Comparative Primate Anatomy The Hardware of Human Culture

We could not be us without... We could not be us without... A language to communicate with and to use for learning A language to communicate with and to use for learning An ability to make and use tools An ability to make and use tools All the abilities that standing and walking on two feet allow us All the abilities that standing and walking on two feet allow us So without understanding our anatomy, we cannot understand our culture So without understanding our anatomy, we cannot understand our culture

Comparative Hominid Anatomy Anatomically, we are very similar to apes and even to monkeys Anatomically, we are very similar to apes and even to monkeys But we are not identical: Humans are fully bipedal, for example, while chimps are not. But we are not identical: Humans are fully bipedal, for example, while chimps are not. We have two arches in our foot; chimps do not. We have two arches in our foot; chimps do not. Therefore we need to compare our own anatomy with (a) other living primates and (b) fossil hominin forms. Therefore we need to compare our own anatomy with (a) other living primates and (b) fossil hominin forms.

Overview: The Human Skeleton You do need to know some of the parts of the human skeleton You do need to know some of the parts of the human skeleton Use the online graphics (such as this) or your printed handouts Use the online graphics (such as this) or your printed handouts We make a detailed comparison of skeletal parts later We make a detailed comparison of skeletal parts later

The Roots of Culture: The Brain If culture is symbolic, then it is founded on language If culture is symbolic, then it is founded on language The source of language is located in parts of the brain The source of language is located in parts of the brain Our ability to make and use tools is also begins in the brain Our ability to make and use tools is also begins in the brain Therefore, we start by examining the parts of the brain Therefore, we start by examining the parts of the brain

Structure of the Brain: Description I You may want to switch back and forth between the description in the next two slides and the diagram that follows them in the third slide You may want to switch back and forth between the description in the next two slides and the diagram that follows them in the third slide Frontal Lobe: The lobe that allows us to think and plan ahead Frontal Lobe: The lobe that allows us to think and plan ahead Motor Cortex: The strip along the edge of the motor cortex that moves the facial muscles (lips, tongue, vocalization) and the arm, hand, and finger muscles Motor Cortex: The strip along the edge of the motor cortex that moves the facial muscles (lips, tongue, vocalization) and the arm, hand, and finger muscles Parietal Lobe: The lobe that enables us to touch and taste Parietal Lobe: The lobe that enables us to touch and taste

Structure of the Brain: Description II Occipital Lobe: The lobe of the brain that enables us to see Occipital Lobe: The lobe of the brain that enables us to see Temporal Lobe: The lobe that enables us to hear Temporal Lobe: The lobe that enables us to hear Olfactory Bulb: The part of the brain that enables us to smell Olfactory Bulb: The part of the brain that enables us to smell Supplementary Motor Cortex: The part that provides sensory feedback from an action involving the motor cortex Supplementary Motor Cortex: The part that provides sensory feedback from an action involving the motor cortex

Structure of the Brain: Diagram Structure of the Brain: Diagram Frontal Lobe and Motor Cortex: Frontal Lobe and Motor Cortex: Cognition: Thinking Ability Cognition: Thinking Ability Motor Abilities Motor Abilities Parietal Lobe: Touch and Taste Parietal Lobe: Touch and Taste Temporal Lobe: Hearing Temporal Lobe: Hearing Occipital Lobe: Vision Occipital Lobe: Vision Olfactory Bulb: Smell Olfactory Bulb: Smell

The Motor Cortex The next diagram gives a schematic view of the functions of the motor cortex or strip The next diagram gives a schematic view of the functions of the motor cortex or strip Lower part: The strip regulates the facial and oral muscles Lower part: The strip regulates the facial and oral muscles They include the tongue, the lips, the organs for vocalization, and the jaws They include the tongue, the lips, the organs for vocalization, and the jaws These are related to the language function These are related to the language function Upper part: The strip regulates the arm, the hand, and their fingers Upper part: The strip regulates the arm, the hand, and their fingers These are related to the tool manufacture and use functions. These are related to the tool manufacture and use functions.

Parts of the Brain: Motor Cortex Related to Language: Lower Part Related to Language: Lower Part Lips Lips Tongue Tongue Vocalization Vocalization Related to Tool Making and Use: Upper part Related to Tool Making and Use: Upper part Fingers and Thumb Fingers and Thumb Hand Hand Arm Arm

Language Functions of the Brain: Description I Again, you may want to move back and forth between the descriptions and the diagram that follows the descriptions Again, you may want to move back and forth between the descriptions and the diagram that follows the descriptions The language functions all occur on the left hemisphere of the brain in most humans The language functions all occur on the left hemisphere of the brain in most humans Broca’s Area functions to process the generating of speech Broca’s Area functions to process the generating of speech Notice that it is located at the base of the motor cortex, which handles the tongue, vocalization, and lip movements Notice that it is located at the base of the motor cortex, which handles the tongue, vocalization, and lip movements Wernicke’s Area functions to process the reception of speech Wernicke’s Area functions to process the reception of speech Notice its location in the temporal lobe, which processes hearing Notice its location in the temporal lobe, which processes hearing

Language Functions of the Brain: Description II The angular gyrus is the part that coordinates all the sense functions housed in the brain The angular gyrus is the part that coordinates all the sense functions housed in the brain They coordinate the senses of sight from the occipital lobe, of the touch and taste of the parietal lobe, of the smell from the olfactory lobe, and of hearing from the temporal lobe They coordinate the senses of sight from the occipital lobe, of the touch and taste of the parietal lobe, of the smell from the olfactory lobe, and of hearing from the temporal lobe If you smell the scent of a rose and visualize a rose in the mind’s eye If you smell the scent of a rose and visualize a rose in the mind’s eye Its function for language is to translate all the sensory information into the sense of hearing so we can assign meaning to speech. Its function for language is to translate all the sensory information into the sense of hearing so we can assign meaning to speech.

Parts of the Brain: Language Centers Parts of Cerebrum Frontal Lobe Frontal Lobe Motor Cortex Motor Cortex Broca’s Area Broca’s Area Temporal Lobe Temporal Lobe Auditory Cortex Auditory Cortex Wernicke’s Area Wernicke’s Area Arcuate Fasciculus Arcuate Fasciculus Parietal Lobe Parietal Lobe Occipital Lobe Occipital Lobe Angular Gyrus Angular Gyrus

Comic Relief, Anyone? (Courtesy of Geico) So easy a caveman can do it....? So easy a caveman can do it....?

So Why Do We Pick on the Bones? With few exceptions bones are all we have to reconstruct past human and humanlike life forms With few exceptions bones are all we have to reconstruct past human and humanlike life forms Therefore we have to coordinate what we know about anatomy—human and nonhuman primate—to reconstruct what our ancestors might have been like. Therefore we have to coordinate what we know about anatomy—human and nonhuman primate—to reconstruct what our ancestors might have been like. Bottom Line: We rely heavily on inference to trace our ancestry Bottom Line: We rely heavily on inference to trace our ancestry

Human Skill: A Description The forehead is high, making room for the frontal lobe The forehead is high, making room for the frontal lobe The skull is rounded, allowing a greater volume for the entire brain The skull is rounded, allowing a greater volume for the entire brain There is no brow ridge or supraorbital torus There is no brow ridge or supraorbital torus The jaw does not jut forward; it is not prognathous The jaw does not jut forward; it is not prognathous

Human Skull: Bones that Cover the Lobes The bones of the skull are named after the lobes they cover The bones of the skull are named after the lobes they cover The frontal bone covers the frontal lobe The frontal bone covers the frontal lobe The parietal bone covers the parietal lobe The parietal bone covers the parietal lobe The occipital bone covers the occipital lobe The occipital bone covers the occipital lobe The temporal bone covers the temporal lobe The temporal bone covers the temporal lobe Refresh your memory: what are each of these lobes for? Refresh your memory: what are each of these lobes for?

Human Skull: The Diagram Note the following: Note the following: High forehead High forehead Rounded skull Rounded skull No brow ridge No brow ridge Chin is present Chin is present Teeth are small Teeth are small The bones are named after the lobes of the brain they cover The bones are named after the lobes of the brain they cover

Comparative Primate Anatomy: Human and Chimpanzee In the next diagrams, the differences are significant to biological capacity for culture In the next diagrams, the differences are significant to biological capacity for culture The area for brain of a chimp is more limited than human brain because of its sloping forehead and the heavy supraorbital torus that covers much of the forehead The area for brain of a chimp is more limited than human brain because of its sloping forehead and the heavy supraorbital torus that covers much of the forehead The chimp jaw has a prognathism absent in humans The chimp jaw has a prognathism absent in humans Chimps have larger canine teeth than humans; so much so that there is a diastema (gap) for the opposite canine to fit. Chimps have larger canine teeth than humans; so much so that there is a diastema (gap) for the opposite canine to fit.

Skull Morphology: Chimp and Human Note the following Note the following Larger brow ridge (supraorbital torus) of chimp compared to human Larger brow ridge (supraorbital torus) of chimp compared to human Sloping forehead of chimp compared to human Sloping forehead of chimp compared to human More prognathous (jutting) jaw of chimp compared to human More prognathous (jutting) jaw of chimp compared to human Larger canine and gap (diastema) of chimp compared to human Larger canine and gap (diastema) of chimp compared to human

Comparative Brain Structure: Human and Chimpanzee In the next diagram, the human brain has a Broca’s area for processing speech. In the next diagram, the human brain has a Broca’s area for processing speech. The chimp brain has a Brodman’s area, where calls may originate, but no speech The chimp brain has a Brodman’s area, where calls may originate, but no speech Our Wernicke’s area, which receives speech, is at the same place as the planum temporale among the chimps Our Wernicke’s area, which receives speech, is at the same place as the planum temporale among the chimps The chimp brain is much smaller than humans’—400 cubic centimeters compared with our 1400 cc. The chimp brain is much smaller than humans’—400 cubic centimeters compared with our 1400 cc. The frontal lobe of the chimp is smaller than the human’s, partly owing to the sloping forehead The frontal lobe of the chimp is smaller than the human’s, partly owing to the sloping forehead

Human and Chimp Skulls Compared: Brain Structure Compare the following Compare the following Chimp’s brain is much smaller (400cc vs. 1400cc) Chimp’s brain is much smaller (400cc vs. 1400cc) It has reduced frontal lobe It has reduced frontal lobe It has no Broca’s or Wernicke’s area It has no Broca’s or Wernicke’s area It does have Brodmann’s area 10, where calls may originate— but no speech It does have Brodmann’s area 10, where calls may originate— but no speech It does have planum temporale, where calls are received—but not processed as language It does have planum temporale, where calls are received—but not processed as language

What This All Means Our brains are larger than the chimps’ Our brains are larger than the chimps’ We have a well-developed frontal lobe We have a well-developed frontal lobe We have well developed language areas: Broca’s and Wernicke’s area We have well developed language areas: Broca’s and Wernicke’s area The motor strip is more well developed among humans than among chimps The motor strip is more well developed among humans than among chimps

Comparative Primate Anatomy: Chewing Mechanism The next diagrams compare human dentition (structure of teeth) with that of the chimps The next diagrams compare human dentition (structure of teeth) with that of the chimps Our overall dental arcade (arrangement of teeth) is more rounded (arc-like) than the chimps Our overall dental arcade (arrangement of teeth) is more rounded (arc-like) than the chimps Chimpanzee have a more rectangular dental arcade, with the back teeth more parallel Chimpanzee have a more rectangular dental arcade, with the back teeth more parallel Our teeth are much smaller than the chimps’ Our teeth are much smaller than the chimps’ We have small canines (jagged teeth) We have small canines (jagged teeth) Chimps have large canines, so large that they need a gap (diastema) in the opposite jaw for them to fit Chimps have large canines, so large that they need a gap (diastema) in the opposite jaw for them to fit

Human Dentition: Diagram For each jaw (upper or maxilla or lower or mandible: For each jaw (upper or maxilla or lower or mandible: Incisors (4) in the front for cutting food) Incisors (4) in the front for cutting food) Canines (cuspid) (2) for piercing Canines (cuspid) (2) for piercing Premolars (4) for light grinding of food Premolars (4) for light grinding of food Molars (6) in back for heavy grinding of food Molars (6) in back for heavy grinding of food

Chimp and Human Dentition Note the following: Note the following: Dental Arcade: Humans’ are arc-like; apes, parallel back teeth Dental Arcade: Humans’ are arc-like; apes, parallel back teeth Canines and Diastema (gap): Apes have larger canines and gaps in opposite jaw to fit them; humans do not Canines and Diastema (gap): Apes have larger canines and gaps in opposite jaw to fit them; humans do not

Comparative Primate Anatomy: Hand Structure Our fingers are straight; that of the chimps and other apes are curved Our fingers are straight; that of the chimps and other apes are curved We have a much longer thumb than do the apes We have a much longer thumb than do the apes Importance: we are capable of a more precise grip than the apes Importance: we are capable of a more precise grip than the apes This implies that we can make finer tools than those apes who can make and use tools This implies that we can make finer tools than those apes who can make and use tools

Human Hand Structure: Diagram Note The Following: Note The Following: Our digits are straight Our digits are straight Our thumb is opposable Our thumb is opposable The thumb is long The thumb is long

Ape and Human Hands: Diagram Hands of orangutan, chimpanzee, gorilla and human Hands of orangutan, chimpanzee, gorilla and human Note the following: Note the following: Our thumbs are longer than the others’ Our thumbs are longer than the others’ We can make a finer grip than the others can We can make a finer grip than the others can Less visible: apes’ digits are curved, ours are straight Less visible: apes’ digits are curved, ours are straight

Power and Precision Grip Note the Following: Power grip: Fingers and thumbs wrap around the object Power grip: Fingers and thumbs wrap around the object Precision grip: Forefingers and thumb hold the object Precision grip: Forefingers and thumb hold the object Importance: We can do finer work compared to nonhuman primates Importance: We can do finer work compared to nonhuman primates

Comparative Primate Anatomy: Bipedalism vs. Quadrupedalism Homo sapiens is the only mammal capable of bipedalism, or the ability to stand and walk entirely on two feet. Homo sapiens is the only mammal capable of bipedalism, or the ability to stand and walk entirely on two feet. Kangaroos stand on two feet, but they hop rather than walk and their forepaws are too small for any function. Kangaroos stand on two feet, but they hop rather than walk and their forepaws are too small for any function. Chimpanzees can walk on two feet, but not very efficiently; they are closer to quadrupedalism, or the ability to move around on four feet. Chimpanzees can walk on two feet, but not very efficiently; they are closer to quadrupedalism, or the ability to move around on four feet. What are the advantages of bipedalism over quadrupedalism. Answer the question and then look at the next slide. What are the advantages of bipedalism over quadrupedalism. Answer the question and then look at the next slide.

Advantages of Bipedalism Efficient locomotion Efficient locomotion Freeing of hands for many proposes: Freeing of hands for many proposes: Foraging and hunting/scavenging Foraging and hunting/scavenging Tool making and use Tool making and use Care and provisioning of offspring Care and provisioning of offspring Increased height for viewing across landscape: Increased height for viewing across landscape: Tracking migrating herds Tracking migrating herds Predator avoidance Predator avoidance

Bipedalism: Diagram We are the only mammals that can stand and walk on two feet We are the only mammals that can stand and walk on two feet Apes are semi-bipedal, but use their knuckles to get around (top photo) Apes are semi-bipedal, but use their knuckles to get around (top photo) The bottom photo compares the “quadrupedalism” of a human with that of a chimp The bottom photo compares the “quadrupedalism” of a human with that of a chimp Notice the human is on his knees, not just his feet Notice the human is on his knees, not just his feet The chimp is using its hind feet, not its knees. The chimp is using its hind feet, not its knees.

Comparative Human Anatomy: Locomotion You will need to make a close comparison of human and chimp anatomy in the next diagram You will need to make a close comparison of human and chimp anatomy in the next diagram Pelvis: Compare the length of the ilium of the chimp with that of the human Pelvis: Compare the length of the ilium of the chimp with that of the human Compare the arm length of the chimp with the human Compare the arm length of the chimp with the human Compare the leg bones of the chimp with the human Compare the leg bones of the chimp with the human Compare the foot structure of the chimp with the human Compare the foot structure of the chimp with the human What are the differences between each set of characteristics? Write your answers, then look at each of these characteristics in detail. What are the differences between each set of characteristics? Write your answers, then look at each of these characteristics in detail.

Chimp and Human Locomotion Compared

Vertebral Column and Pelvis Note the following: Note the following: Human vertebral column is S-shaped, supporting the upper torso Human vertebral column is S-shaped, supporting the upper torso Chimp vertebral column is bow-shaped Chimp vertebral column is bow-shaped Human pelvis, with ilium, is bowl-shaped; muscles from the thigh keep him upright Human pelvis, with ilium, is bowl-shaped; muscles from the thigh keep him upright Chimp pelvis is long, with flat ilium Chimp pelvis is long, with flat ilium

Pelvis and Femur Note the following: Note the following: Longer ilium of chimp Longer ilium of chimp Shorter, more curved ilium of human Shorter, more curved ilium of human Straight vertical orientation of chimp femurs, which do not support the upper body well Straight vertical orientation of chimp femurs, which do not support the upper body well Inward angle of human femurs, which support the upper body more efficiently Inward angle of human femurs, which support the upper body more efficiently

Foot Structure Note the following: Note the following: Large toe of chimp foot (right) is opposable to other digits Large toe of chimp foot (right) is opposable to other digits Large toe of human foot (left) is aligned with other digits Large toe of human foot (left) is aligned with other digits Ankle bones (tarsals) of human food are larger and more rigid than the chimps Ankle bones (tarsals) of human food are larger and more rigid than the chimps

Foot Arch: Longitudinal and Transverse Note the following: Note the following: Longitudinal arch that runs from the first metatarsal to the calcaneus (heel bone) Longitudinal arch that runs from the first metatarsal to the calcaneus (heel bone) Large tarsals to the rear contribute to the rigid structure of the foot and its arch Large tarsals to the rear contribute to the rigid structure of the foot and its arch Transverse arch can be inferred from lower placement of outside foot to the instep Transverse arch can be inferred from lower placement of outside foot to the instep

What We Have Learned We have learned the hardware essential to culture We have learned the hardware essential to culture They include our brain, where language and tool use originate They include our brain, where language and tool use originate We have learned about our ability to stand and walk on two feet and the importance of this ability We have learned about our ability to stand and walk on two feet and the importance of this ability We have also learned about the characteristics of ape anatomy We have also learned about the characteristics of ape anatomy This comparison gives us a clue on the next phase of this unit, human biological evolution This comparison gives us a clue on the next phase of this unit, human biological evolution