Primary Productivity
Energy flow links what 4 components?
primary producer, consumer, decomposers, and abiotic environment
Ecologists can estimate productivity by harvesting and weighing dry biomass, or by using satellites to detect what pigment?
chlorophyll (remote sensing)
Fungi belong to which domain of life?
Eukarya
What is the largest pool of nitrogen on Earth, but most primary producers can't use it directly?
The atmosphere (as N₂ gas)
These three things are the inputs to photosynthesis.
Sunlight, H₂O, and CO₂
Which biome accounts for the largest share of global NPP, even though its rate per unit area is low?
Open oceans
Fungal cell walls are made of what tough material, the same one found in arthropod exoskeletons?
Chitin
Which two inorganic forms of nitrogen can be taken up by primary producers?
Ammonium (NH₄⁺) and nitrate (NO₃⁻)
Xylem and phloem define this group of land plants, moving water and nutrients respectively.
vascular plants
A researcher studies a 1 m² grassland plot for one growing season. The plants fix 900 g C through photosynthesis and release 400 g C through cellular respiration. No herbivores graze the plot. How much carbon is available to consumers, and how much new plant biomass accumulated?
500 g C/m² (NPP = GPP − R = 900 − 400)-- The plot gained 500 g C/m² of biomass because nothing was eaten.
How do fungi (chemoheterotrophs) digest food?
Hint: They release digestive enzymes into the environment and then do this.
Absorb the nutrients (Digestion happens outside the fungal body.)
A "pool" of nitrogen, like the atmosphere or the soil, is also called this.
Reservoir
Gymnosperms and angiosperms share what pair of traits, but only angiosperms also produce what two structures?
What are seeds and pollen (shared), and flowers and fruit (angiosperms only)
In an Arctic tundra ecosystem, grasses produce 50,000 kJ/m²/year of NPP. Lemmings eat the grasses, arctic foxes eat the lemmings, and golden eagles eat the foxes. Assuming 10% of energy is transferred from each trophic level to the next, how much energy per m² per year reaches the eagles? And where does the rest of the energy go at each step?
50 kJ/m²/year ; At each step, 90% is lost as heat from cellular respiration, or never becomes consumer biomass
A mushroom is only the small visible part of a fungus. The huge hidden network of hyphae underground is called this.
Mycelium
In anoxic environments, some decomposing bacteria use NO₃⁻ in respiration, converting nitrogen back to N₂. What is this process called?
Denitrification
What term describes excessive algal growth caused by nutrient enrichment, often leading to hypoxia?
Eutrophication
A pond has a GPP of 20,000 kJ/m²/year. The producers use 40% of their GPP in cellular respiration. Energy transfer between trophic levels is 10%. The pond's top predator, a tertiary consumer, needs 40 kJ/m²/year to sustain its population. Can the pond support it? Show how much energy actually reaches the tertiary consumers
No; Only 12 kJ/m²/year reaches the tertiary consumers (30% of what they need)
Mycorrhizal fungi wrap around plant roots. Name what the fungi give the plant and what the plant gives the fungi in return.
Phosphate (fungi to plant) ; Carbohydrates such as glucose and other sugars (plant to fungi)
Put these events in order, starting with fertilizer runoff from the Mississippi River: phytoplankton die, oxygen declines, algal bloom, decomposers increase, huge detrital pool.
algal bloom → phytoplankton die → huge detrital pool → decomposers increase → oxygen declines (dead zone)