Year 13 Human Evolution

1. Year 13 Human Evolution 90719 External Achievement Standard

2. Taxonomy.. Again!1. ORDER

3. Taxonomy • Kingdom • Phylum • Class • Order • Family • Genus • Species • Animalia • Vertebrata • Mammalia • Primates • Hominidae • Homo • Sapiens • Kind • Professors • Can • Often • Fail • Good • Students

4. Why are we in these groups? • Kingdom: Animalia • Conscious, not plants or protists • Phylum: Vertebrata • Have vertebral column • Class: Mammalia • Milk feeding, live young

5. Order: Primates • Adaptations associated with arboreal (tree) life • 1. Pentadactyl limb • Five digits (most mammals have lost at some) • Bones of lower arm and leg are separate giving more mobility (most mammals have at least partly fused now) • Plantigrade foot posture where the entire foot contacts the ground • Forelimbs prehensile (can grasp objects – branches)

6. Order: Primates • 2. Eyes • Eyes face forwards • 3. Stereoscopy (3-D Vision) • Binocular vision in which the visual fields overlap • Brain receives input from both eyes to both sides of the brain giving ability to judge distance

7. Stereoscopy

8. Order: Primates • 4. Colour vision • Photoreceptors- Rods and cones on retina • Important for identifying edible fruit • 5. High Visual Acuity • Can see fine detail due to the fovea (sensitive spot on the retina with a nerve fibre per photoreceptor rather than one per group) • Precision

9. Order: Primates • 6. Well developed clavicle • Helps with weight bearing, swinging and grasping • 7. Skin • Tips of the fingers and toes have ridges which increase the sensitivity to touch • Precision • 8. Nails instead of claws • Give broad base of support for fleshy end of finger- good for grasping

10. Order: Primates • 9. Smell reduced- can not use this to track prey • 10. Highly developed balance and awareness of body in space (Proprioception/ Kinaesthetic awareness) • Essential for balance up trees, and ability to sense limb positions in space

11. Order: Primates • 11. Very large brain • Essential for processing information rapidly • 12. Reproduction • Invest greater resources in each offspring • Long gestation as young need to be developed • Carry young • Singular young • Pectoral mammary glands as young suckle in sitting position

12. Order: Primates • 13. Singular uterus

13. Order: Primates • 14. Sitting posture • Sit in an upright manner to enable head movement without affecting balance

14. Order: Primates • 15. Social life: Live in groups • Protection • Find food • Learn • Find mates • Rearing of young

15. 2. FAMILY

16. Family: Hominoids • Apes rather than monkeys (Old World Monkeys family: Cercopithecoidea) • Apes, gibbons, orangutan, chimp, gorilla, humans • Same as Cercopithecoidea as have • 2 premolar teeth in each half of each jaw • Menstrual bleeding • DIFFERENCES RELATED TO Brachiation • Swinging in Branches by arms

17. Family: HominoidsBrachiation • 1. Very powerful arms that are longer than legs • 2. Flatter chest • 3. Scapular is at the back rather than the side • 4. No tail • 5. Can supinate forearm • 6. Larger clavicle

18. Family: HominoidsBrachiation • 7. Short lumbar region of spine • 8. More highly developed brain • 9. Lower molars have a Y-5 cusp patter • 10. No sitting pads (Ischial callosities) • 11. African Apes: Knuckle walking

19. Describe how each of the following can be related to arboreal life • Ridges on the skin and fingertips • A well developed clavicle • Separate tibia and fibula • Production of single young • Long gestation period • Stereoscopic vision • Colour vision • Large brain

20. 3. Genus

21. Family to Genus… • The family of Hominoids splits into • Genus 1: Homo • Genus 2: Australopithecus

22. Genus: Homo • Large brain • More ‘human’ like Genus: Australopithecus • Bipedal • Brain significantly smaller but bigger than a chimp • Canines reduced and non protruding • Shorter • Large degree of sexual dimorphism • No evidence of stone tools but perhaps stick tools • (Now extinct)

23. Other genus: • Chimps, Bonobos- Pan • Gorilla- Gorilla • Orangutan- Ponga

24. 4. Species

25. Species: Homosapien • Bipedalism • Humans are the only primates that can stand and walk on two legs for extended periods of time

26. Species: Homosapien • Bipedalism • 1. Body • is concentrated into a narrow column above feet therefore body weight is supported by bone • 2. Skull • Foramen magnum is situated in the middle of the skull as opposed to being at the rear as in apes

27. Species: Homosapien • 3. Backbone (COG) • Has a gentle S shape to take weight directly above hips • Apes have one curve and weight is carried forward of hips

28. Species: Homosapien • 4. Short hip girdle • In quadrupedal species the hip bone is longer • Humans have a bowl shaped hip bone which is smaller • This help to transmit and carry weight better

29. Species: Homosapien • 5. Knee joints • Directly below hip girdle so can walk without swaying • When one leg is lifted, the other is only slightly out from the center of gravity so less tendency to sway • A chimp has to lean the other way to keep balanced

30. Species: Homosapien • 6. Foot • Human foot is a platform through which thrust occurs to push forward • Large big toe that points forward • Chimps foot is a prehensile structure therefore big toe points sideways • High arch in human foot to make long distance walking possible

31. Species: Homosapien • 7. Hand- Thumb • Longer • Saddle joint that allows opposition • Flexor pollicislongus flexes the tip of the thumb • Gives precision grip rather than just power grip

32. Species: Homosapien • 8. Teeth and Jaws • Teeth and jaws much smaller in humans than apes • Canines about same size in males and females of humans • Canines significantly larger in males than females of apes • Bowl shaped dental arcade in humans compared to the U shape in apes • No diastema in humans

33. Species: Homosapien • 9. Brain • HUGE • Cortex of Cerebrum is folded lots giving more volume and surface area • Gives reasoning, maths, language, artistic skills, abstract thought, imagination, perception of senses • Cerebellum is large giving good balance and muscular co ordination

34. Species: Homosapien • Speech • Development of Broca’s area giving the ability to organise sounds into meaningful sentences • Wernicke’s Area is well developed giving the ability to interpret the sounds heard

35. Questions… • 1. Discuss the importance of diet in the evolution of the primate brain (E) • 2. To which class of vertebrates to primates belong? • 3. Three important characteristics of primates that have contributed to their success are; Grasping hands, Well developed vision and Highly developed vocal communication. Explain why each of these characteristics is important for arboreal life (M) • 4. Ape and human hips, legs and feet differ frome ach other. Explain how one of these would differ between apes and humans and why it is different. Relate this to locomotion (M)

36. 5.

37. The Journey to today Australopithecines to Homo’s =] (Different genus’s!)

38. Genus: Australopithecines • (Bipedal, Brain significantly smaller but bigger than a chimp, Canines reduced and non protruding, Shorter, Large degree of sexual dimorphism, No evidence of stone tools but perhaps stick tools, Now extinct) • Earliest known pre-humans • Fossil record of 4 million to 1 million years ago • 9 species within this genus • Fossils found in Africa, mostly in the East African Rift Valley • This is an area where two tectonic plates are moving apart and volcanic activity caused the burial and fossilisation of animals including pre humans

39. Genus: Australopithecines • Fossils show that bipedalism preceded brain expansion • Giving more freedom to the hands, bipedalism paved the way for intellectual activities such as tool making • According to teeth and skull anatomy, Australopithecines can be seen as Robust or Gracile (slender) • Robust types are thought to be specialised herbivores and evolutionary side branches • Most became extinct and did not lead to humans but side branches of the evolutionary tree

40. Australopithecines Africanus • Sum up and write down what you call tell about this species by your evolutionary tree…. • Forward foramen magnum therefore considered to be bipedal • Small canines, parabolic tooth row, less protruding jaw, lack of simian shelf, and lack of diastema

41. Australopithecines Africanus

42. Australopithecus Afarensis • Sum up and write down what you call tell about this species by your evolutionary tree…. • LUCY!! • Bipedal due to features of the knee, hip, big toe and valgus angle • Primate like (primitive) due to • Strong sexual dimorphism • Small brain • Large canines • Parallel side tooth rows • Slightly curves and longer phalanges

43. Australopithecus Afarensis

44. Australopithecus Robustus and Australopithecus Boisei • Sum up and write down what you call tell about this species by your evolutionary tree…. • Both seen as ‘robust species’ • Different to A. Africanus and A. Afarensis due to • Huge flat molars (herbivores) • But smaller incisors and canines • Prominent sagittal crest* • Wide cheek bones (zygomatic arches)* • * Suggests massive temporal muscle to raise the lower jaw powerfully

45. Australopithecus Robustus and Australopithecus Boisei continued.. • Huge molars and jaw muscles, as well as small incisors and canines suggests…. (pg. 396 Study Guide)

46. Australopithecus Robustus (South Africa) and Australopithecus Boisei (East Africa) continued..

47. ArdipithecusRamidus • Sum up and write down what you call tell about this species by your evolutionary tree…. • Forward foramen magnum suggesting bipedalism • Relatively large canines • Longer arm bones than A. Afarensis

48. Australopithecus Anamensis • Who’s great greatgreatgreatgreat Grandad is this? • Sum up and write down what you call tell about this species by your evolutionary tree…. • Humerus and tibia that have been found show bipedalism • Large canines, thick enamel covering teeth

49. Australopithecus Anamensis

50. The Evolution of Bipedalism • The most important event in human evolution