The food we eat: nutrients and digestion, food chains and webs
Introduction:
Food is essential for human survival, providing us with the nutrients and energy we need to carry out daily functions. However, the food we eat goes through a complex process of digestion before being converted into useful energy. Additionally, the food we eat is part of the larger ecological system of food chains and webs, highlighting the interdependence of different organisms.
Nutrients and Digestion:
- Nutrients: substances that provide nourishment for the body, including carbohydrates, proteins, fats, vitamins, and minerals.
- Digestion: the process by which food is broken down into smaller molecules that can be absorbed and used by the body.
- Key organs involved in digestion: mouth, esophagus, stomach, small intestine, large intestine.
- Enzymes: proteins that help break down food molecules into smaller pieces during digestion.
- Relevant equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP (cellular respiration equation)
- Example: Digestion of carbohydrates begins in the mouth with the enzyme amylase, which breaks down starches into simple sugars like glucose.
Food Chains and Webs:
- Food Chains: the linear sequence of organisms in which each organism feeds on the one below it in the chain.
- Food Webs: the complex interconnection of many food chains within an ecosystem, highlighting the complex relationships between different organisms.
- Trophic levels: positions within a food chain, including producers, primary consumers, secondary consumers, and so on.
- Relevant equation: Energy transfer between trophic levels is depicted by the 10% rule, where only 10% of the energy is transferred from one level to another.
- Example: A food chain might include grass (producer) → rabbit (primary consumer) → fox (secondary consumer), with energy and nutrients flowing from the grass, through the rabbit, to the fox.
References for Further Learning:
- Khan Academy. (2021). Digestive System Introduction. https://www.khanacademy.org/science/high-school-biology/hs-human-body-systems/hs-the-digestive-and-excretory-systems/a/hs-introduction-to-the-digestive-system
- National Geographic. (n.d.). Food Chain. https://www.nationalgeographic.org/encyclopedia/food-chain/
- ScienceDirect. (2021). Trophic Levels. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/trophic-level
