Figure 07_09 Figure 07_11 Sterner & Elser 2001 Ecological - - PDF document

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Oct 07, 2022 210 likes •298 views

Figure 07_09 Figure 07_11 Sterner & Elser 2001 Ecological Stoichiometry organelles macromolecules N:P balance of different mammalian organs biotic components (where they keep N and P) (Elser et al. 1996) H 375,000,000 O

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Figure 07_09 Figure 07_11

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Sterner & Elser 2001 “Ecological Stoichiometry” N:P balance of different biotic components (where they keep N and P) (Elser et al. 1996) macromolecules

rganelles

mammalian organs

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H375,000,000 O132,000,000 C85,700,000 N6,430,000 Ca1,500,000 P1,020,000 S206,000 Na183,000 K177,000 Cl127,000 Mg40,000 Si38,600 Fe2,680 Zn2,110 Cu76 I14 Mn13 F13 Cr7 Se4 Mo3 Co1 ????????????

Heterotroph growth equation G = IN-(EG+EX)

G = growth of the organism IN = ingestion rate EG = egestion rate (unassimilated) EX = excretion rate (metabolic waste)

GGE=G/IN gross growth efficiency

gut

rganism

IN EG EX What about the stoichiometric quality of the food? Must take in C N P etc. in appropriate proportions…

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Plants & Algae Invertebrate herbivores Unbalanced diet? Problem: C:N ratio of phloem sap is very high compared to the C:N of aphids. (nutritional imbalance) Solution: excrete excess C as “honeydew” which is sometimes collected by ants who guard aphid livestock. (maintain C:N homeostasis)

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Stoichiometric homeostasis? In a plant? In animals? Plants are not just what they “eat.” Light response curve of a plant Too little light for photosynthesis N E T a s s i m i l a t i

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Figure 07_21

Functional response - ingestion rate depends on food availability What sort of functional response was the plant light response curve?

Sit and wait Constant search Prey Switching

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