{"id":486,"date":"2017-08-17T07:40:06","date_gmt":"2017-08-17T07:40:06","guid":{"rendered":"http:\/\/americanboard.org\/Subjects\/biology\/?page_id=486"},"modified":"2017-10-13T04:35:37","modified_gmt":"2017-10-13T04:35:37","slug":"fossils-evolution-diversity","status":"publish","type":"page","link":"https:\/\/americanboard.org\/Subjects\/biology\/fossils-evolution-diversity\/","title":{"rendered":"Fossils, Evolution, &#038; Diversity"},"content":{"rendered":"<div class=\"twelve columns\" style=\"margin-top: 10%;\">\n<div class=\"advance\"><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/genetic-engineering\">\u2b05 Previous Lesson<\/a><a class=\"button\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/basic-science-core\">Workshop Index<\/a><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/human-body-systems\">Next Lesson \u27a1<\/a><\/div>\n<h1 id=\"title\">Fossils, Evolution, &amp; Diversity<\/h1>\n<h4>Objective<\/h4>\n<p>In this lesson, you will review genetic diversity. Scientists, regardless of their specialization, need to possess a basic level of science literacy across all disciplines. This lesson provides an overview of the major concepts pertaining to fossils, evolution, and diversity that all students of the sciences should know. The chapters that follow will focus in greater detail on these ideas.<\/p>\n<h4>Previously Covered:<\/h4>\n<ul>\n<li>Genetic information is passed from generation to generation via DNA.<\/li>\n<li>Genetic diversity is increased through sexual reproduction and changes in the genetic code, or mutations.<\/li>\n<li>Genetic diversity is advantageous for species under changing environmental conditions.<\/li>\n<\/ul>\n<section>Now we will see that genetic change is the mechanism of evolution.Fossils are the remains of once living things that were preserved in the Earth&#8217;s crust. Fossilization most often occurs when the remains of an organism become covered by sediments or volcanic ash. Metal ions and inorganic compounds in solution harden in the bones and tissues. As sediments build up, pressure is exerted on the hardening remains, solidifying them. Often the hard parts of a living organism leave an impression in the sedimentary rock that provides an imprint of their body structure. These imprints have provided valuable clues into the body styles of pre-existing plants and animals.The method by which fossils are formed also gives a clue to their relative ages. This was something determined by <abbr title=\"(1797 \u2013 1875) Considered to be the founder of modern geology through publication of his work; Principles of Geology Lyell used fossil evidence as a means to date the ages of rocks as an indicator of Earth's age He proposed that the idea that organisms remained virtually unchanged for long periods of time He became one of the biggest proponents of Charles Darwin's work relating to evolution\">Charles Lyell<\/abbr>, a geologist, and <abbr title=\"(1769-1832) promoted the idea of functional integration of organisms to support his argument against evolutionary biology; Cuvier argued that organisms did not evolve over time rather they were functionally whole in their present form Using his extensive knowledge of comparative anatomy, he began to classify animals around the theory that function determines form\">Georges Cuvier<\/abbr>, an anatomist who studied fossils. By the early 1800s, geologists and naturalists had recognized that species change over time. Darwin did not come up with the idea of evolution. His major idea was simply an explanation for how evolution might have happened: the process of <abbr title=\"the process of organisms best adapted to their environment the most likely to survive and transmit their hereditary characteristics to subsequent generations\">natural selection<\/abbr>. In fact, Darwin and a fellow named <abbr title=\"(1823-1913) Writing from the field in the mid-1850's Wallace began promoting the idea of geographic distribution as a factor in evolutionary biology Independent of Darwin, Wallace also developed the idea of natural selection Wallace wrote Darwin seeking support for this theory only to discover that they were both working on the same idea In 1858 the scientists published a joint paper on the subject Both graciously credited the other for the work that became pivotal to the understanding of evolution\">Alfred Wallace<\/abbr> developed the idea of evolution through natural selection at the same time. They presented their ideas together; however, it was Darwin\u2019s book <em>The Origin of Species<\/em> that got all the attention.<\/p>\n<table>\n<tbody>\n<tr>\n<td><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/CharlesLyell.jpg\" alt=\"Charles Lyell\" \/><\/p>\n<p class=\"figcaption\">Charles Lyell<\/p>\n<\/td>\n<td><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/Georges_Cuvier.jpg\" alt=\"Georges Cuvier\" \/><\/p>\n<p class=\"figcaption\">Georges Cuvier<\/p>\n<\/td>\n<\/tr>\n<tr>\n<td><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/wallace.jpg\" alt=\"Alfred Wallace\" \/><\/p>\n<p class=\"figcaption\">Alfred Wallace<\/p>\n<\/td>\n<td><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/darwin.jpg\" alt=\"Charles Darwin\" \/><\/p>\n<p class=\"figcaption\">Charles Darwin<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The distribution of vertebrate fossils and species played a big part in Darwin\u2019s work. The position of fossils in the geologic strata showed a progressive change from ancient to modern organisms. Fossils found in Australia resembled modern species in Australia; fossils in Africa more closely resembled modern African species. Darwin found this to be true for each of the continents he visited during the voyage of <em>The<\/em><em>Beagle<\/em>.<\/p>\n<p><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/fossil-map.gif\" alt=\"Fossil evidence for plate tectonics\" \/><\/center><\/p>\n<p class=\"figcaption\">Fossil evidence for plate tectonics<\/p>\n<p>Both Darwin and Wallace proposed that variation within a species of organisms was due to nature acting on certain characteristics to favor reproductive success for some individuals over others. Like Mendel, Darwin and Wallace knew about artificial selection, the intentional manipulation of inherited traits of plants and animals by people. They proposed that nature might act in the same way, and that over very long periods of time, species would be expected to change as a result.<\/p>\n<div class=\"figures u-pull-left\">\n<p><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/fossil-trilobite.jpg\" alt=\"Fossil trilobyte\" \/><\/p>\n<p class=\"figcaption\">Fossil trilobyte<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<p>To Darwin, survival of the fittest did not mean that the biggest and strongest organisms would live the longest. To Darwin, fitness was about reproductive success. What survived were not individuals, but characteristics that were passed from generation to generation. Characteristics that lead to greatest adaptation increase fitness. Darwin and Wallace figured out, unlike Jean Baptiste Lamarck before them, that it was species that change, not individuals.<\/p>\n<\/section>\n<\/div>\n<p>&nbsp;<\/p>\n<div class=\"twelve columns\" style=\"margin-top: -5%;\">\n<section>\n<section class=\"question\">\n<h4>Question<\/h4>\n<p>Besides Darwin, who also developed the idea of evolution through natural selection?<\/p>\n<ol>\n<li>Jean Baptiste Lamarck<\/li>\n<li>Charles Lyell<\/li>\n<li>Alfred Wallace<\/li>\n<li>George Cuvier<\/li>\n<\/ol>\n<p><a class=\"q-answer button button-primary\">Reveal Answer<\/a><\/p>\n<p class=\"q-reveal\">The correct answer is C. Wallace worked on the evolution theory at the same time as Darwin. Lamarck is considered the forerunner of evolution. Lyell was a geologist and Cuvier was an anatomist, who both studied and aged fossils.<\/p>\n<\/section>\n<section class=\"question\">\n<h4>Question<\/h4>\n<p>What was Darwin\u2019s greatest contribution to evolutionary theory?<\/p>\n<ol>\n<li>His comparative anatomy based on fossils<\/li>\n<li>His description of extinction and speciation<\/li>\n<li>His ideas about natural selection<\/li>\n<li>His system for classifying organisms based on morphology<\/li>\n<\/ol>\n<p><a class=\"q-answer button button-primary\">Reveal Answer<\/a><\/p>\n<p class=\"q-reveal\">If you selected C, you are correct! Think natural selection when you think about Darwin. Ideas about evolution were around long before Darwin.<\/p>\n<\/section>\n<p><img decoding=\"async\" class=\"u-pull-right\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/continental-drift.jpg\" alt=\"Pangaea\" \/><\/p>\n<p>The phenomenon of <abbr title=\"the theory that Earth originally had a single landmass that split and began to drift apart some 200 million years ago\">continental drift<\/abbr> also supports evolutionary theory. Earlier scientists had hypothesized about this idea, but it was <abbr title=\"(1880-1930) Wegner is credited with the ideas of continental drift and plate tectonics Examining fossil and geological evidence, Wegener thought that Earth's landforms had at one time been connected Species evidence suggested significant similarities across the expanse of the Atlantic Ocean His ideas were dismissed in support of land bridges as a solution to problem of species similarities It was not until the 1960's and further study of Earth's crust led scientists back to Wegener's theories\">Alfred Wegener<\/abbr> (1915) who outlined the theory that Earth once had one land mass, named Pangaea. This land mass split and began to drift apart around 200 million years ago. The shape of the continents and current movement of tectonic plates supports the idea of continental drift. Species that evolved more than 200 million years ago, such as conifers and reptiles, have relatively similar fossils around the world; those that evolved later, such as mammals and flowering plants, are much more diverse across the globe.<\/p>\n<div class=\"figures u-pull-left\">\n<p><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/Alfred_Wegener.jpg\" alt=\"Alfred Wegener\" \/><\/p>\n<p class=\"figcaption\">Alfred Wegener<\/p>\n<\/div>\n<p>Today we know that the incredible diversity of life on Earth is the result of subtle changes in DNA over billions of years. The favored method for creating phylogenies is via studying conserved genes, those that code for basic life functions common to all organisms.<\/p>\n<p>The way biologists keep track of all that diversity has changed over time. Long before Darwin\u2019s time, humans classified living things based on their common characteristics. Aristotle classified organisms as plant or animal, and further subdivided those groups based on appearance or whether they were found on land, in water, or in the air!<\/p>\n<p>By Darwin\u2019s day, classification was most often based on morphology or comparative anatomy. As we learned more about heritability, reproductive modes and development became important taxonomic tools. Biochemical characteristics and modes of metabolism have often been used to classify bacteria. Today, <abbr title=\"the characteristics representative of the development of an individual organism or related groups of organisms\">phylogenies<\/abbr> based on molecular genetics show us just how similar we are to all living things, despite the great diversity in life. <abbr title=\"a classification diagram used to represent phylogenetic relationships\">Cladograms<\/abbr> are a way of showing the degree of relatedness of organisms. All living things can be placed somewhere on a branch of the tree of life, as is demonstrated by the impressive <abbr title=\"the collaborative, global effort of biologists that provides organism information regarding diversity, phylogeny, and characteristics\">Tree of Life Web Project<\/abbr>.<\/p>\n<p><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/phylogenytree.jpg\" alt=\"Primate cladogram\" \/><\/center><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/Cladogram.gif\" alt=\"Insect cladogram\" \/><\/center><\/p>\n<p class=\"figcaption\">Primate and insect cladograms<\/p>\n<p>Today, living things are grouped into 3 domains: Archaea, Bacteria, and Eukarya. The two prokaryote domains, Archaea and Bacteria, are thought to have evolved from a common prokaryote ancestor, the first kind of living organism.<\/p>\n<p><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/thumb12.jpg\" alt=\"The Three Domains\" \/><\/center>There are 6 kingdoms of organisms, the two prokaryotic domains and the eukaryotic protists, fungi, plants and animals. Modern eukaryotic cells are thought to have evolved from symbioses between early eukaryotes and bacteria, which became incorporated as mitochondria and chloroplasts.<\/p>\n<p><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/thumb13.jpg\" alt=\"The Six Kingdoms\" \/><\/center>Organisms are further classified into phylum, class, order, family, genus, and species \u2013 each of which has sub-groupings. For example, the classification for humans looks something like this:<\/p>\n<p><center><img decoding=\"async\" src=\"http:\/\/americanboard.org\/Subjects\/biology\/wp-content\/uploads\/sites\/2\/2017\/08\/human-classification.jpg\" alt=\"Human classification\" \/><\/center><\/p>\n<section class=\"question\">\n<h4>Question<\/h4>\n<p>In which domain can a prokaryote be classified?<\/p>\n<ol>\n<li>Chordata<\/li>\n<li>Archaea<\/li>\n<li>Animalia<\/li>\n<li>Eukarya<\/li>\n<\/ol>\n<p><a class=\"q-answer button button-primary\">Reveal Answer<\/a><\/p>\n<p class=\"q-reveal\">If you chose B, you are correct! Choice A is a phylum, choice C is a kingdom, and choice D is domain, yet it is for eukaryotes.<\/p>\n<\/section>\n<p>By bringing together the concepts of heredity put forth by Mendel, ideas about natural selection developed by Darwin and Wallace, and our ever expanding knowledge of the genomes of living things, the modern tenets of biology point to an underling unity beneath the diversity of life on Earth today.<\/p>\n<h3>Summary<\/h3>\n<ul>\n<li>Fossils, anatomies of living things, embryonic development, and continental drift are among the evidence that supports the theory of evolution.<\/li>\n<li>Although Darwin is commonly credited for the theory of evolution, there were several people who were instrumental in the development of the theory.<\/li>\n<li>All living things fall into three domains and six kingdoms.<\/li>\n<\/ul>\n<\/section>\n<div class=\"advance\"><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/genetic-engineering\">\u2b05 Previous Lesson<\/a><a class=\"button\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/basic-science-core\">Workshop Index<\/a><a class=\"button button-primary\" href=\"http:\/\/americanboard.org\/Subjects\/biology\/human-body-systems\">Next Lesson \u27a1<\/a><\/div>\n<p><a class=\"backtotop\" href=\"#title\">Back to Top<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u2b05 Previous LessonWorkshop IndexNext Lesson \u27a1 Fossils, Evolution, &amp; Diversity Objective In this lesson, you will review genetic diversity. Scientists, regardless of their specialization, need to possess a basic level of science literacy across all disciplines. This lesson provides an overview of the major concepts pertaining to fossils, evolution, and diversity that all students of [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-486","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/pages\/486","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/comments?post=486"}],"version-history":[{"count":13,"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/pages\/486\/revisions"}],"predecessor-version":[{"id":1251,"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/pages\/486\/revisions\/1251"}],"wp:attachment":[{"href":"https:\/\/americanboard.org\/Subjects\/biology\/wp-json\/wp\/v2\/media?parent=486"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}