Transcript Who`s in charge here??

Who’s in charge here??
FORM,
FUNCTION,
HOMEOSTASIS
More than just a common ancestor
 All organisms require chemical energy for growth,
repair, physiological processes, regulation, and
reproduction

characteristics of life anyone?
 The comparative study of animals reveals that form
and function are closely correlated
 The study of bioenergetics
 tells us much about an animal’s adaptations
The link between form and funciton
 Size and shape affect
 how organism interacts with
it’s environment
 how the animal exchanges
energy and materials with its
surroundings.
 Convergence occurs
because natural selection
shapes similar adaptations
when diverse organisms
face the same
environmental challenge,
such as the resistance of
water to fast travel.
“All for One, and One for All!”
 Animals are complex,
multicellular organisms
No ONE organ
or ogran system
can stand
alone!!!
http://www.comp.dit.ie/dgordon/League/OtherL
eagues/c17/threemuskeeters2.jpg
LE 40-4
Respiratory
system
0.5 cm
Heart
Nutrients
Digestive
system
Cells
Circulatory
system
50 µm
External environment
CO2 O
Food
2
Mouth
Animal
body
A microscopic view of the lung
reveals that it is much more
spongelike than balloonlike. This
construction provides an
expansive wet surface for gas
exchange with the environment
(SEM).
10 µm
Interstitial
fluid
Excretory
system
The lining of the small intestine, a
digestive organ, is elaborated with
fingerlike projections that expand the
surface area for nutrient absorption
(cross-section, SEM).
Anus
Unabsorbed
matter (feces)
Metabolic waste
products (urine)
Inside a kidney is a mass of
microscopic tubules that exchange
chemicals with blood flowing
through a web of tiny vessels called
capillaries (SEM).
Tissues are classified into four categories
Epitheleal
Connective
 Covers the outside of
 Binds and supports
the body
 Lines organs and
cavities
 Cells are closely joined
together
Types:
other tissues
 sparsely packed cells
scattered throughout
an extracellular matrix
Types:
LE 40-5_2
CONNECTIVE TISSUE
120 µm
Chondrocytes
Chondroitin
sulfate
Collagenous
fiber
Elastic
fiber
100 µm
Loose
connective
tissue
Cartilage
Fibrous
connective tissue
Adipose tissue
Fat droplets
150 µm
Nuclei
30 µm
Blood
Central
canal
Bone
Red blood cells
White blood cell
Plasma
Osteon
700 µm
55 µm
Four categories of tissues cont’d
Muscle
Nervous
 consists of long cells
 senses stimuli
called muscle fibers
 contract in response to
nerve signals
 transmits signals
throughout the animal
Types
Types
LE 40-5_3
MUSCLE TISSUE
100 µm
Multiple
nuclei
Skeletal muscle
Muscle fiber
Sarcomere
Cardiac muscle
Nucleus Intercalated50 µm
disk
Nucleus
Smooth muscle
Muscle
fibers
25 µm
NERVOUS TISSUE
Neuron
Process
Cell body
Nucleus
50 µm
How is homeostasis maintained?
 Bioenergetics, the flow of energy through an animal,
limits behavior, growth, and reproduction
 Energy-containing molecules from food are used to
make ATP to power cellular work
 After the needs of staying alive are met, remaining
food molecules can be used in biosynthesis
LE 40-7
Organic molecules
in food
External
environment
Animal
body
Digestion and
absorption
Heat
Energy
lost in
feces
Nutrient molecules
in body cells
Carbon
skeletons
Cellular
respiration
Energy
lost in
urine
Heat
ATP
Biosynthesis:
growth,
storage, and
reproduction
Heat
Cellular
work
Heat
“I’m not fat, I just have a slow metabolism”
 An animal’s metabolic rate is closely related to its
bioenergetic strategy
 Basal Metabolic Rate:
 Metabolic rate is affected by size and activity of the
organism

maximum metabolic rate is inversely related to the duration of
the activity
Bioenergetic strategies
Endothermic organisms
Ectothermic organisms
Example: Birds and
mammals
Example: Amphibians ,
fish, and reptiles
 Bodies are warmed by
mostly by heat generated
by metabolism
 Typically have higher
metabolic rates
 more energetically
expensive
 Gain heat from their
external environment
 Have lower metabolic
rates
 tolerate greater variation
in internal temperature
LE 40-9
Maximum metabolic rate
(kcal/min; log scale)
500
A = 60-kg alligator
AH
100
A
H
A = 60-kg human
50
H
10
H
H
5
A
1
A
A
0.5
0.1
1
second
1
minute
1
hour
Time interval
Key
Existing intracellular ATP
ATP from glycolysis
ATP from aerobic respiration
1
day
1
week
Bioenergetic strategies
Regulators
 uses internal control
mechanisms to
moderate internal
change in the face of
external,
environmental
fluctuation
Conformers
 allows its internal
condition to vary with
certain external
changes
The term “internal environment” is in reference
to the interstitial fluid
LE 40-10
Endotherms
Ectotherm
800,000
Reproduction
Temperature
Basal
regulation
(standard)
metabolism
Growth
Activity
340,000
8,000
4,000
60-kg female human
from temperate climate
4-kg male Adélie penguin
from Antarctica (brooding)
0.025-kg female deer mouse 4-kg female python
from temperate
from Australia
North America
Total annual energy expenditures. The slices of the pie charts indicate energy
expenditures for various functions.
438
Human
233
Deer mouse
Python
Adélie penguin
36.5
Energy expenditures per unit mass (kcal/kg•day). Comparing the daily energy
expenditures per kg of body weight for the four animals reinforces two important
concepts of bioenergetics. First, a small animal, such as a mouse, has a much greater
energy demand per kg than does a large animal of the same taxonomic class, such as
a human (both mammals). Second, note again that an ectotherm, such as a python,
requires much less energy per kg than does an endotherm of equivalent size, such as
a penguin.
5.5
Mechanisms of homeostasis
receptor
control center
effector
Negative Feedback
Positive Feedback
 buildup of the end
 change in a variable
product shuts the
system off
 Allows certain internal
environmental
conditions to be
maintained within a
range
For Example?
triggers mechanisms
that amplify rather
than reverse the
change
 Pushes a system
further until the
stimulus is removed
For Example?
LE 40-13
Radiation
Evaporation
Convection
Conduction
Thermoregulation…..
This guy’s got it easy!
…a delicate balance between heat loss and heat
gain
 Five general adaptations help animals
thermoregulate:

Insulation

Circulatory adaptations

Cooling by evaporative heat loss

Behavioral responses

Adjusting metabolic heat production
Back to that “All for One” philosophy
Insulation
Circulatory adaptations
Integumentary system
 reduces heat flow
between an animal and
its environment
Circulatory system
 alter the amount of blood
flowing between the body
core and the skin


Vasodilation

Vasoconstriction
Structures of the skin
*Countercurrent heat exchanger
Back to that “All for One” philosophy
Cooling by evaporative
heat loss
 lose heat through
evaporation of water in
sweat
 Bathing moistens the
skin
Aaaahhhhh….muuuuuch better!
upload.wikimedia.org/wikipedia/commons/thumb/...
Back to that “All for One” philosophy
Some terrestrial
invertebrates have
postures that minimize
or maximize absorption
of solar heat
Some animals can regulate
body temperature by
adjusting their rate of
metabolic heat
production
LE 40-21
Sweat glands secrete
sweat that evaporates,
cooling the body.
Thermostat in
hypothalamus
activates cooling
mechanisms.
Increased body
temperature (such
as when exercising
or in hot
surroundings)
Blood vessels
in skin dilate:
capillaries fill
with warm blood;
heat radiates from
skin surface.
Body temperature
decreases;
thermostat
shuts off cooling
mechanisms.
Homeostasis:
Internal body temperature
of approximately 36–38°C
Body temperature
increases;
thermostat
shuts off warming
mechanisms.
Decreased body
temperature
(such as when
in cold
surroundings)
Blood vessels in skin
constrict, diverting blood
from skin to deeper tissues
and reducing heat loss
from skin surface.
Skeletal muscles rapidly
contract, causing shivering,
which generates heat.
Thermostat in
hypothalamus
activates
warming
mechanisms.
Neuronal pathways
that control energy
balance and their
regulation by
hormonal signals
such as insulin and
leptin
Negative feedback and appetite?
http://www.medscape.com/viewarticle/448465
The Stork….or Positive Feedback?
 Childbirth is the best
example of the positive
feedback mechanism at
work
 Fever is also considered
http://www.sciencedaily.com/images
/2007/04/070402215329.jpg