Jessica has taught junior high history and college seminar courses. She has an M.A in instructional education.
I'm guessing that today's lesson on the Replacement model of human origin will be very new to most of us. For this reason, we're going to stick to the very basics of this rather complex theory. However, before we get to these basics, we need to spend some time digging into the word 'theory.'
A theory is a supposition used to account for a situation or justify a course of action. A theory is not set in stone, nor is it proven fact. Due to this, science, especially archaeology, often finds itself unearthing things that call old theories into question. Today's lesson on the Replacement model will be an excellent example of one such theory, as many scholars disagree with the validity of its suppositions. Stating it plainly, some would consider it incorrect at best.
With this little warning of sorts, let's get down to business. I'll first give the scholarly definition of the model. Then, we'll work to break it down into more digestible terms.
The Replacement model asserts that there was a single origin of Homo sapiens in Africa and that these anatomically modern humans migrated out from Africa and replaced all other less evolved humans throughout Europe and Asia - hence the name, Replacement model.
With the official definition fresh in our minds, let's try to break it down a bit. First of all, when science uses the term Homo sapiens, it's referring to the species of humans that exist today. In other words, you and I are Homo sapiens.
When science uses words like 'less evolved humans,' they're referring to the theory made famous by Charles Darwin, that humans advanced over a vast amount of time, moving along the evolutionary ladder from apes to Homo sapiens.
Origin of Homo Sapiens
Putting this all together, the Replacement model asserts that Homo sapiens originated or evolved only in Africa, then spread out over Europe and Asia. When speaking of this theory, the word 'only' is probably one of the most important words since the hallmark of the theory is that Homo sapiens only evolved in Africa. Then as these Homo sapiens migrated out of Africa, the model asserts that all lesser-evolved human species somehow became extinct, leaving Homo sapiens as the only remaining human species. For this reason, the Replacement model is also referred to as the Out of Africa model.
Drawing from this, proponents of the Replacement or Out of Africa model assert that all humans alive today can trace their ancient, ancient ancestry back to Africa.
Studies & Criticism
Leaning greatly on biological science, some studies have seemed to support the idea that all modern-day humans originated from Africa. These studies assert that the DNA record of humans does, in fact, seem to lean toward the idea that there is one main branch of human DNA from which the other more modern branches sprung from and that this main branch did originate in Africa. These findings have helped to elevate this theory to one of the most agreed upon within the scientific community.
However, opponents of the replacement model argue that the computer and data entry programs used in these studies were flawed and therefore unreliable. Adding to the criticism of the model, most of those who champion it are willing to admit they really can't give any solid dating on when or why the emergence or migration of these first Homo sapiens took place.
A theory, is a supposition used to account for a situation or justify a course of action. The Replacement model of human origin is an excellent example of a theory since many agree with it, but many others do not.
Building from the theories of Charles Darwin who theorized that humans advanced over a vast amount of time, moving along the evolutionary ladder from apes to Homo sapiens, the Replacement model is also referred to as the Out of Africa model.
It gains this name from its assertion that there was a single origin of Homo sapiens in Africa, and that these anatomically modern humans migrated out from Africa and replaced all other less evolved humans throughout Europe and Asia. In short, it holds that all Homo sapiens or the species of humans that exist today evolved only in Africa and then spread throughout the world. When this occurred, all lesser-evolved humans somehow became extinct.
Supported by some scientific studies on DNA, Replacement model theorists assert that all modern humans are of African origin. However, critics of this theory argue that the testing models used to determine this were faulty and therefore inaccurate. Opening it up for more criticism, the model has no solid dating for the emergence or migration of these ancient Homo sapiens.
Accomplish these objectives when the lesson ends:
- Define theory and determine what Charles Darwin has to do with the Replacement model
- Understand what homo sapiens are
- Discuss the Replacement model and the way in which it came to be called the Out of Africa model
- Reference studies that found that homo sapiens originated in Africa
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Unlock Your Education
See for yourself why 30 million people use Study.com
Become a Study.com member and start learning now.Become a Member
Already a member? Log InBack
Resources created by teachers for teachers
I would definitely recommend Study.com to my colleagues. It’s like a teacher waved a magic wand and did the work for me. I feel like it’s a lifeline.