ANIMAL FORM & FUNCTION Campbell, 6 th ed., Chapter 40 Nancy G. Morris Volunteer State Community College This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation In Slide Show, click on the right mouse button Select “Meeting Minder” Select the “Action Items” tab Type in action items as they come up Click OK to dismiss this box This will automatically create an Action Item slide at the end of your presentation with your points entered.

Unifying themes from A & P: Correlation between form & function Functions are properties that emerge from the specific shape & order of body parts Living things have the capacity to respond & adjust to environmental changes 1) over the long term by adaptation & natural selection 2) over the short term by physiological changes

Levels of Structural Organization There is a structure hierarchy of life: atoms -> molecules -> supramolecules -> cell cell The cell is the smallest unit of life. The hierarchy of multicellular organisms is: cells -> tissues -> organs -> organ systems

Function Correlates with Structure in the Tissues of Animals Tissues Tissues are groups of cells with a common structure and function. Cells may be held together by a sticky coating or woven together in a fabric of extracellular fibers. There are five major groups of tissues: There are five major groups of tissues: –Epithelial –Connective –Nervous –Muscle –Blood

Epithelial Tissues Simple Simple – one layer of cells Stratified Stratified or striated – multiple tiers of cells Pseudostratified Pseudostratified – one layer of cells that appears to be multiple because cells vary in length. cubodialcolumnar squamous Cell shapes are cubodial (like dice), columnar (bricks on end), squamous (like flat floor tiles). absorptionsecretion Some are specialized for absorption or secretion. ciliated Some are ciliated. The structure fits function: simple squamous epithelium is leaky & is specialized for exchange of materials by diffusion. Found lining the blood vessels and air sacs of the lungs.

Connective Tissues Characterized by a sparse cell population scattered through an extensive extracellular matrix. Functions to bind & support. Matrix is web of fibers embedded in a homologous substance. Collagenous fibers – 3 collagen molecules Elastic fibers – long threads of elastin; quick resilience. Reticular fibers – branched w/ tightly woven Fabric joining connective & adjacent tissues Figure 40.3

Nervous Tissues Nervous tissue senses stimuli & transmits signals from one part of the animals to another.

Muscle Tissue Muscle is the most abundant of vertebrate tissues. Consists of long, excitable cells capable of contraction.

Organ systems are interdependent. Tissues are organized into organs in all but the simplest animals. In some organs, the tissues maybe layered (Figure 40.6). Organs are suspended by sheets of mesenteries. Heart & lungs are suspended in the thoracic cavity. The thoracic cavity is separated from the abdominal cavity by the diaphragm.

Organ systems are interdependent. Several organs with separate functions that act in a coordinated way make up an organ system. Systems are interdependent: an organism is a living whole greater than the sum of its parts. Systems are interdependent: an organism is a living whole greater than the sum of its parts.

Bioenergetics Animals are heterotrophs that harvest chemical energy from the food that they eat. Animals exchange energy with the environment. As heterotrophs, animals require energy from organic molecules synthesized by other organisms, (Figure 40.7)

Energy input (ingestion of food) Energy input (ingestion of food) Digestion (emzymatic hydrolysis of food) Absorption (absorption of small energy-containing molecules by body cells) Catabolism (cellular respiration & fermentation harvest chemical energy from food molecules) Some energy stored Some energy lost as ATPas heat to surroundings

Metabolic rate provides clues Bioenergetics:Bioenergetics: the study of the balance between energy intake and energy loss within an organism. provides clues as to how an animal adapts to its environment.

Metabolic Rate Total amount of energy an animal uses per unit time Usually measured in calories or kilocalories Rate based on: –Amount of oxygen used for an animal’s cellular respiration –Amount of an animal’s heat loss per unit of time

Metabolic Rate Every animal has a range of metabolic rates: Every animal has a range of metabolic rates: –Minimal rates support basic life functions, such as breathing, –Maximal rates occurs during peak activities, such as all-out running.

Endo or Ecto? Endotherms Endotherms – animals which generate their own body heat metabolically –birds & mammals Ectotherms Ectotherms – animals that acquire most of their body heat form the environment –fish, amphibians, reptiles, & invertebrates

Metabolic Rate vs. Body Size There is an inverse relationship between metabolic rate and size! Smaller animals consume more calories per gram than larger ones. Correlated with a higher metabolic rate & need for faster rate of O 2 delivery to the tissues. Smaller animals also have higher breathing rates, blood volumes, heart rates.

Body Plans & External Environment Physical support on land depends on adaptation of body proportions & posture. –Greater demand for support comes with increased body weight. –Bioenergetics play a big role in load- bearing, since crouched posture is partly a function of muscle contraction, powered by chemical energy.

Body size and shape affect interactions with the environment… Animal cells must have enough surface area in contact with an aqueous medium to allow adequate environmental exchange of dissolved oxygen, nutrients, & wastes. Cell size is limited by surface area to volume ratio. As cell size increases, volume increases proportionately more than surface area. SO…..

Body size and shape affect interactions with the environment Some animals have a body plan that places all cells in direct contact with their aqueous environments; 1) two layered sac – both layers of the body are bathed in water (Hydra). –2) Flat-shaped body with maximum surface area exposed to the aqueous environment. (tapeworms)

Body size and shape affect interactions with the environment Complex animals have a smaller surface area to volume ratio & thus lack adequate exchange area on the outer surface. 1) They have highly folded, moist, internal surfaces for exchange (lungs, gills). 2) Circulatory system that shuttles materials between specialized exchange surfaces. Figure 40.10

Mechanisms of Homeostasis Interstitial fluid –Fills spaces between cells –Exchanges nutrients, wastes, gases with blood carried in capillaries Homeostasis depends on feedback –1) receptor – detects internal change –2) control center – processes the info form receptor & informs effector –3) effector – provides the response

Mechanisms of Homeostasis As a control system operates: the effector’s response feeds back and influences the magnitude of the stimulus by depressing it = negative feedback (Fig 40.12) OR the effector’ response feeds back and influences the magnitude of the stimulus by enhancing it = positive feedback.(blood clotting)