CHAPTER 40: ANIMAL

FORM AND FUNCTION

Essential Knowledge 2.a.1 – All living systems require

constant input of free energy. 2.c.1 – Organisms use feedback

mechanisms to maintain their internal environments and respond to external environmental changes.

2.c.2 – Organisms respond to changes in their external environments.

4.b.2 – Cooperative interaction within organisms promote efficiency in the use of energy and matter.

Introduction Anatomy –

The study of structure of organism Physiology –

The study of the functions of an organism’s anatomical features

Bioenergetics – How organisms obtain, process

and use their energy resources

Constraints Limits to animal shape and size -

1) Physical lawsPhysics of flightGravityLaws of hydrodynamics

2) Environment Aqueous requirement for cellular medium

Plasma membrane, surface area to volume ratios

Hierarchy of living organismsClimate/Weather

Organizational Levels Illustrate emergent properties

Cell – Basic unit of life Tissue – Group of cells with same function Organ – Group of tissues with same

function Organ system – Group of organs with

same function Individual – All organ systems working

together

Tissue Four Major Types:

Epithelial, muscle, connective, nervous Epithelial

Tightly packed cells (very little space in b/t) Cover outside of body Line organs and cavities Function: barrier against injury, microbes

and fluid loss Classified by: # of layers, shape

# of layers – simple and stratified Shape – cuboidal, columnar, squamous

Tissue, cont. Connective

Function: bind and support other tissue types

NOT tightly packed Three kinds of protein fibers:

CollagenousElasticReticular

Major types of connective tissue:Loose, adipose, fibrous, cartilage, bone

and blood

Tissue, cont. Muscle

Long cells capable of contractingConsumes most of cellular energy work

Stimulated by nerve cells Made of proteins called actin and

myosin Most abundant tissue in animals Three types:

Skeletal, cardiac, smooth

Tissue, cont.Nervous

Sense stimuli and transmits signals Functional unit:

Nerve cell (neuron)Specialized to transmit nerve impulses

Concentrated in brain (anterior end)Remember? Called cephalization

Organs and organ systems

Systems: Digestive Circulatory Respiratory Immune/lymphatic Excretory

Endocrine Reproductive Nervous Integumentary Skeletal Muscular

Energy Two ways to obtain energy:

Heterotroph Autotroph

Bioenergetics: The flow of energy through an animal Limits animal’s behavior, growth,

repair, regulation and reproduction Determines how much food an

animal must consume

Energy sources Animals are heterotrophs

Obtain energy through enzymatic hydrolysis (aka – Cellular Rs)Use food, oxygen to make energy molecules and carbon dioxide (waste product)

Most of energy molecules are made into ATPProduction and use of ATP generates heatAnimal continuously gives off heat

This release of heat helps to regulate internal body temp

Metabolic rate Def – amount of energy animal uses in

a given amount of time Measured in calories (C) Can be determined:

Monitoring an animal’s rate of heat loss using a calorimeter

Measuring oxygen consumption Can use an EKG or heart monitor to measure

Measuring carbon dioxide output

Influences on Metabolic Rate

1) Size Amt of energy to maintain each gram of

weight is inversely related to size Small animals = MORE energy per gram of

weight 2) Activity

More activity = more energy needed 3) Others

Size, sex, age, body/environmental temps

Homeostasis Def - How an animal maintains

stable internal environmental conditions Such as: temp, heart rate,

metabolism “Steady state” Two schools/groups of

animals: Regulators Conformers

Regulators and Conformers

Regulators – use internal control mechanisms to moderate internal changes (despite external fluctuations) Ex: freshwater and saltwater fish

Conformers –allow their internal environment to vary with external fluctuations Ex: lizards

No organism is SOLELY one or another Animals maintain homeostasis while being

BOTH a regulator AND conformer

Homestatic mechanisms

Three functional control mechanisms: 1) Receptor

Detects change 2) Control center/Integrator

Processes change and sends response to effector

3) EffectorChanges internal conditions

Ex: a house thermostat

Positive and Negative Feedback Positive and Negative Feedback Loops

Thermoregulation Def - The process by which

animals maintain an internal body temperature

Most biological body processes are VERY sensitive to changes in body temp

Two strategies: Endotherm Ectotherm

Endotherm Animals that internally control body temp Ex:

Mammals, birds, few reptiles, some fish, most insect species

High metabolic rate Maintain high and very stable internal

temp Ex: Humans – 98.6o F

Source of heat: metabolic heat (ATP)

Endotherm, cont. Advantages:

Can perform rigorous activities for longer periods of time

Elaborate circulatory systems (division of blood)

Elaborate respiratory system (oxygen exchange)

Maintain stable body temp Disadvantages:

Very “expensive” in energy use High metabolic rate

Need to consume much more food than ectotherm

Ecototherm Animals who gain most of heat

from environment Ex:

Reptiles, amphibians, most invertebrates, fishes

Low metabolic rate Regulate body temp by behavioral

mechanisms Hibernation Basking in sun Shade seeking

Modes of Heat Exchange

Ectotherms and endotherms exchange heat using the same processes

Four processes to do so: Radiation Evaporation Convection Conduction

Balance of Heat Exchange

Ultimate goal: To balance heat loss with heat gain

Five adaptations help animals to meet this goal:1) Insulation2) Circulatory Adaptations3) Cooling by Evaporative Heat Loss

4) Behavioral Responses5) Adjusting Metabolic Heat Production

Energy Conservation Animals often times encounter

periods of time that challenge their heat balancing abilities Ex: extreme temps; food is scarce

Torpor – a physiological state in which animal activity is low and metabolism decreases Enables animals to save energy

while avoiding dangerous conditions

Energy Conservation, cont.

Hibernation: Long-term torpor Adaptation to winter temp and lack of

food Vertebrate endotherms hibernate Body temps decline Saves energy and metabolic rate drops Triggered by shorter days (less daylight)

and slight temperature decreases Ex: bears, ground squirrelsBear Hibernating

(1:00)

Other animals hibernating

Energy Conservation, cont.

Estivation: Summer torpor Adaptation to long periods of high

temps and scarce water supply Slow metabolism and inactivity Triggered by long days Ex: frogs, snails, salamanders