CH BIO 39 EXTENDed

What is a biome?

A biome is a major ecological community defined by climate and dominant vegetation.

What organisms fuel biomes?

Autotrophs (plants and other photosynthetic organisms).

Five abiotic factors that affect species composition

Temperature; water availability; sunlight; soil type; wind/climate patterns.

What is climate?

Climate is the long-term pattern of temperature, precipitation, and atmospheric conditions in a region.

Four factors that strongly influence climate

Latitude; sunlight intensity; air circulation patterns; ocean currents.

How does latitude affect solar energy received?

Lower latitudes receive more direct sunlight; higher latitudes receive less direct sun and energy.

What causes the seasons?

Earth’s axial tilt as it orbits the sun.

How do air currents contribute to climate zones?

Rising warm air and descending cool air form global circulation cells that create wet and dry regions.

At which latitudes are deserts found?

About 30° N and 30° S.

At which latitudes are rainforests found?

Near the equator (0–10° latitude).

How do ocean currents contribute to climate zones?

They transport heat, warming or cooling coastal regions depending on current temperature.

What is the rain shadow effect?

Mountains block moist air, causing precipitation on the windward side and dryness on the leeward side.

Two factors that determine dominant plants in a biome

Temperature and precipitation.

Tropical Rain Forest

Climate: warm, high rainfall; Vegetation: broadleaf evergreen trees; Notes: highest biodiversity, nutrient-poor soil.

Temperate Deciduous Forest

Climate: moderate temps, distinct seasons; Vegetation: deciduous trees; Notes: fertile soil.

Coniferous Forest (Taiga)

Climate: cold winters, cool summers; Vegetation: conifers; Notes: largest terrestrial biome.

Tropical Grassland (Savanna)

Climate: warm with wet/dry seasons; Vegetation: grasses and scattered trees; Notes: large grazers.

Temperate Grassland (Prairie)

Climate: hot summers, cold winters, seasonal rain; Vegetation: grasses; Notes: very fertile soil.

Deserts

Climate: very low precipitation; Vegetation: cacti and drought-tolerant shrubs; Notes: 30° latitude.

Chaparral

Climate: mild wet winters, hot dry summers; Vegetation: shrubs, fire-adapted plants; Notes: Mediterranean.

Tundra

Climate: very cold, low precipitation; Vegetation: mosses, lichens, shrubs; Notes: permafrost.

Two major types of aquatic ecosystems

Freshwater and marine ecosystems.

Percent of Earth’s water that is freshwater

3%.

Where most freshwater is stored

Ice caps and glaciers.

Dominant producers in aquatic ecosystems

Phytoplankton (photosynthetic algae and cyanobacteria).

Zone where light penetrates and photosynthesis occurs

The photic zone.

Littoral zone

Shallow water near the shore in lakes and ponds.

Limnetic zone

Open water where light penetrates in lakes and ponds.

Profundal zone

Deep water where light does not penetrate.

Benthic zone

Bottom sediments of lakes, ponds, and oceans.

What is an estuary?

A nutrient-rich area where freshwater mixes with saltwater.

What are coral reefs made of?

Calcium carbonate structures built by coral animals.

What algae live in coral tissues?

Zooxanthellae (photosynthetic dinoflagellates).

What is coral bleaching?

When corals lose zooxanthellae due to stress (often heat), causing whitening and decline.

Intertidal zone

Area between high and low tide.

Neritic zone

Region from low-tide line to continental shelf; highly productive.

Continental shelf

Submerged gentle slope of a continent.

Oceanic zone

Deep open ocean beyond the continental shelf.

Pelagic zone

The open water portion of the ocean.

Photic zone

Upper sunlit ocean layer where photosynthesis occurs.

Profundal zone

Deep ocean water below the photic zone.

Highest productivity aquatic ecosystem

Coral reefs.

How a major shift in ocean currents might affect coastal climates

May warm or cool coastal regions due to changes in heat distribution.

Effects of increased tropical deforestation on biodiversity and climate

Causes biodiversity loss, increases CO₂, warms climate, alters rainfall.

Why deserts form on leeward side of mountains

Rain shadow effect dries descending air.

How rising temperatures affect biome distribution

Biomes shift poleward/upward; deserts may expand; rainfall patterns may change.