{"id":208871,"date":"2025-04-28T07:11:26","date_gmt":"2025-04-28T07:11:26","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=208871"},"modified":"2025-04-28T07:11:28","modified_gmt":"2025-04-28T07:11:28","slug":"mass-extinctions","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/28\/mass-extinctions\/","title":{"rendered":"Mass extinctions"},"content":{"rendered":"\n<p>Mass extinctions<\/p>\n\n\n\n<p>a. cut the number of species to the few survivors left today<br>b. resulted mainly from the separation of the continents<br>c. occurred regularly, about every million years<br>d. were followed by diversification of the survivors<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>The correct answer is <strong>d. were followed by diversification of the survivors.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation:<\/h3>\n\n\n\n<p>Mass extinctions are significant events in Earth&#8217;s history where a large percentage of species across various ecosystems go extinct in a relatively short period of time, often due to catastrophic environmental changes. These extinctions have occurred five major times in the history of life on Earth, with the most famous ones including the Permian-Triassic extinction (about 252 million years ago) and the Cretaceous-Paleogene extinction (about 66 million years ago), which wiped out the non-avian dinosaurs.<\/p>\n\n\n\n<p><strong>Why d is correct:<\/strong><br>After mass extinctions, the surviving species have access to abundant, often less competitive, ecological niches. This leads to a process called <strong>adaptive radiation<\/strong>, where the survivors diversify rapidly into a wide range of species to fill these newly available niches. This diversification is driven by the relatively empty ecosystems that allow survivors to evolve into new forms and occupy various ecological roles. For example, after the extinction of the dinosaurs at the end of the Cretaceous period, mammals, which had been small and less dominant, rapidly diversified into many new forms, leading to the rise of modern mammals, including humans.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why the other options are incorrect:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>a. cut the number of species to the few survivors left today<\/strong>: While mass extinctions dramatically reduce the number of species at the time, they do not determine the number of species left today. Species diversity often rebounds after an extinction event due to diversification.<\/li>\n\n\n\n<li><strong>b. resulted mainly from the separation of the continents<\/strong>: While continental drift and the separation of landmasses have had significant impacts on evolution over long periods, mass extinctions are generally linked to more catastrophic events such as volcanic activity, asteroid impacts, or drastic climate change, not just continental separation.<\/li>\n\n\n\n<li><strong>c. occurred regularly, about every million years<\/strong>: Mass extinctions do not occur on such a regular, predictable schedule. They are rare events, separated by tens of millions of years, and their causes are typically catastrophic rather than cyclical. For instance, the last major extinction event was about 66 million years ago, and we haven&#8217;t had another comparable event since then.<\/li>\n<\/ul>\n\n\n\n<p>In summary, after each mass extinction event, survivors have the opportunity to evolve and diversify into new species, filling the ecological void left by the extinctions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Mass extinctions a. cut the number of species to the few survivors left todayb. resulted mainly from the separation of the continentsc. occurred regularly, about every million yearsd. were followed by diversification of the survivors The correct answer and explanation is : The correct answer is d. were followed by diversification of the survivors. Explanation: [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-208871","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/208871","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=208871"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/208871\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=208871"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=208871"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=208871"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}