Animal Form & Function

I. Characteristics of Life

• A. Livings things have to – obtain oxygen & nutrients, fight off infection, produce offspring

• B. All living these face the challenges of their environment through many different adaptations all living things have found ways to increase fitness. – 1. The form of any adaptation can give clues to the

function of the anatomy of the organism or physiology.

II. Exchange with the Environment• A. All animals must exchange

materials with the environment and this places limits on body plans. – 1. Rate of exchange is proportional

to membrane surface area and the amount of material that must be exchanged to sustain life is proportional to cell volume• a. some organisms need adaptations to

deal with these limitations – interstitial fluid, membrane folding

III. Organization of the Body• A. Every cell in an animal body is both an

independent unit & an interdependent part of an organism.

• B. The levels of organization in a multicellular organism include: cells tissues organs organ systems.

III. Organization of the Body• 1. Cells – are the basic unit of structure & function in

living things and can perform uniquely suited jobs. • 2. Tissues – groups of cells that perform a single

function – 4 basic types of tissue include:• 1. epithelial tissue – includes glands, covers interior & exterior

surfaces (tight junctions)• 2. connective tissue – provides strength & flexibility for the

body (collagenous fibers) & connects parts (reticular fibers), and elasticity • 3. nervous tissue – transmits nerve impulses throughout body• 4. muscle tissue – enables body to move with proteins called

actin and myosin (skeletal, smooth, and cardiac)

III. Organization of the Body• 3. Organs – a group of different

tissues that work together to perform a single function.– Example: eye

• 4. Organ systems – a group of organs that perform closely related functions. – Some organs are part of several

systems– Example: pancrease – digestive &

endocrine

IV. Coordination & Control

• A. All tissues, organs, & systems must act in concert with one another. The body has 2 ways to coordinate the activity between the cells of your body.

• B. Two signaling processes:– Endocrine system – use of hormones, broadcast

across entire body slow acting but long lasting– Nervous system – use of neurons that carry a

message to specific location quickly

V. Maintaining Homeostasis

• A. An organism is a regulator for a particular environmental variable if it uses internal mechanism to control internal change due to external change but a conformer is it allows the internal condition to change with the external change.

• B. Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in external environments.– 1. pH blood 7.4, temp. 98.6C, blood sugar 70-110

VI. Forms of Feedback

• A. Your body has a specific conditions called set points. Any variable that causes fluctuations from these conditions are called a stimulus that are going to trigger a response by the sensor to return the body to the set point.

• B. Two ways to return to set point:– Negative feedback – reduces the stimulus (sweating)– Positive feedback – amplifies the stimulus (childbirth)

VII. Alternations of Homeostasis

• A. Circadian rhythm – physiological changes to set points that occur roughly every 24 hours– 1. melatonin levels

• B. Acclimatization – gradual process by which an animal adjusts to changes in its external environment– 1. sea level to mountains

IIX. Thermoregulation

• A. Thermoregulation – process by which animals maintain their internal temperature controlled by the hypothalamus– 1. every 10 degree changes how effective hemoglobin

binds as well as fluidity of membranes• B. Sources of heat:– 1. Endothermic – warmed by heat generated by

metabolism (birds & mammals, most insects)– 2. Exothermic – gain heat from external sources

(invertebrates)

IX. Variation in Temperature

• A. An animals body temperature that varies with the environment are known as poikilotherms while homeotherms have a relatively constant body temperature. – Not directly correlated with endo- and exo- therms

X. Balancing Heat Loss & Gain

• A. All animals exchange heat by 4 physical processes (heat always moving from hot to cold)– 1. Radiation– 2. Evaporation– 3. Convection– 4. Conduction

• B. Insulation reduces heat transfer between organism and the environment (feathers & fur, vasodilation & vasoconstriction, and countercurrent exchange)

Behavior Responses/Adjusting Metabolic Production

• Nonshivering thermogenesis– Hormones can cause mitochondria to increase activity

and produce heat instead of ATP.

• Bird fluttering– Pouch full of blood vessels

• Alternations of Fur coat• Proportions of saturated/unsaturated fats• “Antifreeze” crystal production

XI. Bioenergetics

• A. Bioenergetics is the overall flow and transformation of energy in an animal determined by nutritional needs and is related to the animal’s size, activity & environment.

• B. Metabolic rate – sum of energy used in biochemical reactions over a given time– 1. Measured by heat loss or carbon dioxide released

XII. Metabolic Rate & Thermoregulation• A. Basal metabolic rate (BMR) – constant rate at rest,

under no stress, empty stomach under a confortable temperature range. Standard metabolic rate (SMR) is the rate at a particular temperature

• B. Influences on Metabolic Rate:– 1. Size – as body size decreases each gram of tissue requires

more energy. (mouse vs. elephant)– 2. Activity – max. metabolic rate can be sustain is inversely

related to duration of activity• Torpor – a state of decreased activity (save energy & avoid difficult

conditions) hibernation – extended torpor state• Estivation – same as torpor but in high temperatures/low water