11 Physical Environment Biosphere

Question 1

Define Ecology

Answer 1

scientific study of the interactions that determine distribution and abundance of organisms.

Question 2

Define Climate. Explain how the sun drives global climate patterns. Specifically, explain why the poles are cold and the tropics are warm.

Answer 2

Climate: long term patterns of weather conditions in a given area

The Sun’s angle and Earth’s curvature determine how much heat different parts of the Earth receive. At the equator (tropics), sunlight hits it directly and at a higher concentration which causes it to have warmer climates. At the poles, sunlight does not directly hit them and has a lower concentration of heat distributed.

Question 3

Describe how heat affects both the movement of air and the amount of moisture the air
can hold. Sketch the consequences of these effects (local air circulation patterns).

Answer 3

• Latitudinal Differences in Solar Intensity establishes a net movement of energy from the equator to the poles, driving global atmospheric circulation
• Warm Air Rising and Cooling, Cooler Air Falling: Indeed, warm air rises due to lower density, cools as it ascends, and then descends as it cools. Cooler air sinks because of its higher density.
• Warm Air Holding More Moisture and Condensation: Correct, warm air has a higher capacity for moisture. As it cools, condensation occurs, leading to cloud formation and potentially precipitation.

Question 4

Demonstrate the consequences of latitudinal variation in solar intensity on global air
circulation patterns. Be able to draw the bands of circulating air around the planet on a
global map, identify latitudes with high moisture and arid (desert) latitudes, and
explain how the cells create those regions

Answer 4

• Global Air Circulation: Latitudinal variation in solar intensity drives global air circulation patterns, with cells of rotating air creating wet and dry latitudes
• Tropic Influence: Hot tropics cause evaporation and warm, wet air rises
• Poleward Movement of Dry Air: Dry air is pushed towards the poles from subtropical regions
• Formation of Subtropical Deserts: Dry air sinks and warms subtropical regions, absorbing moisture from the land and forming deserts as a result
• Sunlight Intensity Variation: Temperature differences across latitudes result from changing angle of the sun relative to the Earth’s surface

Question 5

Describe the three ocean currents we covered and their effects: the Gulf Stream, the
California Current, and the Southern California Countercurrent

Answer 5

• The Gulf Stream: carries warm water from the equator to the North Atlantic, making northwestern Europe warmer in winter than southeastern Canada
• California Current/Southern California Countercurrent: cold water that flows southward along western North America, which supports a coniferous rain forest ecosystem along the Pacific coast

Question 6

Identify the two major regional effects on climate (topographical features like
mountains and inland vs. coastal climates), and explain how these features give rise to
regional climate patterns. (This is partly from the reading.

Answer 6

• Topography influences rainfall (rain shadows): as moist air moves from the ocean and encounters a mountain, it flows upwards, cools and drops large amounts of rain. On the leeward side of the mountain, there is little rain, creating a rain shadow
• Oceans moderate coastal climate: Water has a higher specific heat (amount of energy required to raise temperature) than land or air. Water heats up and cools down more slowly than land does, creating climate that is more moderate near the coasts

Question 7

Define biomes, and identify the major factors used to define biomes in terrestrial
environments. Explain how precipitation and temperature affect biomes. (This is partly
in the reading.)

Answer 7

• Biomes: major life zones characterized by vegetation type or by the physical environment
• Biomes result in large part from how plants respond to climate, especially temperature and precipitation
• Biomes largely come from how plants respond to climate
• Approximate boundaries of biome are determined by average annual temperature and rainfall

Question 8

Recognize a general category of terrestrial biome if you are standing in it (tropical
rainforest, grassland, desert, chaparral, etc.) (This is in the reading.)

Answer 8

• tropical rainforest:
  constant rainfall, typically high temperature
• grassland:
  dry winters and wet summers, cool winter and warm summer
• desert:
  low precipitation, either very hot or very cold
• chaparral:
  highly seasonal, rainy winters, dry summers, cool fall, spring and winter
• Savanna:
  seasonal, long dry season
• Coniferous forest:
  cold winters, moderate summers
• Tundra:
  cold winters and cool summers

Question 10

Describe the features that define Mediterranean-type ecosystems (MTEs) such as the coastal San Diego region

Answer 10

• Diverse but threatened
• By summer plants are highly flammable
• Mediterranean shrub habitats are fire prone
• Seeds germinate after a fire

Question 11

Describe the plant biodiversity of MTEs relative to other biomes

Answer 11

• Cover about 2% of the earth’s land area but contain approximately 20% of named vascular plants
• High diversity

Question 12

• Crown Sprouting: Some plants regenerate from underground parts after fire.
• Dominance of Annuals: Following fires, nutrient-rich conditions favor the growth of annual plants.
• Seed Bank Germination: Seeds in the soil germinate post-fire, aiding in vegetation recovery.
• Shift to Shrubs: As canopies grow denser, shrubs become prevalent, gradually replacing annual plants.

Question 13

Explain what is special about the California Floristic Province

Answer 13

-California Floristic Province is a biodiversity hotspot
-one of only 35 hotspots worldwide (2.3% of land surface)
-has high diversity: 8,000 species, 3,488 natives, 2124 endemics
-major threat is farming
-consists of mostly scrub habitats