Human Ecology
Ecology is the study of an organism within its environment. During this course, we will explore how humans interact within their environment. Human activity will be explored through the following three biological models:
- Madingley Model Processes
- Co-evolutionary Symbiosis
- Niche Construction
The Models
NOTE: Homeostasis is the concept that a system functions at optimal conditions when it exists within a range of boundaries. In-other-words, a species does best when it is not too hot nor too cold.
Madingley Model Processes-- According to this model, all living organisms can be defined by the following processes:
Co-evolutionary Symbiosis-- According to this model, organisms impact one another in significant ways. For example, microorganism can influence an animal's immune system, or an animals may have to adjust to eating a new food source.
Niche Construction-- According to this model, an organism can alter the conditions for its homeostasis by creating its own micro-environments. For example, humans can live in many places because we build shelters.
Madingley Model Processes-- According to this model, all living organisms can be defined by the following processes:
- Reproduction
- Producing (i.e. plants) or Consuming (i.e. animals) Energy. For most animals this comes in the form of eating.
- Metabolism.
- Locomotion/Dispersal
- Death
Co-evolutionary Symbiosis-- According to this model, organisms impact one another in significant ways. For example, microorganism can influence an animal's immune system, or an animals may have to adjust to eating a new food source.
Niche Construction-- According to this model, an organism can alter the conditions for its homeostasis by creating its own micro-environments. For example, humans can live in many places because we build shelters.
The Human Species
I. Metabolism-- how an organism extracts energy from the environment
A. Human Nutrition: humans need the following macro-nutrients (carbohydrates, fats, and proteins) in large amounts and micro-nutrients in smaller amounts.
B. Human Brains: even though the human brain is around 2% of the body weight, it consumes around 20% of all our energy. Therefore, we need energy-rich, nutritious diets.
C. Human Digestive Systems: because humans walk upright, we have short guts which require us to extract a large amount of nutrients in a short period of time. In order for us to maximize the amount of nutrients we pull from our food, we often pre-process what we eat through cooking, grinding plants, and chopping meats. Because we walk upright, our hands are free to help us with these tasks.
Macronutrients
Micronutrients
Activities: create an illustrated graphic organizer on one of the following topics
1. Why are macro-nutrients important in human diets?
2. Why are micro-nutrients important in human diets?
3. Illustrate how metabolism works for humans.
B. Human Brains: even though the human brain is around 2% of the body weight, it consumes around 20% of all our energy. Therefore, we need energy-rich, nutritious diets.
C. Human Digestive Systems: because humans walk upright, we have short guts which require us to extract a large amount of nutrients in a short period of time. In order for us to maximize the amount of nutrients we pull from our food, we often pre-process what we eat through cooking, grinding plants, and chopping meats. Because we walk upright, our hands are free to help us with these tasks.
Macronutrients
Micronutrients
Activities: create an illustrated graphic organizer on one of the following topics
1. Why are macro-nutrients important in human diets?
2. Why are micro-nutrients important in human diets?
3. Illustrate how metabolism works for humans.
II. Homeostasis-- maintaining certain boundaries
Organisms require 'Goldilocks' conditions (such as, temperature, salinity, humidity, etc) that require conditions to be just right (or at least within a certain window). In order to survive and reproduce, organisms must maintain a balance two extremes, such as hot or cold, wet or dry, salty or fresh.
A. Most organisms exist within a set of boundaries that are necessary for the species to survive (i.e. temperature, precipitation, radiation, etc.)
B. Homeostasis is the process of a keeping an organism within this parameters through a series of internal and external feedbacks.
C. Thermoregulation (the ability to stay within a set boundary of temperature boundary) is one of the most important homeostatic processes for an organism.
D. In order to maintain proper function, humans must keep our brains within a very narrow temperature window. Our bodies regulate heat through the following:
A. Most organisms exist within a set of boundaries that are necessary for the species to survive (i.e. temperature, precipitation, radiation, etc.)
B. Homeostasis is the process of a keeping an organism within this parameters through a series of internal and external feedbacks.
C. Thermoregulation (the ability to stay within a set boundary of temperature boundary) is one of the most important homeostatic processes for an organism.
D. In order to maintain proper function, humans must keep our brains within a very narrow temperature window. Our bodies regulate heat through the following:
- Our Skin. Human skin is the most important organ for keeping us cool or warm. Here are some of it keep features: hairlessness (unlike most land mammals, human do not have hair or fur covering their bodies); pigmentation (the color of our skin is important for two reasons: 1) it protects from harmful Ultra-Violet (UV) radiation from the Sun, and 2) it assists in the synthesis of Vitamin D production that is essential for calcium absorption in bones. See the map below); bipedalism allows to get away from the hot ground, catch a breeze, and reduces the amount of skin that is exposed to the Sun's mid-day rays. Also, we have sweat glands near the surface.
Image Source: WW Norton
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III. Locomotion-- how an organism moves around.
A. Humans walk on two feet (bipedalism). This allows us to use our hands for making tools and carrying items. It also allows us to see things that are far away. Humans are a migratory species, which means that we tend to travel great distances fairly efficiently.
B. Humans are extremely well adapted to long-distance endurance running.
B. Humans are extremely well adapted to long-distance endurance running.
Credit: Laszlo Meszoly (Endurance Running)
Reproduction
A. Our large skulls that house our brains make it hard for us to be born, especially through a bipedal pelvis (see right).
B. Humans are born extremely underdeveloped. It takes our brains years to mature, so we spend a long period of time in a helpless of vulnerable state. It also takes us a long time to move on our own. C. Social networks are critical for our survival. We share the responsibility of caring for infants and children. |
Image Source: PNAS
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