Transcript Cell Division and Mitosis

Chapter 49
The Biosphere
We have talked about predation, competition and species
interactions and how they affect the structure of
populations, communities and ecosystems.
This chapter considers the physical forces shaping the
biosphere itself…
Biogeography — the study of the distribution of
organisms, past and present, and of diverse processes that
underlie their distribution patterns.
Climate
Climate refers to the average weather conditions.
Climate includes:
Temperature
Humidity
Wind velocity
Cloud cover
Rainfall
Climate
Climate is shaped by four factors:
(1) Variations in the amount of incoming solar radiation
(2) The earth’s daily rotation and path around the sun
(3) The world distribution of continents and oceans
(4) The elevation of land masses
These all interact to produce prevailing winds and ocean
currents that influence the global patterns of climate
Ocean Currents
are affected by:
1) Latitudinal and seasonal variations in solar heating,
creating variations in temperature of ocean waters on a
vast scale
2) Earth’s rotation / wind friction
Clockwise rotation - Northern hemisphere
Counterclockwise - Southern hemisphere
3) Position of land masses and shape of ocean basins
Climate zones correlated with surface currents & drifts
warm surface current
cold surface current
dry
warm temperate
subpolar
tropical
cool temperate
polar (ice)
cold
Rain Shadow Effect
Rain shadow effect, a reduction of rainfall on the side of high
mountains facing away from prevailing winds (aka leeward side).
Only plants adapted to arid or semiarid conditions grow in rain
shadows.
Biome and Ecoregions
Biome is a large region of land characterized by habitat
conditions and by its community structure.
Biome distribution corresponds w/ climate, topography and soil type
The form of the dominant plant tells us something of the weather
conditions