Homo floresiensis

The fossils of Homo floresiensis were discovered in 2003 in Liang Bua, a large limestone cave on the Indonesian island of Flores. The species name floresiensis is derived from the name of the island. What shocked the world of science is that the bones found on Flores were not Homo erectus or any previously identified early hominin. The remains found in Liang Bua, and thus named LB1, appear to be those of an entirely new species: a dwarf-like hominin about 1 meter tall with a small brain. One archeologist referred to the fossil as a "hobbit," and this is the name that stuck. The discovery caused a sensation by pointing to an unknown species in human evolution, and it sparked the publication of many scientific articles and news stories.

Brief History

Biologist Alfred Russel Wallace and his colleagues scoured the island of Flores for ten years in the mid-nineteenth century, searching for evidence of the aboriginal ancestors of Australia. These ancient humans would have traveled through the chain of islands known as Indonesia on their way to the main continent of Australia, placing their arrival about 60,000 years ago. Homo erectus and other animals (giant lizards and stegodons, a type of elephant) crossed into that region around 840,000 years ago. There is debate whether the eruption of Mount Toba decimated the population of Homo sapiens living in India along with Homo floresiensis, sending the world into a six-year winter and thousand-year ice age.

Scientists disagree about Homo floresiensis. Some contend the skeletal remains are of a distinct species that lived at the same time as modern Homo sapiens. Others believe the bones indicate a modern hominin of the genus Homo who had a medical condition such as Down Syndrome or microcephaly. Studies suggest certain features, such as the teeth, are congruent with the Homo genus; other features are less so (nonexistent chin, small head and brain, and extremely short stature). A total of eight fossils were discovered, and LB1 was the most complete. All fossil evidence shows that the oldest of the H. floresiensis fossils are older than 100,000 years. Some stone tools that are attributed to the species date back to 190,000 years ago. An elephant of the genus Stegodon was also found in the same layer of sediment. Archeologists believe Homo floresiensis hunted the pygmy elephants. In 2017, researchers found 700,000 years old fossils on Flores that may represent an even older iteration of H. floresiensis, suggesting their evolutionary history on the island is long.

The island of Flores is one of 17,000 islands that make up the Indonesian archipelago. Flores and other islands are isolated from the contents of Asia and Australia. The islands in this area are called the Wallacean Islands after Wallace, the father of modern biology and co-discoverer with Charles Darwin of natural selection. Flores is home to only a small number of land mammals and reptiles. The island was discovered and colonized by the Portuguese in the sixteenth century, and the name Flores means flower in Portuguese. According to Australian and Indonesian archaeologists, the find was a lucky one: Bones rarely survive as fossils. The cave deposits are a snapshot of human activity over the last 100,000 years. While some evolutionary questions are answered, many questions remain, such as how H. floresiensis got to the island and how they became extinct.

Overview

The classification of human fossils is of extreme importance in the understanding of human evolution. When scientists uncovered the fossil remains of H. floresiensis, they found stone tools and animal remains in the same layer of sediment. The tools were Stone Age tools, the most primitive type. The animal remains were identified as rats, bats, Komodo dragons, and stegodon. The presence of fire-cracked rocks and charred bones suggests this early human used fire. Researchers think H. erectus could be the ancestor of H. floresiensis. Another theory is H. floresiensis evolved from H. habilis.

A study published July 22, 2015, in the Proceedings of the Royal Society B, analyzed a dataset of 380 skull and dental features of twenty known hominin species and concluded that H. floresiensis was, in fact, a distinct species. In addition to verifying a new species of hominin, the study suggests H. floresiensis is a descendant of a small-bodied hominin that migrated out of Africa to Southeast Asia (pre-Homo erectus).

The genus Homo is purportedly well-known, yet poorly defined. The Latin noun homo means "wise man." Carl Linnaeus created the binomial term Homo sapiens. Genus Homo encompasses H. habilis, H. rudolfensis, H. ergaster, H. erectus, H. neanderthalensis, H. floresiensis, and H. sapiens. This classification includes modern humans (H. sapiens) and extinct, ancestral species. The genus is around 2.8 million years old. H. habilis is the first ancestor that evolved from Australopithecus. Australopithecus emerged from the genus Pan (chimpanzees). Hominins are all species of the genus Homo in addition to species of Australopithecus, who arrived after the split from Pan. Archeologists believe Homo sapiens (modern humans) arrived 200,000 years ago in East Africa. It is the only surviving species of the genus Homo. Homo sapiens migrated from Africa 60,000 years ago during the Paleolithic Era and spread throughout Africa, Eurasia, Oceania, and the Americas.

Bibliography

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