4 Biome Distributions and Environmental Controls Free Online FlashCards

What is a biome?

A broad region with recurring environmental conditions and characteristic communities of life. Biome boundaries are gradual rather than sharp.

Which climate factors most strongly shape terrestrial biomes?

Temperature and precipitation are the main climate factors shaping terrestrial biome distribution and vegetation.

How does increasing elevation affect vegetation zones?

As elevation increases, temperatures generally fall, creating vegetation zones that can resemble those at higher latitudes.

How does a mountain create a rain shadow?

Moist air rises and produces wetter conditions on the windward slope; the leeward rain shadow is drier.

How can fire help maintain a savanna or grassland?

By limiting tree growth, recurring fires can help maintain grasslands or savannas.

What conditions support dense tropical wet forests?

Warm temperatures and abundant rainfall support dense, multilayered tropical forests.

What plants characterize tundra?

Tundra has very cold conditions and a short growing season; its characteristic plants include mosses, lichens, sedges, and low shrubs.

What defines the aquatic photic zone?

The photic zone is the sunlit water layer where photosynthesis can occur; it supports algae, aquatic plants, and phytoplankton.

How do organisms below the photic zone obtain energy?

Below the photic zone, light is too limited for photosynthesis. Organisms depend on food produced elsewhere or other energy sources.

How does salinity shape aquatic habitats?

Salinity distinguishes freshwater, marine, and brackish habitats, and organisms must tolerate the salt conditions where they live.

What makes estuary salinity variable?

Estuaries form where freshwater meets seawater. Tides and river flow cause salinity to fluctuate, so inhabitants must tolerate changing conditions.

How does river current speed influence aquatic organisms?

Fast-flowing water favors organisms that can cling to surfaces or swim against currents; slower margins provide different habitat conditions.