Featured Research

from universities, journals, and other organizations

Early Apes Walked Upright 15 Million Years Earlier Than Previously Thought, Evolutionary Biologist Argues

Date:
October 10, 2007
Source:
Public Library of Science
Summary:
An extraordinary advance in human origins research reveals evidence of the emergence of the upright human body plan over 15 million years earlier than most experts have believed. More dramatically, the study confirms preliminary evidence that many early hominoid apes were most likely upright bipedal walkers sharing the basic body form of modern humans.

(A)-The LTP (lumbar transverse process) in humans differs markedly from related primates. It is dorsal to the position of the spinal canal. It is thick and strong (triangular or box-like cross-section) instead of flat and thin. (B,C)-Styloid comparison. Lateral view of lumbar vertebrae of human, macaque monkey and Proconsul africanus. The human vertebra, like Morotopithecus, appears to demonstrate absence of the styloid process and relocation of the LTP onto the arch of the vertebra at the base of the structure that carries the facet joint. (D) The Middle Miocene proconsulid hominoid Proconsul africanus appears to have the more primitive LTP and styloid as seen in most euarchontoglirans.
Credit: Courtesy of Aaron Filler, MD, PhD

An extraordinary advance in human origins research reveals evidence of the emergence of the upright human body plan over 15 million years earlier than most experts have believed. More dramatically, the study confirms preliminary evidence that many early hominoid apes were most likely upright bipedal walkers sharing the basic body form of modern humans. 

Research from Harvard UniversityΉs Museum of Comparative Zoology and from the Cedars Sinai Institute for Spinal Disorders connects several recent fossil discoveries to older fossils finds that have eluded adequate explanation in the past. The report deals with the "homeotic" genetic mechanisms that encode anatomical assembly in the embryo, and their relevance to a series of discoveries of hominoid fossil vertebrae.

The report analyses changes in homeotic embryological assembly of the spine in more than 200 mammalian species across a 250 million year time scale. It identifies a series of modular changes in genetic assembly program that have taken place at the origin point of several major groups of mammals including the newly designated 'hominiform' hominoids that share the modern human body plan.

It concludes that a specific gene change ­ in the Pax system -- that generated the upright bipedal human body form -- may soon be identified. The various upright "hominiform" hominoids appear to share this morphogenetic innovation with modern humans. Homeotics concerns the embryological assembly program for midline repeating structures such as the human vertebral column and the insect body segments.

The critical event involves a dramatic embryological change unique to the human lineage that was not previously understood because the unusual human condition was viewed as "normal."

"From an embryological point of view, what took place is literally breathtaking," says Dr. Aaron Filler, a Harvard-trained evolutionary biologist and a medical director at Cedars Sinai Medical Center's Institute for Spinal Disorders.

In most vertebrates (including most mammals), he explains, the dividing plane between the front (ventral) part of the body and the back (dorsal) part is a "horizontal septum" that runs in front of the spinal canal. This is a fundamental aspect of animal architecture. A bizarre birth defect in what may have been the first direct human ancestor led to the "transposition" of the septum to a position behind the spinal cord in the lumbar region. Oddly enough, this configuration is more typical of invertebrates.

The mechanical effect of the transposition was to make horizontal or quadrupedal stance inefficient. "Any mammal with this set of changes would only be comfortable standing upright. I would envision this malformed young hominiform -- the first true ancestral human -- as standing upright from a young age while its siblings walked around on all fours."

The earliest example of the transformed hominiform type of lumbar spine is found in Morotopithecus bishopi an extinct hominoid species that lived in Uganda more than 21 million years ago. "From a number of points of view," Filler says, "humanity can be redefined as having its origin with Morotopithecus. This greatly demotes the importance of the bipedalism of Australopithecus species such as Lucy (Australopithecus afarensis) since we now know of four upright bipedal species that precede her, found from various time periods on out to Morotopithecus in the Early Miocene."

Citation: Filler AG (2007) Homeotic Evolution in the Mammalia: Diversification of Therian Axial Seriation and the Morphogenetic Basis of Human Origins. PLoS One 2(10): e1019. doi:10.1371/journal.pone.0001019, http://www.plosone.org/doi/pone.0001019


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Cite This Page:

Public Library of Science. "Early Apes Walked Upright 15 Million Years Earlier Than Previously Thought, Evolutionary Biologist Argues." ScienceDaily. ScienceDaily, 10 October 2007. <www.sciencedaily.com/releases/2007/10/071009212545.htm>.
Public Library of Science. (2007, October 10). Early Apes Walked Upright 15 Million Years Earlier Than Previously Thought, Evolutionary Biologist Argues. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2007/10/071009212545.htm
Public Library of Science. "Early Apes Walked Upright 15 Million Years Earlier Than Previously Thought, Evolutionary Biologist Argues." ScienceDaily. www.sciencedaily.com/releases/2007/10/071009212545.htm (accessed August 1, 2014).

Share This




More Fossils & Ruins News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Where Did The World Trade Center Shipwreck Come From?

Where Did The World Trade Center Shipwreck Come From?

Newsy (July 31, 2014) — Scientists say a ship remnant discovered underneath Ground Zero dates back to the 18th century. Why it sank is still uncertain. Video provided by Newsy
Powered by NewsLook.com
Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) — Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) Video provided by AP
Powered by NewsLook.com
London's Famed 'Gherkin' Goes on Sale for £650 Mln

London's Famed 'Gherkin' Goes on Sale for £650 Mln

AFP (July 29, 2014) — London's "Gherkin" office tower, one of the landmarks on the British capital's skyline, went on sale for about £650 million ($1.1 billion, 820 million euros) on Tuesday after being placed into receivership. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) — The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins