Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The would have the highest total annual energy expenditure, and the would have the highest energy expenditure per unit mass.
a. Elephant; mouse
b. Elephant; human
c. Mouse; snake
d. Penguin; mouse

Verified step by step guidance

1. Understand the concept of energy expenditure: Energy expenditure refers to the amount of energy an organism uses to maintain its bodily functions and activities over a period of time.
2. Consider the size and metabolic rate of each animal: Larger animals like elephants have higher total energy expenditures due to their size, but smaller animals like mice have higher energy expenditures per unit mass due to their faster metabolism.
3. Analyze the options given: Option a suggests that the elephant has the highest total energy expenditure and the mouse has the highest energy expenditure per unit mass. This aligns with the general understanding of metabolic rates.
4. Compare the metabolic rates: Elephants, being large, have a high total energy expenditure, while mice, being small and having a high metabolism, expend more energy per unit mass compared to larger animals.
5. Conclude based on metabolic principles: The elephant is likely to have the highest total annual energy expenditure due to its size, and the mouse is likely to have the highest energy expenditure per unit mass due to its high metabolic rate.

Key Concepts

Energy Expenditure

Energy expenditure refers to the total amount of energy an organism uses to maintain its bodily functions and perform activities. It includes basal metabolic rate, thermogenesis, and physical activity. Larger animals like elephants have higher total energy expenditures due to their size, while smaller animals may have higher energy expenditures per unit mass due to their faster metabolism.

Basal Metabolic Rate (BMR)

Basal Metabolic Rate is the rate at which an organism uses energy while at rest to maintain vital bodily functions such as breathing, circulation, and cell production. BMR is influenced by factors like body size, age, and temperature regulation. Smaller animals, like mice, often have higher BMRs per unit mass compared to larger animals, leading to higher energy expenditure relative to their size.

Metabolic Scaling

Metabolic scaling describes how metabolic rate changes with body size. Generally, larger animals have lower metabolic rates per unit mass compared to smaller animals, a concept known as allometric scaling. This means that while an elephant has a higher total energy expenditure, a mouse has a higher energy expenditure per unit mass due to its rapid metabolism and smaller size.