c hapter 40: a nimal f orm and f unction. essential knowledge 2.a.1 – all living systems require...
TRANSCRIPT
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 laws
Physics 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 contracting
Consumes 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