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General Biology: Biomes and the Biosphere

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  • What is a biome?

    A biome is a terrestrial community shaped by climate, soil, and disturbance patterns, distinct from aquatic or oceanic communities.

  • Define the biosphere.

    The biosphere includes all organisms on Earth plus the environments in which they live.

  • What are the two key climatic factors that define biomes?

    Temperature and precipitation are the main factors that influence biome distribution and characteristics.

  • What does a climate diagram show?

    A climate diagram displays temperature (°C) and precipitation over a year, showing monthly variation and their relationship to plant growth.

  • Key characteristic of tropical rainforests?

    Intense competition for light due to continuous warm temperatures and very high precipitation near the equator.

  • Why do tropical rainforests have poor soils?

    Many nutrients are leached out by heavy rainfall, making soil nutrient-poor despite high biodiversity.

  • What is the key factor distinguishing tropical seasonal forests and savannas?

    Seasonality of water, with distinct wet and dry periods affecting vegetation types like deciduous trees and grasses.

  • What role do fire and grazing play in savannas?

    Fire and grazing maintain grasslands by limiting tree growth and promoting grasses and shrubs.

  • Why are deserts found around 30° north and south latitude?

    Hadley cells cause air to descend at these latitudes, creating high pressure zones that inhibit cloud formation and precipitation.

  • Difference between hot and cold deserts?

    Hot deserts have high temperatures and low precipitation; cold deserts have low precipitation but very cold winters.

  • Adaptations of desert plants like cacti and euphorbs?

    Fleshy lobes for water storage and upright forms to minimize sun exposure during peak heat.

  • Key factors maintaining temperate grasslands?

    Fire and grazing maintain grasslands with warm, moist summers and cold, dry winters.

  • Why are temperate grasslands highly fertile?

    Warm, moist summers and precipitation exceeding temperature promote high soil fertility, making them productive agricultural areas.

  • Characteristic climate of temperate shrublands and woodlands?

    Dry, hot summers and wet winters with evergreen shrubs and trees, typical of Mediterranean-type climates.

  • Key precipitation feature of temperate seasonal (deciduous) forests?

    At least 50 cm of precipitation annually, with precipitation exceeding temperature, supporting deciduous tree dominance.

  • Why do temperate seasonal forests have mostly deciduous trees?

    Deciduous trees lose leaves during cold periods below zero degrees to conserve energy.

  • What distinguishes temperate evergreen forests?

    Dominated by evergreen trees, often with acidic soils due to pine needle litter, and found in 30-50° latitudes.

  • Why are boreal forests significant carbon stores?

    Cold temperatures and permafrost slow decomposition, storing large amounts of organic carbon in soils.

  • Key features of the tundra biome?

    Found above 65° north, characterized by cold temperatures, low precipitation, permafrost, and low-growing vegetation like shrubs and mosses.

  • What defines ocean zones in marine ecology?

    Ocean zones are defined by depth, including the photic zone (0.5-200 m) where light supports primary production, and benthic (bottom) vs pelagic (water column) habitats.