Download 7-1 What Factors Influence Climate?

Climate and Terrestrial Biodiversity
Chapter 7
7-1 What Factors Influence Climate?
 Concept 7-1 An area's climate is determined
mostly by solar radiation, the earth’s rotation,
global patterns of air and water movement,
gases in the atmosphere, and the earth’s
surface features.
7-1 What Factors Influence Climate?
 Weather is a local area’s short-term physical
conditions such as temperature and precipitation.
 Climate is a region’s average weather conditions
over a long period of time.
“Climate is what we expect, weather is what we get.”
-- Mark Twain
7-1 What Factors Influence Climate?
 Climate varies from place to place because the
air circulation in the lower atmosphere due to:
1. Uneven heating of the earth’s surface by the sun
2. Rotation of the earth on its axis
3. Properties of air, water, and land
7-1 What Factors Influence Climate?
1. Uneven heating of Earth’s surface by the sun:
•
•
•
•
Equator vs. poles – round planet
Earth’s tilt – 23.5º
Albedo – how strongly it reflects light
Insolation – solar radiation received by a given
area in a given time (kWh/m2/day)
7-1 What Factors Influence Climate?
7-1 What Factors Influence Climate?
2. Rotation of Earth on its axis
•
•
•
Rotation is FASTER at equator than
poles…causes the Coriolis Effect – the deflecting
of air masses by the rotation of the Earth
Also causes complex global air circulation
Wind belts produce ocean surface currents
7-1 What Factors Influence Climate?
If the Earth didn’t
rotate, we could
expect wind to flow
in the following
manner…
7-1 What Factors Influence Climate?
Instead it looks
like this…
7-1 What Factors Influence Climate?
3. Properties of air,
water, and land
•
Convection cells form
due to interaction
between air/water/land
7-1 What Factors Influence Climate?
7-1 What Factors Influence Climate?
 Heat and moisture are
distributed over the earth’s
surface by vertical air
currents, which form six
giant convection cells at
different latitudes.
7-1 What Factors Influence Climate?
 Ocean Currents are caused by:
• Prevailing wind belts
• Earth’s rotation
 Ocean currents influence climate by distributing heat
from place to place.
 The temp. of the water affects the temp. of the air
7-1 What Factors Influence Climate?
Generalized Map of the Earth’s Current Climate Zones
7-1 What Factors Influence Climate?
 The Greenhouse effect keeps the entire planet
warmer than it would be without it
 Greenhouse gases:
•
•
•
•
Water vapor – H2O
Carbon Dioxide – CO2
Methane – CH4
Nitrous Oxide – N2O
7-1 What Factors Influence Climate?
The Rain Shadow Effect
 Interactions between land and oceans and disruptions of
airflows by mountains and cities affect local climates.
 Microclimate – local and regional climates different than
the larger regional climate
7-2 How Does Climate Affect the Nature and
Locations of Biomes?
 Concept 7-2 Differences in average annual
precipitation and temperature lead to the
formation of tropical, temperate, and cold
deserts, grasslands, and forests, and largely
determine their locations.
7-2 How Does Climate Affect the Nature and
Locations of Biomes?
 Climate Affects Where Organisms Can Live
 Biomes – large terrestrial regions characterized
by similar climate, soil, plants, and animals
• Biomes vary by, and are determined by:
• Latitude and elevation
• Annual precipitation
• Temperature
7-2 How Does Climate Affect the Nature and
Locations of Biomes?
7-2 How Does Climate Affect the Nature and
Locations of Biomes?
Generalized Effects of Elevation and
Latitude on Climate and Biomes
7-2 How Does Climate Affect the Nature and
Locations of Biomes?
Average Precipitation and Average Temperature as Limiting Factors
BIOMES
The following is a BRIEF discussion of the
different biomes...the majority of information
on these topics should come from the time
we spent in the computer lab and the
informational packet you filled out.
There Are Three Major Types of Deserts
 Deserts have little
precipitation and little
vegetation.
 Fragile ecosystem
• Slow plant growth
• Low species diversity
• Slow nutrient recycling
 Desert plants have
adaptations that help them
get enough water.
 Desert animals adapt to the
heat and lack of water
through their behavior and
physiology.
There Are Three Major Types of Grasslands
 Grasslands occur in
areas too moist for desert
and too dry for forests.
 Tropical Grassland
• Savanna
 Temperate Grassland
• Prairie
 Cold Grassland
• Tundra
• Arctic
• Alpine
Tropical Grasslands - Savanna
 Savannas are
(tropical grasslands)
with scattered trees
and herds of hoofed
animals
 Distinct wet and dry
seasons
Temperate Grasslands - Prairie
 Temperate Grassland (Prairie)
• Tall-grass prairies
• Short-grass prairies
 The cold winters and hot dry summers have deep and
fertile soil that make them ideal for growing crops and
grazing cattle.
Polar Grasslands - Tundra
 Polar grasslands (Tundra) are covered with ice
and snow except during a brief summer.
 Arctic tundra: fragile biome
• little rain
• short growing season
• long cold winters
 Permafrost - areas were the ground is frozen year round
Temperate Shrubland - Chaparral
 Chaparral has a moderate
climate but its dense thickets of
spiny shrubs
 Near the sea – people like
living/vacationing here
 Subject to fires during the dry
season (summer)
There Are Three Major Types of Forests
 Forests have enough
precipitation to support
trees and are found in
tropical, temperate,
and polar regions.
• Tropical Rain
• Temperate Deciduous
• Coniferous
• Boreal forest
• Taiga
Tropical Rain Forest
 Tropical rain forests have
heavy rainfall and year-round
warm temperatures
• Found near the equator
• Rich diversity of species
• Poor soil
• Leaching by heavy rains
• Rapid recycling of nutrients
• Stratification of specialized
plant and animal niches
Tropical Rain Forest
 Filling niches enables species to avoid or minimize
competition in the dense biodiversity of a tropical rain forest
Temperate Deciduous Forest
 Temperate deciduous forests
• Broad-leaf deciduous trees
• Larger temperature swings from season to season
• Most of the trees survive winter by dropping their
leaves, which decay and produce a nutrient-rich soil.
Coniferous Forests (Taiga, Boreal Forest)
 Coniferous forests
• Also called boreal forests or taigas
• Long, cold winters, short moderate summers
• Cone-bearing evergreen trees keep their needles
year-round to survive long and cold winters.
Temperate Rain Forests
 Temperate rain forests
• Proximity to oceans keeps them cool and moist
• Huge cone-bearing evergreen trees such as redwoods
and Douglas fir
Mountains Play Important Ecological Roles
 High-elevation islands
of biodiversity
 Often have snowcovered peaks that
reflect solar radiation
and gradually release
water to lowerelevation streams and
ecosystems.
7-3 How Have We Affected the Word’s
Terrestrial Ecosystems?
 Concept 7-3 In many areas, human activities
are impairing ecological and economic services
provided by the earth’s deserts, grasslands,
forests, and mountains.
7-3 How Have We Affected the Word’s
Terrestrial Ecosystems?
 Human
activities have
damaged or
disturbed
more than half
of the world’s
terrestrial
ecosystems.