Learning Chapter Objectives
Chapter 40
Concept 40.1: Animal form and function are correlated at all levels of organization
Explain how physical laws constrain animal form
o Body shape is determined by the environment
Ex. Fish have a streamlined body contour
Water is 1000x denser than air
Any little thing will cause resistance and slow the fish down
o Influence animal body plans with regard to maximum size
As body dimensions increase, thicker skeletons are required to maintain
adequate strength
This limitation affects internal skeletons, such as those of
vertebrates, as well as external skeletons, such as those insects
and other arthropods
o As bodies increase in size, the muscles required for locomotion must represent
an ever-larger fraction of the total body mass
At some point, mobility becomes limited
Define cell, tissue, organ, organ system
o Cell
The basic structural building block of living organisms, consisting of
protoplasm delimited by a cell membrane
o Tissue
An integrated group of cells with a common function, structure or both
o Organ
A specialized center of body function composed of several different types
of tissues
o Organ system
A group of organs that work together in performing vital body functions
From the list below explain how their structure relates to their functions and note
examples of each
o Epithelial tissue
Covers the outside of the body and lines organs and cavities within the
body
The close packing of epithelial cells, often involving tight junctions,
enables epithelial tissue to function as a barrier against mechanical injury,
pathogens, and fluid loss.
o Connective tissue
Bind and support other tissues in the body
Consists of a sparse population of cells scattered through an extracellular
matrix
The matrix generally consists of a web of fibers embedded in a
uniform foundation that may be liquid, jellylike, or solid
6 major types
Loose connective tissue
Adipose tissue
Fibrous connective tissue
Cartilage
Bone
Blood
o Muscle tissue
Responsible for nearly all types of body movement
Consist of filaments containing the proteins actin and myosin, which
together enable muscles to contract
Most abundant tissue in many animals, and muscle activity accounts for
much of the energy-consuming cellular work in an active animal
3 types
Skeletal (striated) muscle
Cardiac muscle
Smooth muscle
o Nervous tissue
Sense stimuli and transmit signals in the form of nerve impulses from one
part of the animal to another
Neuron
Nerve cells, which have extensions called axons that are uniquely
specialized to transmit nerve impulses
Compareandcontrastthenervousandendocrinesystemswithrespecttospecificityoftarget
cellsandspeedanddurationofresponse.
o Nervoussystem
Doesntbroadcastthesignaltothewholebody
Eachsignal(nerveimpulse)travelstoatargetcellalongadedicated
communicationline,consistingmainlyoftheneuronextensioncalled
axons
Wellsuitedfordirectingimmediateandrapidresponsestotheenvironment
Especiallyincontrollingfastlocomotionandbehavior
o
Endocrinesystem
Wellsuitedforcoordinatinggradualchangesthataffecttheentirebody
Suchasgrowthanddevelopmentandrapidresponsestotheenvironment
o Especiallyincontrollingfastlocomotionandbehavior
Concept 40.2: Feedback control loops maintain the internal environment in many animals
Distinguish between regulators and conformers for a particular environmental variable
o Regulator
An animal for which mechanisms of homeostasis moderate internal
changes in the face of external fluctuations
o Conformer
An animal for which an internal condition conforms with a change in an
environmental variable
Define homeostasis. Describe three functional components of a homeostatic control
system
o Homeostasis
The steady-state physiological condition of the body
o Functional components
Receptor
Detects the stimulus and triggers a response
Control center
Effector
Distinguish between positive and negative feedback mechanisms
o Positive Feedback
Triggers mechanisms that amplify rather than diminish the stimulus
Example
During childbirth, the pressure of the babys head against
receptors near the opening of the mothers uterus stimulates the
uterus to contract.
These contractions result in greater pressure against the opening
of the uterus, heightening the contractions and thereby causing
even greater pressure, until the baby is born
o Negative Feedback
A response that reduces, or damps, the stimulus
Example
When you exercise vigorously, you produce heat, which increases
body temperature.
Your nervous system detects this increase and triggers sweating
As you sweat, the evaporation of moisture from your skin cools
your body, helping return your body temperature to its normal
point
Concept 40.3: Homeostatic processes for thermoregulation involve form, function and behavior
Define thermoregulation. Explain in general terms how endotherms and ectotherms
manage their heat budgets
o Thermoregulation
The process by which animals maintain an internal temperature within a
tolerable range
o Endotherms
Maintain stable body temperatures even in the face of large
environmental temperature fluctuations
o Ectotherms
Dont generate enough heat for thermoregulation
But many adjust temperature body by behavioral means
o Ex. Seeking out shade or basking in the sun
Name four physical processes by which animals exchange heat with their environment
o Radiation
The emission of electromagnetic waves by all objects warmer than
absolute zero. Radiation can transfer heat between objects that are not in
direct contact, as when a lizard absorbs heat radiating from the sun
o Evaporation
The removal of heat from the surface of liquid that is losing some of its
molecules as gas. Evaporation of water from a lizards moist surfaces that
are exposed to the environment has a strong cooling effect
o Convection
The transfer of heat by movement of air or liquid past a surface, as when
a breeze contributes to heat loss from a lizards dry skin, or blood moves
heat from the body core to the extremities
o Conduction
The direct transfer of thermal motion (heat) between molecules of objects
in direct contact with each other, as when a lizard sits on a hot rock
Discuss the role of hair, feathers, and adipose tissue in insulation
o Hair and feathers
React to cold by raising the fur or feathers
This action traps a thick layer of air, thereby increasing the
insulating power of the fur or feather layer
Adipose tissue
Connective tissue that insulates the body and serves as a fuel
reserve
o Contains fat-storing cells called adipose cells
Explain the role of vasodilation and vasoconstriction in modifying the transfer of body
heat with the environment. Explain the role of countercurrent heat exchangers in
maintaining body temperature.
o Vasodilation
Increase in the diameter of superficial blood vessels (those near the body
surface)
As a consequence of the increase in vessel diameter, blood flow in the
skin is elevated.
In endotherms, vasodilation usually warms the skin and increases the
transfer of body heat to the environment by radiation, conduction, and
convection
o Vascoconstriction
Reduces the blood flow and heat transfer by decreasing the diameter of
superficial vessels
Diameter is decreased, so therefore the blood flow is decreased
o Countercurrent Exchange
The flow of adjacent fluids in opposing directions that maximizes transfer
rates of heat or solutes
Warm blood flows through the arteries as it flows, it transfers heat to the
cold blood flowing through the veins
Describe animal adaptations to facilitate evaporative cooling
o Cooling by evaporative heat loss
Evaporation from a surface causes heat loss
Sweating
Panting
Bathing
Other behavioral responses
Basking in the sun and moving into the shade
Maintaining a certain posture
Concept 40.4: Animals use the chemical energy in food to sustain form and function
Describe the basic sources of chemical energy and their fate in animal cells
o Animals harvest chemical energy from food
o Use chemical energy theyve harvested to fuel metabolism and activity
o Food is digested by enzymatic hydrolysis
Nutrients are absorbed by body cells
o Energy containing molecules are used to generate ATP
Produced by cellular respiration and fermentation powers cellular work
Enables cells, organs, and organ systems to perform the functions
that keep the animal
o Once energetic needs are met remaining molecules are used in biosynthesis
o ATP generates heat, most of which the animal gives off to its surroundings
Define bioenergetics and biosynthesis
o Bioenergetics
The overall flow and transformation of energy in an organism
The study of how energy flows through organisms
o
Biosynthesis
The formation of organic compounds by living organisms
Needed for body growth and repair, synthesis of storage material such as
fat, and production of gametes
Define metabolic rate and explain how it can be determined for animals
o Metabolic rate
The amount of energy an animal uses in a unit of time
The sum of all the energy-requiring biochemical reactions over a given
time interval
Can be determined in several ways
Because nearly all of the chemical energy used in cellular
respiration eventually appears as heat, metabolic rate can be
measured by monitoring an animals rate of heat loss
From the amount of oxygen consumed or carbon dioxide
produced by an animals cellular respiration
To calculate metabolic rate over longer periods, researchers
record the rate of food consumption, the energy content of the
food, and the chemical energy lost in waste products
Describe the relationship between metabolic rate and body size
o The energy it takes to maintain each gram of body weight is inversely related to
body size
o Metabolic rate is roughly proportional to body mass to the three-quarter power
m3/4
Distinguish between basal metabolic rate and standard metabolic rate
o Basal Metabolic Rate (BMR)
The minimum metabolic rate of a non-growing endotherm that is at rest,
has an empty stomach, and is not experiencing stress
BMR is measured under a comfortable temperature range a range
that requires no generation or shedding of heat above the minimum
o Standard Metabolic Rate
The metabolic rate of fasting, nonstressed ectotherm at rest at a
particular temperature
The minimum metabolic rate of Ectotherms is determined at a specific
temperature alter body temperature and therefore metabolic rate