__button" id="acc-button-data" data-accordion="button" aria-controls="acc-panel-data" aria-expanded="false"> <span class="accordion__button__label"> Data </span> </button> <div class="accordion__panel" id="acc-panel-data" data-accordion="panel" aria-labelledby="acc-button-data" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/data-analysis-and-interpretation/154">Data Analysis and Interpretation</a></li> <li><a href="/en/library/process-of-science/49/uncertainty-error-and-confidence/157">Uncertainty, Error, and Confidence</a></li> <li><a href="/en/library/process-of-science/49/statistics-in-science/155">Statistics in Science</a></li> <li><a href="/en/library/process-of-science/49/using-graphs-and-visual-data-in-science/156">Using Graphs and Visual Data in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-communication" data-accordion="button" aria-controls="acc-panel-scientific-communication" aria-expanded="false"> <span class="accordion__button__label"> Scientific Communication </span> </button> <div class="accordion__panel" id="acc-panel-scientific-communication" data-accordion="panel" aria-labelledby="acc-button-scientific-communication" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/understanding-scientific-journals-and-articles/158">Understanding Scientific Journals and Articles</a></li> <li><a href="/en/library/process-of-science/49/utilizing-the-scientific-literature/173">Utilizing the Scientific Literature</a></li> <li><a href="/en/library/process-of-science/49/peer-review-in-scientific-publishing/159">Peer Review in Scientific Publishing</a></li> <li><a href="/en/library/process-of-science/49/the-how-and-why-of-scientific-meetings/186">The How and Why of Scientific Meetings</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-scientists-and-research" data-accordion="button" aria-controls="acc-panel-scientists-and-research" aria-expanded="false"> <span class="accordion__button__label"> Scientists and Research </span> </button> <div class="accordion__panel" id="acc-panel-scientists-and-research" data-accordion="panel" aria-labelledby="acc-button-scientists-and-research" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/scientists-and-research/58/from-stable-chromosomes-to-jumping-genes/184">From Stable Chromosomes to Jumping Genes</a></li> <li><a href="/en/library/scientists-and-research/58/an-elegant-experiment-to-test-the-process-of-dna-replication/187">An Elegant Experiment to Test the Process of DNA Replication</a></li> <li><a href="/en/library/scientists-and-research/58/the-founding-of-neuroscience/233">The Founding of Neuroscience</a></li> <li><a href="/en/library/scientists-and-research/58/tracking-endangered-jaguars-across-the-border/189">Tracking Endangered Jaguars across the Border</a></li> <li><a href="/en/library/scientists-and-research/58/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> <li><a href="/en/library/scientists-and-research/58/revolutionizing-medicine-with-monoclonal-antibodies/220">Revolutionizing Medicine with Monoclonal Antibodies</a></li> <li><a href="/en/library/scientists-and-research/58/uncovering-the-mysteries-of-chronic-mountain-sickness/238">Uncovering the Mysteries of Chronic Mountain Sickness</a></li> </ul> </div> <button class="accordion__button" id="acc-button-profiles-in-science" data-accordion="button" aria-controls="acc-panel-profiles-in-science" aria-expanded="false"> <span class="accordion__button__label"> Profiles in Science </span> </button> <div class="accordion__panel" id="acc-panel-profiles-in-science" data-accordion="panel" aria-labelledby="acc-button-profiles-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/luis-e.-miramontes/232">Luis E. Miramontes</a></li> <li><a href="/en/library/scientists-and-research/58/bernardo-houssay/237">Bernardo Houssay</a></li> <li><a href="/en/library/scientists-and-research/58/craig-lee/256">Craig Lee</a></li> <li><a href="/en/library/scientists-and-research/58/david-ho/241">David Ho</a></li> <li><a href="/en/library/scientists-and-research/58/louis-tompkins-wright/244">Louis Tompkins Wright</a></li> <li><a href="/en/library/scientists-and-research/58/carlos-j.-finlay/217">Carlos J. Finlay</a></li> <li><a href="/en/library/scientists-and-research/58/cecilia-payne/290">Cecilia Payne</a></li> <li><a href="/en/library/scientists-and-research/58/jazmin-scarlett/291">Jazmin Scarlett</a></li> <li><a href="/en/library/scientists-and-research/58/ramari-stewart/292">Ramari Stewart</a></li> <li><a href="/en/library/scientists-and-research/58/johnson-cerda/300">Johnson Cerda</a></li> <li><a href="/en/library/scientists-and-research/58/ellen-ochoa/201">Ellen Ochoa</a></li> <li><a href="/en/library/scientists-and-research/58/ruth-benerito/205">Ruth Benerito</a></li> <li><a href="/en/library/scientists-and-research/58/franklin-chang-díaz/219">Franklin Chang Díaz</a></li> <li><a href="/en/library/scientists-and-research/58/percy-lavon-julian/221">Percy Lavon Julian</a></li> <li><a href="/en/library/scientists-and-research/58/luis-walter-alvarez/229">Luis Walter Alvarez</a></li> <li><a href="/en/library/scientists-and-research/58/france-anne-dominic-córdova/230">France Anne-Dominic Córdova</a></li> </ul> </div> </div> </div> </div> </div> </li> <li>  <button class="button" data-toggle="dropdown">Biology </button> <div class="nav__dropdown box-shadow-1 padding-1"> <div class="accordion accordion--secondary font-size-sm"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-sub-button-biological-molecules" data-accordion="button" aria-controls="acc-sub-panel-biological-molecules" aria-expanded="false"> <span class="accordion__button__label"> Biological Molecules </span> </button> <div class="accordion__panel" id="acc-sub-panel-biological-molecules" data-accordion="panel" aria-labelledby="acc-sub-button-biological-molecules" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/carbohydrates/61">Carbohydrates</a></li> <li><a href="/en/library/biology/2/fats-and-proteins/62">Fats and Proteins</a></li> <li><a href="/en/library/biology/2/biological-proteins/243">Biological Proteins</a></li> <li><a href="/en/library/biology/2/blood-biology-i/242">Blood Biology I</a></li> <li><a href="/en/library/biology/2/lipids/207">Lipids</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-cell-biology" data-accordion="button" aria-controls="acc-sub-panel-cell-biology" aria-expanded="false"> <span class="accordion__button__label"> Cell Biology </span> </button> <div class="accordion__panel" id="acc-sub-panel-cell-biology" data-accordion="panel" aria-labelledby="acc-sub-button-cell-biology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/discovery-and-structure-of-cells/64">Discovery and Structure of Cells</a></li> <li><a href="/en/library/biology/2/respiration/285">Respiration</a></li> <li><a href="/en/library/biology/2/membranes-i/198">Membranes I</a></li> <li><a href="/en/library/biology/2/membranes-ii/204">Membranes II</a></li> <li><a href="/en/library/biology/2/cellular-organelles-i/195">Cellular Organelles I</a></li> <li><a href="/en/library/biology/2/cell-division-i/196">Cell Division I</a></li> <li><a href="/en/library/biology/2/cell-division-ii/212">Cell Division II</a></li> <li><a href="/en/library/biology/2/membranes-and-chemical-transport/106">Membranes and Chemical Transport</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-energy-in-living-systems" data-accordion="button" aria-controls="acc-sub-panel-energy-in-living-systems" aria-expanded="false"> <span class="accordion__button__label"> Energy in Living Systems </span> </button> <div class="accordion__panel" id="acc-sub-panel-energy-in-living-systems" data-accordion="panel" aria-labelledby="acc-sub-button-energy-in-living-systems" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/energy-metabolism-i/215">Energy Metabolism I</a></li> <li><a href="/en/library/biology/2/energy-metabolism-ii/225">Energy Metabolism II</a></li> <li><a href="/en/library/biology/2/photosynthesis-i/192">Photosynthesis I</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-evolutionary-biology" data-accordion="button" aria-controls="acc-sub-panel-evolutionary-biology" aria-expanded="false"> <span class="accordion__button__label"> Evolutionary Biology </span> </button> <div class="accordion__panel" id="acc-sub-panel-evolutionary-biology" data-accordion="panel" aria-labelledby="acc-sub-button-evolutionary-biology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/origins-of-life-i/226">Origins of Life I</a></li> <li><a href="/en/library/biology/2/origins-of-life-ii/227">Origins of Life II</a></li> <li><a href="/en/library/biology/2/extinction/295">Extinction</a></li> <li><a href="/en/library/biology/2/mass-extinctions/294">Mass Extinctions</a></li> <li><a href="/en/library/biology/2/charles-darwin-i/110">Charles Darwin I</a></li> <li class="current">Charles Darwin II</li> <li><a href="/en/library/biology/2/charles-darwin-iii/112">Charles Darwin III</a></li> <li><a href="/en/library/biology/2/adaptation/68">Adaptation</a></li> <li><a href="/en/library/biology/2/taxonomy-i/70">Taxonomy I</a></li> <li><a href="/en/library/biology/2/taxonomy-ii/89">Taxonomy II</a></li> <li><a href="/en/library/biology/2/introduction-to-paleoanthropology/258">Introduction to Paleoanthropology</a></li> <li><a href="/en/library/biology/2/the-piltdown-hoax/263">The Piltdown Hoax</a></li> <li><a href="/en/library/biology/2/future-of-human-evolution/259">Future of Human Evolution</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-genetics" data-accordion="button" aria-controls="acc-sub-panel-genetics" aria-expanded="false"> <span class="accordion__button__label"> Genetics </span> </button> <div class="accordion__panel" id="acc-sub-panel-genetics" data-accordion="panel" aria-labelledby="acc-sub-button-genetics" role="region"> <ul class="nav text-color-link"> 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text-color-link"> <li><a href="/en/library/biology/2/biodiversity-i/276">Biodiversity I</a></li> <li><a href="/en/library/biology/2/ecosystem-services/279">Ecosystem Services</a></li> <li><a href="/en/library/biology/2/animal-ecology/283">Animal Ecology</a></li> <li><a href="/en/library/biology/2/biodiversity-ii/281">Biodiversity II</a></li> <li><a href="/en/library/biology/2/animal-behavior/286">Animal Behavior</a></li> <li><a href="/en/library/biology/2/population-biology/287">Population Biology</a></li> <li><a href="/en/library/biology/2/trophic-ecology/293">Trophic Ecology</a></li> </ul> </div> </div> </div> </div> </li> </ul> </nav>  <div id="theTop"></div> <main id="skip-header-content"> <div class="margin-bottom-5"> <article class="container wide module"> <header class="grid grid--sidebar-right module__header"> <div class="module__header__title"> <span class="subcategory"> <strong><em>Evolutionary Biology</em></strong> </span> <h1>Charles Darwin II: <sub><em>Natural selection</em></sub></h1> <p class="byline">by Alfred L. Rosenberger, Ph.D.</p> <nav class="module__header__tabs"> <ul class="tabs-nav tabs-nav--horizontal library"> <li> <a href="/en/library/biology/2/charles-darwin-ii/111/reading" aria-current="page" >Reading</a> </li> <li> <a href="/en/library/biology/2/charles-darwin-ii/111/quiz">Quiz</a> </li> <li> <a href="/en/library/biology/2/charles-darwin-ii/111/resources">Teach with this</a> </li> </ul> </nav> </div> <script type="application/ld+json"> { "@context": "http://schema.org", "@type": "AudioObject", "contentUrl": "https://www.visionlearning.com/img/library/moduleAudio/module_111.mp3", "description": "Recording of Charles Darwin II : The second in a series discussing the work of Charles Darwin, this module takes a deeper look into the processes that led to Darwin's theory of natural selection and examines specific mechanisms that drive evolutionary change. Key points on which the idea of natural selection rests are outlined. Examples from Darwin's personal life shed light on his thinking about change within a species and the "struggle for existence."", "encodingFormat": "mp3", "name": "module_111.mp3" } </script> <div class="module_header_audio"> <div class="audio-player border border-radius"> <audio id="audio"> <source src="https://www.visionlearning.com/img/library/moduleAudio/module_111.mp3" type="audio/mpeg"> Your browser does not support the audio element. </audio> <div class="audio-player__title"> <p>Listen to this reading</p> <span class="audio-player__timestamp" id="timestamp"> 00:00 </span> </div> <div class="audio-player__controls" id="controls"> <button class="button button--icon-only" id="play-pause-button"> <span class="icon icon-play" aria-hidden="true"></span> </button> <div class="audio-player__progress" id="progress-bar" tabindex="0" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0" aria-label="Use arrow keys to forward or rewind the audio" role="slider"> <div class="audio-player__progress__fill"> <span class="audio-player__thumb"></span> </div> </div> <div class="audio-player__volume-container"> <button id="mute-button"> <span class="icon icon-volume"></span> </button> <div class="audio-player__volume" tabindex="0" aria-valuemin="0" aria-valuemax="100" aria-valuenow="100" aria-label="Use arrow keys to adjust volume" role="slider"> <div class="audio-player__volume__fill"> <span class="audio-player__thumb"></span> </div> </div> </div> </div> </div> </div> </header> <hr class="divider"/>   <div class="grid grid--sidebar-right grid--divider"> <div class="order-2 order-1--lg module__main"> <div class="narrow margin-x-auto margin-y-5"> <div class="accordion margin-bottom-5">  <button class="accordion__button" id="acc-button-key-concepts" data-accordion="button" aria-controls="acc-panel-key-concepts" aria-expanded="true" tabindex="0"> Did you know? </button> <div class="accordion__panel shown show" id="acc-panel-key-concepts" data-accordion="panel" aria-labelledby="acc-button-key-concepts" role="region"> <div class="accordion__panel__content"> <p>Did you know that Darwin's experience with his ten children fueled his thinking about evolution? He theorized that some human behaviors, such as a young child's selfishness, were based upon instincts that were adaptations. These natural differences that always exist among individuals are at the heart of the principle of natural selection as the engine of evolutionary change.</p> </div> </div>  <button class="accordion__button" id="acc-button-table-of-contents" data-accordion="button" aria-controls="acc-panel-table-of-contents" aria-expanded="false" tabindex="0"> Key concepts </button> <div class="accordion__panel" id="acc-panel-table-of-contents" data-accordion="panel" aria-labelledby="acc-button-table-of-contents" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <ul class="bulleted"><li><p>Variation within a species increases the likelihood that at least some members of a population will survive under changed environmental conditions.</p></li> <li><p>The common characteristics of individuals within a population will change over time, as those with advantageous traits will come to be most common or widespread.</p></li> <li><p>While evidence of evolution by natural selection exists, its effects cannot be predicted.</p></li></ul> </div> </div>  <button class="accordion__button" id="acc-button-terms-you-should-know" data-accordion="button" aria-controls="acc-panel-terms-you-should-know" aria-expanded="false" tabindex="0"> Terms you should know </button> <div class="accordion__panel" id="acc-panel-terms-you-should-know" data-accordion="panel" aria-labelledby="acc-button-terms-you-should-know" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <dl> <dt><a href="/en/glossary/view/population">population </a></dt> <dd> all individuals of a certain kind of plant or animal that live in a particular habitat </dd> <dt><a href="/en/glossary/view/species">species </a></dt> <dd> a distinct variety of animal or plant that can produce offspring among its kind </dd> <dt>bred </dt> <dd> (past tense and past participle of the verb breed) mated to ensure offspring of a certain kind to promote certain characteristics </dd> <dt>breed </dt> <dd> (noun) a group of related plants or animals that share most characteristics, such as a breed of dog</dd> </dl> </div> </div> </div> <hr class="border-color-dark" /> <section> <div class="container narrow"> <p>How <mark class="term" data-term="Charles Darwin" data-term-def="English naturalist and geologist born in Shrewsbury, Shropshire (1809-1882). While serving as naturalist aboard HMS Beagle, Darwin developed his theory of&hellip;" data-term-url="/en/glossary/view/Darwin%2C+Charles/4507">Charles Darwin</mark> came to understand <mark class="term" data-term="evolution" data-term-def="Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift." data-term-url="/en/glossary/view/evolution/5284">evolution</mark> is a fascinating and important story. In our <a href="/en/library/Biology/2/Charles-Darwin-I/110">Charles Darwin I</a> module, we focused on how he arrived at an alternative to the idea that each <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> was uniquely created and unchangeable. Here we look more closely at how Darwin came to propose the mechanism of evolutionary change, which he called "natural selection." <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">Natural selection</mark> is the force that promotes changes in a species over <mark class="term" data-term="generation" data-term-def="Offspring at the same step in the line of descent from a common ancestor." data-term-url="/en/glossary/view/generation/8293">generations</mark>. It is also the force that produces new species from the changes that accumulate in a <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark> over long <mark class="term" data-term="period" data-term-def="A row of elements in the periodic table." data-term-url="/en/glossary/view/period/8565">periods</mark> of time.</p> <p>Darwin learned the importance of <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark> in bits and pieces as he developed his scientific skills and credentials. He lived during one of the most interesting times, the heyday of Great Britain's Victorian era, from 1809 to 1882, when the sciences, and openness to questioning the <mark class="term" data-term="status quo" data-term-def="The existing state or condition." data-term-url="/en/glossary/view/status+quo/5290">status quo</mark>, were growing cultural forces. He had a long, productive, brilliant career, and was almost famous even before returning from his five-year voyage around the world on the H. M. S. <i>Beagle</i>. Luckily, his correspondence, diaries, and personal workbooks, as well as the writings of his relatives, friends, colleagues, and rivals, document Darwin's adult life extensively. They tell us that every facet of the man reflected his passion for the patterns of <mark class="term" data-term="evolution" data-term-def="Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift." data-term-url="/en/glossary/view/evolution/5284">evolution</mark>, its rules and consequences. Once he fully grasped how it worked, Darwin's life became so steeped in thinking about evolution that today we might call his fascination an obsession.</p> <p><section id="toc_1" class=""> <h2>Darwin builds on the ideas of others</h2></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_9918.jpg"> <img src="/img/library/modules/mid111/Image/VLObject-9918-160629090626.jpg" alt="Figure 1: The title page of Darwin's most famous book, On the Origin of Species by ^~Means of Natural Selection." /> </button> <figcaption> <p><strong>Figure 1</strong>: The title page of Darwin's most famous book, <em>On the Origin of Species by ^~Means of Natural Selection</em>.</p> </figcaption> </figure> </div> <p>Although we properly credit Darwin with being the founding father of evolutionary <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">theory</mark>, one of his own great gifts was being able to spot a good idea and synthesize information from many fields of knowledge. Darwin's success was due, in part, to having learned from others, just as the great physicist <mark class="term" data-term="Isaac Newton" data-term-def="English alchemist, physicist, astronomer and mathematician born in Woolsthorpe-by-Colsterworth, Lincolnshire (1643-1727). In 1672, Newton offered an experimental proof that light is&hellip;" data-term-url="/en/glossary/view/Isaac+Newton/3725">Isaac Newton</mark> claimed to have stood "on the shoulders of giants." </p><p>Thus, to develop the concept of <mark class="term" data-term="evolution" data-term-def="Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift." data-term-url="/en/glossary/view/evolution/5284">evolution</mark> by <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark>, Darwin did not have to invent the idea that animals and plants were adapted to their <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> because that was already recognized in the late 1700s. He did not have to buck the Biblical story of a seven-day creation because the father of modern geology, <mark class="term" data-term="Charles Lyell" data-term-def="A British geologist born in Scotland (1797-1875 CE). His most important work was <i>The Principles of Geology: An Attempt to Explain&hellip;" data-term-url="/en/glossary/view/Lyell%2C+Charles/4467">Charles Lyell</mark>, had already shown that Earth's history extended over at least millions of years, not the thousands implied by the Bible. Darwin did not even have to come up with the idea of natural selection by himself – it was inspired by someone else! Another Englishman, <mark class="term" data-term="Thomas Robert Malthus" data-term-def="English ordained minister and economist born in Dorking, Surrey (1766-1834). In 1798 he published his <i>Essay on Population</i>, suggesting that a&hellip;" data-term-url="/en/glossary/view/Malthus%2C+Thomas+Robert/4554">Thomas Robert Malthus</mark>, who was a clergyman and an economist, wrote <em>Essay on the <mark class="term" data-term="principle" data-term-def="In the sciences, a principle is a fundamental, primary, or general law or truth. For instance, one of the most basic&hellip;" data-term-url="/en/glossary/view/principle/5289">Principle</mark> of Population</em> in 1798. Malthus argued (from an economic standpoint) that human <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark> growth, if it were not reigned in by disease, starvation, war, and other factors, would naturally expand beyond our capacity to produce the food we need to sustain it. In other words, societies of people also are locked in a "struggle for existence." In his autobiography, <mark class="term" data-term="Charles Darwin" data-term-def="English naturalist and geologist born in Shrewsbury, Shropshire (1809-1882). While serving as naturalist aboard HMS Beagle, Darwin developed his theory of&hellip;" data-term-url="/en/glossary/view/Darwin%2C+Charles/4507">Charles Darwin</mark> acknowledges this thought as the beginnings of natural selection:</p><blockquote><p> <p>In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on <em>Population</em>, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work.</p> <p align="right"> Charles Darwin, 1876</p> </p></blockquote> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc5749"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Darwin is credited as being the first person to recognize that plants and animals adapt to their environment.</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-5749-0-option-a" name="quiz-option-5749" type="radio" value="True" > <span class="option__label"> <span class="screen-reader-only">a.</span> True </span> </label> <span class="quiz__response" id="response-5749-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-5749-1-option-b" name="quiz-option-5749" type="radio" value="False" > <span class="option__label"> <span class="screen-reader-only">b.</span> False </span> </label> <span class="quiz__response" id="response-5749-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_2"> <h2>Darwin learns from <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> and life experience</h2> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid111/Image/VLObject-2691-040205110254.jpg" alt="Figure 2: Down House - Charles Darwin's home and research laboratory." /> </button> <figcaption> <p><strong>Figure 2:</strong> Down House - Charles Darwin's home and research laboratory.</p> </figcaption> </figure> </div> <p>After his famous five-year voyage around the world on the <em>Beagle</em>, most of Darwin's life was spent at his home on the outskirts of London, which he used as a base of scientific operations. His efforts involved much more than writing about big ideas like <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark>. He worked hard to build his knowledge of all manners of animals and plants from the ground up, learning lessons from many diverse <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> projects that were always underway in the Darwin household. Many of them might seem small and trivial, but they left him with enormous insight and they added up to a vast body of experience that earned Darwin a great reputation among the public, as well as among scientists from many different fields. Darwin pioneered studies of barnacles, coral reefs, hybridization between <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark>, orchid fertilization, human origins, animal behavior, and other topics that are now basic to oceanography, botany, genetics, ecology, geology, and psychology.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid111/Image/VLObject-2692-040205010212.jpg" alt="Figure 3: Annie Darwin (March 2, 1841 to April 23, 1851), the second child and eldest daughter of Charles and Emma Darwin." /> </button> <figcaption> <p><strong>Figure 3:</strong> Annie Darwin (March 2, 1841 to April 23, 1851), the second child and eldest daughter of Charles and Emma Darwin.</p> </figcaption> </figure> </div> <p>With his interest in the behaviors of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark>, even Darwin's family life provided lessons about <mark class="term" data-term="evolution" data-term-def="Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift." data-term-url="/en/glossary/view/evolution/5284">evolution</mark>. While he was a doting father to all of his ten children, he also studied them carefully for clues about how nature gave way to nurture. From watching them he theorized that some human behaviors, such as a young child's selfishness, were based upon instincts that were <mark class="term" data-term="adaptation" data-term-def="A change that allows an organism to function better in a particular environment." data-term-url="/en/glossary/view/adaptation/8284">adaptations</mark>, while other behaviors were learned, shaped by culture. The death of one of his <mark class="term" data-term="daughter" data-term-def="A material that is derived from the breakdown or division of another. For example, a product of the radioactive decay of&hellip;" data-term-url="/en/glossary/view/daughter/10177">daughters</mark>, Annie, at the age of ten was also a painful reminder to Darwin that all <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> are captives of their <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> and undergo a "struggle for existence" during each <mark class="term" data-term="generation" data-term-def="Offspring at the same step in the line of descent from a common ancestor." data-term-url="/en/glossary/view/generation/8293">generation</mark>. Disease was an environmental hazard to all individuals, a potential obstacle to their success. Some individuals were better able to cope with disease than others, just as some are better able to escape predation. Some won and some lost; some grew up and others did not; some lived to have many children while others had few or none. These natural differences that always exist among individuals are at the heart of the <mark class="term" data-term="principle" data-term-def="In the sciences, a principle is a fundamental, primary, or general law or truth. For instance, one of the most basic&hellip;" data-term-url="/en/glossary/view/principle/5289">principle</mark> of <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark> as the engine of evolutionary change.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc5750"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">In Darwin's family life, he found</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-5750-0-option-a" name="quiz-option-5750" type="radio" value="lessons about evolution as he studied his children's behavior." > <span class="option__label"> <span class="screen-reader-only">a.</span> lessons about evolution as he studied his children's behavior. </span> </label> <span class="quiz__response" id="response-5750-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-5750-1-option-b" name="quiz-option-5750" type="radio" value="no connection to his ideas about evolution and the "struggle for survival."" > <span class="option__label"> <span class="screen-reader-only">b.</span> no connection to his ideas about evolution and the "struggle for survival." </span> </label> <span class="quiz__response" id="response-5750-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_3"> <h2>Fundamentals of natural selection</h2><p>The idea of <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark> rests on several key points:</p><ul class="bulleted"> <li>More individuals are born to a <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> in every <mark class="term" data-term="generation" data-term-def="Offspring at the same step in the line of descent from a common ancestor." data-term-url="/en/glossary/view/generation/8293">generation</mark> than actually live to reproduce.</li> <li>All individuals differ in structure and behavior, and many of these variations are <mark class="term" data-term="inherited" data-term-def="Passed down from one generation to another generation." data-term-url="/en/glossary/view/inherited/8738">inherited</mark>.</li> <li>Some individuals have a greater ability to survive and reproduce than do others because their inherited <mark class="term" data-term="trait" data-term-def="A specific characteristic that is genetically determined." data-term-url="/en/glossary/view/trait/8271">traits</mark> are better adapted to the conditions of the <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> than the other traits present in different individuals of the same <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark>.</li> <li>Because the rate at which offspring are produced in every species is greater than the rate at which the environment can provide food, shelter, and other needs, individuals who carry the advantageous traits will come to outnumber those without them, causing a shift in the common characteristics of the species over time.</li> </ul><p>That shift is a change, an evolutionary adjustment that takes place across generational time. The <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark> behind it is <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark>. Darwin chose the term because the process works much like "artificial selection," the <mark class="term" data-term="method" data-term-def="A procedure or process; a systematic way of performing a task or conducting research." data-term-url="/en/glossary/view/method/8238">methods</mark> people have long used to produce and maintain the breeds of animals and plants that we live with. Both rely on <em>differential reproduction</em> to have an effect. That is, both promote the reproduction of certain members of a <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark> with a desirable set of characteristics. For example, dogs are commonly bred to be protective but not overly aggressive. Eventually, those <mark class="term" data-term="trait" data-term-def="A specific characteristic that is genetically determined." data-term-url="/en/glossary/view/trait/8271">traits</mark> become established as key features of the breed or population.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid111/Image/VLObject-2693-040205010249.jpg" alt="Figure 4: Dogs with different traits. The collie (left) is frequently used to herd sheep and other livestock. They are bred for their thick coats, which protect them from injury and from intemperate weather while they work, and for their intelligence. The Dalmatian (middle) is similarly intelligent, and is bred for its distinctive black and white coat. The dachshund (right) is a short-legged, elongated dog, originally bred to chase rabbits and other small game living in burrows. " /> </button> <figcaption> <p><strong><strong>Figure 4:</strong> </strong>Dogs with different traits. The collie (left) is frequently used to herd sheep and other livestock. They are bred for their thick coats, which protect them from injury and from intemperate weather while they work, and for their intelligence. The Dalmatian (middle) is similarly intelligent, and is bred for its distinctive black and white coat. The dachshund (right) is a short-legged, elongated dog, originally bred to chase rabbits and other small game living in burrows. </p> <span class="credit">image ©Corel Corporation</span> </figcaption> </figure> </div> <p>Unlike <mark class="term" data-term="artificial selection" data-term-def="The process of mating certain animals or plants to intentionally pass along desirable traits to the next generation; also called selective breeding." data-term-url="/en/glossary/view/artificial+selection/11400">artificial selection</mark>, <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark> is ever present, ongoing, long-term, and utterly beyond human <mark class="term" data-term="control" data-term-def="In science, a control is a system for which the expected change or outcome is well known and is measured or&hellip;" data-term-url="/en/glossary/view/control/3801">control</mark> or prediction. After all, there is no telling what new disease might pop up to threaten a <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark>, how severe a drought might be to limit the food supply during a bad summer, or if the predator from the next valley should decide to swim the river and hunt in a new territory just when vulnerable babies are being born. At the same time, there is no telling how well a <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> can resist the disease, how many nearly starved individuals are able to travel a long distance to the next food-rich plateau, or how clever some individuals might be in protecting their kids from the new carnivore that is tracking them.</p><p>Archaeologists have shown that <mark class="term" data-term="artificial selection" data-term-def="The process of mating certain animals or plants to intentionally pass along desirable traits to the next generation; also called selective breeding." data-term-url="/en/glossary/view/artificial+selection/11400">artificial selection</mark> of animals and plants has been going on for at least 10,000 years. But Darwin knew that the Earth was far older than that – at least millions of years old – thus a lot of change can accumulate in a <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> through <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark>. In some years, food may be abundant and disease rate low, so the <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> exerts less of a "pruning" effect on individuals. A species' total <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark> size may then grow unchecked. However, this means that more individuals who are less fit for lean times will survive, and selective pressure, the forces that shape reproductive success, will be greater when conditions shift. So, it is difficult to tell what types of <mark class="term" data-term="trait" data-term-def="A specific characteristic that is genetically determined." data-term-url="/en/glossary/view/trait/8271">traits</mark> will be favored by natural selection in the long run.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc6084"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Selective pressure weeds out traits that do not help a species to</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-6084-0-option-a" name="quiz-option-6084" type="radio" value="understand its heritage." > <span class="option__label"> <span class="screen-reader-only">a.</span> understand its heritage. </span> </label> <span class="quiz__response" id="response-6084-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-6084-1-option-b" name="quiz-option-6084" type="radio" value="survive and reproduce." > <span class="option__label"> <span class="screen-reader-only">b.</span> survive and reproduce. </span> </label> <span class="quiz__response" id="response-6084-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_4"> <h2>Natural selection applied to the scientific method</h2><p>The scientific <mark class="term" data-term="method" data-term-def="A procedure or process; a systematic way of performing a task or conducting research." data-term-url="/en/glossary/view/method/8238">method</mark> has its own ways of pruning, as lesser ideas are separated from good ones that explain the <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark> in better ways. The idea of <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark> has survived many tests and challenges as progress in many fields leapt far beyond what was known in Darwin's day. One might have guessed, for example, that the <mark class="term" data-term="principle" data-term-def="In the sciences, a principle is a fundamental, primary, or general law or truth. For instance, one of the most basic&hellip;" data-term-url="/en/glossary/view/principle/5289">principle</mark> of natural selection would fail when we finally learned the basics of <mark class="term" data-term="heredity" data-term-def="The passing of genetic traits from parent to offspring." data-term-url="/en/glossary/view/heredity/8287">heredity</mark> decades after <em>Origin</em> was published: Darwin didn't have a clue how <mark class="term" data-term="trait" data-term-def="A specific characteristic that is genetically determined." data-term-url="/en/glossary/view/trait/8271">traits</mark> were passed down across the <mark class="term" data-term="generation" data-term-def="Offspring at the same step in the line of descent from a common ancestor." data-term-url="/en/glossary/view/generation/8293">generations</mark>. Yet the <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">theory</mark> still stands. For every decade that passes, it only becomes stronger as genetics, molecular biology, geology, paleontology, and other disciplines continue to explain phenomena new and old without having to invent another evolutionary mechanism to replace natural selection.</p> </div> </section> <hr class="border-color-dark" /> <footer class="module__footer"> <p class="citation"> <em> Alfred L. Rosenberger, Ph.D. “Charles Darwin II” Visionlearning Vol. BIO (4), 2004. </em> </p>  <div class="title-list" name="further"> <p class="h6 title-list__title"> Further Reading </p> <ul class="grid grid--column-2--md grid--column-3--md gap-1"> <li> <a class="no-hover-focus height-100" href="/en/library/Process-of-Science/49/Theories-Hypotheses-and-Laws/177"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_177-23061210061323.jpeg" alt="Theories, Hypotheses, and Laws"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Theories, Hypotheses, and Laws: <em>Definitions, examples, and their roles in science</em> </h2> </div> </article> </a> </li> <li> <a class="no-hover-focus height-100" href="/en/library/Biology/2/Charles-Darwin-III/112"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_112-23061209063207.jpg" alt="Charles Darwin III"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Charles Darwin III: <em>Descent with modification</em> </h2> </div> </article> </a> </li> </ul> </div> </footer> </div>   </div>  <div class="order-1 order-2--lg module__tools"> <div class="narrow margin-x-auto position-sticky-top font-size-md"> <div class="padding-2 border-radius box-shadow-1--lg"> <div class="tabs" role="tablist"> <nav> <button class="button button--icon-label" id="tab-button-in-this-module" aria-label="Table of Contents" aria-controls="tab-panel-module__tools" aria-selected="true" role="tab"> <span class="icon icon-list" aria-hidden="true"></span> <span class="button__text">Contents</span> </button> <button class="button button--icon-label" id="tab-button-toggle-terms" aria-controls="tab-panel-toggle-terms" aria-selected="false" role="tab"> <span class="icon icon-glossary-highlight"></span> <span class="button__text">Glossary Terms</span> </button> </nav> <hr class="divider" /> <div class="tabs__panel shown" id="tab-panel-module__tools" aria-labelledby="tab-button-module__tools" role="tabpanel"> <p class="font-weight-bold margin-bottom-1"> Table of Contents </p> <div class="table-of-contents" id="module-toc"> <ul> <li><a href="/en/library/biology/2/charles-darwin-ii/111#toc_1">Darwin builds on the ideas of others</a> </li> <li><a href="/en/library/biology/2/charles-darwin-ii/111#toc_2">Darwin learns from research and life experience</a> </li> <li><a href="/en/library/biology/2/charles-darwin-ii/111#toc_3">Fundamentals of natural selection</a> </li> <li><a href="/en/library/biology/2/charles-darwin-ii/111#toc_4">Natural selection applied to the scientific method</a> </li> </ul> </div> </div>   <div class="tabs__panel" id="tab-panel-toggle-terms" aria-labelledby="tab-button-toggle-terms" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="termsToggleSwitch" id="terms-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Highlight Glossary Terms </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate glossary term highlighting to easily identify key terms within the module. Once highlighted, you can click on these terms to view their definitions. </em> </p> </div> </div> </div> <div class="tabs__panel" id="tab-panel-toggle-ngss" aria-labelledby="tab-button-toggle-ngss" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="ngssToggleSwitch" id="ngss-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Show NGSS Annotations </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate NGSS annotations to easily identify NGSS standards within the module. 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