Questoin One: The Leakey Family 1) Who are the members of the Leakey Family who
ID: 156163 • Letter: Q
Question
Questoin One: The Leakey Family
1) Who are the members of the Leakey Family who are involved in Paleontology?
2) What site is the Leakey Family most stringly associated with?
3) Briefly, what findings were made at this site?
Question Two: Dating Techniques
1) What is the difference between Relative and Absolute Dating?
2) Choose one of the Relative Dating Techniques: Describe the technique.
3) Choose one of the Absolute Dating Techniques: Describe the technique.
Please provide the sources where you obtained the information.
Explanation / Answer
1) When Louis Leakey and Mary Nicol first met, he asked her to help with illustrations for his upcoming (1934) book Adam's Ancestors: An Up-to-Date Outline of What is Known about the Origin of Man. Within a few years they were married. They and their children (especially Richard and his wife Meave) became known as the first family of paleontology.
Louis Leakey was born in 1903 in Kenya, where his English parents were missionaries. He learned the Kikuyu language and customs, and while searching for birds as a young man often found prehistoric stone tools in the riverbeds. These early influences would shape his career. After World War I, he went to secondary school and university in England, but took a year off to recover from a sports injury. In his year off, he joined a fossil-finding expedition to what is now Tanzania, which opened his eyes to the field and to the question of human origins. He graduated in 1926, not long after Raymond Dart first found very early human remains in South Africa.
In 1931, Leakey made his first trip to the Olduvai Gorge, in what is now Tanzania -- the site of some of his most important finds. Though he found a few things of interest, he didn't return for a serious excavation until the 1950s.
Mary Douglas Nicols was born in 1913 to a family of artists and archaeologists. Early influences also encouraged her to study geology and archeology, and to plan a career in it, an unusual step for a woman at the time. Her specialty was in the early Stone Age and she was expert at drawing early tools and other artifacts.
Louis and Mary met on a dig in England, and both worked briefly at the Olduvai Gorge before being married in England. It was Leakey's second marriage. They returned to Kenya in 1937 and had three children.
Their son Richard, born in Kenya in 1944, made his first fossil find at age six -- a part of an extinct giant pig. He resisted following his parents' career, feeling he didn't want to ride on their coat tails. He dropped out of high school to lead photo safaris in the early 1960s. But by 1963 he was leading a team to a dig in (now) Tanzania, where they made an important find. In the next few years he joined and led several more expeditions. In 1964 he married Margaret Cropper, a fellow fossil-hunter, but the couple divorced in 1970. He began to work for the Center for Prehistory and Paleontology which his father had established in Nairobi, and at the age of 23 became administrative director of the National Museum of Kenya.
In the 1960s Louis became ill and Mary Leakey took over the work at Olduvai Gorge. Their relationship began to deteriorate somewhat at this point, perhaps through professional rivalry. He was absorbed in administrative and fund-raising tasks, and branched out into many related areas, including primate research (with Dian Fossey and Jane Goodall his proteges) and special excavations in Israel and North America. Mary stayed in field work in Africa where she made several dramatic finds and found herself critical of some of Louis' work of the time, calling it not rigorous. In 1976 and 1977, Mary made what she considers the most exciting find of her career. About 30 miles south of the Olduvai Gorge at a site called Laetoli, Mary and her team found fossilized footprints in what was once a wet sandy region probably near a watering hole. Among them were human-like footprints showing a small striding primate that walked on two feet. The footprints seemed to match the fossils found in the same area, belonging to the species Australopithecus afarensis. This made upright walking an older trait for hominids than either brain size expansion or modern tooth structure, and therefore required changes in theories as to why some primates, such as human ancestors, evolved to walk on two feet.
In 1970 Richard married another paleontologist, Meave Epps. He made an important find which validated some of his father's work, and helped reconcile their relationship, which had also been strained. Louis Leakey died in 1972 of a heart attack. Mary, Richard, and Meave continued to work on discovering human origins and untangling the primate family tree. In the 1970s, however, Richard also had health problems. In 1979 he underwent a kidney transplant, with his brother as donor. Through the following decades the Leakey family made significant fossil finds, rethought others, and sometimes disputed claims by other workers, such as Donald Johanson, who felt his fossil Lucy was of the same family as some of the Leakey's finds.
The Leakey family has been remarkable in the sheer numbers of fossil and tool discoveries and the vast amount of data its members have contributed to the fields of paleontology and anthropology. Louis Leakey has been criticized as opinionated, too eager to create new categories of hominids, too ambitious...but he made radical changes in the way we now view early humans. He confirmed that human evolution began in Africa, pushed back the dates for the existence of various species, suggested the existence of parallel lines of evolution in the human family, and stimulated research in new fields like primatology, as well as sparking general interest in all the fields he touched.
2) Sciences such as geology, paleontology and archeology are very interested in identifying the age of objects found and these scientists sometimes use either relative dating or absolute dating to characterize the age of the objects they study.
Before radiometric dating it was difficult to determine the actual age of an object. Radiometric dating, based on known rates of decay of radioactive isotopes in objects, allows a specific age of an object to be determined to some degree of accuracy.
Relative dating is a scientific process of evaluation used to determine the relative order of past events, but does not determine the absolute age of an object. The circumstances of the object may allow one to say that one object is older than another without being able to assign a particular age to the objects.
For example:
If an archaeologist is studying past civilizations, the archaeologist may be able to say that in a particular location the ruins of once civilization were found to have been build on another and so the layers unearthed in an excavation convey the sequence of historical occupations without revealing the actual dates. If the archaeologist finds a sample suitable for carbon dating, then an absolute date may be assigned to an object.
Similarly for paleontologists who find layers of fossils. By deducing which fossils are formed in the sequence of time, the periods when the particular fossilized entities existed can be arranged in order without the actual dates of when the fossils were laid down. Radioactive isotopes can also be used by a paleontologists to assign an age to a fossil in some cases and that is an example of absolute dating with radiometric methods.
For geologists, it is similar. Looking at how rock formations are structured, a geologist may be able to say which rock was developed in which layer in a particular order but not be able to determine that actual geologic age of the layers. Geologists deal with the oldest of samples and radiometric dating with uranium is one of the few methods of absolute dating.
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