{"id":5593,"date":"2020-01-13T22:43:27","date_gmt":"2020-01-13T22:43:27","guid":{"rendered":"https:\/\/course.oeru.org\/eths101\/?page_id=5593"},"modified":"2020-01-13T22:43:27","modified_gmt":"2020-01-13T22:43:27","slug":"biosphere","status":"publish","type":"page","link":"https:\/\/course.oeru.org\/eths101\/learning-pathways\/earth-systems\/biosphere\/","title":{"rendered":"Biosphere"},"content":{"rendered":"<div id=\"content\" class=\"mw-body container\" role=\"main\">\n<div class=\"row\">\n<div class=\"col-md-12\">\n<div class=\"panel\">\n<div class=\"panel-body\">\n<div id=\"bodyContent\">\n<div id=\"mw-content-text\" lang=\"en\" dir=\"ltr\" class=\"mw-content-ltr\">\n<h2><span class=\"mw-headline\" id=\"Overview\">Overview<\/span><\/h2>\n<ol>\n<li>Life on earth can only live in a very thin layer.\n<\/li>\n<li>This is because the second law of thermodynamics means that all life needs a more-or-less continuous input of high grade energy (that&#8217;s what food really is).\n<\/li>\n<li>The energy almost all comes from the sun via photosynthesis, which converts carbon dioxide and water into food and oxygen.\n<\/li>\n<li>Photosynthesis only occurs where there is enough light (i.e. above ground, or in top layer of the ocean, rivers or lakes).\n<\/li>\n<li>All living things also need enough water to survive.\n<\/li>\n<li>Most life lives in shallow water or just above the ground\n<\/li>\n<li>Some food falls down into the deep ocean, so there is life there\n<\/li>\n<li>Some food is carried down into the soil so there is lots of life there as well\n<\/li>\n<li>Life doesn&#8217;t exist anywhere else on earth\n<\/li>\n<\/ol>\n<p>\n<\/p>\n<h2><span class=\"mw-headline\" id=\"Where_Life_is\">Where Life is<\/span><\/h2>\n<p>Life on earth exists in a tiny proportion of the earth &#8211; the biosphere.  Calling the biosphere a \u201csphere\u201d is bit misleading, it is really a very thin layer smeared on top of the geosphere.  Life only exists in this small volume because living organisms depend on having suitable amounts of a set of different things, and this happy combination only occurs in very restricted places.  The first and most important thing is that life needs energy in a usable form (food) because of the second law of thermodynamics, as explained in this mini-lecture.\n<\/p>\n<div class=\"panel iDevice\">\n\t<div class=\"panel-heading idevice-heading\">\n\t\t<div>\n\t\t\t<img decoding=\"async\" class=\"pedagogicalicon\" alt=\"media\" src=\"https:\/\/course.oeru.org\/eths101\/wp-content\/themes\/oeru_course\/idevices\/Icon_multimedia.png\">\n\t\t<\/div>\n\t\t<div>\n\t\t\t<h2>Biosphere 1<\/h2>\n\t\t<\/div>\n\t<\/div>\n\t<div class=\"panel-body\">\n\t\t<div class=\"col-md-12\">\n\t\t\t<\/p>\n<div class=\"plainlinks\"><iframe loading=\"lazy\" width=\"425px\" height=\"355px\" src=\"\/\/www.youtube.com\/embed\/ulKATsSAMPs?rel=0\" frameborder=\"0\" allowfullscreen=\"\"><\/iframe><\/div>\n<p>\n<\/p>\n<p>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<h2><span class=\"mw-headline\" id=\"Where_the_biosphere_is_and_why\">Where the biosphere is and why<\/span><\/h2>\n<p>So, all life needs energy in a usable form (&#8220;food&#8221;) because of the second law of thermodynamics.  Life gets this energy either directly via photosynthesis or from eating things that obtained their food from photosynthesis. The only exception that we know of is a set of interesting organisms that exploit energy stored in chemicals created geologically.  If you want more information on these, do a web search for \u201cchemoautotroph\u201d.\n<\/p>\n<p>This need to get energy from photosynthesis is the first reason that the biosphere is so small.  Photosynthesis needs light, carbon dioxide and water, so life is centred on the places where these are available together.  This is explained in this second mini-lecture\n<\/p>\n<div class=\"panel iDevice\">\n\t<div class=\"panel-heading idevice-heading\">\n\t\t<div>\n\t\t\t<img decoding=\"async\" class=\"pedagogicalicon\" alt=\"media\" src=\"https:\/\/course.oeru.org\/eths101\/wp-content\/themes\/oeru_course\/idevices\/Icon_multimedia.png\">\n\t\t<\/div>\n\t\t<div>\n\t\t\t<h2>Biosphere 2<\/h2>\n\t\t<\/div>\n\t<\/div>\n\t<div class=\"panel-body\">\n\t\t<div class=\"col-md-12\">\n\t\t\t<\/p>\n<div class=\"plainlinks\"><iframe loading=\"lazy\" width=\"425px\" height=\"355px\" src=\"\/\/www.youtube.com\/embed\/kLsOi7mRrjQ?rel=0\" frameborder=\"0\" allowfullscreen=\"\"><\/iframe><\/div>\n<p>\n<\/p>\n<p>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<p><!-- \nNewPP limit report\nCPU time usage: 0.034 seconds\nReal time usage: 0.039 seconds\nPreprocessor visited node count: 320\/1000000\nPreprocessor generated node count: 1262\/1000000\nPost\u2010expand include size: 3512\/2097152 bytes\nTemplate argument size: 460\/2097152 bytes\nHighest expansion depth: 7\/40\nExpensive parser function count: 0\/100\n--><\/p>\n<p><!-- Saved in parser cache with key we_en-mw_:pcache:idhash:185059-0!*!*!!en!2!* and timestamp 20200113224324 and revision id 1064527\n -->\n<\/div>\n<div class=\"visualClear\"><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"row\">\n<div class=\"col-md-12\">\n<ul class=\"pager\">\n<li class=\"previous\">\n            <a href=\"\/eths101\/learning-pathways\/earth-systems\/atmosphere\">\u2190 Previous<\/a>\n          <\/li>\n<li class=\"next\">\n            <a href=\"\/eths101\/learning-pathways\/earth-systems\/humansphere\">Next \u2192<\/a>\n          <\/li>\n<\/ul><\/div>\n<\/p><\/div>\n<\/div>\n<footer>\n<br \/>\n<\/footer>\n","protected":false},"excerpt":{"rendered":"<p>Overview Life on earth can only live in a very thin layer. This is because the second law of thermodynamics means that all life needs a more-or-less continuous input of high grade energy (that&#8217;s what food really is). The energy almost all comes from the sun via photosynthesis, which converts carbon dioxide and water into [&hellip;]<\/p>\n","protected":false},"author":155,"featured_media":0,"parent":5583,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-5593","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/pages\/5593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/users\/155"}],"replies":[{"embeddable":true,"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/comments?post=5593"}],"version-history":[{"count":1,"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/pages\/5593\/revisions"}],"predecessor-version":[{"id":5594,"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/pages\/5593\/revisions\/5594"}],"up":[{"embeddable":true,"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/pages\/5583"}],"wp:attachment":[{"href":"https:\/\/course.oeru.org\/eths101\/wp-json\/wp\/v2\/media?parent=5593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}