Module 7 Flashcards
Dispite differences in social organization and mating behaviro, ape life histories are quite similar, especially in comparison with monkeys
- Larger body size
- Larger brain size
- Longer lifespan
- Slower reproductive rates
- Later age of first reproduction
- Longer investment in offspring
Orangutan (great apes)
- Lifespan ~ 50 + years - Age of first reproduction ~ 15 years - Interbirth Interval ~ 7-10 years - Age of weaning ~ 6 years - Infant mortality ~ 15% Body size ~ Males 190lbs ~ Females 85lbs - Brain size ~ 350g
Gorilla (great apes)
- Lifespan ~ 40+ years - First Reproduction ~ 10 Years - Interbirth Interval ~ 4 years - Age of weaning ~ 3 Years - Infant mortaldity ~ 25% - Body size ~ Males 350 lbs ~ Females 200 lbs - Brain size ~ 400 g
Chimpanzee (close to humans)
- Lifespan ~ 50+ years - First Reproduction ~ 14 Years - Interbirth Intervals ~ 5-6 years - AGe of weaning ~ 4 years - Infant mortality ~ 25% - body size ~ males 100 lbs ~ females 80 lbs - Brain size ~ 390 lbs
Monkey
- Lifespan ~ 25 years - First reprodiction ~ 6 yers - Interbirth Intervals ~ 2 years - Age of weaining ~ 1.5 years - Infant mortality ~50% - Body size ~ Mlaes 55 lbs ~ Femlaes 30 lbs - Brain size ~ 140g
Lemur
- lifespan ~ 18 years - First reproduction ~ 3 years - Interbirth interval ~ 1.2 years - Age of weaning ~ 6 months - Infant mortality ~ 50-70% - Body size ~ 5-8 lbs - Brain size ~ 24 g
Humans
- lifespan ~ 70-100 years - First reproduction ~ 18+ years - Interbirth Intervals ~ 1-4 years - age of weaning ~ 0-4 years (not independent until teens) - Infant mortality ~ 1-25% - Body size ~ males 95-190 lbs ~ females 90-160 lbs - Brain size ~ 1500 g
Much about human life can be explained simply because we are great aps
- to understand the reasons for slow life history in humans we need to look much further back in time (25 million years ago) than the emergence of our species (~300,000-800,000 years ago)
Characteristics of an extreme “slow” life history pattern
- long lifespan
- later age of maturity
- Low infant mortality
Many traits are vastly out of porportion with bosy size
- humans live linger the expencted for body size
- brain size is much larger then expected for body size
Some traits are faster than expected
- Higher birth rates compared to apes
Other traits are completely novel
- human children are not nutritionally independent at weaning
- multiple dependent offspring
- conscious limitation on reproduction
- females live long past last reproduction (menopause)
Lifespan
- through modern medicine frequently extends life, humans longevity is Not merely a product of modern living
- But it is commonly reported that life expectancy of people in the third world are only 30 or 40 years
- Thie apparent paradox is due to an important difference between life expectancy and lifespan
Life expectancy
- the average number of years lived by individulas ina population from a particular age forward (usually birth)
Lifespan of longevity
- Refers to the years lived under ideal conditons
What is the difference
- life expectancy at birth can be highly skewed when a large number of death occur in infancy
- However, in all humans populations, people who live to adulthood have a higher probability of living to ripe old age
Childhood Mortality
- Among children in the !Kung ~ 85% due to infectious diseases - Among children in developing countries ~ Acute respiratory infection ~ Diarrhea ~ Measles ~ Malaria ~ Malnutrition - In the US ~
Adult 15-59 years mortality
- !Kung ~ Infectious diseases 80% ~ Degenerative disease 3% ! Accidents 0% ~ Violence 17% - Ache ~ Infectious diseases 28% ~ Degenerative diseases 3% ~ Accidents 23% ~ Violence 46% - Yanomamo ~ Infectious diseases 74% ~ Degenerative diseases 6% ~ Accidents 7% ~ Violence 13% - US ~ Infectious diseases 3% ~ Degenerative diseases 71% ~ Accidents 5% ~ Violence 2% ~ Unspecified 19%
FIrst reproduction
- Fecundity +physiological ability to reproduce
~ age of puberty/ menarche
~ Adolescent subfecundity =poor conception success - Sexual behavior, having a partner
- Conscious control
Last Reproduction
- Menopause occurs cross-culturally (45-50)
- Unlike other life history features, it is unclear if menopause varies systematically across cultures
- Evidence of correlation to BMI (lower BMI = earlier menopause)
- But reproduction often stops before menopause
Brain size
- human brains grows faster but also longer than in other primates
- This mat in part lead to longer childhood
Allocation
- Energy for the brain can’t be spent for other things
- brain growth slows body growth
- Brain developmental energy period peaks at age five for males
- Body developmental energy peaks at age 14-15 for males
Trade off between 2 expensive systems
- Brains
- Guts
Human vs. Nonhuman Primate Diets
- Humans eat fewer foods that are high in fiber and toxins
- Humans use more tools and tactics for hunting and foraging
- Humans tend to eat calorically dense resources
- Humans process (cook, pound) foods to remove toxins, fiber, and packaging
Cooking food (meat or vegetables) Catching Fire By Richard Wrangham (How cooking made us human)
- Makes it possible to consume calories more quickly (less chewing)
- Lowers the cost of digestion
- Increases nutrient availability in food, especially plants
- Makes some foods easier to store
- Kills pathogens
Human Birth intervals
- Human infants are very expensive in comparison to primate infants (large bodies + large brains)
- Yet, even in food-limitated conditions, we produce them at fast rated
- This means we often have more than one dependent offspring at a time
Human life history of females
- Typical Hunter Gather ~ Age of Menarche * 17 years ~ First reproduction * 20 years ~ Menopause * 50 years ~ Lifespan * 80 years ~ Number of offspring produced * 5-8 years ~ Duration of lactation * 2-4 years ~ Interbirth interval * 3-4 Years - Inductrialized (US) ~ Menarche * 12 years ~ Friet reproduction * 25 years ~ Menopause * 50 Years ~ lifespan * 90 years ~ Number of offspring produced * 2 ~ Duration of lactation * 6 months ~ Interbirth interval * 2 years