Biology - 34.9 to 34.18 *Open-ended Questions* Flashcards
Why are the soils in most tropical rain forests so poor in nutrients that they can only support farming for a few years after the forest is cleared?
Climate conditions favor rapid decomposition of organic litter in the soil and immediate uptake of the resulting nutrients by plants. Thus, most of the ecosystem’s nutrients are tied up in the vegetation that is cleared away before farming rather than being stored in the soil.
How do fires help to maintain savannas as grassland ecosystems
By repeatedly preventing the spread of trees and other woody plants; grasses survive because the growing points of their shoots are underground
Why isn’t “cold desert” an oxymoron?
Because deserts are defined by low precipitation and dry soil, not by temperature
What is one way that homeowners in chaparral areas can protect their neighborhoods from fire?
They can keep the area clear of dead brush, which is highly flammable
What factors prevent woody plants from growing in temperate grasslands?
Low rainfall, fires, and grazing by large mammals
How does the soil of a temperate broadleaf forest differ from that of a tropical rain forest?
The soil in temperate broadleaf forest is rich in inorganic and organic nutrients, while the soil in tropical rain forests is low in nutrients
How and why does the soil of the northern coniferous forests differ from that of a broadleaf forest?
The soil is thinner, nutrient-poor, and acidic because conifer needles decompose slowly in the low temperatures
What three abiotic factors account for the rarity of trees in arctic tundra?
Long, very cold winters (short growing season), high winds, and permafrost
How does the vegetation found in polar ice regions compare with tundra vegetation?
Neither biome is hospitable to plants because of the cold temperatures. However, tundra supports the growth of small shrubs, while polar ice vegetation is limited to mosses and lichens
What is the main way that living organisms contribute to the water cycle?
Plants move water from the ground to the atmosphere via transpiration
