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

• 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

56% corn

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 Cycle1. 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 Stagesfor Various Animal Species

Diameter of Birth Canal and Head Length and Breadth of Newborns

Providing for Juveniles (Table 13-3)Percent Who Survive

Weaning AdolescenceLion 28 15Baboon 45 33Macaque 42 13Chimpanzee 48 38Human Populations!Kung 80 58Yanomamo 73 50Paleoindian 86 50

Life Spans (Table 13-4)

OrganismApproximate Maximum

Life Span (in years)Bristlecone pine 5,000

Tortoise 170Human 120

Blue whale 80Indian elephant 70

Gorilla 39Domestic dog 34

Rabbit 13Rat 5

The Loss of BiodiversityThe Loss of Biodiversity

• BiodiversityBiodiversity is the totality of all living things, from is the totality of all living things, from bacteria and fungi to trees and humans.bacteria and fungi to trees and humans.

• We are currently losing biodiversity, but we don’t know We are currently losing biodiversity, but we don’t know the exact rate of loss or what its impact will be.the exact rate of loss or what its impact will be.

• The geological record indicates that in the past 570 The geological record indicates that in the past 570 million years, there have been at least 15 mass million years, there have been at least 15 mass extinction events, two of which altered all of the extinction events, two of which altered all of the earth’s ecosystems.earth’s ecosystems.

Mass Extinction EventsMass Extinction Events Occurring now? Occurring now?

Many scientists believe several large mammalian species were pushed Many scientists believe several large mammalian species were pushed toward extinction by humans, near the end of the Pleistocene, some toward extinction by humans, near the end of the Pleistocene, some 10,000 years ago. 10,000 years ago.

In North America, at least 57 mammalian species became extinct, In North America, at least 57 mammalian species became extinct, including the mammoth, mastodon, giant ground sloth, saber-toothed including the mammoth, mastodon, giant ground sloth, saber-toothed cat, several large rodents, and numerous grazing animals.cat, several large rodents, and numerous grazing animals.