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Human evolution

Human evolution. Primates. Kingdom: Animalia. Phylum: Chordata Class: Mammals Order: Primates Suborder: Anthropoidea Superfamily: Hominoidea Family: Hominidae Genus: Homo Species: sapiens. Human classification. Phylum Chordata Sub phylum Vertebrata.

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Human evolution

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  1. Human evolution

  2. Primates

  3. Kingdom:Animalia Phylum:Chordata Class: Mammals Order: Primates Suborder: Anthropoidea Superfamily: Hominoidea Family: Hominidae Genus:Homo Species:sapiens Human classification

  4. Phylum ChordataSub phylum Vertebrata • Animals with a dorsal nerve cord surrounded by bony vertebrae.

  5. Class Mammalia • Mammals suckle their young on milk secreted from mammary glands. • The have hair and sweat glands • They are homeothermic • They have a four chambered heart and a diaphragm • They have an external ear (pinna)

  6. More features of mammals • They have four different kinds of teeth – incisors, canines, premolars and molars • They are highly intelligent because they have a larger forebrain than other animals

  7. Three groups of mammals • Monotremes – lay eggs • Marsupials – carry their babies in a pouch for a large part of their development • Placental mammals – nourish their young in a uterus via a placenta

  8. Hominoidea - Superfamily (family) Hylobatidae (family) Gibbons

  9. Hominins, hominids and hominoids • Hominoids – humans, great apes (chimps and gorillas) and lesser apes (gibbons) • Hominids- humans and great apes • Hominins - humans and ancestral species

  10. Order Primates The features of primates are largely related to their arboreal (tree living) way of life.

  11. Brain size • Large and more complex than other mammals.

  12. Collar bone • Is well developed and the arms have a wide range of movement.

  13. Posture • More upright, particularly in the upper body. Associated with sitting, standing and in some cases walking.

  14. Reproduction • Usually have only one baby at a time – this baby is born well developed after a relatively long gestation period. • The mammary glands are pectoral (on the chest) so the mothers suckle their young in a sitting position.

  15. Limb joints • Bones of the lower limbs (radius and ulna, tibia and fibula) are not fused. • Primitive skeleton – has undergone less evolutionary change than other animal groups.

  16. Hands and feet • Hands and feet have five digits • Grasping hands, (not claws) with nails - both fore and hind limbs • Tips of the fingers have ridges which make them more sensitive most have opposable thumb • Plantigrade foot posture – whole foot is in contact with the ground

  17. Teeth shape and dental arrangement • Dental pattern seen in most primates, particularly in the molars. Unspecialised teeth mean primates can adopt a flexible omnivorous diet.

  18. Face shape and snout Reduced snout. Olfactory (smell) regions of brain are reduced. Smell is less important in the life of a tree-living animal than vision.

  19. Vision • Forward facing eyes which allow binocular vision – makes it easier to judge distance Colour vision and ability to see detail.

  20. Social organisation • Live in social groups where the individuals gain protection from predators, food is shared, rearing of young can be shared and individuals can learn from each other.

  21. Page 328 – fill in

  22. Main Menu APE FEATURES • Features of apes: • No tail • Rib cage is flattened • Molars have 5 cusps (monkeys have 4) • Locomotion is brachiating, knuckle-walking, or bipedalism. • Posture partly (or fully) erect… leaving the hands free The Y5 molar pattern

  23. Trends in human biological evolution A trend refers to a change over a period of time

  24. We will look at 3 trends in human biological evolution: • 1) Trends in changes linked to skull and endocranial features; • 2) Trends in changes linked to bipedalism • 3) Trends in changes to the manipulability of the hand.

  25. Differences between ape and human skulls

  26. 329 Biozone

  27. Pages 343 and 344

  28. Skull and endocranial changes

  29. Brain size • The human brain is much larger at 1400 cm3 compared to 450cm3 in apes.

  30. Brain development • The cerebral cortex is much larger in humans allowing for higher order thinking, speech and language. • The cerebellum allows for hand eye co-ordination and fine motor skills. • These are both larger and more developed than apes. cerebellum

  31. In modern humans 2 areas of the brain (cerebral cortex) have become highly developed: • Broca’s area – this is concerned with speech. It controls the muscles of the jaw, lips, tongue, soft palate and vocal chords during speech. • Wernicke’s area – this is concerned with language of comprehension and the ability to listen.

  32. Page 342

  33. Look at chimp, human and gorilla skull. Using notes, see if can identify parts.

  34. Brow ridge • Area of support for large jaw muscles and jaw bone. It is thought that when chewing occurs some stresses can be minimised with the help of the brow ridge

  35. Pelvic inlet This is the large space in the pelvis. This is much larger in humans compared to apes and other hominins This is due to larger brain size of young needed a larger opening during birth

  36. Direct comparison between human and ape skulls • Read page 263 and 264. Make a table comparing the skull anatomy of humans and apes. Also do ‘teeth’ on page 265.

  37. Trends in skeletal changes linked to bipedalism

  38. http://www.youtube.com/watch?v=l0tAQcpLILQ&feature=video_responsehttp://www.youtube.com/watch?v=l0tAQcpLILQ&feature=video_response • http://www.youtube.com/watch?v=IHi3xYS3cOs • http://www.youtube.com/watch?v=ubEi-dyVDyo • http://www.youtube.com/watch?v=qPag2gVcRe8

  39. Why did bipedalism evolve ? Mammals thought to have originated in the Permian age (225-280 million years ago), branching from primitive reptiles. Survival during time of dinosaurs indicates intelligence and development of keen senses. Once dinosaurs disappeared, mammals flourished.

  40. At end of Cretaceous period (63 million years ago) the two supercontinents, Laurasia and Gondwanaland, started breaking up and moving apart. • In the Palaeocene and Eocene, land masses started to look like they do now. Earliest primates evolved. • Shifting continents caused great changes in climate. North America and Europe became cooler and plants changed from sub-tropical vegetation to tougher trees and grasses.

  41. Changing climate and bipedalism Page 360

  42. Advantages of bipedal walking - copy • See better over greater distances – advantageous to see predators or prey. • Easy harvesting of fruit from small trees • Hands free to carry food, tools etc. • Can carry babies. – necessary when no longer hairy.

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