Transcript 4 - plant adaptations - Hicksville Public Schools / Homepage

AIM: How are plants adapted to carry out
photosynthesis?
DN: Explain how increasing carbon
monoxide, light intensity and temperature
affect the rate of photosynthesis.
HW: Read pages 595-598
page 606#14-20
Thursday: page 218 #29-33
How are we adapted for
Heterotrophic nutrition?
The many parts of a plant
help it to maintain
homeostasis!!!!!
Roots
 Used
to anchor the plant
 Absorb water
 Stores nutrients
 Absorption of water and
nutrients
 Root hairs
Increase surface area for water
absorption
Stems
Provides
support
Transports materials from the
roots to the upper part of the
plant by vascular tissue
Xylem
Transports water from the
roots to the leaves (up)
Phloem
Transports glucose (food) from
the leaves to the roots (down)
Transpiration
The
evaporation of water
from the leaves
Where does photosynthesis
happen?
LEAVES
 Where
most photosynthesis
occurs
 Stomata: openings in the leaf
that allow for gas exchange
CO2, O2, H2O
 Cuticle: waxy covering on leaves
to prevent water loss
Moist environment: thin cuticle
Dry environment: thick cuticle
Where in the leaf does
photosynthesis happen?
Cuticle
Keeps moisture
Palisade
Photosynthetic cells
Absorb light
Spongy layer
Photosynthetic cells
Allow gas passage
How do H2O and nutrients get
into the leaf?
Stomata
 Controls
the rate
of gas exchange
through the leaves
 Found mostly on
the underside of
the leaf
 Guard cells
surround the
stomatal opening
Guard Cells
Surround
the
stomata
Two bean
shaped cells
What happens to the guard cells
when:
 In
an environment
of excessive
water?
 Open to release
excess water
 In
a dry
environment?
 Closed to
prevent water
loss
How do guard cells control the
rate of transpiration?
 Open
when
photosyntesis is
occurring
 Closed when
photosynthesis
is not occurring
(to prevent water
loss)
In some land plants, guard cells are found only on the
lower surfaces of the leaves. In some water plants,
guard cells are found only on the upper surfaces of the
leaves. Explain how guard cells in both land and water
plants help maintain homeostasis. In your answer, be
sure to:
•Identify one function regulated by the guard cells in
leaves
•Explain how guard cells carry out this function.
•Give one possible evolutionary advantage of the
position of the guard cells on the leaves of land
plants.
•Gas exchange, photosynthesis,
respiration
•They change the size of the leaf
opening
•Prevents excess evaporation of
water from the leaves, keeps out
pollutants