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.
What are Hadley cells?
A: Circulation cells near the equator where warm air rises, cools, and causes rain, while dry air descends around 30° latitude, forming deserts.
How does the ITCZ influence wet and dry seasons?
A: It shifts seasonally, creating alternating rainfall patterns in tropical regions.
What is the Coriolis effect?
A: The deflection of winds and ocean currents due to Earth’s rotation
Why are deserts commonly found at 30° latitude?
A: Descending dry air from Hadley cells creates arid conditions.
How do mountains influence local climates?
A: They cause orographic precipitation on windward sides and rain shadows on leeward sides.
How do invasive species benefit from warming climates?
A: They expand their ranges into regions previously unsuitable due to colder temperatures.
Q: Why do higher latitudes experience summer-winter temperature differences?
A: Due to the angle of sunlight and the tilt of Earth’s axis.
What causes rain shadows?
A: Mountains block moist air, causing precipitation on the windward side and dry conditions on the leeward side.
What is an environmental gradient?
A: A gradual change in abiotic factors (e.g., temperature, salinity) across a spatial scale.
How do species perform along environmental gradients?
A: Performance peaks at optimal conditions and declines outside tolerance ranges
How does global warming disrupt atmospheric circulation?
A: It shifts circulation cells and alters precipitation patterns, impacting ecosystems and species distributions
