1. Bio 115 Ecology and Evolution
Human Evolution

13. Haploid chromosome number.
Humans have not lost a chromosome; rather, two smaller chromosomes fused to make a single chromosome.

15. Darwinius masillae
Middle eocene (47 Mya)
Germany
Root species of primates.

19. Human – rhesus money (OW) Human – spider monkey (NW)
Percent divergence in DNA
Species pair
% Divergence of DNA
Human - Chimpanzee
1.7
Human – Gorilla
1.8
Human - orangutan
3.3
Human - Gibbon
4.3
Human – rhesus money (OW)
7.0
Human – spider monkey (NW)
10.8
Human - Tarsier
24.6

23. Ardipithecus ramidis (4.4 Mya)
Science October 2, 2009

24. Ardipithecus ramidus
Unexpected anatomy. Ardi has an opposable toe (left) and flexible hand (right); her canines (top center) are sized between those of a human (top left) and chimp (top right); and the blades of her pelvis (lower left) are broad like Lucy's (yellow).

25. Ardipithecus ramidus
Filling a gap. Ardipithecus provides a link between earlier and later hominins, as seen in this timeline showing important hominin fossils and taxa.
Filling a gap. Ardipithecus provides a link between earlier and later hominins, as seen in this timeline showing important hominin fossils and taxa.

26. Hominoid relationships
Hominoid relationships. Schematic representation of the inferred evolutionary relationships between Miocene apes, early hominins, and extant hominoids. Solid gray bars represent the known time range of each genus, thin dark lines are inferred relationships between the genera, and thin dashed lines with “?” denote uncertain relationships.
Science 29 January 2010 (327) p532.

28. Dr. Tim White

29. Evolution of hominids and African apes since the gorilla/chimp+human (GLCA) and chimp/human (CLCA) last common ancestors. Pedestals on the left show separate lineages leading to the extant apes (gorilla, and chimp and bonobo); text indicates key differences among adaptive plateaus occupied by the three hominid genera.

30. Map showing the Middle Awash area (star) and rift locations (red lines). Photo shows the 4.4-Ma volcanic marker horizon (yellow bed) atop the locality where the skeleton and holotype teeth of Ar. ramidus were discovered. Also shown are some of the fossil seeds.

32. Abundance of birds (left) associated with Ar. ramidus
Abundance of birds (left) associated with Ar. ramidus. These distributions are consistent with a mostly woodland habitat. (above) An example of the many small mammal and bird bones.

33. (Right) Oblique and side views of a female chimpanzee (right) and the Ar. ramidus female reconstruction (left; the oblique view includes a separate mandible). (Left) Comparison of brain and tooth sizes (arrows) of chimps (Pan, blue), Ar. ramidus (red), and Australopithecus (green). Means are plotted except for individual Ar. ramidus and Au. afarensis cranial capacities. Canine unworn heights (bottom) are based on small samples, Ar. ramidus (females, n = 1; males, n = 3), Au. afarensis (n = 2), Pan (females, n = 19; males n = 11).

34. Dentitions from human (left), Ar
Dentitions from human (left), Ar. ramidus (middle), and chimpanzee (right), all males. Below are corresponding samples of the maxillary first molar in each. Red, thicker enamel (~2 mm); blue, thinner enamel (~0.5 mm). Contour lines map the topography of the crown and chewing surfaces.

35. Two views of the left hand of Ar
Two views of the left hand of Ar. ramidus showing primitive features absent in specialized apes. (A) Short metacarpals; (B) lack of knuckle-walking grooves; (C) extended joint surface on fifth digit; (D) thumb more robust than in apes; (E) insertion gable for long flexor tendon (sometimes absent in apes); (F) hamate allows palm to flex; (G) simple wrist joints; (H) capitate head promotes strong palm flexion. Inset: lateral view of capitates of Pan, Ar. ramidus, and human (left to right). Dashed lines reflect a more palmar capitate head location for Ar. ramidus and humans, which allows a more flexible wrist in hominids.

36. The Ar. ramidus pelvis has a mosaic of characters for both bipedality and climbing. Left to right: Human, Au. afarensis (“Lucy”), Ar. ramidus, Pan (chimpanzee). The ischial surface is angled near its midpoint to face upward in Lucy and the human (blue double arrows), showing that their hamstrings have undergone transformation for advanced bipedality, whereas they are primitive in the chimpanzee and Ar. ramidus (blue arrows). All three hominid ilia are vertically short and horizontally broad, forming a greater sciatic notch (white arrows) that is absent in Pan. A novel growth site [the anterior inferior iliac spine (yellow arrows)] is also lacking in Pan.

37. Foot skeleton of Ar. ramidus (bottom; reconstruction based on computed tomography rendering shown) lacked many features that have evolved for advanced vertical climbing and suspension in extant chimpanzees (pan, top left). Chimpanzees have a highly flexible midfoot and other adaptations that improve their ability to grasp substrates. These are absent in Ar. ramidus.

38. Cladogram adding Ar. ramidus to images of gorilla, chimpanzee, and human, taken from the frontispiece of Evidence as to Man's Place in Nature, by Thomas H. Huxley (London, 1863) (with the positions of Gorilla and Pan reversed to reflect current genetic data). Numerous details of the Ar. ramidus skeleton confirm that extant African apes do not much resemble our last common ancestor(s) with them.

41. COVER The right forearm and hand (hand skeleton ∼12
COVER The right forearm and hand (hand skeleton ∼12.3 centimeters long) of (Australopithecus sediba), specimen Malapa Hominin 2. Papers in this issue present a detailed look at the hands, feet, pelvis, brain endocast, and age of this hominid, which lived 2 million years ago, near the emergence of our genus, Homo.

42. The bar diagram shows when various hominins (two australopiths, red, and various Homo species, blue) appear in the fossil record. The pale blue bar represents fragmentary fossils that are generally thought to come from early Homo. Of these, an upper jawbone from Hadar, Ethiopia (black line on the pale blue bar), is well dated at 2.35 million years (Myr) old, and is the most convincingly Homo-like. Lines connecting bars indicate hypothetical ancestry between species. The most recent addition to the diagram is Australopithecus sediba — two skeletons2, 3, 4, 5, 6 of the hominin found at Malapa, South Africa, are ± Myr old. Two scenarios have been proposed1, 6 in which A. sediba is the ancestor of the genus Homo. In the first scenario1, fossils at Malapa come from a late-surviving population of A. sediba, whose earlier representatives (pink bar) were ancestral to Homo (dashed line). In the second scenario6, the A. sediba population at Malapa was itself ancestral to early Homo (dotted line), which means that fossils pre-dating 2 Myr ago (pale blue) cannot be attributed to Homo.

43. Cradle of humankind. One group of Australopithecus, somewhere in Africa, gave rise to early Homo before 2 million years ago.

44. Deathtrap. Lee Berger (left), his son Matthew, and dog Tau visit the pit at Malapa.

45. Head first. This virtual reconstruc-tion of Au
Head first. This virtual reconstruc-tion of Au. sediba's skull shows the endocast of its brain surface (green) with an enlarged frontal gyrus (blue) (Areas reconstructed from a mirror image shown in yellow).

46. Australopithecus sediba Australopithecus africanus
Fig. 3 Comparisons of virtual endocasts in (A) superior, (B) inferior, (C) anterior, and (D) left lateral views.
Homo Sapiens
Australopithecus sediba
Australopithecus africanus
Australopithecus africanus
Australopithecus sediba
Pan troglodytis
Comparisons of virtual endocasts in (A) superior, (B) inferior, (C) anterior, and (D) left lateral views. MH1 is in the center of each cluster surrounded by a representative modern human at the top, then proceeding clockwise, Sts 60 (Australopithecus africanus), a representative chimpanzee, and Sts 5 (Au. africanus). All endocasts are scaled to the estimated volume of the MH1 endocast (420 cm3) for illustration purposes. Scale bars, 2 cm.
K J Carlson et al. Science 2011;333:
Published by AAAS

47. Fig. 2 Comparison of the MH1 (left), Sts 14 (center), and MH2 (right, mirror-imaged) pelves in anteroinferior (top row) and anterosuperior (bottom row) views.
Comparison of the MH1 (left), Sts 14 (center), and MH2 (right, mirror-imaged) pelves in anteroinferior (top row) and anterosuperior (bottom row) views. Areas represented in white or light gray in the MH1 and MH2 pelves represent reconstructed portions of the pelvis (SOM text S1). Sts 14 is attributed to Au. africanus and is represented by the virtual reconstruction of (41). Scale bar in centimeters [note that the anterosuperior view of Sts 14, as provided by (41), is in a slightly different orientation than those of MH1 and MH2]. An additional comparison is provided in fig. S7.
J M Kibii et al. Science 2011;333:
Published by AAAS

48. Arm vs. hand. Au. sediba's hand has some humanlike traits (large tumb and shorter fingers), but its arm is long and primitive.

49. Fig. 1 Au. sediba MH2 right hand.
Au. sediba MH2 right hand. Palmar (left) and dorsal (right) views of all MH2 right hand bones found in association with the right upper limb. Features of the MH2 hand traditionally considered primitive or australopith-like are labeled in gray (palmar view), and features considered derived are labeled in white (dorsal view) [(2, 3, 5), but see (14)]. The thumb is pictured in opposition, overlapping with the second metacarpal.
T L Kivell et al. Science 2011;333:
Published by AAAS

50. Fig. 6 Relative length of the thumb in the Au. sediba MH2 hand.
Relative length of the thumb in the Au. sediba MH2 hand. Shown is a box-and-whisker plot of the relative length of the thumb calculated as a ratio of the total length of the Mc1 and first proximal phalanx to the total length of the Mc3 and third proximal and intermediate phalanges within the same individual (bones highlighted in dark gray in outline of MH2 hand) in all taxa apart from Au. afarensis, for which that ratio is derived from multiple individuals from different sites (30, 38). MH2 has a relatively longer thumb than that of other hominins and falls outside the range of variation in modern humans (highlighted by shaded box). See table S14 for sample and methods.
T L Kivell et al. Science 2011;333:
Published by AAAS

53. Paranthropus boisei

61. Homo erectus

63. Homo floresiensis Flores, Indonesia
A life-sized reconstruction of Homo floresiensis, a.k.a. the hobbit, will go on display on 11 December at the Musée de l'Homme in Paris. The model of the 18,000-year-old female, whose bones were discovered in 2003 on the Indonesian island of Flores, was created by French anthropological sculptor Elisabeth Daynès, aided by three anthropologists. The team relied on a three-dimensional stereolithograph of the hobbit's skull as well as publications on the skeleton.

65. Homo floresiensis

68. Three-dimensional (3D)  rendering of computed tomographic (CT) data of Homo floresiensis (LB1). The virtual endocast (brain) of LB1 is red.

69. Homo sapiens microcephalic
Homo floresiensis
Superior and right lateral views of the brains of a normal contemporary human (HS), a human microcephalic (mcHs), a Homo erectus (He), and a chimp (Pt). Homo floresiensis (LB1) is in the middle. The brains are all scaled to the same size. 
Homo erectus
Chimpanzee

73. Hominoid relationships
Hominoid relationships. Schematic representation of the inferred evolutionary relationships between Miocene apes, early hominins, and extant hominoids. Solid gray bars represent the known time range of each genus, thin dark lines are inferred relationships between the genera, and thin dashed lines with “?” denote uncertain relationships.
Science 29 January 2010 (327) p532.