Final answer:
Nutrition in organisms is a process by which they obtain and use nutrients for growth, metabolism, and repair, involving ingestion, digestion, and absorption. Animals can be herbivores, carnivores, or omnivores based on their diet and have evolved digestive systems suited to their nutritional needs.
Step-by-step explanation:
Nutrition involves the activities by which organisms obtain and process nutrients for growth, metabolism, and repair. This multistep process includes ingestion, digestion, absorption, and in the case of animals, the eventual elimination of waste. While autotrophic organisms like plants can produce their own food through photosynthesis, heterotrophic organisms, which include animals, obtain nutrition by consuming other organisms or their byproducts. For animals, digestion involves breaking down the food into smaller molecules that can be absorbed. Nutrients such as amino acids, lipid molecules, nucleotides, and simple sugars are essential at the cellular level, despite the consumed food consisting of proteins, fats, and complex carbohydrates.
Depending on dietary habits, animals can be categorized as herbivores, carnivores, or omnivores. Herbivores feed on plants, carnivores on other animals, and omnivores on a mix of both. Each has evolved digestive systems to efficiently handle their specific diets to extract the needed nutrients and energy from food. The animal nutrition strategy is contrasted with organismal nutrition which can be affected by factors such as being autotrophic or heterotrophic, and their evolutionary history.