Discoveries at Lake Turkana reveal information about the history of human evolution.
  • In 1995, National Geographic Explorer-in-Residence Meave Leakey and her team made a very important discovery at Lake Turkana, Kenya. They found fossils of what turned out to be an Australopithecus anamensis. The discovery indicates that the date of the occurrence of bipedalism needed to be moved back by half a million years, to about 4.2 million years ago. This was not the first major paleoanthropologic discovery at Lake Turkana. In 1972, Bernard Ngenyeo, colleague to Richard and Meave Leakey, discovered the fossil of a Homo habilis, that was about 1.9 million years old. In 1984, the Leakey team found an almost-complete fossilized skeleton that was dated to about 1.5 million years ago. This was a Homo erectus and is famously known as "Turkana Boy."

    This clip is an excerpt from the film Bones of Turkana. The film takes place in the area around ancient Lake Turkana. This area is known as a cradle of human life. There is evidence of hominids that lived here 4.2 million years ago. This film depicts the lives of some human ancestors.

    This video from Bones of Turkana focuses on significant fossil discoveries made at Lake Turkana.

    The video assumes some familiarity with the theory of evolution, the process of how organisms developed from earlier forms of life. Evolution is not a linear process, but a dynamic one. One species does not morph directly into another, but diverges from its ancestors. Evolution takes place throughout a population over a long period of time due to environmental pressures. This video sometimes uses the phrases "more advanced or less advanced" which actually don't apply to evolution. Species evolve to fit the particular environment that they are occupying at a given time, not to "advance" to a different evolutionary stage.

    1. What evidence can you give for proving that Australopithecus anamensis was bipedal? Why was this significant?

      The tibia, the large bone of the lower leg (shin), was very similar to a modern human tibia, indicating that Australopithecus anamensis may have walked in a similar fashion as modern humans. Many paleoanthropologists did not think that bipedalism occurred this early in hominid development. The discovery brings the date of bipedalism back by half a million years.

    2. When did Homo habilis, or "handyman," start making stone tools? What can we infer about its brain size? What else can you predict from this information?

      Homo habilis started making tools about 1.9 million years ago. We can infer that it had an increased brain size based on the shape of its skull. Using this information about increased brain size, we can predict that Homo habilis could complete a task more quickly than organisms with smaller brains, or that a greater range of communication would be possible.

    3. Who is Turkana Boy?

      He is the Homo erectus whose (almost) complete skeleton was found by Richard Leakey’s team near Lake Turkana in the mid-1980s.

    4. Compare and contrast Australopithecus anamensis, Homo habilis, and Homo erectus.

      Compare: They are all hominids. They are all bipedal. Their fossils have all been found near Lake Turkana.

      Contrast: Australopithecus anamensis is the oldest of the three, at 4.2 million years old. These hominids may have been the first bipeds. They were not yet making stone tools. Homo habilis is about 1.9 million years old. These hominids had a 30% larger brain than A. anamensis. They were probably one of the earliest hominids to make stone tools. Homo erectus is the youngest of the three, at 1.5 million years old. These hominids were bipedal, made stone tools, and perhaps had the brain size of a modern 2-year-old human. They are probably our closest ancestors.

  • Term Part of Speech Definition Encyclopedic Entry
    anthropology Noun

    science of the origin, development, and culture of human beings.

    Encyclopedic Entry: anthropology
    Australopithecus anamensis Noun

    (4.9 million years ago-3.2 million years ago) species of primates (hominid) whose fossils have been found in Africa.

    bipedalism Noun

    form of movement where an animal consistently uses two legs for standing or walking.

    evolution Noun

    change in heritable traits of a population over time.

    field work Noun

    scientific studies done outside of a lab, classroom, or office.

    Encyclopedic Entry: field work
    fossil Noun

    remnant, impression, or trace of an ancient organism.

    Encyclopedic Entry: fossil
    hominid Noun

    biological family of primates, including humans, chimpanzees, gorillas, and orangutans, and their ancestors.

    Homo erectus Noun

    (1.8-1.3 million years ago) species of primates (hominid) whose fossils have been found in Africa and Asia.

    Homo habilis Noun

    (2.5-1.5 million years ago) species of primates (hominid) whose fossils and stone tools have been found in Africa.

    paleontology Noun

    the study of fossils and life from early geologic periods.

    Encyclopedic Entry: paleontology