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AP Biology
Transition to Land Biomes
• What is the main material in all life forms?
• Water
• Because life is mostly made of water, all life forms
will be greatly affected by…..
• Sunlight intensity
• Why is water so important to life and to the earth?
• It regulates temperature
• What controls the expression of genes in an
organism?
• Enzymes
• What is the ultimate source of energy for the
earth?
• Sunlight
• What are some of the functions of sunlight?
• Powers photosynthesis
• Keeps the earth warm
• Determines the types of biomes
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What actually causes the Hadley cells to form?
Intensity of sunlight
Wind patterns
Where is light intensity greatest?
At the equator
What results from this?
Massive evaporation of water from oceans
• How is the light intensity in the polar regions?
• Much less, so there is very little evaporation
• Why are the tropics considered to be mainly
deserts?
• High light intensity
• Little water availability
• High evaporation
• What happens to sunlight during photosynthesis?
• The process of photosynthesis converts the
sunlight energy into energy stored up in the
chemical bonds of carbohydrates
C6H12O6
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What is another way that sunlight affects plants?
It directs plant growth
What is auxin?
A growth hormone released by plants
Where is it released?
From the meristems
(the tip end of the shoots)
• How does auxin affect a plant?
• It travels down the dark side of
the plant
• This makes the cells on that
side elongate
• Unequal growth occurs when
one side grows faster than the
other
• The plant begins to bend
toward the side that is slower
in growing
• If it is bending toward the side
that is getting light, then it is
bending toward the light
• What is phototropism?
• The growth of or the movement of an organism
toward light
• What does “photo” mean?
• Light
• What does “tropism” mean?
• Turning movement or growth in response to a
stimulus
• Who was the first person to recognize and
describe phototropism?
• Charles Darwin
• What causes flowering to
occur in plants?
• The absence of sunlight
• What determines
flowering?
• Genetics and
protein/enzyme activation
• What are these proteins
called?
• Phytochromes
• What is their function?
• To act as biological clocks
• How is the Signal Transduction Pathway involved
in the activity of plants?
• Sunlight causes a shape change in the receptor
protein
• The shape change allows the activation of
transcription and translation of genes
• These genes give instruction for making some of
the leaves into flowers
• This is accomplished by adding different reflecting
pigments to the cells, which changes their color
• What are long-night flowers?
• Plants that require long, uninterrupted periods of
dark in order to flower
• These plants usually flower in the fall or winter
• What are short night flowers?
• Plants that require short periods of dark in order
to flower
• What is the critical limit?
• The duration of night (amount of dark) needed in
order for the plant to flower
• What is transpiration?
• Water loss by plants through the stomata in the
leaves
• How is transpiration controlled?
• By the guards cells
• What controls the guards cells?
• The phytochromes and potassium ions
• Why don’t the stomata stay closed all the time in
order to prevent water loss?
• They have to be open for carbon dioxide to come
in
• What is the continuous battle for plants?
• Letting enough carbon dioxide in, while preventing
too much water loss
• What causes the differences between C3, C4, and
CAM plants?
• The types of environments and water availability
• What influences transpiration rate?
• Light intensity
• Wind
• Humidity
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What is osmoregulation?
The control of water loss in animals
Why is osmoregulation important?
All organisms must maintain homeostasis in order
to live
• What is required for homeostasis?
• Large amounts of energy
• What are some things that will remove water from
animal cells?
• Sweating
• Panting
• Breathing
• Waste removal
oxygen
Carbon
dioxide
• What must be removed from animals in order to
keep them from dying?
• Ammonia
• How is the ammonia produced?
• During the process of cellular respiration when
amino acids are broken down
• What is this process called?
• Deamination
• How do fish get rid of the ammonia?
• They release it directly into the water
• How do birds and reptiles get rid of the ammonia?
• They change it to uric acid, which is a paste-like
substance that does not require too much water
• How do mammals and amphibians get rid of the
ammonia?
• They change it into urea, and then dilute it with
lots of water, which is then called urine
• Besides causing a loss of water, what do sweating
and panting do for the organism?
• They help to cool the organism
• Water acts as a heat “trapper”, so removing the
water takes heat away
• What is evaporative cooling?
• Air movement removing water as it evaporates
• What are endotherms?
• Organisms that maintain their own internal heat
• What are ectoderms?
• Organisms whose body temperature conforms to
the temperature of their environment
• What is counter-current heat exchange?
• Transferring heat from within the body to outer
parts of the body through the blood
• What are ways body temperature can be
increased?
• Shivering and metabolism
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What is thermoregulation?
Control of heat within an organism
What accomplishes this control?
Hypothalamus
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How is heat lost by different organisms?
Through moist surfaces
Fish – gills
Amphibians – skin
Mammals - lungs
one-celled
amphibians
echinoderms
insects
fish
mammals
cili
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size • water vs. land • endotherm vs. ectotherm
Hadley Cell Model
Meristematic Tissues
Darwin’s experiment on Phototropism
Phytochrome activation
Signal Transduction Response
Long night plants
Short night plants
Transpiration
Guard Cell operation
Amino Acid structure
(Remove the amine on the left)
Nitrogenous Waste forms
Countercurrent Heat
Exchange
Canada
goose
Pacific
bottlenose
dolphin
Blood flow
Artery Vein
35°C
33°
30°
27°
20°
18°
10°
9°
Vein
Artery
Temperature control
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.
Gas Exchange in Many Forms…
one-celled
amphibians
echinoderms
insects
fish
mammals
cilia
size
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water vs. land
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endotherm vs. ectotherm