Objective: Explain how population sizes in nature are regulated.
Natural population regulation has to do with reproduction and food availability. When there are sufficient amounts and available nutrients, then the population will increase, when the population increases it consumes more food and applies greater amounts of stress on the food sources. Once the amount and availability of food have decreased the consumers of the food resource reciprocally decrease in population. The food resource depletion can happen through increased consumption or natural negative influences such as weather or disease. The consuming population decreases from starvation, diseases associated with malnourishment, or from conflict with competing consumers. In some cased the consumer population can migrate to new areas of food abundance, however, there may already be an established population of consumers in the area. These actions of natural population regulation fall under the concept of natural laws. Humans are not outside of these natural laws and have increased our population to the point of excessive population staining the supply of food resources, without implementing augmentation and support of natural supply systems the human population faces natural law reduction. (DeWitt)
Sam explains that fish, bird, and animal populations are kept in balance by observation and talking to other people about what they see. When the number of animals goes down, you move hunting efforts elsewhere. By using good judgment or common sense a balance or sustainability comes into use. (Demientieff)
Objective: Explain the difference between parasitism and predation.Â
Parasitism is the act of absorbing nutrients and coopting biological mechanisms for feeding and reproduction from a host plant or animal. The parasite cannot survive on its own and reduces the health of its host, usually creating the need of the parasite to move quickly to a new host before the original host dies. These activities are similar, but not the same in organisms that have symbiotic relationships. In symbiosis, an organism seeks out another organism that offers necessary food or biological mechanisms for reproduction, however, the difference is in a symbiotic relationship both organisms benefit from the relationship. However, if one species outgrows a symbiotic relationship it can become a parasite. Parasites usually live on the host until it is dead or too diseased to benefit the parasite, while predation is the purposeful hunting and harvesting of an organism for consumption of nutrients. Predation, in the natural law theme, usually culls out the slower members of a group. (DeWitt)
Objective: Explain how symbiotic relationships may evolve.Â
Indigenous people have symbiotic relationships with the environment and evolve together. Some species and systems become dependent on the human populations’ activities. We are dependent on the environment for clothing, sustenance, shelter, implements, recreation, and spirituality. The ecosystem, if people are there long enough, creates equilibrium. Once a contributing species is removed from the ecosystem or no longer fulfills its role then the ecosystem becomes imbalanced for a period of time, as long as there are no other influencing factors a new state of equilibrium will be created. (DeWitt)