1. Chapter 6: Climate and Terrestrial Biodiversity
© Babak, Steve

2. Weather & Climate Differences between weather and climate:
weather: short–term atmospheric conditions that include: temperature, pressure, humidity, precipitation, solar radiation, cloud cover, wind direction and speed.
troposphere: the inner layer where weather occurs; contains the air we breathe.
climate: long–term weather of a region.
global temperature and precipitation patterns are determined by uneven heating of Earth by Sun and lead to distinct climate zones according to latitude.
© Babak, steve

3. Weather & Climate Con’t.
Fig. 7–2

4. Global Patterns major factors influencing climate:
incoming solar radiation patterns: leads to uneven heating of troposphere from beneath;
air circulation patterns: determined by
uneven heating of Earth's surface
seasonal changes due to Earth's tilt on axis and revolution about the sun
Earth's rotation on its axis
ocean currents
influenced by factors that influence air circulation plus differences in water density.

5. Geometry of the Earth & Sun
Earth's rotation (24-hr period), tilted axis (23.5º), and revolution about the sun (365¼ day period) play a major role in weather and climate.
Fig. 7–3

6. Convection Currents
Convection currents: currents in the air or water that are caused by temperature differences.
Warm air rises while cooler air falls.
Fig. 7–5

7. Greenhouse Effect Fig. 7–9
The greenhouse effect is a natural process in which gases (CO2, H2O, methane, etc.) trap heat in the troposphere. Without the greenhouse effect, Earth would be cold and lifeless.
Humans activities are increasing the levels of these gases increase in global temperature.
Fig. 7–9

8. Air Circulation Patterns
Prevailing winds include westerlies at temperate latitudes, trade winds in the subtropics, & doldrums (stiller air) along the equator.
Fig. 7–4
© Brooks/Cole Publishing Company / ITP

9. Air Circulation Patterns
Major patterns:
air circulation is driven by solar energy
Coriolis effect: a deflection effect occurs as the Earth rotates, resulting in a deflection of air masses to the right in N hemisphere & the left in S hemisphere
Low & high air pressure:
low pressure: warm and low density. Leads to high rainfall as air rises.
high pressure: cool and dense air. Results in deserts as dry air descends

10. Ocean Currents Major Patterns:
Large circular patterns of water movement in ocean basins resulting from the Coriolis effect.
Deep currents driven by cooling and increased salinity – both make water denser and cause it to sink.
Currents redistribute heat and influence climate and vegetation.
Currents help in the cycling and distribution of nutrients and d.o. for aquatic life.

11. Upwelling
The replacement of outgoing surface water with deep, cold, nutrient–rich bottom waters.
Leads to increased primary productivity, with large populations of phytoplankton, zooplankton, fish, and fish–eating birds.
Fig. 7–7

12. El Niño–Southern Oscillation (ENSO)
Periodic shift (3-4 years) where westerly winds in the Pacific Ocean weaken or reverse direction, surface water along N and S America becomes warmer.
Normal upwellings stop and reduction in primary productivity.
Strong ENSO affects over two–thirds of the globe.

13. El Niño–Southern Oscillation (ENSO)
Fig. 7–8

14. Topography
Topography, water bodies and other local features create local climate conditions known as microclimate. For example mountains commonly result in high rainfall on the windward side and low rainfall in the rain shadow of the leeward side.
Fig. 7–10

15. Biomes Biome: the major types of terrestrial ecosystems
determined primarily by climate (prec. & temp.)
major biomes:
tundra - tropical rain forest
desert - mountains
chaparral - tropical dry forest
boreal forest (taiga) - tropical savanna
temperate grassland
temperate deciduous forest
Climate influences the types of plants and animals found in each biome.

16. Earth’s Major Biomes
Fig. 7–11

17. Desert Biomes
Climate graphs (Climatograms) show typical variation in annual temperature and precipitation for tropical, temperate and polar deserts.
Fig. 7–14

18. Desert Biomes Characteristics:
typically < 25 cm (10 in) annual precipitation;
sparse, widely spaced, mostly low vegetation
cover 30% of land surface, especially at 30° N and 30° S latitude
largest deserts on interiors of continents
plants either are typically deep rooted shrubs with small leaves, succulents, or short–lived species that flourish after rain
animals are typically nocturnal and have physical adaptations for conserving water and dealing with heat.

19. Deserts
                                                                                    
Fig. 7–15

20. Grassland, Tundra and Chaparral Biomes
Climatograms showing typical variations in annual temperature and precipitation in tropical, temperate and polar grasslands.
Fig. 7–17

21. Grassland Biomes Characteristics:
sufficient rainfall to support grass, but often too dry for forests
mostly found on interiors of continents
maintained by seasonal drought, grazing and periodic fires that prevent invasion by shrubs and trees
plants include high diversity of grasses and herbaceous plants that typically have broad distributions and that have resistance to drought, grazing and fire
animals include large and small herbivores, along with predators adapted to feed on these herbivores.

22. Grasslands
Figs. 7–19 & 7–20

23. Forest Biomes
Climatograms showing typical variations in annual temperature and precipitation in tropical, temperate and polar forests.
Fig. 7–22

24. Forest Biomes Characteristics: See Figs 7–24, 7–25, & 7–26
sufficient rainfall to support growth of trees; three types:
tropical, typically broadleaf evergreen trees with high diversity
temperate, typically deciduous broadleaf tree with moderate diversity;
boreal, typically conifers (needle leaves) with low diversity.
community of plants and animals typically distributed in various layers:
understory of herbaceous plants and shrubs;
subcanopy of tree saplings;
canopy of full–grown trees.
See Figs 7–24, 7–25, & 7–26

25. Forests
Fig. 7–23

26. Mountain Biomes Characteristics:
diversity of habitat because of diversity of altitude, slope orientation, corresponding microclimate and soil over short distances
correspondingly complex patterning of vegetation
make up 20% of Earth's surface
each 100 m (300 ft) gain in elevation
mountain regions contain majority of world's forests;
timberline: elevation above which trees do not grow;
snowline: elevation above which there is permanent snow
important as watersheds for lowlands.

27. Perspectives on Geographical Ecology
Things to remember:
everything is connected;
temperature and precipitation patterns result from interplay of incoming solar radiation and Earth's rotation
temperature and precipitation are major determinants of the distribution of organisms