Re: Human skull evolution

Glenn R. Morton (
Mon, 08 Jun 1998 20:24:40 -0500

At 02:00 PM 6/8/98 -0500, J. McKiness wrote:
>I believe that in terms of paleontological species, a population of
>hominids that consistently differ on such a trait from the norm may be
>appropriately classified as a seperate species. (Something I know Glenn
will object to.
>;-) )

Hi John,

Actually I will surprise you here. I don't disagree with you or the need
for a paleospecies as opposed to a biological species concept. I follow
Relethford's suggestion,

"First, a species can change over time. According to this mode of
evolutionary change, a single species exists at any given point in time but
evolves over a period of time. An example is the evolution of humans. The
most likely scenario ofhuman evolution over the past two million years is a
change from a species known as Homo habilis into a species known as Homo
erectus into our own species Homo sapiens. While a single species exists
within the genus Homo at any point in time, there is continued
evolutionary change such that the most recent forms (ourselves) are quite
different from the earliest forms."
"This mode of species change is known as anagenesis, or straight-line
evolution. It is illustrated as a straight line, as shown in Figure 3.7
where form A evolves into form B and then into form C. Although this mode
of evolutionary change is fairly straightforward, complications arise when
considering the naming of species. Should form A be called a different
species from form B? The problem is that the traditional biological
species concept doesn't really apply. Form A and form B are by are by
necessity isolated from each other reproductively since they lived at
different times.
"Many researchers modify the species concept to deal with this type of
situation. Different physical forms along a single lineage (an evolutionary
line such as that shown in Figure 3.7) are given different species names
out of convenience, and as a label to represent the types of physcial
change shown over time. Such forms are referred to as paleospecies and are
used more as labels than as units representing the spcies concept." ~ John
H. Relethford, Fundamentals of Biological Anthropology, (Toronto: Mayfield
Publishing Co., 1994), p. 71


Adam, Apes and Anthropology
Foundation, Fall and Flood
& lots of creation/evolution information