Chapter 4
4-1 The Role of Climate
Weather: day-to-day condition at a particular place and time
Climate: average, year-after-year conditions in a region
Green House Effect: CO2, Methane, H2O vapor and other gases trap heat energy in
the atmosphere.
The Effect of Latitude on Climate: Solar radiation strikes different parts of the
Earth's surfaces at different angles.
This also causes SEASONS
3 main climate zones:
Polar = cold areas
Temperate = hot to cold seasons
Tropical = direct sunlight, always warm
Q: How is heat transported in the biosphere?
A: Wind and Ocean Currents
Wind currents: air is heated near the equator and rises, reaches the cooler
atmosphere and sinks back to land.
(This creates a wind current. See Figure 4-3, page 89)
Water Currents: Cold water near the poles sink, warm water near the equator
rises. This creates a circular pattern of movement. (see page 89)
4-2 What shapes an Ecosystem?
Biotic - ALL living organisms
Abiotic - non-living components (soil, rocks, sunlight, wind, rain)
Habitat - The place where a population lives
Niche - The physical and biological conditions in which an organism lives and the
way in which the organism uses those conditions.
No two species can share the same niche in the same habitat. ( See Fig. 4-5 )
Community Interactions
Competition -compete for resources | Competitive Exclusion Principle - no two
species can occupy the same niche
Predation - one organism captures and feeds on another organism (prey)
Symbiosis - two species live closely together
a. Mutualism - both species benefit (insects pollinate flowers)
b. Commensalism - one member is benefits and the other is neither helped or
harmed
c. Parasitism - one organism lives in or on another and harms it (blood sucking tick)
Ecological Succession - predictable changes that occurs in a community over time
Primary Succession - occurs on land where no soil exists (ex; volcanic eruptions)
see figure 4-7
Pioneer species - the first species to populate this area
Secondary Succession - occurs in areas where there has been previous growth (ex:
fires, abandoned fields)
*Climax Community*
Marine Succession - "whale-fall" 3 distinct stages see Figure 4-9
4-3 Biomes
Environments are grouped into BIOMES
group of ecosystems that have same climate & dominant communities
10 major world biomes:
TROPICAL RAIN FOREST
has most species
canopy = top
understory = second story below canopy
hot & wet year round; thin, poor soil
TROPICAL DRY FOREST
rainfall is seasonal not year-round
trees are deciduous -lose leaves
warm year round; wet/dry seasons; rich soil
TROPICAL SAVANNA
less rainfall than dry forest, but more than desert
covers of grasses spotted with trees
large animal herds & frequent fires
lions & giraffes
DESERT
dry (less than 25 cm rainfall/year)
extreme temperature changes (hot/cold)
cacti/succulent plants
organisms able to tolerate extreme conditions
TEMPERATE GRASSLAND
plains & prairies; Midwest
very fertile soil
4 seasons - seasonal precipitation, less rain than temperate forest
TEMPERATE WOODLAND & SHRUBLAND
Chaparral= dominated by shrubs
frequent fires
example:Los Angeles, CA
TEMPERATE FOREST
deciduous & coniferous trees (cone-bearing)
rich in humus - decaying leaves
4 seasons - but more rain than grassland
NORTHWESTERN CONIFEROUS FOREST
Abundant rainfall (except summer); lush vegetation
AKA temperate rainforest
Mild temperatures
Pacific NW coast of United States &Canada
BOREAL FOREST (Taiga)
Evergreen forests
Bitterly long winters/ short, mild summers
Moose, black bear, wolves
TUNDRA
permafrost = layer of permanently frozen subsoil
Strong winds -no trees, small plants
mosses, lichens, grasses
arctic fox, caribou
Other land areas include:
Mountain ranges
Polar Ice Caps
4-4 Aquatic Ecosystems
Freshwater Ecosystems
A. Flowing-water ecosystem, rivers, streams, creeks, & brooks
B. Standing- water ecosystem, lakes & ponds
Estuary = area where freshwater meets sea
Wetlands = water covers soil
Marine Ecosystem
A. Photic zone - area sunlight reaches
B. Aphotic zone- permanently dark
(See fig. 4-17 p. 109)
*Plankton - microscopic organisms found in water