Transcript power point

How Organisms Work
Microevolution
Adaptations are considered “microevolution” :
Change driven by natural selection in terms of
shifting environmental conditions.
Regulation of water
Water moves by osmosis
Remember – water follows the salt !!
Lets look at Osmoregulation
(a Very Big Deal)
Balloon in
water
brackish
(neutral)
Balloon in
salt water
Balloon
in fresh
water
Osmolarity
1. Ocean water has about 35
g NaCl per liter of water
(and lots of other ions as
well)
2. Marine invertebrates &
cartilaginous fish have
internal osmolarity =
surroundings
1. Stenohaline: Lives in a narrow range of salinity
variations large changes
2. Euyhaline: Tolerates large salinity changes
Osmoregulators: Organisms that
maintain Hypoosmotic pressure
• Worms and amphibians use the surface
of the skin to maintain osmoic pressure
• Marine fish teleost (boney) fish are
hypoosmotic (lower osmoic pressure
inside)
– The chloride cells in the gills export Na+
and Cl- ions
– Marine mammals produce urine that is
more concentrated than their blood
Physiological systems Evolve
Gills active uptake
of ions from cells
Skin absorbs water,
transport salt out
Salt glands expedite the excretion
and defecation of salt
• Active Transport:
transport of a substance
against a gradient
– Primary ATP dependent
mechanism
– Secondary ATP generated
electrical gradient
• Substance is moving
down its own
concentration gradient
• The Sodium and
Potassium pump is the
most familiar primary
active transport system
Active
transport
Terrestrial Animals
• Intake of Gas
• Water Loss
• The water in
exhaled air is
recovered using
countercurrent
circulatory
systems (cool air
holds less
moister)
Heat Flow In the Gills Countercurrent
conserves heat
Warm venous
blood from
muscles
provides heat to
the cold arterial
blood. This
limits the
amount of heat
lost in the
extremities.
Counter current O2 Exchange
1. Unoxygenated blood from the
heart is pumped into the gills
2. Oxygen diffuses from the
water to the bloodstream
3. The fish also moves water
through the gills in the
opposite flow
Diffusion is Slow
Ram
ventilation
Water must move continually
bringing fresh water with high
levels of oxygen to the gills
Lungs 1
Lungs 2
• A lung is an invagination of skin to form a
respiratory surface
• In humans the total surface of are of the
lungs is 100 m2 = a tennis court
• Counter current exchange works for the flow
of oxygen and carbon
A fish with fingers? “Fishapod”
• It had the scales, teeth and
gills of a fish, but also a big,
curved rib cage that suggests
the creature had lungs as well.
• The ribs interlock, moreover,
unlike a fish's, implying they
were able to bear fishapod's
weight—an unnecessary trait
in a fish.
• It had a neck—most unfishlike.
• its pectoral fins included bones
that look a primitive wrist and
fingers
• Lived about 383 million years
ago.
“Fishapod” from about 383
million years ago. Link
• Potassium ions move out of the vacuole and
out of the cells, Water moves out of the
vacuoles, and the guard cells shrink in size.
The stoma closes.
• Potassium ions move into the vacuoles, water
moves into the vacuoles, guard cells expand
• Evaporation of water
from the stomata
creates a positive
pressure upward
• The forces of Cohesion &
adhesion are central to
the effective movement of
water through the xylem
Transpiration in plants
90-95% water loss is through leaves.
Animals transport
fluids
• Open circulatory
systems:
•
A system in which
the circulating fluid
is not enclosed in
vessels at all times;
found in insects,
crayfish, some
mollusks, and other
invertebrates
Closed
circulatory
System
• In a Closed
circulatory system,
gas exchange takes
place across thin
walls of capillaries –
the blood never
mixes in a
“hemocoel”
Physiological systems evolve
Evolution of Lungs
It is all about surfactants and surface area
Surfactants & surface area
Evolution: Desiccation
• 9000 adults  1000
survivors after 20-60
hours without food or
water
• After many generations
of selection, the fruit flies
lost water at 50% of the
rate of the controls
• Survivors had greater
amount of bulk water
• Survivors had Increased
amounts of long chain
hydrocarbons in the
epicutical
Desicattion
1. Bulk water storage
2. Water resistant
outer covering
3. Root system
4. Life history
modification
Nitrogen Tolerance and waste
• Elimination of
waste is
provides a
“peak” at
evolution
What else can we do to
fruit flies?
Ammonia adaped fruit
flies had more glutamate
dehydrogenase
Feed more slowly, and
were less vigorous
foregers
Fat is beautiful when starvation is part
of life history
1.
Starvation resistant
flies develop larger
reserves of fat in
the first four days
of adult life.
2. The starvation resistant flies grew
faster, and had 40% mass that
was lipid (as compared to the 16%
lipid in the control group)
3. There is also an association with
starvation resistance and
longevity. These traits may be
genetically connected
Energy production Terminology
• Catabolism (break down)
– Anaerobic metabolism (no oxygen)
• Glucose + 2 ADP + Pi 2ATP + Lactate
– Aerobic metabolism (with oxygen)
• Glucose + 36 ADP 36ATP + 6CO2 + 6H2O
• Anabolism (The building up of tissue or fat
reserves)
Energy Production and Utilization
• Ectotherms: The rate of energy intake and loss
increases as ambient temperature increases
• There is an “optimal temperature for growth”
If maintenance costs are lowered,
then more energy is used for growth
How does one lower
maintenance cost in a muscle?
• Basal Metabolic rate (BMR):
– stable rate of metabolism measured
under conditions of minimal stress
– At rest, at normal temperature, after
fasting
• Standard metabolic rate (SMR):
– Animals resting and fasting metabolism
at a specific temperature (also known
as the RMR – resting metabolic rate)
• Maximum metabolic rate:
– Highest measurable rate under stress
and exertion
– The ratio of maximum metabolic rate to
basal metabolic rate is the factorial
aerobic scope
• Vertebrates 5-12
• Invertebrates  2-10
(insects are higher)
Metabolic
rates
•
Is Longevity related to metabolic
rate?
Experimental fruit
flies population
were selected for
longevity
• There was no
difference in
metabolic rate
• Correlation does
not mean cause
and effect
Cost of transport
Part of maintenance is the need
for movement.
1. Foraging
2. Escape from predation
3. Mating
4. Raising young
5. Seeking shelter
Animals instinctively adjust
speed and gait for maximum
energy conservation
Energy cost is dependent on
lifestyle
•
Aquatic
•
•
•
Aerial
•
•
Animals that swim in
water spend little or no
energy supporting their
own weight
The high density of
water does produce a
high drag
Flying animals must
overcome gravity,
making use of
aerodynamic lift
Terrestrial
•
The most costly
locomotion
• The Physiology of Birds
• The Pectoral Muscles:
The Mechanics of Flight:
• The Strategy of Size and
Flying
Energy and Life Trade offs
• Birds in high latitudes lay many egg per clutch.
• They spend more energy on fecundity than on competition,
• Birds in low latitudes lay fewer eggs per clutch
• They spend more energy on competition than on
fecundity
Chapter 6
• Species concept
• Factors that lead to
speciation & the types
of speciation
• Concept of
punctuated
equilibrium
• Concept of extinction
• Allopatry
• Sympatry
• Extinction & mass
extinction
• Hybridization
• Reproductive isolation
• Burgess shale
• Isolating mechanism
Chapter 7
• Life history concept
• Semelparous vs
iteroparous
• Univoltine
• Fitness and
definitions of fitness
• Age structure
• Trade off in survival
and reproduction
• Evolution and aging
• Fecundity
• Senescence
• viability
Chapter 8
Physical ecology
Temperature and
light
Q10
Ectotherms and
endotherms
Limitations of size
in terms heat, and
gas exchange