integrated lec 14 Flashcards
The Ecological Niche
Definition:
The combination of physiological tolerances and resource requirements of a species.
Informally: A species’ “place in the world”—what climate it prefers, what it eats, etc.
The Hutchinsonian Niche:
Defined as an “n-dimensional hypervolume” where each axis represents an ecological factor essential to the species.
Example: Scarlet macaw niche based on climate data and eBird records.
climate as a key niche axis - global gradients
Global Gradients:
Temperature: Primarily determined by latitude.
Higher latitudes: Colder; seasonal variations driven by summer-winter temperature differences.
Lower latitudes: Warmer; seasonal variations determined by rainfall (wet/dry seasons).
Rainfall: Influenced by:
Atmospheric circulation (e.g., Hadley cells).
Ocean currents.
Rain shadows (mountain effects).
hadley cells
Heated air rises near the equator, cools and condenses into rain.
Descending dry air at ~30° latitude creates deserts.
intertropical convergence zone
A band of rain clouds near the equator.
Shifts seasonally, producing alternating wet and dry seasons in the tropics.
coriolis effect
Earth’s rotation deflects winds, influencing prevailing wind patterns and atmospheric circulation.
biomes
Definition:
Large ecological regions defined by specific combinations of temperature and moisture.
Whittaker’s Diagram:
Highlights how vegetation structure and productivity are determined by climate.
Examples:
Deserts: Found near 30° latitude due to descending dry air.
Rainforests: Near the equator with high precipitation.
factors modifying biomes
Ocean Currents: Cold-water upwellings lead to dry deserts inland.
Mountains:
Orographic precipitation: Air rises, cools, and precipitates on windward slopes.
Rain shadows: Dry leeward sides of mountain ranges.
ecological niche modeling
Definition:
Uses current species distributions to predict where they can live under different scenarios (e.g., climate change, invasions).
Applications:
Modeling biological invasions.
Predicting range shifts due to climate change.
Tracking the spread of vector-borne diseases (e.g., dengue).
What is an ecological niche?
A: The combination of physiological tolerances and resource requirements of a species.
What is the Hutchinsonian niche?
A: An n-dimensional hypervolume where each axis represents an ecological factor important for a species’ survival and reproduction.
Provide an example of a species’ niche.
A: The scarlet macaw, which occupies a specific climatic range and feeds on certain fruits.
How does latitude influence temperature?
A: Higher latitudes are colder with larger seasonal temperature variation, while lower latitudes are warmer with rainfall-dominated seasons.
What drives global rainfall patterns?
A: Atmospheric circulation, influenced by Hadley cells, ITCZ, and ocean currents.
