BotanicalAdaptationNotes06

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Transcript BotanicalAdaptationNotes06

Botanical Adaptation Notes
Introduction:
What is an adaptation?
Characteristic that helps organism survive
Why adapt?
Increase reproductive fitness (# of successful
offspring)
Taxonomy: Plants with similar adaptations are
grouped together.
For example, peas, beans, lupine (Lupinus arboreus)
all part of the Leguminosae family (Legumes)
Adaptations:
Photosynthetic pathways:
What is photosynthesis?
Conversion of light energy into chemical energy
(6CO2 + 6H2O + light => C6H12O6 + 6O2)
C3
Adaptations:
Photosynthetic pathways:
Who does it?
Most plants (dicots)
Where in the leaf does it occur?
Mesophyll (leaf cells)
What enzyme is used to help the reaction occur?
Rubisco - can’t tell the difference between CO2 and O2
When does it work well?
Moderate temperatures. At high temperatures energy is
wasted on photorespiration (O2 used instead of
CO2 ) so plants must keep stomatae open (see
below) to take in more CO (and lose H O :( )
C4
Adaptations:
Photosynthetic pathways:
Who does it?
Grasses (monocots)
Where in the leaf does it occur?
Bundle sheath (surround plant “veins”)
What enzyme is used to help the reaction occur?
PEP- can tell the difference between CO2 and O2
When does it work well?
High temperatures and dry. Can close stomatae (no
H2O loss :) ) and still recognize CO2 inside leaf
CAM
Adaptations:
Photosynthetic pathways:
Who does it?
Succulents, pineapple
Where in the leaf does it occur?
Mesophyll (same as C3)
What enzyme is used to help the reaction occur?
PEP (same as C4)
When does it work well?
Stomatae open at night and CO2 stored for use in dark
reaction when sun is out. Keeps stomatae closed in
day (no H2O loss :) )
Adaptations:
Structures:
Seeds and Fruits
(See prior studies)
A epicotyl
B radicle
C cotyledon
D seed coat
Seeds used to disperse
plant species.
Monocots-one cotyledon
Dicots- two cotyledons
Adaptations: Structures:
Flowers
Sexually
reproductive
structures
which allow
for the
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
recombination
of gametes
(pollen and
ova) to form
fertilized
seeds/fruits
and increase
variation.
Monocots-stamen, other parts in multiples of 3’s
Dicots-stamen, other parts in multiples of 4’s or 5’s, easy to identify sepal
Stems
Adaptations:
Structures:
Xylem:
H2O up plant (like a vein)
Phloem:
food down plant (like an artery)
both are examples of “vascular” tissue (tubes)
Monocots-xylem and phloem in separate bundles
Dicots- xylem and phloem organized in rings (see diagram)
Leaves:
Adaptations:
Structures:
External:
stomatae (pores)
C3, C4 open in day, close when hot, CAM open at
night
Middle:
mesophyll (C3, CAM occurs here)
Internal:
bundle sheath (C4 occurs here), vascular system
Monocots-parallel leaf veins
Dicots- networked leaf veins (see diagram)
Adaptations:
Structures:
Other modified structures:
Modified leaves:
bulbs
Modified stems:
corms, rhizomes, tubers
Modified roots:
storage roots, (i.e. Carrots)
Adaptations:
Other Adaptations
For dealing with…
Heat, dryness-C4 and CAM photosynthesis
High light-Modify leaf shape
Salt-Dilute salt with water, remove it mechanically
Flooding-Plants accumulate ethylene to avoid
drowning, Specialized roots
Defenses and Competitive Mechanisms
Structures, chemicals, reproductive timing, etc. (more
on this later)