claudiusde
Sat, Mar-29-08, 17:17
An ecology based approach to understanding human origins
New species don't just spring up out of the blue. They are
part and parcel to new biomes (ecosystems). Likewise new
biomes don't just spring up out of the blue, they are the
result of changes in environments/climatic conditions.
Here's the way speciation works. Ecosystems experience a
change in climate. The change in climate causes a period of
extreme stress whereupon a whole set of niches disappear and a
whole new set of niches appear. New species either find their
way to a new niche (and this almost always involves a whole
host of new adaptations and new behaviors being achieved
simultaneously rather than just one or two adaptations) or
they go extinct.
The gradualistic, just-so-story approach to understanding the
origins of new species, an approach to which all
paleoanthropologist subscribe, is an archaic approach that was
developed in the nineteenth century when ecological ignorance
was the rule. We know better now. Species evolve in a
punctuated fashion. (If you don't know what this means then I
suggest doing some research on a concept called punctuated
equilibrium.) And, like I said above, they evolve a whole host
of strategies and traits at once to fit the lifestyle
requirements of the new niche. Consequently hominid evolution
could only have produced the dramatic shift to bipedalism if
it coincided with a complete shift to a new lifestyle that
involved the requirements of a new niche in a new ecosystem.
What is this new ecosystem and what is this new niche?
In the light of this understanding it becomes obvious what
steps a scientist should take with respect to assessing what
took place 8 to 10 mya in Africa with the emergence of this
new ecosystem. Obviously we'd want to be explicit about what
factors are in this new habitat that were not in the old
habitat. These new and different factors should introduce new
and different problems which they, our earliest hominid
ancestors, must overcome if they are to survive and
reproduce. Only after we have an explicit picture of the
ecological problems/opportunities in the new niche should be
venture to begin hypothesizing what shift in behavior best
explains the evidence.
I'm going to employ a very simple analytical method to attempt
the ends I describe in the above paragraph. I'm going to
subtract the factors in the ancestral habitat from the factors
in the new habitat. (See the "Formula" below.) The idea here
is to focus on the factors in the new environment that did not
exist in the ancestral environment. And we want to be as
explicit as possible so that we get an idea of what would have
been the implications of these new factors, and implications
of implications.
The data we will employ for this analysis is the following:
Source: http://www.sfu.ca/archaeology/dept/fac_bio/skinner/ar-
ch131/lecture5.htm
THE ANCESTRAL HABITAT: The Tropical Forest biome: tends to be
hot and humid with a 70 meter high rain forest canopy with
high precipitation up to 250 cm rain annually. In this canopy
habitat there are few predators with a great variety of food
in the form of fruit, insects. Tends to be ecologically
complex with many species of life but few individuals of
anyone species; treeshrews, prosimians, pongids, NW monkeys,
most OW monkeys, mandrill baboon (but on forest floor),
orangutans and gorillas and gibbons. Group Size tends to be
quite small usually less than 20.
THE NEW HABITAT: Woodland Savannah biome: tropical arid with
seasonal rainfall and woodland along stream margins where
primates tend to live with some venturing out into savannah;
some lemurs, chimps, baboons, Macaques; grass is primary food
source with nutrients locked up in tubers and bulbs. In this
habitat there are lots of grazers, browsers and predators; the
latter hunting in social packs (lions, hyenas, dogs);
consequently the primates tend to show group defence
strategies with well defined social roles which ensure
protection of young; group sizes tend to be larger with 20 to
40 (or even up to 100) in some baboon troops
Formula: THE NEW HABITAT minus THE ANCESTRAL HABITAT equals
WHAT IS DISTINCTIVE ABOUT THE NEW HABITAT
* CLIMATE *
THE NEW HABITAT: tropical arid with seasonal rainfall
Minus
THE ANCESTRAL HABITAT: tends to be hot and humid with high
precipitation up to 250 cm rain annually.
equals:
What I see here is the appearance of a monsoon climate. Much
of the year, maybe even most of the year, it would have been
very similar to the climate in the Tropical Forest biome (hot,
humid, daily rain and relatively little fluctuation in these
conditions). However, for large stretchs of months every year,
upwards of six months, the rain stops. This produces
dessication (dryness) and the implications of dryness: a
tendency for temperatures to fluctuate between hot during the
day and cold during the night.
* ENVIRONMENT *
THE NEW HABITAT: woodland along stream margins. Treeless,
savanna habitat in the surrounding areas. Primates tend to
live with in woodland along stream margins where, some
venturing out into treeless savannah; some lemurs, chimps,
baboons, Macaques.
Minus
THE ANCESTRAL HABITAT: Forest canopy 70 meters high. (Note:
little sunshine makes it to the ground.) This rainforest
habitat would have been extensive, continuous, and relatively
uninterrupted by treeless habitat.
equals:
Treed habitat would have been more patchy and isolated at
locations close to sources of perrenial water, lakes,
rivers, streams, areas with high ground water. (Note: the
size of these remaining patches of treed habitat would have,
firstly, varied greatly from patch to patch and, secondly,
these patches might have been larger than we tend to assume.
It was considerably wetter back then that it is now in
Eastern Africa.)
* FOOD *
THE NEW HABITAT: Grass is primary food source with nutrients
locked up in tubers and bulbs.
Minus
THE ANCESTRAL HABITAT: forest canopy (extensive, continuous
and uninterrupted by treeless habitat. A great variety of food
in the form of fruit, insects.
equals:
I think there would have continued to be fruit and insects in
these remaining patches of treed habitat. However, with the
disappearance of the canopy there would have been more
sunlight hitting the ground within these patches. This would
have produced more foodstuff on the ground, such as tubers,
bulbs, and even grasses for our primate ancestors.
* PREDATION *
THE NEW HABITAT: Lots of predators. They have a tendency to
hunt social packs (lions, hyenas, dogs).
Minus
THE ANCESTRAL HABITAT: Few predators
equals:
Obviously our ancestors now found themselves in a much more
hostile habitat. One that is populated by predators bigger
than they themselves.
* INTERSPECIES COMPETITION *
THE NEW HABITAT: In this habitat there are lots of grazers,
browsers. We also find some lemurs, baboons, Macaques;
primates tend to show group defence strategies with well
defined social roles which ensure protection of young; group
sizes tend to be larger with 20 to 40 (or even up to 100) in
some baboon troops.
Minus
THE ANCESTRAL HABITAT: Tends to be ecologically complex with
many species of life but few individuals of anyone species;
treeshrews, prosimians, pongids, NW monkeys, most OW monkeys,
mandrill baboon (but on forest floor), orangutans and
gorillas and gibbons. Group Size tends to be quite small
usually less than 20;
equals:
This new habitat has a lot more competition from grazers and
browsers, which did not exist in the ancestral habitat. Also
we see a relative explosion of social stratetgies/adaptations
in all species in this new habitat. The competitive nature of
this new habitat tends to be relatively more group vs. group.
Comprehensive Analysis:
The next step is to put all of this together and see if we can
paint a larger picture of how these implications would have
effected our chimpanzeelike ancestors.
The following factors were precipitated out of the post
quoted above:
(1) The Emergence of Monsoon Climate: Warmer and wetter than
is the climate currently at this region of Africa but with
a distinct and severe dry season.
(2) The Emergence of Grassland Habitat: The dissipation of
the rainforest and emergence of grasslands and resulting
patchiness of the remaining forest habitat, which
persisted at locations where water was perrenially
available (rivers, streams, lakes, areas with high
ground water).
(3) The Emergence of Mosaic of Habitats: The resulting spatial
mixture of grassland and forest habitat produces an
environment that is less predictable from location to
location or from one point in time to another than had
been the rainforest habitat.
(4) The Emergence of the Ethiopian Fauna: relatively large,
intelligent, and fast moving (quadrupedal) browsing and
grazing mammals; and large, intelligent, fast moving
predatory mammals that prey upon these large browsing and
grazing mammals.
(5) The Emergence Ground based foodstuffs: With the
disappearance of the forest canopy came a shift of
foodstuff toward the ground, tubers, bulbs, and even
grasses, in and in the vicinity of the remaining patches
of forested habitat.
(6) The Emergence of Social Strategies: primates, grazers,
browsers, predators and mammals in general.
When we put all of these factors together we get a sense of a
very different habitat than the rainforest habitat. Most
notably it is the inclusion of a severe dry season that puts a
sense of foreboding in the environment. The onset of a period
of dryness may have been especially unforgiving to the
primates in this biome, including our chimpanzeelike
ancestors, in that being adapted to arboreality they were less
able to travel from one isolated forested location to another.
Consequently, if the foodstuff in at these locations--
regardless of whether it is up in trees or on the
ground--becomes depleted then this does not bode well for
their survival through the depths of the dry season.
Complicating the situational factors in the above paragraph
would have been the seasonal migration of browser, grazers,
and the predators that followed them. With the onset of
seasonal dessication we would expect these animals to
generally migrate from the more dessicate grassland and into
the treed patches. This supposition, in conjuction with the
fact that foodstuff, tubers, bulbs, and grasses, were now more
prevalent on the ground than it had been in the rainforest
habitat, indicates there would have been dramatic competition
between the primates at these treed patches and the
inmigrating browsers and grazers during these periods of
seasonal dessication. And this competition may have been
especially dramatic for our chimpanzee-like ancestors in that
they were generally more preadapted to ground conditions than
were other primates and, consequently, were more dependent on
the availability of ground based and low-branch foodstuffs
than would have been the smaller primates that could more
readily find food and avoid predators in the higher branches.
The picture that is starting to emerge in the above paragraphs
is one whereby our chimpanzee-like ancestor's fate was more
closely linked with the relative level of scarcity/abundance
at their particular treed patch. The inclusion of predators in
this scenario, most notably large and intelligent predators
that employ social hunting strategies, provides us, IMO, even
more of a reason to hypothesize this linkage. Firstly, the
strategy of primates to avoid predation involves trees as
refuge. Not only does this supposition serve as a rationale
for the conjecture that they were isolated at these treed
patches, as indicated above, but it provides us an
understanding of why the selective factors of this scenario
would have been so closely linked with the relative level of
scarcity/abundance at their particular treed patch. When the
resources at a particular treed patch (community site) became
depleted the primates therein would have little choice but to
spend more time foraging and, consequently, more time away
from the trees thus becoming more vulnerable to predators.
Predators are always looking for vulnerabilities. It seems
likely they would have noticed that the primates at one treed
patch were easier pickings and, consequently, they would have
concentrated their efforts at these treed patches.
Consequently, the primates at treed patches (community sites)
that are more depleted would be more likely to be decimated by
predation. Those at treed patches (community sites) that were
relatively more abundant--regardless of causal factors
underlying this relative abundance--would tend to be ignored
by predators.
Given these situational factors, what adaptations/behaviors
would we expect to emerge for our chimpanzee-like ancestor?
Would this or would this not indicate a shift to communal
territorialism and its associated mob oriented, stick
wielding, rock throwing aggression as indicated in my
Ecological Gatekeeper Hypothesis?
Ecological Gatekeeper Hypothesis
I started thinking about migration in the context of the
environmental assumptions of my hypothesis: seasonal
dessication, spatial polarity of resources (patches of forest
that persist near sources of perrenial water, lakes, ponds,
streams, rivers, areas of high ground water). (For a more
comprehensive description of the environmental assumptions of
this hypothesis see a post I put on this newsgroup recently
entitled: Questions Regarding Selective . . . ) Then I asked
myself what kind of migrational patterns would I expect given
these assumptions. The answer was obvious. During periods
[of] increasing dessication and resulting scarcity there
would be a tendency for all of the species in this
environment to begin to migrate toward and into these treed
havens, our ancestor's "community sites." And with the onset
of the rainy season they would migrate back out again. Then I
started thinking about how all of this would appear from the
perspective of our earliest, recently rainforest dwelling,
prehominid ancestors. Every year their patches of remaining
forest, their "community sites," got overrun with other
species. Many of these species would have competed directly
with them for food and thus would have caused the depletion
of resources at a time when these resources were increasingly
scarce, the dry season. Other herbivores may not have
directly competed with them, but all of them brought
predators with them: lions, tigers, hyenas, dogs, etc. The
negative implications are obvious. When these inmigrating
species had depleted the resources at these community sites
they would simply migrate over to other less depleted areas
(other community sites). But our tree dwelling ancestors,
being less mobile, had fewer options. They were now left
vulnerable to starvation and/or predation. Lacking the
ability to run fast, they didn't have much choice but to stay
put, wait out the predators, and hope the rains returned.
Surely their population would often have been decimated as a
result. Among a number of other adaptations, which I will get
to shortly, I predict that territorial based peskiness will
have begun to be selected among our chimpanzee-like ancestor.
This would have been a direct result of the above described
factors associated with migration. The reason I believe this
scenario predicts the relatively rapid adaptation of
territorial based peskiness behaviors among these still tree
dwelling apes is because apes that have such predisposition
will tend to harass any other animals that it percieves to be
trespassing on its territory. This will act as a deterent to
these inmigrating species who--all other things being
equal--will follow the path of least resistance to their
migratory goals. If one patch of forest is associated with
pesky apes-- regardless of the fact that these pesky apes may
be mostly harmless to them--and another patch of forest is
relatively free of pesky apes then the inmigrating
individuals would follow the path of least resistance to the
patch that is relatively free of pesky apes. More
specifically, how and why do I contend that these above
mentioned implications predict the rapid adaptation of
territorial peskiness amongst our earliest prehominid
ancestors? I think the answer to this question is fairly
obvious. The members of community sites that reduced
inmigration, even if only marginally (let's say, for example,
they reduced it by only 10%), would increase their own
community's probability of surviving through and, at one and
the same time, reduce the probability of survival of those
who reside at other, neighboring, community sites who,
lacking territorial based peskiness behaviors, would now have
to deal with more inmigration and, of course, more of the
negative implications thereof: more depletion of resources,
more predators, and more resulting decimation. This comprises
a classic group selectionist scenario: behavior that
increases one's own communities survival decreases the
survival of other communities. This is not to say that the
members of these respective communities would have had the
ability to recognize that they were competing against other
communities on a community vs. community basis. In fact it
seems unlikely--especially in the earliest years of hominid
evolution--that they would have even had the ability to
recognize that they were members of communities. Regardless
of wether they were capable of realizing it, apes that had
whatever behavior and/or morphology that would enable or
cause them to dissuade other species from migrating into
their community site would have a tremendous selective
advantage over those that lacked such. The more their
behavior dissuaded inmigration the greater the selective
advantage to their own community and the greater the
selective disadvantage to neighboring communities. It is, of
course, normal to be hesitant about asserting group selective
factors such as those that I have asserted here. But in the
context of this scenario this hesitancy is, I contend,
completely unwarranted. ?This contention is based on the
group selective implications of the two factors mentions
above, 1) the patchiness of the remaining forested habitat
which divided our ancestors up into "communities" between
which gene flow (interbreeding) was greatly reduced, and 2)
the fact that the grim reaper,seasonal dessication, focussed
on whole communities whose territorial resources at their
community sites had become, for whatever reason, deplete. So,
the selective realities of our ancestors shifted from those
of the chimpanzee lifestyle--focussed only on being
successful individuals and members of successful breeding
groups (bands, extended family units)--to those of the A'pith
lifestyle--focussed on being successful individuals and
members of successful breeding groups AND on being members of
communities that successfully effect the preservation of
resources at their community sites in the face of the
onslaught of multi-species inmigration to their community
sites. It is also important to point out that there is a
positive feedback aspect associated with inmigration.
Specifically this has to do with the herding or grouping
instincts of the inmigrating species: if one or a few members
of an inmigrating species is able to infiltrate a community
site then the probability is higher that more members of the
same species, and/or members of ecologically related species,
will follow. When this aspect is considered in conjunction
with the fact that this scenario clearly indicates the
community as the group entity that is being selected, it is
apparent, I contend, that the better a community is at
closing the gate of its ecosystem--sealing its borders--the
more likely the members of the community will survive the
grim reaper of this habitat, seasonal dessication (the dry
season). In the context of these peculiar selective factors,
we can start to ask ourselves what other adaptations, in
addition to territorial peskiness, would we expect to evolve?
This can be more explicitly delineated in the context of what
is mentioned in the above paragraph: what additional
behaviors or morphologies would cause/enable these
chimpanzee-like territorially pesky apes to be better able
and/or more inclined to "close the gate" and effectively seal
the borders of their community sites? I propose the
following: Cooperation (in the context of mob oriented
harassing behaviors): The tendency to confront and attempt to
prevent inmigrating species collectively rather than just
individually. This would involve collecting into larger
groups from neighboring and other closely situated
"properties" (see below) within a community site and
confronting inmigrating species: throwing rocks, sticks, and
generally making a big racket. As I envision it, this would
involve the same kind of emotion based behaviors that we
currently associate with a mob mentality, including sports
fanaticism. Communicativeness: The ability to communicate the
relative level of threat associated with potential
inmigrating species so that mobs can form at vulnerable
infiltration points quickly and efficiently. This also
involves such behaviors as cheering, booing, and other
behaviors that would tend to draw attention of other members
of a community to such events. Consciousness: Awareness of
the meaning of emotional outbursts that they might see or
hear in the distance so that one might be excited into being
additive to whatever mob oriented activities are taking place
in one's vicinity. Awareness of the property of others due to
the implications of the, below mentioned, selective benefits
of property oriented communal territorialism. Property
Oriented Communal Territorialism (rather than just communally
oriented territorialism): Property oriented communal
territorialism involves a community being comprised of
subgroups each of which has its associated property in the
context of the larger community site. The reason, I contend,
that we would predict property oriented territorialism is
because this would, firstly, cause them--by way of their
percieved incentive--to spread out to the different
infiltration points of the community site so that they will
be in position to better effect the collective sealing of the
community sites borders. Secondly, property oriented
territorialism will give them the percieved incentive to
defend "their" property. (Which, as indicated above, could
also include calling out to one's neighboring property
holders for assitance to effect a mob and/or responding to
one's neighbors call for assistance.) The particular group
that I envision as the entity that maintains ownership of the
different intracommunal "properties" of a community site
would be based upon the band or extended family unit, similar
in size and composition to that of the bands that extant
chimpanzees tend to form. Gamesmanship: I think it's possible
that the behavior that is indicated in this hypothesis was to
they themselves little more than a game. ?Those who were
passionate about the game achieved the survival of themselves
and their whole community (by way of driving off inmigrating
species). (In other words, we're descended from sports
enthusiasts.) Also, this scenario gives us a sense of how and
why we evolved to be so controlling of other species. It even
suggests how we began to develop our weapon oriented hunting
skills and inclination, not to mention our weapon oriented
and mob oriented approach to intraspecies conflicts (war). (I
can foresee there being "Hunting Hypothesis," variants of
this hypothesis.) Additionally, this scenario is the perfect
setup for the scenario in my larger hypothesis (which I now
realize is much more dependent upon the pre-existence of a
community), which better explains the evolution of other
hominid traits, such as our political, ideological nature,
our attentiveness to dance, art, storytelling, and other
artistic, our economic predisposition for trade, our complex
and logic oriented languages, and our pursuit of knowledge
and truth. However, the beginning of the dynamics in my
greater hypothesis (the Intraspecies Capitalism stuff which
is very difficult to explain), may have to be pushed forward
in time all the way up to the transition to homo. But this
may be a good thing in that it better coorelates to the
growth of brain capacity in the homo lineage (which, as you
know, is greatly lacking in the A'pith lineage).
New species don't just spring up out of the blue. They are
part and parcel to new biomes (ecosystems). Likewise new
biomes don't just spring up out of the blue, they are the
result of changes in environments/climatic conditions.
Here's the way speciation works. Ecosystems experience a
change in climate. The change in climate causes a period of
extreme stress whereupon a whole set of niches disappear and a
whole new set of niches appear. New species either find their
way to a new niche (and this almost always involves a whole
host of new adaptations and new behaviors being achieved
simultaneously rather than just one or two adaptations) or
they go extinct.
The gradualistic, just-so-story approach to understanding the
origins of new species, an approach to which all
paleoanthropologist subscribe, is an archaic approach that was
developed in the nineteenth century when ecological ignorance
was the rule. We know better now. Species evolve in a
punctuated fashion. (If you don't know what this means then I
suggest doing some research on a concept called punctuated
equilibrium.) And, like I said above, they evolve a whole host
of strategies and traits at once to fit the lifestyle
requirements of the new niche. Consequently hominid evolution
could only have produced the dramatic shift to bipedalism if
it coincided with a complete shift to a new lifestyle that
involved the requirements of a new niche in a new ecosystem.
What is this new ecosystem and what is this new niche?
In the light of this understanding it becomes obvious what
steps a scientist should take with respect to assessing what
took place 8 to 10 mya in Africa with the emergence of this
new ecosystem. Obviously we'd want to be explicit about what
factors are in this new habitat that were not in the old
habitat. These new and different factors should introduce new
and different problems which they, our earliest hominid
ancestors, must overcome if they are to survive and
reproduce. Only after we have an explicit picture of the
ecological problems/opportunities in the new niche should be
venture to begin hypothesizing what shift in behavior best
explains the evidence.
I'm going to employ a very simple analytical method to attempt
the ends I describe in the above paragraph. I'm going to
subtract the factors in the ancestral habitat from the factors
in the new habitat. (See the "Formula" below.) The idea here
is to focus on the factors in the new environment that did not
exist in the ancestral environment. And we want to be as
explicit as possible so that we get an idea of what would have
been the implications of these new factors, and implications
of implications.
The data we will employ for this analysis is the following:
Source: http://www.sfu.ca/archaeology/dept/fac_bio/skinner/ar-
ch131/lecture5.htm
THE ANCESTRAL HABITAT: The Tropical Forest biome: tends to be
hot and humid with a 70 meter high rain forest canopy with
high precipitation up to 250 cm rain annually. In this canopy
habitat there are few predators with a great variety of food
in the form of fruit, insects. Tends to be ecologically
complex with many species of life but few individuals of
anyone species; treeshrews, prosimians, pongids, NW monkeys,
most OW monkeys, mandrill baboon (but on forest floor),
orangutans and gorillas and gibbons. Group Size tends to be
quite small usually less than 20.
THE NEW HABITAT: Woodland Savannah biome: tropical arid with
seasonal rainfall and woodland along stream margins where
primates tend to live with some venturing out into savannah;
some lemurs, chimps, baboons, Macaques; grass is primary food
source with nutrients locked up in tubers and bulbs. In this
habitat there are lots of grazers, browsers and predators; the
latter hunting in social packs (lions, hyenas, dogs);
consequently the primates tend to show group defence
strategies with well defined social roles which ensure
protection of young; group sizes tend to be larger with 20 to
40 (or even up to 100) in some baboon troops
Formula: THE NEW HABITAT minus THE ANCESTRAL HABITAT equals
WHAT IS DISTINCTIVE ABOUT THE NEW HABITAT
* CLIMATE *
THE NEW HABITAT: tropical arid with seasonal rainfall
Minus
THE ANCESTRAL HABITAT: tends to be hot and humid with high
precipitation up to 250 cm rain annually.
equals:
What I see here is the appearance of a monsoon climate. Much
of the year, maybe even most of the year, it would have been
very similar to the climate in the Tropical Forest biome (hot,
humid, daily rain and relatively little fluctuation in these
conditions). However, for large stretchs of months every year,
upwards of six months, the rain stops. This produces
dessication (dryness) and the implications of dryness: a
tendency for temperatures to fluctuate between hot during the
day and cold during the night.
* ENVIRONMENT *
THE NEW HABITAT: woodland along stream margins. Treeless,
savanna habitat in the surrounding areas. Primates tend to
live with in woodland along stream margins where, some
venturing out into treeless savannah; some lemurs, chimps,
baboons, Macaques.
Minus
THE ANCESTRAL HABITAT: Forest canopy 70 meters high. (Note:
little sunshine makes it to the ground.) This rainforest
habitat would have been extensive, continuous, and relatively
uninterrupted by treeless habitat.
equals:
Treed habitat would have been more patchy and isolated at
locations close to sources of perrenial water, lakes,
rivers, streams, areas with high ground water. (Note: the
size of these remaining patches of treed habitat would have,
firstly, varied greatly from patch to patch and, secondly,
these patches might have been larger than we tend to assume.
It was considerably wetter back then that it is now in
Eastern Africa.)
* FOOD *
THE NEW HABITAT: Grass is primary food source with nutrients
locked up in tubers and bulbs.
Minus
THE ANCESTRAL HABITAT: forest canopy (extensive, continuous
and uninterrupted by treeless habitat. A great variety of food
in the form of fruit, insects.
equals:
I think there would have continued to be fruit and insects in
these remaining patches of treed habitat. However, with the
disappearance of the canopy there would have been more
sunlight hitting the ground within these patches. This would
have produced more foodstuff on the ground, such as tubers,
bulbs, and even grasses for our primate ancestors.
* PREDATION *
THE NEW HABITAT: Lots of predators. They have a tendency to
hunt social packs (lions, hyenas, dogs).
Minus
THE ANCESTRAL HABITAT: Few predators
equals:
Obviously our ancestors now found themselves in a much more
hostile habitat. One that is populated by predators bigger
than they themselves.
* INTERSPECIES COMPETITION *
THE NEW HABITAT: In this habitat there are lots of grazers,
browsers. We also find some lemurs, baboons, Macaques;
primates tend to show group defence strategies with well
defined social roles which ensure protection of young; group
sizes tend to be larger with 20 to 40 (or even up to 100) in
some baboon troops.
Minus
THE ANCESTRAL HABITAT: Tends to be ecologically complex with
many species of life but few individuals of anyone species;
treeshrews, prosimians, pongids, NW monkeys, most OW monkeys,
mandrill baboon (but on forest floor), orangutans and
gorillas and gibbons. Group Size tends to be quite small
usually less than 20;
equals:
This new habitat has a lot more competition from grazers and
browsers, which did not exist in the ancestral habitat. Also
we see a relative explosion of social stratetgies/adaptations
in all species in this new habitat. The competitive nature of
this new habitat tends to be relatively more group vs. group.
Comprehensive Analysis:
The next step is to put all of this together and see if we can
paint a larger picture of how these implications would have
effected our chimpanzeelike ancestors.
The following factors were precipitated out of the post
quoted above:
(1) The Emergence of Monsoon Climate: Warmer and wetter than
is the climate currently at this region of Africa but with
a distinct and severe dry season.
(2) The Emergence of Grassland Habitat: The dissipation of
the rainforest and emergence of grasslands and resulting
patchiness of the remaining forest habitat, which
persisted at locations where water was perrenially
available (rivers, streams, lakes, areas with high
ground water).
(3) The Emergence of Mosaic of Habitats: The resulting spatial
mixture of grassland and forest habitat produces an
environment that is less predictable from location to
location or from one point in time to another than had
been the rainforest habitat.
(4) The Emergence of the Ethiopian Fauna: relatively large,
intelligent, and fast moving (quadrupedal) browsing and
grazing mammals; and large, intelligent, fast moving
predatory mammals that prey upon these large browsing and
grazing mammals.
(5) The Emergence Ground based foodstuffs: With the
disappearance of the forest canopy came a shift of
foodstuff toward the ground, tubers, bulbs, and even
grasses, in and in the vicinity of the remaining patches
of forested habitat.
(6) The Emergence of Social Strategies: primates, grazers,
browsers, predators and mammals in general.
When we put all of these factors together we get a sense of a
very different habitat than the rainforest habitat. Most
notably it is the inclusion of a severe dry season that puts a
sense of foreboding in the environment. The onset of a period
of dryness may have been especially unforgiving to the
primates in this biome, including our chimpanzeelike
ancestors, in that being adapted to arboreality they were less
able to travel from one isolated forested location to another.
Consequently, if the foodstuff in at these locations--
regardless of whether it is up in trees or on the
ground--becomes depleted then this does not bode well for
their survival through the depths of the dry season.
Complicating the situational factors in the above paragraph
would have been the seasonal migration of browser, grazers,
and the predators that followed them. With the onset of
seasonal dessication we would expect these animals to
generally migrate from the more dessicate grassland and into
the treed patches. This supposition, in conjuction with the
fact that foodstuff, tubers, bulbs, and grasses, were now more
prevalent on the ground than it had been in the rainforest
habitat, indicates there would have been dramatic competition
between the primates at these treed patches and the
inmigrating browsers and grazers during these periods of
seasonal dessication. And this competition may have been
especially dramatic for our chimpanzee-like ancestors in that
they were generally more preadapted to ground conditions than
were other primates and, consequently, were more dependent on
the availability of ground based and low-branch foodstuffs
than would have been the smaller primates that could more
readily find food and avoid predators in the higher branches.
The picture that is starting to emerge in the above paragraphs
is one whereby our chimpanzee-like ancestor's fate was more
closely linked with the relative level of scarcity/abundance
at their particular treed patch. The inclusion of predators in
this scenario, most notably large and intelligent predators
that employ social hunting strategies, provides us, IMO, even
more of a reason to hypothesize this linkage. Firstly, the
strategy of primates to avoid predation involves trees as
refuge. Not only does this supposition serve as a rationale
for the conjecture that they were isolated at these treed
patches, as indicated above, but it provides us an
understanding of why the selective factors of this scenario
would have been so closely linked with the relative level of
scarcity/abundance at their particular treed patch. When the
resources at a particular treed patch (community site) became
depleted the primates therein would have little choice but to
spend more time foraging and, consequently, more time away
from the trees thus becoming more vulnerable to predators.
Predators are always looking for vulnerabilities. It seems
likely they would have noticed that the primates at one treed
patch were easier pickings and, consequently, they would have
concentrated their efforts at these treed patches.
Consequently, the primates at treed patches (community sites)
that are more depleted would be more likely to be decimated by
predation. Those at treed patches (community sites) that were
relatively more abundant--regardless of causal factors
underlying this relative abundance--would tend to be ignored
by predators.
Given these situational factors, what adaptations/behaviors
would we expect to emerge for our chimpanzee-like ancestor?
Would this or would this not indicate a shift to communal
territorialism and its associated mob oriented, stick
wielding, rock throwing aggression as indicated in my
Ecological Gatekeeper Hypothesis?
Ecological Gatekeeper Hypothesis
I started thinking about migration in the context of the
environmental assumptions of my hypothesis: seasonal
dessication, spatial polarity of resources (patches of forest
that persist near sources of perrenial water, lakes, ponds,
streams, rivers, areas of high ground water). (For a more
comprehensive description of the environmental assumptions of
this hypothesis see a post I put on this newsgroup recently
entitled: Questions Regarding Selective . . . ) Then I asked
myself what kind of migrational patterns would I expect given
these assumptions. The answer was obvious. During periods
[of] increasing dessication and resulting scarcity there
would be a tendency for all of the species in this
environment to begin to migrate toward and into these treed
havens, our ancestor's "community sites." And with the onset
of the rainy season they would migrate back out again. Then I
started thinking about how all of this would appear from the
perspective of our earliest, recently rainforest dwelling,
prehominid ancestors. Every year their patches of remaining
forest, their "community sites," got overrun with other
species. Many of these species would have competed directly
with them for food and thus would have caused the depletion
of resources at a time when these resources were increasingly
scarce, the dry season. Other herbivores may not have
directly competed with them, but all of them brought
predators with them: lions, tigers, hyenas, dogs, etc. The
negative implications are obvious. When these inmigrating
species had depleted the resources at these community sites
they would simply migrate over to other less depleted areas
(other community sites). But our tree dwelling ancestors,
being less mobile, had fewer options. They were now left
vulnerable to starvation and/or predation. Lacking the
ability to run fast, they didn't have much choice but to stay
put, wait out the predators, and hope the rains returned.
Surely their population would often have been decimated as a
result. Among a number of other adaptations, which I will get
to shortly, I predict that territorial based peskiness will
have begun to be selected among our chimpanzee-like ancestor.
This would have been a direct result of the above described
factors associated with migration. The reason I believe this
scenario predicts the relatively rapid adaptation of
territorial based peskiness behaviors among these still tree
dwelling apes is because apes that have such predisposition
will tend to harass any other animals that it percieves to be
trespassing on its territory. This will act as a deterent to
these inmigrating species who--all other things being
equal--will follow the path of least resistance to their
migratory goals. If one patch of forest is associated with
pesky apes-- regardless of the fact that these pesky apes may
be mostly harmless to them--and another patch of forest is
relatively free of pesky apes then the inmigrating
individuals would follow the path of least resistance to the
patch that is relatively free of pesky apes. More
specifically, how and why do I contend that these above
mentioned implications predict the rapid adaptation of
territorial peskiness amongst our earliest prehominid
ancestors? I think the answer to this question is fairly
obvious. The members of community sites that reduced
inmigration, even if only marginally (let's say, for example,
they reduced it by only 10%), would increase their own
community's probability of surviving through and, at one and
the same time, reduce the probability of survival of those
who reside at other, neighboring, community sites who,
lacking territorial based peskiness behaviors, would now have
to deal with more inmigration and, of course, more of the
negative implications thereof: more depletion of resources,
more predators, and more resulting decimation. This comprises
a classic group selectionist scenario: behavior that
increases one's own communities survival decreases the
survival of other communities. This is not to say that the
members of these respective communities would have had the
ability to recognize that they were competing against other
communities on a community vs. community basis. In fact it
seems unlikely--especially in the earliest years of hominid
evolution--that they would have even had the ability to
recognize that they were members of communities. Regardless
of wether they were capable of realizing it, apes that had
whatever behavior and/or morphology that would enable or
cause them to dissuade other species from migrating into
their community site would have a tremendous selective
advantage over those that lacked such. The more their
behavior dissuaded inmigration the greater the selective
advantage to their own community and the greater the
selective disadvantage to neighboring communities. It is, of
course, normal to be hesitant about asserting group selective
factors such as those that I have asserted here. But in the
context of this scenario this hesitancy is, I contend,
completely unwarranted. ?This contention is based on the
group selective implications of the two factors mentions
above, 1) the patchiness of the remaining forested habitat
which divided our ancestors up into "communities" between
which gene flow (interbreeding) was greatly reduced, and 2)
the fact that the grim reaper,seasonal dessication, focussed
on whole communities whose territorial resources at their
community sites had become, for whatever reason, deplete. So,
the selective realities of our ancestors shifted from those
of the chimpanzee lifestyle--focussed only on being
successful individuals and members of successful breeding
groups (bands, extended family units)--to those of the A'pith
lifestyle--focussed on being successful individuals and
members of successful breeding groups AND on being members of
communities that successfully effect the preservation of
resources at their community sites in the face of the
onslaught of multi-species inmigration to their community
sites. It is also important to point out that there is a
positive feedback aspect associated with inmigration.
Specifically this has to do with the herding or grouping
instincts of the inmigrating species: if one or a few members
of an inmigrating species is able to infiltrate a community
site then the probability is higher that more members of the
same species, and/or members of ecologically related species,
will follow. When this aspect is considered in conjunction
with the fact that this scenario clearly indicates the
community as the group entity that is being selected, it is
apparent, I contend, that the better a community is at
closing the gate of its ecosystem--sealing its borders--the
more likely the members of the community will survive the
grim reaper of this habitat, seasonal dessication (the dry
season). In the context of these peculiar selective factors,
we can start to ask ourselves what other adaptations, in
addition to territorial peskiness, would we expect to evolve?
This can be more explicitly delineated in the context of what
is mentioned in the above paragraph: what additional
behaviors or morphologies would cause/enable these
chimpanzee-like territorially pesky apes to be better able
and/or more inclined to "close the gate" and effectively seal
the borders of their community sites? I propose the
following: Cooperation (in the context of mob oriented
harassing behaviors): The tendency to confront and attempt to
prevent inmigrating species collectively rather than just
individually. This would involve collecting into larger
groups from neighboring and other closely situated
"properties" (see below) within a community site and
confronting inmigrating species: throwing rocks, sticks, and
generally making a big racket. As I envision it, this would
involve the same kind of emotion based behaviors that we
currently associate with a mob mentality, including sports
fanaticism. Communicativeness: The ability to communicate the
relative level of threat associated with potential
inmigrating species so that mobs can form at vulnerable
infiltration points quickly and efficiently. This also
involves such behaviors as cheering, booing, and other
behaviors that would tend to draw attention of other members
of a community to such events. Consciousness: Awareness of
the meaning of emotional outbursts that they might see or
hear in the distance so that one might be excited into being
additive to whatever mob oriented activities are taking place
in one's vicinity. Awareness of the property of others due to
the implications of the, below mentioned, selective benefits
of property oriented communal territorialism. Property
Oriented Communal Territorialism (rather than just communally
oriented territorialism): Property oriented communal
territorialism involves a community being comprised of
subgroups each of which has its associated property in the
context of the larger community site. The reason, I contend,
that we would predict property oriented territorialism is
because this would, firstly, cause them--by way of their
percieved incentive--to spread out to the different
infiltration points of the community site so that they will
be in position to better effect the collective sealing of the
community sites borders. Secondly, property oriented
territorialism will give them the percieved incentive to
defend "their" property. (Which, as indicated above, could
also include calling out to one's neighboring property
holders for assitance to effect a mob and/or responding to
one's neighbors call for assistance.) The particular group
that I envision as the entity that maintains ownership of the
different intracommunal "properties" of a community site
would be based upon the band or extended family unit, similar
in size and composition to that of the bands that extant
chimpanzees tend to form. Gamesmanship: I think it's possible
that the behavior that is indicated in this hypothesis was to
they themselves little more than a game. ?Those who were
passionate about the game achieved the survival of themselves
and their whole community (by way of driving off inmigrating
species). (In other words, we're descended from sports
enthusiasts.) Also, this scenario gives us a sense of how and
why we evolved to be so controlling of other species. It even
suggests how we began to develop our weapon oriented hunting
skills and inclination, not to mention our weapon oriented
and mob oriented approach to intraspecies conflicts (war). (I
can foresee there being "Hunting Hypothesis," variants of
this hypothesis.) Additionally, this scenario is the perfect
setup for the scenario in my larger hypothesis (which I now
realize is much more dependent upon the pre-existence of a
community), which better explains the evolution of other
hominid traits, such as our political, ideological nature,
our attentiveness to dance, art, storytelling, and other
artistic, our economic predisposition for trade, our complex
and logic oriented languages, and our pursuit of knowledge
and truth. However, the beginning of the dynamics in my
greater hypothesis (the Intraspecies Capitalism stuff which
is very difficult to explain), may have to be pushed forward
in time all the way up to the transition to homo. But this
may be a good thing in that it better coorelates to the
growth of brain capacity in the homo lineage (which, as you
know, is greatly lacking in the A'pith lineage).