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Caution:
This
information has been
gathered from many web sites. Often the information
on the web sites is contradictory, and I have picked
numbers somewhere in the middle of the ranges. This information is only generally
accurate, but I hope that it will work for world
builders as we learn to understand the concepts.
Your comments
and suggestions are
welcome!
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 Caloric Values of Proteins, Carbohydrates,
and Fats
I am assuming that carbon life forms on other planets
will have metabolisms similar to animals here. This may not be true,
but our life forms work! Certainly all life forms need energy in
order to live and reproduce.
The experts here seem to agree that the following
values hold:
- 1 gram
of protein = 4 Kilocalories
(food calories)
-
1 gram
of carbohydrate = 4 Kilocalories
-
1 gram
of fat = 9 Kilocalories
One
ounce = 28.3 grams.
Let's multiply and get an estimate that is easy
to work with.
Translating the food values to ounces we get:
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1 ounce
of protein = (28.3 * 4
KiloCalories = 113.2) about
100 Kilocalories
1 ounce
of carbohydrate = (28.3 * 4 KiloCalories = 113.2)
about
100 Kilocalories
1 ounce
of fat = (28.3 * 9 KiloCalories = 254.7)
about
250 Kilocalories
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Use these numbers to figure out how many calories are in the
bodies of your animals. In real life foods vary in calorie
content, but we are working to understand the process of figuring
out how a biome works, and these numbers are easy to work with and
somewhere near probable.
In general,
meat is protein, plants are carbohydrates. Meat (protein)
builds animal bodies: carbohydrates provide energy for moving, breathing,
digestion, etc. If an animal eats only meat, it will burn some of
the protein for energy.
Foods are usually
made up of a mixture of components: carbohydrates, proteins, fat,
roughage (indigestible things like stalks, hair, feathers, etc)
minerals, vitamins, and so on. For this project we will assume that
the minerals and vitamins work out all right in the foods that our
aliens eat.
Scientists use
the metric system, so I have given you information in that format
as well as in pounds and ounces. Begin by using measurements that
make sense to you so that you can think about what you
are doing.
- 1000 grams
= 1 Kilogram
- one ounce
= 28.3 grams
(I have been using ounces times 30 = grams to get approximate
values)
The stated caloric
values of foods vary, so for this project I am picking the following
values. These are from pages for human dieters. I have rounded off
the numbers to simplify the math.
Notice that
some of the plants have a very low caloric content per ounce. This
is because plant tissues may contain up to 90% water.
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Calories
in Ounces or Grams for Different Types of Foods
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Food
|
KiloCalories per
Gram of Food
|
KiloCalories
per Ounce of Food
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Comments
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Fruit |
0.5 |
15 |
contain a sugar, fructose |
leafy vegetables,
leaves |
0.13 |
4 |
carbohydrates
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meat from mammals |
3 |
100 |
mostly protein |
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meat from birds |
2 |
50 |
mostly protein |
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fish and sea food |
1 |
30 |
mostly protein |
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nuts |
5 |
140 |
shelled nuts are 180 Kcal per ounce |
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barley
(and other grains?) |
3 |
100 |
mostly carbohydrates |
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legumes: peas, beans |
1 |
30 |
contain some protein |
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roots: tubers |
0.3 |
10 |
mostly carbohydrates |
I found the
following information from the manufacturers of animal food. I also
got some information from zoos. These foods keep the animals healthy
and reproducing. These are specially prepared feeds, and probably
ideal for the animals involved. However, in the wild the food might
be lower in calories per gram because it might also contain indigestible
items like feathers, hair, tough stalks, twigs, and bones.
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Calories
in Ounces or Grams of Commercial Animal Food
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Food
is for
|
KiloCalories
per Gram of Food
|
KiloCalories
per Ounce of Food
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Comments
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Rodents: mice, hamsters |
3 |
90 |
grain,
seeds |
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Rabbit |
2 |
60 |
larger rodent |
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Grazing Herbivores |
1.3 |
39 |
need roughage - poor pasture? |
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Large Herbivore: elephant |
2.6 |
78 |
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Carnivores: cat, dog |
3.5 |
105 |
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Omnivore |
3.2 |
96 |
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Carnivore: meat and bones |
1.8 |
54 |
meat
and bones |
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Fish Eaters |
1 |
30 |
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Reptiles |
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Herbivores eat
low calorie carbohydrates that the plants make. They have
adapted to low calorie leaves and stems by developing long digestive
tracts that can deal with a lot of roughage. Now they need the
roughage in order for their digestions to work properly.
Meat eating animals, on the other hand, eat fprotein ood
that is high in calories. Their intestines are relatively short,
as this concentrated food does not require a long period of
digestion. High calorie food is also less bulky than low
calorie food.
Now go on to Caloric Requirements for the Animals in Your Eco Systems to calculate
how many calories your animal will need each day.
Photographs from
Corel CD-ROMs : for viewing only, not for downloading. More
Information.
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