1. EvolutionEvolution Year 10 Semester 2

2. Introduction 1.How old is the universe? About 15 billion years since Big Bang. 2.How old is the Earth? About 4.5 billion years. 3.How long has there been life on the Earth? About 3.5 - 4 billion years 4.When did the separation of man and ape from a common unnamed ancestor occur? Between 5 and 10 million years ago.

3. 5.How old is the human species (Homo sapiens)? 100,000 to 200,000 years old. 6.Evolutionary theory teaches that humans evolved from monkeys. True or False? False - humans and modern monkeys had a common ancestor. 7.Pope John Paul II does not approve of the theory of evolution. True or False? False, according to book Voices for Evolution. 8.Major Protestant Churches have no problem with the theory of evolution. True or False? True, according to Voices for Evolution. Introduction

4. What do you notice about living things? Describe each of the environments in each era.

9. Common Idea…… Life, both plants and animals, have changed over time to meet the conditions of the environments they live in.

10. Adaptations Three main types: –Physiological: ? –Structural: ? –Behavioural: ? An adaptation is a characteristic of a living thing which allows it to survive in the conditions provided by its environment.

11. Evolution The modern day theory of evolution states that all living organisms share a common origin dating back more than 4 billion years. Over this period, new species have arisen and others have disappeared.

12. EVOLUTION EVOLUTION is a process of change.

13. Charles Darwin The Theory of Natural Selection 1.Variation exists within a population of organisms 2.All organisms face a daily struggle to survive 3.Those organisms with adaptations that best suit their environment have the best chance of survival & reproduction 4.Those organisms survive & reproduce to pass on their characteristics 5.Over time, the population changes to be best suited to their environment.

14. Jean Baptist Lamarck Stated that animals have some structures that they use frequently & others they do not use. The ones that are used frequently are strengthened & passed on. He also states that animals can acquire characteristics if they need them

16. How Does Evolution Work? Evolution occurs because of Natural Selection

17. Natural Selection Within a particular species, there is variation between individuals. As a result, some individuals are better adapted to their environment and are more likely to survive and reproduce. These adaptations are then passed onto the next generation. SURVIVAL OF THE FITTEST

18. Artificial Selection For thousands of years, humans have made use of two very important facts: 1.There is variation within a species 2.Offspring resemble their parents Knowing this, humans have selectively bred animals and plants for desired characteristics This is artificial selection

19. Genetic Variation Three main sources of genetic variation: 1.Meiosis 2.Sexual Reproduction 3.Mutations Genetic variation is important to the process of natural selection.

20. Remember: Chromosomes are made of DNA & DNA consists of genes. The genes control the physical characteristics of an organism. A change in gene can lead to a change in characteristic.

21. An Example … The English Peppered Moth

22. Speciation Species: organisms that interbreed to produce fertile, healthy offspring. Over time, the process of natural selection can cause such changes in characteristics that it leads to the formation of an entire new species. This is speciation. It is most often caused by geographical isolation.

24. Types of Evolution Divergent Evolution –one common ancestor evolves into two species, which continue to evolve and become less and less alike over time.

25. Types of Evolution Parallel Evolution –Two related species arise from a common ancestor. The two species then evolve in much the same way over time, probably in response to similar environmental selection pressures.

26. Types of Evolution Convergent Evolution –Occurs when two or more groups that are not closely related come to resemble each other more and more as time passes. This is usually the result of occupation of similar habitats and the adoption of similar environmental roles.

27. Types of Evolution Which is which? DivergentConvergentParallel

28. Evidence for Evolution There is a variety of evidence that supports evolution. This includes: –Fossil evidence –Comparative anatomy –Comparative embryology –Biogeography –DNA evidence

29. Fossil Evidence: Evidence for many species that existed in the past can be seen from fossilised remains of plants & animals that were once trapped during the process of rock formation. The rock strata & the fossils in them, can be dated & arranged in sequence to show how life on Earth evolved over time. Fossils also provided evidence about locations of continents & oceans, & the changing environments of the past. Evidence for Evolution

30. Only primitive fossils are found in older sediments New fossil types mark changes in environment Fossil types differ in each sedimentary rock layer Numerous extinct species Recent fossils are found in recent sediments Most recent sediments Oldest sediments

31. Comparative Anatomy: Involves looking at the structure of limbs in birds, reptiles, amphibians & mammals. All show similar structures suggesting common ancestry (known as homologous structures). Evidence for Evolution

33. Comparative Embryology Involves comparing the embryonic forms of different organisms. Closely related organisms go through similar stages in their embryonic development, often showing similarities among structures that become so altered later in development that their common origin would not be seen in the adult form. Evidence for Evolution

35. Biogeography Study of geographic distribution of a species using present – day observations & the fossil record. The distribution & evolution of a species can be affected by geographic boundaries such as mountains, lakes, oceans & deserts. Evidence for Evolution

36. DNA Hybridisation Most powerful piece of evidence: an organisms genetic code. Fossil evidence suggests that the earliest forms of life were bacteria, so it seems likely that bacteria developed the code shared by all living things. The degree to which two species differ in their genetic sequences can be measured by DNA hybridisation. Evidence for Evolution

37. DNA Hybridisation Steps: Double – stranded DNA from each species is heated causing the strands to separate The single – strands of DNA are ‘cut’ into smaller segments using enzymes The segments from two species are mixed and allowed to cool together in a petri dish – any complementary bases of the two species will bond and rewind to form a double – helix The degree to which there is there is a match between the two strands demonstrates the genetic similarity between the two species

38. Extract human DNAExtract chimpanzee DNA Some of the opposing bases in the DNA sequence do not match Mix strands to form a hybrid Unzip the DNA using heat (both human and chimpanzee DNA unwinds at 86°C)

39. Human Evolution

40. Primate Classification ProsimiansNew World Monkeys ApesHominidsOld World Monkeys

41. Hominids Anatomical features and habits: Bipedal with modified feet, thigh bone, pelvis, and spine Large cerebral cortex (forebrain) Reduced canines (and teeth in general) Prominent nose and chin, reduced eye ridges Body hair short or very reduced to assist cooling Highly sensitive skin Complex social behaviour Examples: Australopithecus Paranthropus Homo Ardipithecus Paranthropus boiseiHomo neanderthalensisHomo sapiens

42. Orrorin tugenensis Other Name“Millennium Man” Known Date 6.0 million years ago Brain Size? cc Height? m Physique Possibly bipedal, and a forest dweller. Little else known. Skull Shape? Teeth and Jaws ? Geographical Distribution Kenya, Eastern Africa O. tugenensis, or ‘Millennium man’ was discovered in late 2000. A new hominin from Kenya, it is claimed to be the oldest hominin yet described. Thirteen pieces, consisting of teeth, fragments of the arm, thigh bone, and a finger, from at least five different individuals have been found. The size and morphology of the teeth are intermediate between those of a chimpanzee and those of a human.

43. Ardipithecus ramidus Other Name Two subspecies: A. ramidus ramidus A. ramidus kadabba Known Date 4.4 - 5.8 million years ago Brain Size? cc Heightc. 1.2 m Physique Possibly bipedal forest dweller. Little else known. Skull Shape Foramen magnum more forward than apes. Teeth and Jaws Smaller, narrow molars; thinner jaw Geographica l Distribution Eastern Africa Discovered in 1994, this species was originally thought to be an early hominin, with limited evidence of bipedalism. Two subspecies have been identified: A. ramidus ramidus (4.4 my old) A. ramidus kadabba (5.8 my old) This species is regarded by some researchers as ‘simply an ape with some unusual characteristics’. Some individuals may have been 1.2 m tall. Other fossils found with this hominin indicate that it may have been a forest dweller.

44. Other Name:None Known Date:4.2 – 3.9 million years ago Brain Size:? cc Height:? m Physique: Partial leg bones strongly suggest bipedalism; humerus extremely humanlike Skull Shape: Primitive features in the skull, possibly apelike Teeth and Jaws: Very similar to those of older fossil apes, but canines vertical; teeth have thicker tooth enamel as in humans Geographical Distribution: Eastern Africa Australopithecus anamensis Anamensis was discovered at Kanapoi, Kenya in 1994. The find consists of complete upper and lower jaws, teeth, a piece of skull, and arm and leg bones. Anamensis had a mixture of primitive, ape-like features and advanced, human-like features. The teeth and jaws are similar to older fossil apes, but the lower leg bones show evidence of bipedalism and the upper arm bone is extremely human-like.

45. Australopithecus afarensis Other Name‘Lucy’, ‘First Family’ Known Date3.9 – 2.5 million years ago Brain Size400 – 500 cc Height1.07 – 1.52 m Physique Light build. Some apelike features: relatively long arms, curved fingers and toes, sexual dimorphism Skull Shape Apelike face, low forehead, bony brow ridge, flat nose, no chin Teeth and Jaws Human-like teeth, canines smaller than apes, larger than humans. Jaw shape is half way between that of an ape and a human. Geographical Distribution Eastern Africa Photos courtesy of: SkullsUnlimited.com

46. The Primitive Features of 'Lucy' This is a reconstructed skeleton of ‘Lucy’ Australopithecus afarensis – one of the earliest known bipedal hominins. The skeleton exhibits features consistent with a species adapted for walking bipedally.... But it also possesses many ‘primitive’ features normally associated with an arboreal existence. Sexual dimorphism in the canine teeth (a primitive trait) Shoulder joint that is orientated towards the head Relatively long arms compared to legs Finger bones are curved Toes are long and curved Jaw shape half way between V-shape of ape's and U-shape of human jaw Chest (thorax) is funnel- shaped Wrist has high mobility Relatively short legs Ankle joint is highly mobile Redrawn from a photograph by © David L. Brill 1985

47. Low forehead Australopithecus afarensis A Modern Human Skull (for comparison) Brow ridge Large, dish- shaped face Wide midface Flat nose Big, ape-like incisor Diastema (gap) Canines larger than in humans Large, thickly enameled molars Little of the skull is behind the foramen magnum Small brain (410cc)

48. Other NameNone Known Date~3.0 - 2.3 million years ago Brain Size400 – 500 cc Height1.1 – 1.4 m Physique Light build. Probably long arms, more ‘human’ features, probably less sexual dimorphism than A. afarensis Skull Shape Brow ridges less prominent; higher forehead and shorter face. Teeth and Jaws Teeth and jaws much larger than in humans; shape of jaw fully parabolic as in humans; canine teeth further reduced. Geographical Distribution Southern Africa Australopithecus africanus

49. A Modern Human Skull (for comparison) Lower face protrudes forward into a snout (prognathism) Low facial angle Brow ridge No sagittal crest Small brain (450cc) same size as gorilla's but organization is different from an ape's Very large molars compared with modern humans (not shown here)

50. Paranthropus robustus Other NameAustralopithecus robustus Known Date2.2 - 1.5 million years ago Brain Size530 cc Height1.1 - 1.3 m Physique Heavy build. Relatively long arms. Moderate sexual dimorphism. Skull Shape Long, broad, flat face; crest on top of skull; moderate facial buttressing. Teeth and Jaws Very thick jaws; small incisors and canines; large molar-like premolars; very large molars (megadont). Geographical Distribution Southern Africa

51. Paranthropus robustus A Modern Human Skull (for comparison) Small incisors (missing in this specimen) Massive molars with thick enamel are well worn suggesting a tough vegetarian diet Massive zygomatic arch and cheek bones Low facial angle Heavy brow ridge Very prominent sagittal crest for the attachment of powerful jaw muscles Small brain (530cc) Part of the rear and top of this skull is missing Little of the skull is behind the foramen magnum

52. Homo habilis Other NameHomo rudolfensisHomo habilis Known Date 2.4 - 1.6 million years ago 2 - 1.6 million years ago Brain Size600 - 800 cc500 - 650 cc Heightc. 1.5 m1.0 m Physique Robust but ‘human’ skeleton. Relatively long arms Skull Shape Larger, flatter face Small face with developed nose Teeth and Jaws Large, narrow molars; robust jaw Smaller, narrow molars; thinner jaw Geographical Distribution Eastern Africa Eastern, and possibly Southern Africa

53. Homo habilis A Modern Human Skull (for comparison) Small variant Large variant Projecting jaw (prognathism) Flat nose Smaller, narrower face than the australopithecines Brow ridge Rounded cranium with no sagittal crest Tooth row displays a modern curve, with narrow molars Bigger brain (650-680cc) Bulge in the Broca's area of the brain for speech production More of the skull is behind the foramen magnum Jaw is less massive than in the australopithecines

54. Homo erectus Other Name Homo ergaster for older African forms Known Date1.8 - 0.3 million years ago Brain Size750 - 1250 cc Height1.3 - 1.5 m Physique Robust but ‘human’ skeleton Skull Shape Flat, thick skull with sagittal keel and large brow ridge Teeth and Jaws Smaller teeth than H. habilis, robust jaw in larger individuals Geographical Distribution Africa, Asia, Indonesia, and possibly Europe

55. Shelving forehead Homo erectus A Modern Human Skull (for comparison) Older African forms More recent Asian forms Projecting jaw No chin Teeth are smaller than H. habilis, but more massive than our own Flat face Thick brow ridge Long, flattened cranium with a distinctive keel along the top Bigger brain Earliest: 850cc Latest: 1100cc Bulge in the Broca's area of the brain for speech production Bulge in Wernicke's area of the brain for speech recognition Occipital lobe (bun-like swelling) Attachment for strong neck muscles to stop the head from sagging forward

56. Homo heidelbergensis Other NameHomo heidelbergensis Known Date 400 000 - 100 000 years ago Brain Size1100 - 1400 cc Height? m Physique Robust but ‘human’ skeleton Skull Shape Higher cranium, less face protruding. Many regional variants with mosaics of modern and more primitive features. Teeth and Jaws Similar to H. erectus, but smaller teeth Geographical Distribution Africa, Asia, and Europe Atapuerca skull Stenheim skull Rhodesia skull

57. Occipital 'bun' for neck muscle attachment Broad, upright face Homo heidelbergensis A Modern Human Skull (for comparison) Teeth are generally modern in form No muzzle (no prognathism) Broad nasal opening Large brow ridge Sloping forehead Large brain (1200 - 1430cc) Flat, oblong shape to the cranium

58. Homo neanderthalensis Other Name The Neanderthals; H. sapiens neanderthalensis Known Date150 000 - 28 000 years ago Brain Size1200 - 1750 cc Height1.5 - 1.7 m Physique Robust but ‘human’ skeleton, adapted for cold climates Skull Shape Double-arched brow ridge, high rounded orbits, midface projection, weak chin, long low skull, small mastoid process, Teeth and Jaws Similar to Archaic H. sapiens; except for incisors, smaller teeth. Geographical Distribution Europe and western Asia.

59. Homo neanderthalensis A Modern Human Skull (for comparison) Weak chin Swept back, lightly built cheek bones Large prominant nose and mid-facial projection Double-arched brow ridge Sloping forehead Low, long cranium Teeth are smaller than H. erectus, but bigger than our own Powerful jaw but reduced compared to H. erectus Skull widest at the base (unlike modern skulls which are widest near the top) Occipital lobe (bun-like swelling) Large brain (1600cc) Larger than a modern brain but organized differently

60. Homo sapiens Other Name Early anatomically modern humans; Homo sapiens sapiens Known Date 195 000 - 60 000 years ago (for early humans) Brain Size1200 - 1700 cc Height1.6 - 1.85 m Physique Modern skeleton possibly adapted for warmth Skull Shape Small or no brow ridge; shorter and higher skull Teeth and Jaws Teeth may be smaller; shorter jaws than Neanderthals; chin developed Geographical Distribution Africa and western Asia (for early forms)

61. No brow ridge, just a slight swelling of the glabella Homo sapiens A Modern Human Skull (for comparison) Sizable jaw with projecting chin No muzzle (no prognathism) Vertical face High, vertical forehead Convex cranial vault Reduced tooth size with thinner enamel Sizable mastoid process Low, rounded occipital area Skull widest high up Large brain (1400cc)

62. Human Evolution Timeline In 2001, the 6-7 my old remains of a nearly complete skull with gorilla-like features was unearthed in Chad. Nicknamed “Toumai” and assigned to a new genus, Sahelanthropus tchadensis, scientists debate whether it is human or the remains of a proto-gorilla. Photos courtesy of: SkullsUnlimited.com

63. Human Evolution Timeline Photos courtesy of: SkullsUnlimited.com Orrorin tugenensis, or ‘Millennium man’ was discovered in late 2000 at a site in Kenya. It is claimed to be the oldest hominin yet described.

64. Human Evolution Timeline Originally given the name Australopithecus ramidus, it was reclassified under a new genus, Ardipithecus. Two subspecies have been identified: A. ramidus ramidus (4.4 my old) A. ramidus kadabba (5.8 my old) Regarded by some researchers as ‘simply an ape with some unusual characteristics’.

65. Human Evolution Timeline Discovered at Kanapoi, Kenya in 1994, this earliest known species of the genus Australopithecus had a mixture of primitive, ape-like features and advanced, human-like features.

66. Human Evolution Timeline

67. Discovered in Kenya, a new genus Kenyapithecus appears to be an offshoot from the main evolutionary branches Photos courtesy of: SkullsUnlimited.com

68. Human Evolution Timeline As many as four species from the genus Australopithecus emerge, with a wide geographic distribution, ranging from southern Africa, through East Africa, to Chad in the north.

69. Human Evolution Timeline A group of species from the genus Paranthropus emerge in southern and eastern Africa. Superbly adapted to exploit low grade vegetarian diet, they coexist with the emerging genus Homo.

70. Human Evolution Timeline From a probable Australopithecine ancestor emerges the first species of genus Homo. A small-brained species with fully developed bipedal locomotion, it has a talent for shaping tools from stone. This hominin does not venture out of Africa.

71. Human Evolution Timeline What followed was an adaptive radiation of the genus Homo, leading to increased body height, brain capacity, complex social behavior, and a geographic distribution that extended well beyond Africa.

72. Human Evolution Timeline The most recent, and perhaps most perplexing part of this emerging story, is the discovery in 2003 of what appears to be a ‘pygmy’ species of human that lived on the Indonesian island of Flores between 95 000 - 13 000 years ago.