Final Exam - BIOL 1001.docx - Final Exam u2013 BIOL 1001...

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Final Exam – BIOL 1001 Lecture 9 The Class Mammalia Phylum: o Chordata Dorsal hollow nerve cord o Subphylum Vertebrata (vertebrates) Characteristics of mammals 1. Mammary glands a. Mothers produce milk for their young 2. Hair a. Heat retention; camouflage; protection 3. Differentiated teeth a. Incisors, canines, premolars, molars 15 living orders Primates o Lemus, tarsiers, monkeys and apes o Humans are a member of the ape group Derived Characteristics of Primates Primarily tree dwelling ( Arboreal) Most primates have hands and feet adapted for grasping o Flat fingernails o Skin ridges on fingers Forward looking eyes o Depth perception A fully opposable thumb A large brain and developed cerebral cortex Short jaws Living Primates There are three main clades (groups) o Lemurs o Tarsiers o Anthropoids Fossil records indicated that new and old-world monkeys split into groups 35 million years ago Lemurs and tarsiers evolved differently than anthropoids because of the split Hominoids o The other group of anthropoids o Primates that are called apes o They diverged from old-world monkeys 20-25 million years ago
Gibbons Found in southeastern Asia Brachiation o Use of arms to swim from tree to tree Orangutans They are sky o Females live in small groups and males live in solidarity Found in rain forests in Sumatra and Borneo Most of their time is spend in trees o Feet are adapted for grasping Gorillas Polygynous mating system Males are 2X larger than females o Intrasexual selection (male to male competition) Sexual dimorphism Found in roughly groups of 20 Only found in Africa Chimpanzees Live in tropical Africa Feed and sleep in trees but spend a great amount of time on the ground Intelligent, communicative, social Live in large groups Bonobos Closely related to chimps but smaller Found only in Congo Hominoids All hominoids have o Short tails o Large brains relative to body size o Complex social behavior Humans are bipedal hominoids with a large brain (Homo sapiens are 2000 000 years old) Characteristics of Humans Upright posture and bipedal locomotion Shortened jaw with reduced teeth and jaw muscles Shorter digestive tract Large brains o Sophisticated language capabilities o Symbolic thought o The manufacture and use of complex tools
The Earliest Humans Paleoanthropology o The study of human origin Discovered fossil of 25 species of extinct hominoids that are more closely related to humans Hominins o Species that are extinct but resemble humans Originated in Africa 7 million years ago 19th Century Search began for the missing link between humans and apes Assumed large brains evolved first, then upright posture Missing link should be a large-brained quadrupedal ape Early Hominis Not as Expected Many fossils found in 20 th century o Initially, hominins had small brains but probably walked upright Also, hard small bodies and larger teeth with a projecting lower jaw Sahelanthropus Tchadensis 6-7 million years old

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