The Human Life Course and
Population
Chapter 13/14
7 Billion people
• National Geographic
• What’s Your Number? The World at 7 Billion
7 Billion people
• Issues of contraception—who gets to make up
the rules?
• Hans Rosling
– "There was an unmet need for contraceptive
services, of course. But there was also an unmet
need for health services and all kinds of other
services which did not get attention. The focus
became contraception." –BBC
7 Billion people
• "Not to have a full set of health services meant women
were either unable to use family planning, or unwilling to because they could still expect half their kids to die by the
age of five.” --BBC
• Worldwide, major causes of childhood death are infectious
diseases exacerbated by poor nutrition
• 70% of deaths (birth to 4 years old) are due to diarrhea,
respiratory infections, malaria
– …..and diseases for which immunizations are available
• 83% of the deaths are indirectly attributable to
malnutrition
• Leading causes of childhood death in the US and western
Europe are accidents, followed by preterm births
7 Billion people
• "There was an unmet need for contraceptive
services, of course. But there was also an unmet
need for health services and all kinds of other
services which did not get attention. The focus
became contraception." –BBC
• To feed large sedentary populations, easily
producible, cheap foods are needed and were
developed when homo sapiens became
sedentary…
The “Paleo” Diet
• Prior to 10,000 years ago…
– High in Animal Protein, low in fat…particularly saturated
fat
– High in complex carbohydrates (including fiber)
• Human health declined in most parts of the world,
beginning about 10,000 (The Neolithic Transition)
years ago…
• The Ability to Store Fat
– Feast and Famine adaptations in the Mesolithic lead to
obesity and health problems in the Paleolithic
Once adaptive, now maladaptive
What are the cheapest and
most highly caloric foods
you can buy?
Once adaptive, now maladaptive
56% corn
• 80% of new cases of type 2 diabetes appearing between now
and 2025 will be in developing nations
• Type 2 diabetes, linked to poor diet and inadequate exercise,
occurring in children as young as 4
Preagricultural, Contemporary American, and
Recently Recommended Dietary Composition
Nutritional Requirements for Growth
• Nutrients needed for growth, development, and body
maintenance include: proteins, carbohydrates, fats,
vitamins and minerals.
• The amount we need of these nutrients coevolved with
foods available to humans throughout evolutionary
history.
• The specific pattern of amino acids required in human
nutrition (essential amino acids) reflects an ancestral
diet high in animal protein.
– The 9 (of 22) amino acids must be obtained from the food we
eat because they are not synthesized in the body in sufficient
amounts.
Factors Influencing
Growth and Development
• Genetics – set the underlying limitations and potentials for
growth and development
– Environmental factors can influence growth and
development, but an individual can not exceed their
genetic potential.
• Hormones – produced by endocrine glands
– Growth hormone has an impact on almost every cell in the
body.
– Cortisol, elevated during stress, suppresses normal
immune function during high levels
The Human Life Cycle
1. Prenatal begins with conception and ends with birth.
2. Infancy is period of nursing.
3. Childhood, or juvenile phase, is period from weaning to
sexual maturity (puberty in humans.)
4. Adolescence is from puberty to the end of growth.
5. Adulthood is the completion of growth.
6. Menopause beginning one full year after the last menstrual
cycle
Life Cycle Stages
for Various Animal Species
Diameter of Birth Canal and Head Length and
Breadth of Newborns
Providing for Juveniles (Table 13-3)
Lion
Baboon
Macaque
Chimpanzee
Human Populations
!Kung
Yanomamo
Paleoindian
Percent Who Survive
Weaning
Adolescence
28
15
45
33
42
13
48
38
80
73
86
58
50
50
Life Spans (Table 13-4)
Organism
Bristlecone pine
Tortoise
Human
Blue whale
Indian elephant
Gorilla
Domestic dog
Rabbit
Rat
Approximate Maximum
Life Span (in years)
5,000
170
120
80
70
39
34
13
5
The Loss of Biodiversity
• Biodiversity is the totality of all living things, from
bacteria and fungi to trees and humans.
• We are currently losing biodiversity, but we don’t know
the exact rate of loss or what its impact will be.
• The geological record indicates that in the past 570
million years, there have been at least 15 mass
extinction events, two of which altered all of the earth’s
ecosystems.
Mass Extinction Events
Occurring now?
Many scientists believe several large mammalian species were pushed
toward extinction by humans, near the end of the Pleistocene, some
10,000 years ago.
In North America, at least 57 mammalian species became extinct,
including the mammoth, mastodon, giant ground sloth, saber-toothed
cat, several large rodents, and numerous grazing animals.