Presentation on theme: "Overview of Living Primates I. Primates as Mammals II. Primate Evolutionary Trends III. Primate Origin Theories IV. Specific Primate Traits V. Survey of."— Presentation transcript:
Overview of Living Primates I. Primates as Mammals II. Primate Evolutionary Trends III. Primate Origin Theories IV. Specific Primate Traits V. Survey of the Living Primates (Taxonomy)
I. Primates As Mammals A. Primates belong to one of five vertebrate classes ( Mammalia) and are one of +/- 30 placental orders B. Primates share a number of traits with other placental mammals : 1. Fur (body hair) 2. Long gestation period followed by live birth 3. Homeothermy, the ability to maintain a constant body temperature 4. Increased brain size 5. Capacity for learning and behavioral flexibility 6. Presence of the placenta in the mother
I. Primates as Mammals C. Nonhuman primates (prosimians, monkeys, and apes) fall into in two major suborders (Prosimii & Anthropoidea) D. Further divided into infraorders, families, genera, and about 190 total species
II. Primate Evolutionary Trends A. Primates retain many primitive mammalian traits and cannot be defined by one or two traits alone. B. Primates are defined by evolutionary trends that characterize the entire order to one degree or another. C. Traits we will focus on: 1. Limbs and Locomotion 2. Diet and Teeth 3. Senses and the Brain 4. Maturation and Learning Behaviors
1. Limbs & Locomotion a.Primates have a tendency towards erect posture. b.Hands and feet possess a high degree of prehensility or grasping ability. c.Features of the hands and feet include: i.5 digits on hand and feet ii.Opposable thumb/great toe iii.Tactile pads enriched with sensory nerve fibers at the ends iv.Fingernails
2. Diet and Teeth a.Primates lack dietary specialization and tend to eat a wide variety of foods. i.Some primates kill and eat small mammals. ii.Some primates are dietary specialists on leaves. iii.Most eat a combination of fruits, leaves, and insects. b.Primates are generally omnivorous and this is reflected in their generalized dentition. c.Most primates have four types of teeth: incisors, canines, premolars and molars. d.Dental formulae vary 2123, 2132, 2133, 3143, more
3. Senses and the Brain a. Color vision in all diurnal primates. Nocturnal primates lack color vision. b. Depth perception or stereoscopic vision is made possible by eyes positioned forward on the front of the face and by an incomplete cross at the optic chiasma. c. Decreased olfaction. d. Increased complexity.
4. Maturation, Learning, & Behavior a. Longer periods of gestation. b. Reduced numbers of offspring (called k- selection). c. Delayed maturation. d. Extension of the entire life span. e. Dependence on flexible, learned behavior. f. Tendency to live in social groups. g. Males are permanent members of many primate social groups. h. Regular shows of affection, play, and emotion.
III. Primate Origin Theories Two competing theories A.Arboreal Hypothesis 1.Arboreal (tree) living was the most important factor in the evolution of primates. 2.Prehensile hand is adapted to climbing in the trees. 3.A variety of foods led to the omnivorous diet and generalized dentition.
III. Primate Origin Theories B. Visual Predation Hypothesis 1.Flowering plants may have influenced primate evolution. 2.Primates may have first adapted to shrubby forest undergrowth and the lowest tiers of the forest canopy, where they captured insects through stealth. 3.Forward facing eyes enabled primates to judge distance when grabbing for insects.
IV. Specific Primate Traits A. Habitats 1. Most living nonhuman primates live in the tropical or semitropical areas of the new and old worlds. 2. Most primates are arboreal, living in forest or woodland habitats. 3. Some old world monkeys have adapted to life on the ground and gorillas and chimpanzees spend considerable time on the ground. 4. No nonhuman primate is adapted to a fully terrestrial environment; all spend some time in the trees.
V. Overview of Living Primates (Taxonomy) A. Taxonomic Naming: Binomial Nomenclature Homo sapiens; Pan paniscus; P. troglodytes B. Taxonomic Systems 1. Phenetics Based on gross morphological similarity 2. Cladistics Based on shared, derived traits 3. Evolutionary Taxonomy Shared, derived traits AND genetic similarity C. Survey of extant suborders and their families
The most primitive primates Retention of some claws Reliance on olfaction Laterally placed eyes w/postorbital bar Shorter gestation and maturation Dental specialization called the "dental comb” Presence of the tapetum lucidum Elongated snouts Strepsirhine rhinarium (wet nose) Unfused mandible Suborder Prosimii (Lemurs, Lorises, Tarsiers)
Lemurs Lemurs are found on the island of Madagascar and other islands off the coast of Africa. They became extinct elsewhere in the world. Characteristics: Larger lemurs are diurnal and eat vegetable foods: fruit, leaves, buds, and bark. Smaller lemurs are nocturnal and insectivorous (insect -feeding).
Lorises Loris are found in tropical forests and woodlands of India, Sri Lanka, southeast Asia, and Africa. Characteristics: Lorises use a climbing form of quadrupedalism. Some lorises are insectivorous; others supplement their diet with fruit, leaves, gums, and slugs. Females frequently form associations for foraging or in sharing the same sleeping nest.
Tarsiers Tarsiers are small nocturnal primates found on the islands of southeast Asia. Characteristics: Tarsiers eat insects and small vertebrates which they catch by leaping from branches. The basic social pattern appears to be a family unit consisting of a mated pair and their offspring.
Anthropoidea (Monkeys, Apes and Humans) Common traits: Larger brain and body size Reduced reliance on the sense of smell Greater degree of color vision Bony plate at the back of the eye socket Longer gestation and maturation periods Fused mandible Only has nails
Monkeys Monkeys represent about 70% of all primates Monkeys are divided into two large groups separated by geographic area as well as several million years of evolutionary history: New world monkeys (Platyrhini) Old world monkeys (Catarhini)
New World Monkeys Almost exclusively arboreal and found in southern Mexico and central and south America. Two families: Callitrichidae give birth to twins, have claws, live in families composed of a mated pair or a female and two adult males, plus the offspring. Males are involved with infant care. Some of the cebidae family possess prehensile tails and most live in groups of both sexes and all ages, or as monogamous pairs with subadults
Old World Monkeys Habitats range from tropical forests to semiarid desert to snow-covered areas in Japan and China. Characteristics: Most old world monkeys are quadrupedal and arboreal; others have adapted to life on the ground. All old world monkeys belong to one family, the Cercopithecidae, which is divided into subfamilies, the cercopithecines (terrestrial and omnivorous) and the colobines (arboreal and vegetarian).
Hominoids (Apes and Humans) Characteristics that distinguish hominoids from monkeys: Larger body size Absence of a tail Shortened trunk Long arms relative to legs (except humans) More complex behavior More complex brain and enhanced cognitive abilities Increased period of infant development and dependency
Gibbons and Siamangs Found in tropical southeast Asia. Locomotor adaptations for brachiation may be related to feeding behavior while hanging from branches. Diet is largely fruit with supplements of leaves, flowers, and insects. Basic social unit is a monogamous pair and their dependentoffspring. Males and females are territorial and delineate their territories with whoops and “songs”.
Orangutans (Pongo pygmaeus) Found in heavily forested areas of Borneo and Sumatra. Slow, cautious climbers and almost completely arboreal. Large animals (males = 200 pounds, females = 100 pounds) with pronounced sexual dimorphism. Solitary Principally frugivorous (feed-eating).
Gorillas (Gorilla gorilla) The largest of the living primates confined to forested regions of central Africa. Exhibit marked sexual dimorphism; Males can weigh up to 400 pounds, females 200 pounds. Primarily terrestrial, employing a semi-quadrupedal posture called knuckle -walking. Live in groups that consist of one large silverback male, a few adult females, and their subadult offspring.
Chimpanzees (Pan troglodytes) Found in equatorial Africa. Anatomically similar to gorillas particularly in limb proportions and upper-body shape. Locomotion includes knuckle-walking on the ground and brachiation in the trees. Eat a variety of plant and animal foods. Large communities of as many as 50 individuals.
Bonobos (Pan paniscus) Only found in an area south of the Zaire river. Their population is believed to only number a few thousand individuals. Exploit many of the same foods as chimps, including occasional small mammals. Male-female bonds constitute the societal core. Bonobo sexuality includes frequent copulations and occur throughout the female's estrous cycle.
Humans (Homo sapiens) The only living species in the family Hominidae. Characteristics: Primate heritage is evident in anatomy, genetic makeup and aspects of behavior. Human teeth are typical primate teeth. Dependence on vision for orientation to the world Flexible limbs and grasping hands Omnivorous diet Cognitive abilities are the result of dramatic increases in brain size. Bipedal
Endangered Primates Greatest challenge facing primatologists is the urgent need for conservation. Over half of all living primates are endangered and many face immediate extinction. Habitat destruction - most primates live in tropical rain forests that are being destroyed for their natural resources. Hunting of primates for their meat. Live capture for the pet trade or export to collectors.
Hunting of Primates In west Africa the most serious problem is hunting to feed the growing human population. Estimated that thousands of primates, including gorillas and chimpanzees, are killed and sold for meat every year. Primates are also killed for commercial products.
Live Capture Primates have been live captured for zoos, biomedical research, and the exotic pet trade. Live capture has declined dramatically in recent years with the implementation of the convention on trade in endangered species of wild flora and fauna (CITES) in 1973. 87 countries have signed this treaty.
Conservation Efforts Many developing countries such as Madagascar and Costa Rica have designated areas as national parks or reserves. Private organizations, such as the rain forest information center in Ecuador, have purchased land to set up biological reserves. Through conservation and educational programs, primate species may have a chance at escaping extinction.