1. BASIC PRINCIPLES OF ANIMAL FORM AND FUNCTION
Chapter 40
BASIC PRINCIPLES OF ANIMAL FORM AND FUNCTION

2. Size and Shape
An animal’s size and shape depends on physical laws and the environment it lives in.
Animals cannot be so big that they can’t move or that nutrients can’t get inside all of their cells.

3. Tissues
Tissues are groups of cells with a common structure and function.
You must know 4 types:
1. Epithelial
2. Connective
3. Muscle
4. Nervous

4. Epithelial Tissue
Epithelial tissue covers the outside of the body and lines organs and cavities within the body.
Includes: glands and membranes

5. Connective Tissue
Connective tissue functions mainly to bind and support other tissues.
Includes: collagen and elastin

6. Muscle Tissue
Muscle tissue is composed of long cells called muscle fibers that contract when stimulated by nerve signals.
Includes: skeletal, cardiac and smooth muscles

7. Nervous Tissue
Nervous tissue senses stimuli and transmits signals in the form of nerve impulses from one part of the animal to another.
A nerve cell is called a neuron.

8. Organs
Organs are made up of tissues, working together, arranged in layers.
Organ systems consist of several organs working together.

9. Energy
Organisms require energy for growth, repair, normal function, regulation, and reproduction.
Autotrophs get energy from the sun, heterotrophs get energy by converting food (glucose) to energy (ATP) through cellular respiration.
The flow of energy through an animal is called bioenergetics.

10. Metabolism
The amount of energy an animal uses in a unit of time is its metabolic rate.
It is measured in calories (cal) or kilocalories (kcal).
The amount of energy an animal needs is inversely related to its weight: a mouse needs more energy per gram of weight than an elephant does.
Overall, the elephant still needs more energy because it weighs more grams.

11. Metabolism
The basal metabolic rate (BMR) is the average number of calories used for normal life functions each day. (endotherms only)
Women: calories/day
Men: calories/day
The standard metabolic rate (SMR) is the daily energy used by ectotherms.

12. Energy Budgets
The amount of energy an organism needs depends on its environment, behavior, size, and whether its an endotherm or an ectotherm.
It also depends on age, sex, size, quality and quantity of food, activity level, oxygen availability, time of day and hormones.

13. Homeostasis Homeostasis is internal balance, or “steady state”
A regulator uses internal control mechanisms to maintain homeostasis
A conformer allows its internal environment to change with external changes

14. Homeostasis
Negative feedback mechanisms change or counteracts a stimulus (raises your body temperature when you are cold)
Positive feedback mechanisms amplifies the stimulus (hormones continue to increase during childbirth)

15. Homeostasis
Thermoregulation is how animals maintain their body temperature within a tolerable range.
Ectotherms gain their heat from the environment (cold-blooded)
Endotherms generate heat from within to maintain a constant body temperature (warm-blooded)

16. Modes of Heat Exchange
Insulation: hair, feathers, or fat reduces heat loss
Circulatory system: dilating blood vessels increases temperature, constricting them decrease temperature
Evaporative cooling: sweating, panting, opening mouths
Behavior: migration, seeking shade
Shivering

17. Energy Conservation
Torpor: a physiological state in which activity is low and metabolism decreases
Hibernation: long term torpor that is an adaptation to winter cold and food scarcity
Estivation: summer torpor, slow metabolism and inactivity to avoid high temperatures and scarce water
Daily torpor: nocturnal (bats) or diurnal (hummingbird)