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BIO 107 LECTURE 3
Instructor: ANGELI VALERA- MAG-ASO
Light•Light
•Organic molecules
•Inorganic molecules
Heterotrophic Photosynthetic Chemosynthetic
Bacteria
ProtistsProtists
Plants
Fungi
Animals
�� ProducersProducers
((autotrophsautotrophs))
�� ProducersProducers
((autotrophsautotrophs))
�� ConsumersConsumers�� ConsumersConsumers�� ConsumersConsumers
((heterotrophsheterotrophs)
�� ConsumersConsumers
((heterotrophsheterotrophs)
�� DecomposersDecomposers�� DecomposersDecomposers
Food chains describe the energy flow in ecosystemsFood chains describe the energy flow in ecosystems
ECOSYSTEMS HAVE TWO MAJOR FOOD CHAINS:
ECOSYSTEMS HAVE TWO MAJOR FOOD CHAINS:
� Pyramid of
energy flow
� Pyramid of
energy flow
Fig. 4-20 p. 79
� Pyramid of
biomass
� Pyramid of
biomass
� Primary production –Energy accumulated by plants; first and basic form of energy storage
� Gross primary production –Total energy assimilated by the plant; total photosynthesisassimilated by the plant; total photosynthesis
� Net primary production–Energy remaining after respiration and stored as organic matter.
GPP – R = NPP
Using Light and Carbon dioxide
6H2O + 6CO2 ----------> C6H12O6+ 6O2
Cross section
C3 Photosynthesis
C4 Photosynthesis
Crassulacean Acid Metabolism
Mesophyll cells at
night Mesophyll cells
dur ing the dur ing the
day
Pyruvate build-up during
the day is converted to
PEP, which combines with
CO2 the next night
Ratio of Carbon to Nitrogen across Biological Kingdoms (Spector, 1956)
25
0
5
10
15
20
25
Plants Animals Fungi Bacteria
Proportion of temperate and tropical plant bearing toxic alkaloids
(Coley and Aide, 1991)
Sp
eci
es
wit
h a
lka
loid
s (%
)
0
5
10
15
20
25
30
35
Temperate Tropical
Sp
eci
es
wit
h a
lka
loid
s (%
)
Nitrogen Content of live and dead leaves (Killingbeck and Whitford, 1996)
2.5
0
0.5
1
1.5
2
2.5
Live Dead
Nit
rog
en
Co
nte
nt
(%)