Role of consumers in ecosystems Flashcards
A food web based on living primary producers like plants and algae
“green” food web
A food web based on detritus or dead organic material
“brown” food web
A position in a food chain or food web, determined by the number of energy-transfer steps from he primary sources (primary producers, primary consumers. etc)
Trophic level
group of organisms that perform similar ecological roles or functions, regardless of species
functional types
A representation of the energy or biomass at each tropic level, typically narrowing towards the top
Eltonian pyramid
percentage of energy transferred from one trophic level to the next
ecological efficiency
when can energy pyramids be inverted?
when tropic levels are
-Consume rapidly
-highly assimilated
-faster turnover rates
Ecosystem structure is driven by resource availability (nutrients, sunlight)
Bottom-up control
consumers regulate the structure and productivity of lower trophic levels
top-down control
A top-down process where predators indirectly affect primary producers by controlling herbivore populations
trophic cascade
the ability of an organism to maintain a constant elemental composition (C:N:P) despite changes in diet
stoichiometric homeostasis
Do consumers or producers exhibit stronger stoichiometric homeostasis?
consumers
What happens when there is stoichiometric imbalances in food?
Consumers may grow more slowly and later nutrient recycling
What makes Daphnia important in ecological studies?
-fast-growing
-sensitive to nutrient ratios
-central to freshwater trophic cascades
How do wolves affect plant growth on Isle Royale?
By preying on moose
reduce herbivory on trees
allow tree growth (trophic cascade)
Nutrient-phytoplankton-zooplankton models used to predict aquatic productivity
NPZ models
how does nutrient excretion affect ecosystem nutrient balance?
Herbivores excrete nutrients they don’t need
alter N:P ratios
shift which nutrients are limiting
