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Southern New Hampshire University
ATH-101 Introduction to Anthropology
Module 3 Notes
Brief Overview of Climate: Our planet has experienced numerous geological changes
over its 4.5 billion years, affecting the climate. As far back as 1 billion years ago, we see for the
first time plate tectonics creating one large continent (Rodinia). Our planet at that point was
highly hostile and even lacked our current protective ozone layer. Rodinia broke up ~750
million years ago, and shortly after (geologically speaking), the climate became so cold the
planet was covered in ice (snowball earth). Moving forward some 400 million years, we see the
uniting of the plates into one continent called Pangea. The assemblage of Pangea brought about
an extreme climatic disruption, causing the collapse of terrestrial and oceanic ecosystems.
However, it did have its plus sides – it allowed for easy migration paths for plants and animals.
Its break-up ~205 million years ago allowed for the formation of the Atlantic Ocean and
eventually spread the Northern and Southern Hemispheres. Gondwanaland was another
supercontinent that existed in the southern hemisphere, including the continents of Antarctica,
India, Australia, South America, and Africa. It began to break up approximately 200
million years ago. These reconfigurations of the continents and oceans caused global
atmospheric and oceanic circulation patterns to change. These varying climatic changes
enormously impacted the plant and animals; some were beneficial while others were
Climate and Human Evolution: Human evolution and environmental changes occurred
concurrently. The earliest hypothesis on how the latter impacted the former was bipedalism
and/or toolmaking was associated with a drier habitat and the spread of grasslands (known as
(the savannah hypothesis). However, a newer theory states that critical events in human
evolution were shaped by environmental instability. This idea, developed by Dr. Rick Potts of
the Human Origins Program, is called variability selection. This hypothesis draws attention to
the variability observed in all environmental records and that the genus Homo was not limited to
a single type of environment. Throughout human evolution, human ancestors increased their
ability to cope with changing habitats rather than specializing in a single kind of environment.
How did hominins evolve the capacity to respond to shifting surroundings and new
environmental conditions (Climate Effects on Humans, 2016)?
One way that organisms can cope with environmental fluctuation is through genetic
adaptation, where several alleles, different versions of genes, are present in the population at
different frequencies. As conditions change, natural selection favors one allele or genetic variant
over another. Genes that facilitate various forms under different environments (phenotypic
plasticity) can also help an organism adapt to changing conditions. Another response to
environmental change is to evolve structures and behaviors that can be used to cope with
different environments” (Climates effects on human evolution, 2016).
Food Production on Human Development: Agriculture transformed small, mobile, and
relatively egalitarian groups of hunter-gatherers into sedentary societies based in built-up
villages and towns, which radically modified their natural environment using specialized
cultivation and storage technologies (e.g., irrigation) that allowed extensive surplus production.
These developments provided the basis for high population densities, complex labor
diversification, trading economies, centralized administrations, political structures, hierarchical
ideologies, and depersonalized systems of knowledge (e.g., property regimes and writing).
Domestication has been the most important cause of changes in human gene frequencies
in the past 10,000 years. Among the mechanisms responsible are: 1) the spread of human genes
from the agricultural homelands; 2) the evolution of genetic resistance factors (including blood
groups) to our new crowd of infectious diseases; 3) the evolution of adult-persistent lactase in
milk-consuming populations of northern Europe and several parts of Africa; 4) the enzyme
change that allowed for consumption of large quantities of nutritionally essential beer in western
Eurasia; 5) and the evolution of adaptations to a diet higher in simple carbohydrates, saturated
fats and (in modern times) calories and salt, and lower in fiber, complex carbohydrates, calcium,
and unsaturated fats, than the hunter-gatherer diet.
Consequences we see today as a result of moving from foraging to intensive agriculture include a
higher fat, sugar, and carb diet with less fiber and protein. Some grains, legumes, and other
foods we eat nearly daily interfere with our absorption of nutrients. Many health problems we
see today are related to our diet - obesity, diabetes, and heart disease. Food production has also
harmed our environment (e.g., fertilizers polluting our waterways).
The importance of an Anthropological Perspective (Cultural Relativism): As we study
human culture, we must be careful to appreciate the variety, inventiveness, and adaptability of
human societies, rather than impose our own cultural values and norms on other communities
through ethnocentric attitudes. In discovering how other people solve such dilemmas as habitat
degradation, resource distribution, and social unrest, we may find help in resolving these issues
ourselves. At the personal level, understanding the concepts of cultural anthropology, and
familiarizing ourselves with diverse lifestyles, helps us to interact with people of different
backgrounds in our everyday lives by thinking about their point of view.
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