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Primate Evolution. Vocabulary . 1. Characteristics of Primates 2. Hominoid 3. Australopithecine 4. Hominin 5. Homo p.467. . Characteristics of Primates. Opposable first digit Binocular vision Diurnal Flexible bodies All, except humans, walk on all 4 legs - PowerPoint PPT Presentation
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Primate Evolution
Vocabulary
• 1. Characteristics of Primates • 2. Hominoid • 3. Australopithecine • 4. Hominin • 5. Homo p.467
. Characteristics of Primates
• Opposable first digit• Binocular vision• Diurnal• Flexible bodies• All, except humans, walk on all 4 legs• Complex brains! Large areas devoted to vision
and memory• Fewer offspring and more time caring for them
• Humans are mammals in the order Primates. The first primates may have resembled today's tree shrews, rat-size animals with a snout, claws, and sharp front teeth. By 50 million years ago, however, primates had evolved characteristics suitable to move freely through the trees.
• The first primates were prosimians (meaning "premonkeys"). They are represented today by several types of animals, including the lemurs.
• Monkeys, along with apes and humans, are anthropoids. Monkeys evolved from the prosimians about 38 million years ago, when the weather was warm and vegetation was like that of a tropical rain forest.
• There are two types of monkeys: the New World (South America) monkeys such as the spider monkeys, which have long grasping tails and flat noses,
• and the Old World (Africa) monkeys such as the baboons, which are now ground dwellers and lack such tails.
Prehensile tails
• New world Monkeys have them, old world monkeys do not!
• What function is a prehensile tail associated with?
• tree living
2. Hominoid • All non-monkey anthropoids. • Gibbons, orangutans, chimpanzees, gorillas
and humans
• 25 million years ago fossils of hominoids appear
• Fossil evidence is not complete so DNA comparison is used to determine to ancestral path.
• Chimps are about 96% the same as humans in DNA sequences
• Ape (gibbon, gorilla, and chimpanzee) evolved later. The human lineage split from that of the apes occurred about 5 - 10 million years ago in Africa.
4. Hominin
• Humans broke away from the other apes between 8 and 5 mya.
• Hominins are the group of humans and their extinct ancestors.
• Honinins have bigger brains with more complex parts, thinner faces with a flatter surface, smaller teeth, better manual dexterity, are bipedal ( walk upright)
3. Australopithecine
• A fossil found in east central and southern Africa dated to 4.2 and 1 million years ago.
• Males were only 1.5 m tall had ape like jaws and brains but teeth and joints that were human like.
• They walked up right ( bipedal) • “Lucy” is a famous find in 1974 she is
about the size of a chimp but walked up right.
5. Homo p.467• 2.5 to 3 million years ago the genus Homo
first appeared when the environment became colder.
• Homo is the genus that included living and extinct humans.
• Homo habilis used stone tools• Homo ergaster migrated • Homo erectus used fire • Homo floresiensis the hobbit • Homo heidelbergensis brow ridges • Homo neanderthalensis built shelter extinct 30,000
years ago
Systems of primates
• The information on systems is for information only, it will not be on the test on chapter 16.
• Information about the brain size and eyes • ( binocular vision and depth perception) is
important and will be included on the test!
Nervous and Sensory• - A snout is common in animals in which a
sense of smell is of primary importance. In primates, the sense of sight is more important, and the snout has shortened considerably, allowing the eyes to move to the front of the head. This resulted in three-dimensional vision, permitting primates to make accurate judgments about the distance and the position of adjoining tree limbs.
• Primate sense of touch became also highly developed as a result of arboreal
• living. It is useful as an effective feeling and grasping mechanism to grab their insect prey, and to prevent them from falling and tumbling while moving through the trees..
Brain• By far the most outstanding characteristic
of primate evolution has been the enlargement of the brain among members of the order. Primate brains tend to be large, heavy in proportion to body weight, and very complex
2. Placentals
. Placental mammals develop within their mother’s body and are nourished by an organ called the placenta.
A primate• A primate is a member of the mammalian order
Primates, which includes prosimians, monkeys, apes, and humans. The first primates had:
1. Grasping hands and feet
2. Forward orientation of the eyes
• An opposable thumb—such as your own—stands out at an angle from the other fingers and can be bent inward toward them to hold an object.
• This gives the hand a greatly increased level of ability to manipulate objects.
• Apes, which share a common ancestor with monkeys, first appeared about 30 million years ago.
• Modern apes include gibbons, orangutans, gorillas, and chimpanzees.
• Apes have larger brains with respect to their body size than monkeys, and none of the apes have tails.
Hominds• Hominds are primates that walk upright
on two legs.
• Hominids are members of the group that led to the evolution of humans.
• According to the fossil record, hominids first appeared on Earth about 5 million to 7 million years ago.
Lucy
• How does the fossil Australopithecus called “Lucy” contribute to our understanding of hominin evolution?
• Lucy showed that walking upright came long before the development of a larger brain!
Animated reconstruction video
• http://www.youtube.com/watch?v=b1Ozky8xeFQ&feature=youtube_gdata_player
• http://www.youtube.com/watch?v=b1Ozky8xeFQ&feature=fvsr
Homo sapiens• is the only surviving species of the genus Homo.
The name Homo sapiens is from the Latin homo, meaning “man,” and sapiens, meaning “wise.”
• Homo sapiens is a newcomer to the hominid family.
• Early Homo sapiens left behind many fossils and artifacts, including the first known paintings
• The culture of humans sets us apart from all others!
Human Evolution video
• http://www.youtube.com/watch?v=ahloeBhlcYk&feature=youtube_gdata_player
Brain Parts
• Lobes
JAW• Jaw size
decreased to make room for the brain!
Other systems– These are not on Chapter 16 test!
Circulatory
• - Like the other mammals, primates have a four-chambered heart and a double-circuit circulatory system and are able to maintain a constant body temperature. The insulating covering is provided by hair, although in the humans nearly all the hair is lost, and insulation is now provided by clothing.
Digestive -• Most primates are nearly or exclusively
herbivores, but their digestive tract does not show the high degree of morphological specialization seen in many other herbivores. Even some of the smallest primates, which until recently were believed to be carnivorous, subsist on plant food. In humans the large intestine is relatively less voluminous than in apes (which are predominently plant eaters), but nevertheless, humans are surprisingly effective at digesting cellulose.
• Endocrine - Similar for all vertebrates.
Excretory• - The kidney is a major excretory organ of primates
and other vertebrates. The principal responsibility of the organ is to separate urea, toxins, and other types of waste from the blood, while water, salt, and electrolytes are maintained at an appropriate level. Due to this important role, the kidney is also involved in blood pressure and acid-base regulation in the body. Nephrons are the basic filtering units of the kidney, more than a million of them being present in a normal adult human kidney. Working together, the nephrons are able to filter blood at an impressive rate, processing the entire five-quart water content of the human circulatory system about every 45 minutes. Only a minute portion of the material passing through the kidneys is actually excreted, however, the vast majority being reabsorbed by the nephrons.
Immune -• A new study indicates that evolution of the
immune system may be directly linked to the sexual activity of a species. A comparative analysis of 41 primate species demonstrates that the most promiscuous species have naturally higher white blood cell (WBC) counts -- the first line of defense against infectious disease -- than more monogamous species. The findings strongly suggest that the most sexually-active species of primates may have evolved elevated immune systems as a defense mechanism against disease.
Musculo-skeletal• - The limbs of the primates became adapted to
swinging and leaping from branch to branch. Their hands were especially dexterous and mobile because their thumbs were opposable; that is, they closed to meet the fingertips. Therefore, these animals easily could reach out and bring food to the mouth. Claws were replaced by nails, which allowed a tree limb to be grasped and released freely. The skeleton of most mammals including primates is simplified compared to that of most reptiles, in that it has fewer bones. For example, the lower jaw consists of a single bone, rather than several.
Reproductive -• One birth at a time became the norm with
primates; it would have been difficult to care for several offspring as large as primates in trees. The period of postnatal maturation was prolonged, giving immature young an adequate length of time to learn complex behavior patterns.
Respiratory -
• Similar to all mammals, primates have a constant body temperature, an efficient respiratory system featuring a separation between the nasal and mouth cavities, an efficient four-chambered heart that prevents mixing of oxygenated and deoxygenated blood, among other characteristics.
Evolution of Mammals• The first mammals appeared about 220 million
years ago, just as the dinosaurs were evolving from thecodonts.
• It is most likely that mammals were descendants of the therapsids, an extinct order of reptiles that were probably endotherms.
• Mammals are the only vertebrates that have fur and mammary glands.
Modern Mammals
• Modern mammals other than monotremes show one of two patterns of development.
1. Marsupials. Marsupial young are born at a very immature stage and complete their development in their mother’s pouch (called a marsupium).
SC.912.L.15.10 Ch 16 Identify basic trends in hominid evolution from early ancestors six million years ago to modern humans, including brain size, jaw size, language, and manufacture of tools1. What has happened to the size of the brain over the years? _It has enlarged2. What has happened to the jaw over the years? It has gotten smaller! 3. How has language developed over the years? It has become more complex.4. How have tools been used over the years? With the opposable thumb the use has become more intricate and more detailed. 5. What adaptations do primates have that allows the use of tools? Opposable thumbs and forward facing eyes to allow for better depth perception.
