Autotrophs

Autotrophs

assimilate CO2 into organic molecules
and living tissue

Photoautotrophs

use solar energy to convert CO2 into organic molecules in photosynthesis

Chemoautotrophs

use energy derived from oxidation of inorganic
atoms such as S, S2- or Fe2+ to convert CO2 into organic molecules in chemosynthesis 5

Energy fixed by —————- can
be liberated in ——— (including
decomposition) or ———

photosynthesis, respiration, combustion

What biome contributes the most to the global NPP

The tropics

When is Global Net Primary Production increasing

Warmer Temp

where does Photosynthesis happens

chloroplasts

What’s the photosynthesis chemical

Ribulose 1,5 bisphosphate also 3CO2 + 6HO2 = C3H6O3 + 3O2 + 3H20

List the chain of event of chemical photosynthesis

(RuBP; ☛ 5C sugar) + CO2, Rubisco, PGA; ☛ 2x3C sugar)Glucose, starch, amino acids etc

Rubisco

The most abundant enzyme on earth,contains lots of nitrogen. Plant N-nutrition important for primary production

Photosynthesis requires gas exchange between
mesophyll cells and atmosphere: happens in

stomata Tradeoff between carbon gain and loss of water: Open stomata to acquire C lead to loss of H2O

Midday depression:

a reduction of photosynthesis during the hottest hours of a day caused by closing of stomata in order to save water.

Amount of photosynthesis in an ecosystem depends on the leaf area:

More leaf area → higher productivity.

Leaf Area Index (LAI) =

total leaf area per projected ground area, LAI expresses how well vegetation uses the available sunlight

LAI generally varies between 0.5 and 15 m2 per m2. why is it important

Productive environment have a high LAI.

Stressed environments have low LAI

Consequently, shade leaves generally have a larger

area per leaf dry mass = a higher specific leaf area* (SLA).

Advantage of high SLA:

Large area to capture photons per invested mass.

Advantage of low SLA:

Sturdy leaves, more efficient use of photons in full sunlight.

Individual response

Phenotypic plasticity helps a given genotype or species to acclimate to certain environmental conditions in a short term (adjustment)

Population response; Evolution

Genetic variation within and among species is
largely a long-term adaptation to certain
environmental conditions.

Photosynthesis is the process in which

photoautotrophic organisms, such as green plants, capture the energy of sunlight. This energy drives most ecosystems.

Photosynthesis can be limited by other factors then light, such as

drought, lack of mineral nutrients (N, P, K, etc.) or
low temperatures.

Plants show morphological and physiological ——————- in their photosynthetic characteristics in response to environmental conditions

adaptations and acclimation

Important variables for of ecology of photosynthesis are

LAI (in context of ecosystems) and SLA (in context of
individual plant species).

Important molecules for life

Carbon
Oxygen
Hydrogen
Nitrogen
Sulfur
Phosphorus Carbohydrates Proteins

Potassium important in plants for

osmotic regulation,
e.g., in stomatal guard cells, and fruit ripening.

Cytochrome c is an important protein

in electron transport chains associated with photosynthesis, and with respiration. (plants need iron like me!)

Laccases:

copper-containing oxidase enzymes in
many plants, fungi, and microorganisms.
Laccases play a role in the formation and
degradation of lignin.

Senescence happens e.g. when

plants prepare for an
unfavourable season, or when they remobilize the
nutrients to a more useful location, such as from
shaded leaves to sun-exposed leaves.Plants withdraw most of the nutrients from senescing
leaves. But the withdrawal cannot be complete, some
nutrients remain in the falling leaves and will be lost

Both leaf longevity and nutrient withdrawal from
senescing leaves help the plant

to conserve nutrients

Longevity can be obtained by investment in

tough
tissue and protective structures, which reduces growth.

Rate-of-living theory for animals

A negative relationship
between basal metabolic rate
and maximum life span for
mammals and birds has been
indicated.

fast growth an advantage on frequently disturbed sites:

Fast occupation of empty space. No conservation of
resources because they may soon be lost.

Longevity is an advantage in undisturbed sites:

in the long term resource conservation is more
important than fast occupation of space