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NIS - BIOLOGY. Lecture 71 – Lecture 72 – Lecture 73 Primates Ozgur Unal. List the similarities and differences you see among the primates in the pictures. Primates. All primates have a common ancestor. What is the basis for this statement?.
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NIS - BIOLOGY Lecture 71 – Lecture 72 – Lecture 73 Primates OzgurUnal
List the similarities and differences you see among the primates in the pictures. Primates • All primates have a common ancestor. • What is the basis for this statement?
Humans, apes, monkeys and lemurs belong to a group of mammals called primates. • Though primates are highly diverse, they share some general features: • Manual dexterity • Senses (eyesight) • Locomotion • Complex brains • Reproductive rate Characteristics of Primates • Manual dexterity:Primates are distinguished by their flexible hands and feet five digits on each hand and foot • The first digit on most/many primates’ hand & feet are opposable. • Anopposable first digit is set apart from the other digits What is the advantage?
Senses:Primates mostly rely on vision and less on their • sense of smell than other mammals do. • Their eyes are protected by a bony eye socket. • Eyes are at the front of their face overlapping vision called binocular vision. • What is the advantage of forward looking eyes? Characteristics of Primates • Most primates are diurnal active during the day color vision • Some primates are nocturnal active at • night black and white • Flattened faces better binocular vision • Teeth reduced in size and usually unspecialized suitable for different types of diets
Locomotion:Primates have flexible body • They rely on hind limbs for locomotion. • Most primates live in trees and have developed an exrtaordinary ability to move easily from branch to branch. • When on ground, all primates except humans walk on four limbs. • Many primates can walk upright for short distances. • They have a more upright posture compared to 4-legged animals. Characteristics of Primates
Complex brains and behavior: Primates tend to have a larger brain in relation to their body size. • Their brains have fewer areas devoted to smell and more areas devoted to vision, memory and coordinating arm and leg motion. • Many primates have problem solving abilities and well-developed social behaviors (grooming and communication). Characteristics of Primates
Reproductive rate: Most primates have fewer offspring than other animals. • Usually, one offspring at a time • Long pregnancy • Newborns are dependent on their mothers for an extended period of time this allows for the increased learning of complex social interactions • Check out Figure 16.2!! • What factors threaten some • primate population? Characteristics of Primates
Primates are large, diverse group of more than 200 living species. • Most primates are arboreal, or tree-dwelling, living in tropical or subtropical forests. • Primates that live on the ground are considered terrestrial primates. • Primates are classified into two subgroups based on characteristics of their nose, eyes and teeth: • Strepsirrhines wet nosed primates • Haplorhines dry nosed primates • The haplorhines includeanthropoids, a group of large-brained diurnal monkeys and hominoids. Primate Groups
Strepsirrhines can be identified by their large eyes and ears. • They predominantly rely on smell for hunting and social interaction. • Mostly found in Madagascar and nearby islands. • Some can be found in Asia and Africa. • Check out Table 16.1!! Strepsirrhines • Most small lemurs are nocturnal and solitary. • Only a few larges speices (Figure 16.4) are • diurnal and social.
The second group of primates include tarsiers, monkeys and apes. • The apes in turn include gibbons, orangutans, gorillas, chimpanzees and humans. Haplorhines • The tarsier is found only on Borneo and the Philippines. • Small, nocturnal creature with large eyes. • It has the ability to rotate its head 180 degrees • like an owl. • Lives in trees.
Anthropoids are generally larger than strepsirrhines and they have larger brains relative to their body size. • They are more likely to be diurnal • They have more complex social interactions. • They tend to live longer than strepsirrhines. • Anthropoids are split into two groups: • New World Monkeys (Americas) • Old World Monkeys (Africa, Asia and Europe) Haplorhines
New World Monkeys: 60 species of arboreal monkeys • New World monkeys include tamarins and marmosets they lack fingernails and opposable digits • Most of the New World monkeys are distinguished by teir prehensile tails. • A prehensile tail functions like a fifth limb. • It can graps tree branches or other objects and support a monkey’s weight Figure 16.5 Haplorhines
Old World Monkeys: Old World monkeys live in a wide variety of habitats thgourhout Asia and Africa. • There are about 80 species in this group including macaques and baboons. • They are diurnal and live in social groups. • None have prehensile tails, and some have no tails. • Most Old World monkeys have opposable digits. Haplorhines
Apes: Only a handful of ape species exist today. • Apes generally have large brains in proportion to their body size than monkeys • Longer arms than legs, barrel-shaped chest, no tails and flexible wrists • They are classified into 2 subgroups: the lesser apes and the great apes. Haplorhines • The lesser apes are the arboreal primates of the ape family. • They have the ability to walk on either 2 or 4 legs like all great apes, but they generally move from branch to branch using a hand-over-hand swinging motion called brachiation.
The great apes include orangutans, gorillas, • chimpanzees and humans. • Read the textbook as you go over each species. • Orangutans are the largest arboreal primates. • Gorillas are the largest of primates (predominantly terrestrial). • Chimpanzees and bonobos have well developed communication systems, such as body positions and gestures. • Humansare classified in a separate subcategory of hominids called hominins. • Hominins are humanlike primates that appear to be more closely related to present-day humans than they are to present day chimpanzees and bonobos. • Though many species of hominins existed on Earth, only one species survives today. Haplorhines
Most primates today are arboreal with prehensile tails, long limbs, binocular vision, brachiation and opposable digits. • Primates evolved from ground-dwelling animals that searched for food in the top branches of forest shrubbery. • Then they evolved into additional food-gathering niches in trees. • Opposable digits help them grasp • tree branches and catch insects. • The rise of flowering plants also • provided new niche opportunities. Primate Evolution
Primate Ancestors: • Genetic data suggests that the first primates probably lived 85 mya. • The earliest primate fossils Altiatlasius 60 mya • Altiatlasius was a small, nocturnal animal that ate insects and fruits using its hands and feet for grasping. Primate Evolution
Diverging Primates: • Lemurlike primates were widespread by about 50 mya and many species existed on all continents except Australia and Antarctica. • Sometime around 50 mya, the anthropoids diverged from tarsiers. • The earliest anthropoids leaped less and walked more than strepsirrhines and tarsiers. • 30-35 mya, the anthropoids had diverged and spread widely. Primate Evolution
Displacement: • Many strepsirrhines appeared to have become extinct by the end of Eocene due to change in climate or the divergence of anthropoids • The anthropoids of this time generally were larger and had bigger brains than strepsirrhines. • Today, nocturnal strepsirrhines do not interact with the diurnal anthropoids when the habitats of these two groups overlap. Primate Evolution
Monkeys: • At the end of Eocene, the monkeys appeared. • Early monkeys had larger brains than their anthropoid ancestors and their eyes were more forward looking. • They relied less on smell. • New World Monkeys diverged from the line that gave rise to Old World Monkeys sometime between 35 and 25 mya. • New World Monkeys America • Old World Monkeys Africa • How did the New World Monkeys arrive at America? Primate Evolution
Journey to South America: • Many scientists hypothesize that the New World Monkeys evolved from an isolated group of ancestral anthropoids that somehow drifted to South America from Africa. • By rafts of vegetation and soil.... • Sea levels were lower and the • continents were closer. Primate Evolution
Aegyptopithecus: • In Africa and Asia, anthropoids continued to evolve. • Many anthropoid fossils have been found at a site in present-day Egypt called the Fayum basin. • Now a desert, the Fayum was tropical when dozens of anthropoid species lived there 36-31 mya. • The largest among them was Aegyptopithecus often called the dawn ape. • This arboreal animal, which was the size of a domestic cat, was ancestral to the apes. • It might have been part of the anthropoid • line that split from the Old World monkeys • and might have given rise to orangutans, • gorillas, chimps and humans. Primate Evolution