{"id":867,"date":"2018-01-18T22:16:30","date_gmt":"2018-01-18T22:16:30","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-nmbiology2\/chapter\/primates\/"},"modified":"2018-06-19T22:16:38","modified_gmt":"2018-06-19T22:16:38","slug":"primates","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/chapter\/primates\/","title":{"raw":"Primates","rendered":"Primates"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify characteristics of primates<\/li>\r\n \t<li>Describe the evolutionary history of primates<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Characteristics of Primates<\/h2>\r\nOrder <b>Primates<\/b> of class Mammalia includes lemurs, tarsiers, monkeys, apes, and humans. Non-human primates live primarily in the tropical or subtropical regions of South America, Africa, and Asia. They range in size from the mouse lemur at 30 grams (1 ounce) to the mountain gorilla at 200 kilograms (441 pounds). The characteristics and evolution of primates is of particular interest to us as it allows us to understand the evolution of our own species.\r\n\r\nAll primate species possess adaptations for climbing trees, as they all descended from tree-dwellers. This arboreal heritage of primates has resulted in hands and feet that are adapted for <b>brachiation<\/b>, or climbing and swinging through trees. These adaptations include, but are not limited to: 1) a rotating shoulder joint, 2) a big toe that is widely separated from the other toes and thumbs, which are widely separated from fingers (except humans), which allow for gripping branches, 3) <b>stereoscopic vision<\/b>, two overlapping fields of vision from the eyes, which allows for the perception of depth and gauging distance. Other characteristics of primates are brains that are larger than those of most other mammals, claws that have been modified into flattened nails, typically only one offspring per pregnancy, and a trend toward holding the body upright.\r\n\r\nOrder Primates is divided into two groups: prosimians and anthropoids. <b>Prosimians<\/b> include the bush babies of Africa, the lemurs of Madagascar, and the lorises, pottos, and tarsiers of Southeast Asia. <b>Anthropoids<\/b> include monkeys, apes, and humans. In general, prosimians tend to be nocturnal (in contrast to diurnal anthropoids) and exhibit a smaller size and smaller brain than anthropoids.\r\n<h2>Evolution of Primates<\/h2>\r\nThe first primate-like mammals are referred to as proto-primates. They were roughly similar to squirrels and tree shrews in size and appearance. The existing fossil evidence (mostly from North Africa) is very fragmented. These proto-primates remain largely mysterious creatures until more fossil evidence becomes available. The oldest known primate-like mammals with a relatively robust fossil record is <strong><em>Plesiadapis<\/em><\/strong> (although some researchers do not agree that <em>Plesiadapis<\/em> was a proto-primate). Fossils of this primate have been dated to approximately 55 million years ago. Plesiadapiforms were proto-primates that had some features of the teeth and skeleton in common with true primates. They were found in North America and Europe in the Cenozoic and went extinct by the end of the Eocene.\r\n\r\nThe first true primates were found in North America, Europe, Asia, and Africa in the Eocene Epoch. These early primates resembled present-day prosimians such as lemurs. Evolutionary changes continued in these early primates, with larger brains and eyes, and smaller muzzles being the trend. By the end of the Eocene Epoch, many of the early prosimian species went extinct due either to cooler temperatures or competition from the first monkeys.\r\n\r\n[caption id=\"attachment_2602\" align=\"alignright\" width=\"350\"]<img class=\"wp-image-2602\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18221626\/Figure_29_07_01.jpg\" alt=\"The photo shows a black monkey with its mouth open in a howl.\" width=\"350\" height=\"232\" \/> Figure 1.\u00a0The howler monkey is native to Central and South America. It makes a call that sounds like a lion roaring. (credit: Xavi Talleda)[\/caption]\r\n\r\nAnthropoid monkeys evolved from prosimians during the Oligocene Epoch. By 40 million years ago, evidence indicates that monkeys were present in the New World (South America) and the Old World (Africa and Asia). New World monkeys are also called <strong>Platyrrhini<\/strong>\u2014a reference to their broad noses (Figure 1). Old World monkeys are called <strong>Catarrhini<\/strong>\u2014a reference to their narrow noses. There is still quite a bit of uncertainty about the origins of the New World monkeys. At the time the platyrrhines arose, the continents of South American and Africa had drifted apart. Therefore, it is thought that monkeys arose in the Old World and reached the New World either by drifting on log rafts or by crossing land bridges. Due to this reproductive isolation, New World monkeys and Old World monkeys underwent separate adaptive radiations over millions of years. The New World monkeys are all arboreal, whereas Old World monkeys include arboreal and ground-dwelling species.\r\n\r\nApes evolved from the catarrhines in Africa midway through the Cenozoic, approximately 25 million years ago. Apes are generally larger than monkeys and they do not possess a tail. All apes are capable of moving through trees, although many species spend most their time on the ground. Apes are more intelligent than monkeys, and they have relatively larger brains proportionate to body size. The apes are divided into two groups. The lesser apes comprise the family <strong>Hylobatidae<\/strong>, including gibbons and siamangs. The great apes include the genera <em><strong>Pan<\/strong><\/em> (chimpanzees and bonobos) (Figure 2a), <em><strong>Gorilla<\/strong><\/em> (gorillas), <em><strong>Pongo<\/strong><\/em> (orangutans), and <em><strong>Homo<\/strong><\/em> (humans) (Figure 2b). The very arboreal gibbons are smaller than the great apes; they have low sexual dimorphism (that is, the sexes are not markedly different in size); and they have relatively longer arms used for swinging through trees.\r\n\r\n[caption id=\"attachment_2603\" align=\"aligncenter\" width=\"1024\"]<img class=\"size-large wp-image-2603\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18221628\/Figure_29_07_02ab-1024x341.jpg\" alt=\"Part a shows a chimpanzee. Part b shows the skeletons of a gibbon, human, chimpanzee, gorilla, and orangutan. The skeletons are very similar and vary in the length of the limbs, posture, and shape and size of the head.\" width=\"1024\" height=\"341\" \/> Figure 2.\u00a0The (a) chimpanzee is one of the great apes. It possesses a relatively large brain and has no tail. (b) All great apes have a similar skeletal structure. (credit a: modification of work by Aaron Logan; credit b: modification of work by Tim Vickers)[\/caption]","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify characteristics of primates<\/li>\n<li>Describe the evolutionary history of primates<\/li>\n<\/ul>\n<\/div>\n<h2>Characteristics of Primates<\/h2>\n<p>Order <b>Primates<\/b> of class Mammalia includes lemurs, tarsiers, monkeys, apes, and humans. Non-human primates live primarily in the tropical or subtropical regions of South America, Africa, and Asia. They range in size from the mouse lemur at 30 grams (1 ounce) to the mountain gorilla at 200 kilograms (441 pounds). The characteristics and evolution of primates is of particular interest to us as it allows us to understand the evolution of our own species.<\/p>\n<p>All primate species possess adaptations for climbing trees, as they all descended from tree-dwellers. This arboreal heritage of primates has resulted in hands and feet that are adapted for <b>brachiation<\/b>, or climbing and swinging through trees. These adaptations include, but are not limited to: 1) a rotating shoulder joint, 2) a big toe that is widely separated from the other toes and thumbs, which are widely separated from fingers (except humans), which allow for gripping branches, 3) <b>stereoscopic vision<\/b>, two overlapping fields of vision from the eyes, which allows for the perception of depth and gauging distance. Other characteristics of primates are brains that are larger than those of most other mammals, claws that have been modified into flattened nails, typically only one offspring per pregnancy, and a trend toward holding the body upright.<\/p>\n<p>Order Primates is divided into two groups: prosimians and anthropoids. <b>Prosimians<\/b> include the bush babies of Africa, the lemurs of Madagascar, and the lorises, pottos, and tarsiers of Southeast Asia. <b>Anthropoids<\/b> include monkeys, apes, and humans. In general, prosimians tend to be nocturnal (in contrast to diurnal anthropoids) and exhibit a smaller size and smaller brain than anthropoids.<\/p>\n<h2>Evolution of Primates<\/h2>\n<p>The first primate-like mammals are referred to as proto-primates. They were roughly similar to squirrels and tree shrews in size and appearance. The existing fossil evidence (mostly from North Africa) is very fragmented. These proto-primates remain largely mysterious creatures until more fossil evidence becomes available. The oldest known primate-like mammals with a relatively robust fossil record is <strong><em>Plesiadapis<\/em><\/strong> (although some researchers do not agree that <em>Plesiadapis<\/em> was a proto-primate). Fossils of this primate have been dated to approximately 55 million years ago. Plesiadapiforms were proto-primates that had some features of the teeth and skeleton in common with true primates. They were found in North America and Europe in the Cenozoic and went extinct by the end of the Eocene.<\/p>\n<p>The first true primates were found in North America, Europe, Asia, and Africa in the Eocene Epoch. These early primates resembled present-day prosimians such as lemurs. Evolutionary changes continued in these early primates, with larger brains and eyes, and smaller muzzles being the trend. By the end of the Eocene Epoch, many of the early prosimian species went extinct due either to cooler temperatures or competition from the first monkeys.<\/p>\n<div id=\"attachment_2602\" style=\"width: 360px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2602\" class=\"wp-image-2602\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18221626\/Figure_29_07_01.jpg\" alt=\"The photo shows a black monkey with its mouth open in a howl.\" width=\"350\" height=\"232\" \/><\/p>\n<p id=\"caption-attachment-2602\" class=\"wp-caption-text\">Figure 1.\u00a0The howler monkey is native to Central and South America. It makes a call that sounds like a lion roaring. (credit: Xavi Talleda)<\/p>\n<\/div>\n<p>Anthropoid monkeys evolved from prosimians during the Oligocene Epoch. By 40 million years ago, evidence indicates that monkeys were present in the New World (South America) and the Old World (Africa and Asia). New World monkeys are also called <strong>Platyrrhini<\/strong>\u2014a reference to their broad noses (Figure 1). Old World monkeys are called <strong>Catarrhini<\/strong>\u2014a reference to their narrow noses. There is still quite a bit of uncertainty about the origins of the New World monkeys. At the time the platyrrhines arose, the continents of South American and Africa had drifted apart. Therefore, it is thought that monkeys arose in the Old World and reached the New World either by drifting on log rafts or by crossing land bridges. Due to this reproductive isolation, New World monkeys and Old World monkeys underwent separate adaptive radiations over millions of years. The New World monkeys are all arboreal, whereas Old World monkeys include arboreal and ground-dwelling species.<\/p>\n<p>Apes evolved from the catarrhines in Africa midway through the Cenozoic, approximately 25 million years ago. Apes are generally larger than monkeys and they do not possess a tail. All apes are capable of moving through trees, although many species spend most their time on the ground. Apes are more intelligent than monkeys, and they have relatively larger brains proportionate to body size. The apes are divided into two groups. The lesser apes comprise the family <strong>Hylobatidae<\/strong>, including gibbons and siamangs. The great apes include the genera <em><strong>Pan<\/strong><\/em> (chimpanzees and bonobos) (Figure 2a), <em><strong>Gorilla<\/strong><\/em> (gorillas), <em><strong>Pongo<\/strong><\/em> (orangutans), and <em><strong>Homo<\/strong><\/em> (humans) (Figure 2b). The very arboreal gibbons are smaller than the great apes; they have low sexual dimorphism (that is, the sexes are not markedly different in size); and they have relatively longer arms used for swinging through trees.<\/p>\n<div id=\"attachment_2603\" style=\"width: 1034px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2603\" class=\"size-large wp-image-2603\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2840\/2018\/01\/18221628\/Figure_29_07_02ab-1024x341.jpg\" alt=\"Part a shows a chimpanzee. Part b shows the skeletons of a gibbon, human, chimpanzee, gorilla, and orangutan. The skeletons are very similar and vary in the length of the limbs, posture, and shape and size of the head.\" width=\"1024\" height=\"341\" \/><\/p>\n<p id=\"caption-attachment-2603\" class=\"wp-caption-text\">Figure 2.\u00a0The (a) chimpanzee is one of the great apes. It possesses a relatively large brain and has no tail. (b) All great apes have a similar skeletal structure. (credit a: modification of work by Aaron Logan; credit b: modification of work by Tim Vickers)<\/p>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-867\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology. <strong>Provided by<\/strong>: OpenStax CNX. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":25,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\"}]","CANDELA_OUTCOMES_GUID":"2a4b684c-98cb-4e41-8b17-946164cc649f, 4be6677c-a239-4a8d-8486-68a477c82028, 707b3282-429a-4ecd-9c72-3b42ef7252d5","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-867","chapter","type-chapter","status-publish","hentry"],"part":798,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapters\/867","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":2,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapters\/867\/revisions"}],"predecessor-version":[{"id":1473,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapters\/867\/revisions\/1473"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/parts\/798"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapters\/867\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/wp\/v2\/media?parent=867"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/pressbooks\/v2\/chapter-type?post=867"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/wp\/v2\/contributor?post=867"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/atd-herkimer-biologyfundamentals1\/wp-json\/wp\/v2\/license?post=867"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}