Chapter 40 (4)

Animals require chemicaql energy for growth,, repair, activity, and reproduction. The overall flow and transformation of energy in an animal - its __- determines nutritional needs and is related to a animal's size, activity and environment.

Animals use chemical energy harvested from thefood they eat to fuel _ and __. Food s digested by _- and nutrients are absorbed by body cells. Most energy-containing molecules are used to generate __. __ produced by cell resp and __ powes cellular work, enabling cells, organs, and organ systems to perform the functions that keep an animal alive. Energy in the form of AT P is also used in __, whicih is needed for body growth adn repair, synthesis of storage material such as fat, and production of gametes. The production and use of ATP generates heat, which the animal eventually gives off to its surroundings.

The amt of energy an animal uses in a unit of time is called its __- the sum of all the energy-requiring biochemical reactions over a given time interval. Energy is measured in __ or in __ and __.

metabolic rate can be determined in several ways. Because nearly all of the chemical energy used in cell resp eventually appears as __, _- can be measured by monitoring an animal's rate of heat loss. For this approach, resuearchers use a __, which is a closed, insulated chamber equipped with a device that records an animal's heat loss. Metabolic rate can also be determined from the amount of oxygen consumed or carbon dioxide produced by an animal's cellular respiration.

To calculate __ over long periods, researchers record the rate of food con sumption, the energy contont of the food, and the chem energy lost in waste products.

Animals msut maintain a minimum __ for absic functions such as cell maintenance, breathing, and heartbeat. Researchers measure this minimum _- differently for endotherms and ecottherms.

The mimimum __ of a nongrowing endotherm that is at rest, has an empty stomach, and is not experiencing stress is called the __. __ is measured under a comfortable tempp range- a range that requires no generation or shedding of heat above the minimum. The minimum __ of ectotherms is determed at a specific temp because changes in teh environment temp alter body temp and tehrefore __.

the __ of a fasting, nonstressed ectotherm at rest at a particular temp is called its __.

__ is affected by many factors besides whether the animal is an endotherm or an ectotherm. Some key factors are __, __, __, __, _-, and __.

Relationship between body size ad metabolic rate:
LArger animals have more body mass and rtherefore require more chemical energy. Remarkably, the relationship between overall metabolic rate and body mass is constant across a wide range of sizes and forms. For creatures ranging in size from bacteria or blue whales, metabolic rate is roughly proportional to body mass to the __ power.

TRUE OR FALSE:
The relationship of metabolic rate to size profoundly affects energy consumption by body cells and tissues. The energy it takes to maintain each gram of body weight is inversely related to body size.
True False

TRUE OR FALSE:
The smaller animal;s higher metabolic rate per gram demands a greater rate of oxygen delivery. Correlated with its higher metabolic rate per gram, the smaller animal ahas a higher breathing, rate, blood volume (relative to its size, and heart rate. Also, it must eat much more food per unit of body mass.
True False

The reason for the inverse relationship of metabolic rate per unit of body mass to body size is ttill a subject of debate. One hypothesis is that for __ the smaller the animal, the greater the energy cost fof maintaining a stable body temp. In effect, teh smaller an animal is, the greater its __ ratio is and thus the faster it loses heat to (or gains heat from) the surroundings. Logical as this hypothesis seems it doesn't explaint eh fact that the inverse relationship between metabolic rate per gram and size is also observed in ectotherms, which do not use metabolic heat to maintain body temp.

__ considerations associated with body size provide a clear example of how trade-offs shape the evolution of body plans. As body size becomes smaller, each gram of tissue increases in energy cost. As body size increases, energy costs per gram of tissue lessen but an ever-larger fraction of bodyy tissue is required for exchange, support and locomotion.

For both __ and __, activity greatly affects metabolic rate. __ (the highest rates of ATP use) occur during peak activity, like weight lifting, sprinting or high-speed swimming. In general, the __ an animal can sustain is inversely related to the duration of activity.

For all animals, __ and other activites are a major part of the energy budget. Some animals conserve energy by temporarily decreasing their activity to a very low level.

Despite their many adaptations for homeostasis, animals may encounter conditions that severely challenge their abilities to balance their heat, energy and materials budgets. For example, at certain seasons or times of day, temps may be extremely high or low, or food may be unavailable. __, a physiological state in which activity is low and metabbolism decreases is an adaptation that enables animals to save energy while avoiding difficult and dangerious conditions.

__ is long term _- taht is an adaptation to winter cold and food scarcity. When vertebrate endotehrms enter __, their body temps decline as their body's theromstat is turned downn.
- The slow metabolism and inactivity of __, or summer torpor, enables animals to survive long periods of high temps and scarce water supplies.

many small animals and birds exhibit a daiy __taht seems to be adapted to feeding patterns.