{"id":213877,"date":"2025-05-12T18:43:35","date_gmt":"2025-05-12T18:43:35","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=213877"},"modified":"2025-05-12T18:43:37","modified_gmt":"2025-05-12T18:43:37","slug":"which-statement-correctly-describes-the-role-of-chance-in-evolution","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/12\/which-statement-correctly-describes-the-role-of-chance-in-evolution\/","title":{"rendered":"Which statement correctly describes the role of chance in evolution"},"content":{"rendered":"\n

Which statement correctly describes the role of chance in evolution? (4 points)<\/strong><\/p>\n\n\n\n

Mutations result in genetic variation for natural selection to occur.<\/p>\n\n\n\n

Evolution by natural selection proceeds by an accumulation of changes that occur by chance.<\/p>\n\n\n\n

New alleles by random changes can only occur through genetic drift.<\/p>\n\n\n\n

An allele that increases evolutionary fitness cannot be lost from a population by chance occurrence.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answer:<\/strong>
Evolution by natural selection proceeds by an accumulation of changes that occur by chance.<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation (300+ words):<\/strong><\/p>\n\n\n\n

The role of chance<\/strong> in evolution is a fundamental and fascinating concept in biology. While natural selection<\/strong> is often described as a non-random process that favors traits beneficial for survival and reproduction, the raw material<\/strong> upon which natural selection acts\u2014genetic variation<\/strong>\u2014arises primarily through random<\/strong> events.<\/p>\n\n\n\n

The correct statement, “Evolution by natural selection proceeds by an accumulation of changes that occur by chance,” highlights that random mutations<\/strong>, genetic recombination<\/strong>, and random allele frequencies<\/strong> (due to processes like genetic drift<\/strong>) contribute to the genetic variation within populations. These random changes create diversity in traits, and this diversity is crucial for evolution to occur.<\/p>\n\n\n\n

Let\u2019s break this down:<\/p>\n\n\n\n

    \n
  1. Mutations<\/strong> are changes in the DNA sequence. These can be caused by errors during DNA replication or by environmental factors. Importantly, mutations occur randomly<\/strong>\u2014they are not directed toward an organism\u2019s needs.<\/li>\n\n\n\n
  2. Genetic recombination<\/strong> during meiosis (e.g., crossing over) is also a random process that shuffles genes and contributes to variation.<\/li>\n\n\n\n
  3. Genetic drift<\/strong> refers to random<\/strong> changes in allele frequencies, especially in small populations. Even beneficial alleles can be lost, and harmful alleles can increase in frequency due to chance events.<\/li>\n<\/ol>\n\n\n\n

    Thus, while natural selection<\/strong> is not a random process\u2014since it systematically favors traits that increase fitness\u2014the input<\/strong> it depends on (mutations and variation) is<\/strong> random. Evolution is a combination of random<\/strong> (chance) and non-random<\/strong> (selection) processes.<\/p>\n\n\n\n

    Let\u2019s also rule out the other options:<\/p>\n\n\n\n

      \n
    • “Mutations result in genetic variation for natural selection to occur.” \u2014 This is true<\/strong>, but it doesn\u2019t directly describe the role of chance<\/strong> in evolution.<\/li>\n\n\n\n
    • “New alleles by random changes can only occur through genetic drift.” \u2014 This is incorrect<\/strong>; new alleles arise by mutation<\/strong>, not genetic drift.<\/li>\n\n\n\n
    • “An allele that increases evolutionary fitness cannot be lost from a population by chance occurrence.” \u2014 This is false<\/strong>; even beneficial alleles can be lost due to genetic drift<\/strong>, especially in small population?<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

      Which statement correctly describes the role of chance in evolution? (4 points) Mutations result in genetic variation for natural selection to occur. Evolution by natural selection proceeds by an accumulation of changes that occur by chance. New alleles by random changes can only occur through genetic drift. An allele that increases evolutionary fitness cannot be […]<\/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-213877","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213877","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=213877"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213877\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=213877"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=213877"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=213877"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}