Bio 1108 Chapter 48 Biomes and Global Ecology

Biomes

Broad geographic areas with similar sets of communities

Climate

Long-term average weather

What determines climate?

Solar radiation, global patterns of wind and ocean circulation, and Earth's varying topography

Why is it warmer in the summer in places like North America and Europe?

Since Earth's axis is tilted, solar radiation strikes these areas more in the summer than in the winter, so it is warmer in these months

Topography

The physical features of Earth; it contributes to global temperature patterns

Why is warm air less dense than colder air?

The gas molecules that make up air are constantly in motion, and when they are heated they move faster, and the volume of the air expands; this causes the warm air to be less dense than cold air, and so it rises through the atmosphere

What causes wind?

As warm air expands upwards, cool air moves in to replace it

Coriolis effect

As the wind moves air north and south from the equator, the land beneath it rotates to the east, but at a slower speed than the land. The wind, then, appears to have deflected to the right in the Northern Hemisphere, and winds in the Southern Hemisphere deflect to the left.

True or False; Air carries much more heat than water

False; Water can carry much more heath than air, and so ocean currents transport a great deal of heat to higher latitudes

What do cold air and cold water have in common in regards to what it does with warmer air/water?

Cold waters sink beneath less dense water masses, just as colder air sinks below warmer and less dense air

What way does wind and water transfer heat?

Water and wind transfer heat from the equator toward the poles, modifying the direct effects of solar radiation

True or False: Cold air can carry more water vapor than warm air

False

Why does rain occur?

Warm air at the equator carries a great deal of water vapor, but, as it rises and the air cools, the amount of water vapor it can carry decreases. As a result, the vapor condenses and it rains

Rain shadow

A region having little rainfall because it is sheltered from prevailing rain-bearing winds by a range of hills

Why are the lands in the rain shadow of the mountains are arid?

As wet air moves from the ocean up into the mountains, it cools, releasing its moisture as precipitation. Moving past the mountains, air masses descend, warming as they go and taking up water vapor.

What does regional climate and biomes reflect?

The interactions among solar radiation, global patterns of circulation, and Earth's varying topography. Biomes reflect these variations in climate

Evapotranspiration

The sum of evaporation directly from soils and water bodies plus the amount transpired by plants

Potential evapotranspiration

The amount of evapotranspiration that temperature, humidity, and wind would cause if water supply weren't limiting

What does potential evapotranspiration reflect?

The demand on the water resources of an ecosystem, just as precipitation represents the suply

Potential evapotranspiration ratio

The ratio of water demand to supply; It effectively tells us what type of vegetation can be supported in a given region

Tundra biome

Coldest biome; short days in the winter limit growing season; Precipitation is low, but because rates of evaporation are also low and because drainage is commonly poor, the ground is usually waterlogged and permanent ice occurs below a few centimeters of soil

Alpine biome

Similar to tundra but lacks permanent ice below the sold, and the temps. vary more widely. High altitude, these are windy, cold places. Thin atmosphere provides limited protection from UV radiation. Most plants are low/slow growing. Grasses are abundant

Taiga biome

Cool, moist forests; Short summer brings rain, and most of the plants are low-growing conifers. Soils are deep with accumulated organic matter because the low temps. result in slow decomposition, but they are also acidic and poor in nutrients.

Deciduous forest biome

A moderate climate and dominance of hardwood deciduous trees occur across much of eastern North America, Europe, and Asia. Think of trees in the fall season

Temperature grassland biome

Lack of precipitation. Think of the great plains and prairies

Desert biome

Very little precipitation

Chaparral biome

Little precipitation; kind of like the desert

Savanna biome

Tall grass dominates; Warm, dry regions (in Africa)

Tropical rain forest biomes

Most diverse of all terrestrial biomes, tropical rain forests extend north and south of the equator. High precipitation. Tall trees

Lake/River biome

Range high in size. Rivers are characterized by moving water

What are the main freshwater biomes?

Lakes and rivers

Biogeochemical cycles

The cycles of carbon and other biologically important elements. They link organisms and their environment in the chemical cycling of the raw materials needed for life

Tropical biomes have evolved over _______ years, However, biomes at New England attitudes have experienced an ice age within the past _______ years.

A) a few million years; thousand

B) tens of millions; few thousand

C) several thousand; few million

D) a few million; few million

E) few thousand; few thousand

B) tens of millions; few thousand

Which of the following ecosystem factors would affect the rate of tree growth?

A) The ambient light conditions, and thus photosynthetic production

B) The presence of tree parasites

C) All of these responses would affect the growth of trees

D) The distribution of nutrients in each tree's local environment

E) The amount of precipitation, and thus photosynthetic production

C) All of these responses would affect the growth of trees

Some of the characteristics used to describe biomes include:

A) precipitation and number of tropic levels in the communities

B) average annual temperature and species richness

C) average annual precipitation and number of grass species

D) annual average precipitation and average temperature plus variation

D) annual average precipitation and average temperature plus variation

A/an _______ is a community of organisms and the physical environment it occupies.

A) ecosystem

B) biome

C) community

D) all of these

E) none of these

A) ecosystem

Consider the characteristics of biomes. Would you expect more biomass in a tropic pyramid from the topical rainforest compound to one from the taiga?

A) Yes, because there is a high fungal diversity cycling carbon at the equator than at the poles

B) Yes, because there is a higher productivity at the equator than at the poles

C) No, because there are photosynthetic organisms in both biomes that support the tropic pyramids

D) No, because there are other producers at the poles that don't require sunlight so make up the difference in biomass that would be there if only sunlight was used as an energy source.

E) Yes, because there are higher numbers of predators at the equator than at the poles.

B) Yes, because there is a higher productivity at the equator than at the poles