Ch 52 - Introduction to Ecology & the Biosphere

Question 1

Describe the levels of ecological organization.

Answer 1

• Population - ex: population of bison
• Community - interactions between populations (ex: between wolves & bison)
• Ecosystem - all populations in community (grass, wolves, bison) and abiotic factors (pH, etc)
• Biome - climatically and geographically defined as contiguous areas with similar climatic conditions
• Biosphere - the global sum of all ecosystems.

Question 2

Describe global climate patterns.

Answer 2

• Latitudinal Variation in Sunlight Intensity - sunlight hits the tropics most directly so more heat is delivered there; comparatively at higher latitudes the sunlight hits at a low angle and heat is more diffuse.
• Seasonality - the Earth rotates on a tilted axis around the sun; results in changes in day length, light intensity, and temperature - most pronounced in mid-high latitudes.
• Air circulation & precipitation patterns:
  
  • ​Warm, wet air flows from tropics to poles:
    
    • At equator & 60°: Warm air rises, cools, & loses moisture. Results in: tropical rain, temperate forests.
    • At 30° & poles: Cool dry air sinks, reheats, & sucks up moisture. Results in: desert zones, dry tundra.
  • Global wind patterns: cooling eastern tradewinds, warm westerlies.

Question 3

Describe regional/local climate patterns.

Answer 3

• proximity to water: coastal areas usually wetter, large bodies of water buffer temperature on land nearby, but does not necessarily cool coastal areas.
• mountains:
  
  • ​warm, water-laden air cools as rises over mountains:
    
    • condenses as rain/snow on windward side
    • cool dry air warms as travels down leewaerd side
      
      • this dry air creates rain shadow as absorbs moisture from ground
  • changes in altitude on mountain is similar to changes in latitutde
    
    • as altitude increases so does temperature
• ravines & valleys: at night, cold air descends downhill into valleys, in morning air warms and flows uphill.

Question 4

Describe what is required for life.

Answer 4

1. Nutrients to build tissue
2. Energy to power all functions
3. Water for metabolism
4. Suitable temperature for metabolism

Question 5

Describe limiting requirements for life in aquatic and terrestiral environments.

Answer 5

Terrestrial: temperature & rainfall

Aquatic: energy & nutrients

Question 6

Describe the tropical forest biome.

Answer 6

• Equatorial & subequatorial
• Lots of competition for light
• Highly stratified (layered)
• Highest animal diversity
• Human population growth threatens tropical forests due to agriculture & development

Question 7

Describe the desert biodome.

Answer 7

• 30˚ N & S latitudes & in interior of continents
• Low precipitation
• Lots of variation in temperature
• Cold or hot
• Long-distance transport of water/deep water wells have allowed humans to urbanize and develop agriculture in desert environments reducing bio-diversity.

Question 8

Describe the **savanna **biodome.

Answer 8

• Equatorial & subequatorial
• More seasonal variation than tropical forests
• Inhabitants include plants adapted to drought/fire, large grazing mammals, lots of insects
• Cattle ranching, over hunting, and too frequent fires set by humans threaten biome

Question 9

Describe the chaparral biome.

Answer 9

• Mid-latitude coastal regions.
• Fire & drought resistant plants
• Insects, browsers, reptiles, small animals.
• Highly seasonal: cold, rainy winters & hot, dry summers
• Conversion to agriculture and urbanization, and human made fires are a threat to this biome.

Question 10

Describe the temperate grassland biome.

Answer 10

• Mid-latitude on many continents; interiors
• Cold, dry winters; hot, wet summers; periodic drought
• Large grazers, burrorwers, insects
• Conversion to farmland is a major threat to this biome

Question 11

Describe the northern coniferous forest.

Answer 11

• Largest terrestrial biome
• Long, cold winters; warm to hot summers
• PNW coast range is exception to precipitation rule and gets exceptionally more rain
• Logging is a threat to this biome

Question 12

Describe the temperate broadleaf forest.

Answer 12

• Mid-latitudes in northern hemishphere and parts of New Zealand and Austrailia
• Year-round precipitation
• Long, cold winters; hot, humid summers
• Very diverse wildlife and plants have distinct vertical layers
• Logging and land clearing for urbanization are threatening this biome

Question 13

Describe the tundra biome.

Answer 13

• Long, cold winters
• Short, cool summers
• Arctic tundra gets less rain than apline tundra
• Has a layer of perma frost resulting in mostly herbaceous vegetation
• Large grazing mammals and their predators, migratory birds, soil arthropods
• Oil and mineral extraction threatens this biome.

Question 14

Describe the lake biome.

Answer 14

• Standing bodies of water
• Shallow, well-lit littoral zone with rooted & floating aquatic plants
• Deeper, farther limnetic zone with microorganisms
• Profundal (deep) zone fed by detritus (waste)
• Can be eutrophic: nutrient rich, oxygen poor; high primary productivity
• Can be oligiotrophic: nutrient poor, oxygen rich; limited primary productivity & lots of fish
• Agriculture runoff and dumping of waste by humans leads to nutrient enrichment which casuses algae blooms, oxygen depletion, and death of fish

Question 15

Describe the streams & rivers biome.

Answer 15

• Streams are cold, clear, swift, narrow with rocky bottoms
• Rivers are warmer, turbid, wider with silty bottoms
• Salt & nutrients increase from headwaters to mouth
• Human pollution degrade water quality and kill microorganisms, damming and flood control impair natural functioning as well as threaten migratory animals.

Question 16

Describe the wetlands biome.

Answer 16

• Covered in water; permanent or temporary
• Nutrient rich and oxygen poor
• Develops in basins, along rivers, or on coasts of lakes/oceans
• Highly productive and diverse
• Draining and filling destroy wetlands

Question 17

Describe the **estuary **biome.

Answer 17

• Area between river & sea
• Temporal/spatial variations in salinity
• Very productive & highly diverse
• Filling, dredging and pollution from upstream destroy estuaries

Question 18

Describe the **intertidal zones **biome.

Answer 18

• Covered and exposed by tides, twice daily
• Increased variation in temperautre and salinity
• Mechanical force from waves
• Increased oxygen and nutrients renewed by waves
• High biodiversity: sandy beaches have burrowing adaptations, rocky beaches have attachment adaptations
• Oil pollution and and barrier construction to reduce erosion has disrupted thse zones.

Question 19

Describe the **ocean pelagic **biome.

Answer 19

• Open water (70% of earth’s surface)
• Increased oxygen, but decreased nutrients compared to coastal waters
• Year-round thermal stratification in tropics
• Very productive photic zone: lots of free-swimming or drifting organisms
• Overfishing and pollution threaten this biome.

Question 20

Describe the coral reefs biome.

Answer 20

• Photic zones of clear tropical marine waters
• Increased oxygen and decreased nutrients
• 20˚C – 30˚C
• Form by calcium carbonate (CaCO₃) skeletons of hard corals
• Very high biodiversity
• Collecting coral skeletons/overfishing, global warming & pollution, and development for aquaculture threaten coral reefs.

Question 21

Describe the marine benthic zone biome.

Answer 21

• The seafloor below coastal & offshore pelagic zones
• Largely aphotic, most have sufficient oxygen, **detritus **(waste) rain from above
• Abyssal zone: deepest ocean floor, organisms adapted to cold temps and increased pressure
• Deep-sea hydrothermal vents result in chemoautotroph organisms
• Overfishing threathen fish populations, dumping of organic wastes have created O² deprived areas.