Today: FoodToday: Food
Updated Class Schedule:Week of 4/4 Grizzly Bears and NutritionWeek of 4/11 Sensing and Responding...
HumansBears
Both humans and grizzly bears are omnivores.Our digestive systems can tell us about our ancestors.
Fig 41.19
During digestion complex molecules are broken down and then used to build needed molecules and to produce energy
Animals take in complex molecules from the environment for energy production
Animal digestion occurs outside of our cells.
animal and fungal digestion occurs outside of our cells.
Physical digestion:liquefying of food
Chemical digestion:breaking large moleculesinto small molecules
CB 41.13
Amylasein mouth
Chewing and adding saliva begins the process of liquification
Amylase begins the chemical digestion of carbs
Cb 41.11
The primary function of the stomach is food storage
CB 41.10
Pepsinin stomach
Pepsin begins the chemical digestion of proteins.
In the stomach liquification continues.
CB 41.12
The Digestive System
CB 41.10
Most chemical digestion occurs in the first part of the small intestine
CB 41.15
The small intestine has a large surface area to aid in absorbption of nutrients
CB 41.15
Absorptionin the SmallIntestine
CB 41.15
The Digestive System
CB 41.10
CB 41.11
HumansBears
Both humans and grizzly bears are omnivores.Our digestive systems can tell us about our ancestors.
CB41.19
Chimps commonly hunt small animals including other smaller primates.Hunting encourages cooperative behavior and may help produce more cohesive and advanced societies.
http://www-rcf.usc.edu/~stanford/chimphunt.html
Percent of resting metabolic rate needed for brain (adults):Human = 20-25%Other primates = 8-10%Nonprimate mammals = 3-5%
Leonard WR, Robertson ML. 1994. Evolutionary perspectives on human nutrition: the influence of brain and body size on diet and metabolism. Am. J. Hum. Biol. 6:77–88
Table 2 Annual Review of Nutrition Vol. 27: 311-327 Effects of Brain Evolution on Human Nutrition and Metabolism
Brain size, body size, and molar (grinding) tooth area
Food Web
Ecological Interconnections
CB54.11
Producers and Consumers
CB54.11
Higher consumers are usually larger and fewer in number than lower consumers
CB 55.10
Energy is lost in each consumer
1000
CB 55.10
1000
Energy is lost as it is consumed: where does it go?
only a small percent of energy from plants enters the food chain
CB 55.9only a small percent of energy is stored in organism
CB 55.10
Energy is lost in each consumer: the 10% rule
In the U.S. we eat an avg. of ~2800 Cal/dayWe produce ~3774 Cal/person/day
So we waste over 25% of the food we produce
http://www.boingboing.net/2010/08/03/theres-more-energy-i.html
In the U.S. we eat an avg. of ~2800 Cal/dayWe produce ~3774 Cal/person/daySo we waste over 25% of the food we produce
8,080,000,000,000,000 btu to produce our food (quadrillion)2,030,000,000,000,000 btu of this energy is wasted
Wasted Food, Wasted Energy: The Embedded Energy in Food Waste in the United States. Amanda D. Cullar, Michael E. Webber (2010) Environmental Science & Technology DOI: 10.1021/es100310d
In the U.S. we eat an avg. of ~2800 Cal/dayWe produce ~3774 Cal/person/daySo we waste over 25% of the food we produce
8,080,000,000,000,000 btu to produce our food 2,030,000,000,000,000 btu of this energy is wasted= ~2% of total U.S. energy production
Wasted Food, Wasted Energy: The Embedded Energy in Food Waste in the United States. Amanda D. Cullar, Michael E. Webber (2010) Environmental Science & Technology DOI: 10.1021/es100310d
CB 55.10
Energy is lost in each consumer: the 10% rule
Human impact:
As consumers
Use of agriculture in the U.S.About 1/2 of water and ~80% of agricultural land is used for raising animals.
Fossil Fuels:Producing beef consumes over 100 times more fossil fuel than producing potatoes.The typical American could save almost as much gas by going vegetarian as by not driving.
http://bicycleuniverse.info/transpo/beef.html
Updated Class Schedule:Week of 4/4 Grizzly Bears and NutritionWeek of 4/11 Sensing and Responding...