APES CHAPTER 6 OUTLINE - CLIMATE, GEOGRAPHICAL ECOLOGY AND BIOMES
Weather and Climate
I.
Weather
A.
All properties of atmosphere; temp., pressure,
humidity, wind, condition over a 24 hr. period
B.
Weather changes are result of unequal heating of
atmosphere (tilt of earth)
C.
Six atmospheric controls on weather (and climate):
latitude, land and water disparities (water stores
heat), ocean currents, landform barriers to air
movement, altitude, activities of humans.
II.
Climate:
A.
average of weather for a long period of time
(general temperature, etc. averaged over at least 30 years)
B.
Two main control factors: temperature & precipitation
III.
Air Masses
A.
Large bodies of air (thousands of sq. miles in
diameter) with nearly same temp. and humidity
B.
Four types:
dry: continental polar (cP)
continental tropical (cT)
moist: maritime polar (mP)
maritime tropical (mT)
C.
Warm air mass: warmer than the surface over
which it passes
D.
Cold air mass: colder than the surface over
which it passes
IV.
Weather Fronts (where two air masses meet)
A.
Cold Front
1.
Cold air mass overtakes warmer air mass
2.
Average rate of movement is 15-20 mph
(occasionally as high as 50-60 mph)
3.
Warm air pushed up quickly
4.
Steep frontal boundary, squall line, violent
storms, short-lived
B.
Warm Front
1.
Warm air mass overtakes cold
2.
Moves about 5-10 mph
3.
Gradual frontal boundary as warm air rides
up over cold
4.
Less violent but longer storms
C.
Occluded front
1.
Cold front overtakes warm front
2.
Weather varies
D.
Stationary front
1.
Stops moving
2.
Retains frontal boundary and conditions
E.
V.
Weather extremes
1.
Tropical cyclones
a.
severe tropical storms, called hurricanes in
Atlantic and typhoons in Pacific
b.
Form over warm tropical waters in late
summer or early fall
c.
Powered by heat energy from the sea
d.
Major damage is from storm surge (90%
of deaths from this) and winds
2.
Tornadoes – short lived cyclonic winds than can reach in excess of 300 mph
Global Air Circulation and Climate
A.
Two most important factors in climate are temperature
and precipitation
B.
Air circulation result of
1.
Unequal heating and cooling of earth result mainly from tilt of earth’s
axis (causes seasons)
a.
Equator receives more direct sunlight than
poles so more energy and thus warmer
b.
Part of earth tilted toward sun receives
more direct sunlight and thus warmer
We are actually closer to
the sun in the winter than in the summer.
2.
Rotation of earth on axis
a.
Creates Coriolis effect
b.
Wind deflected toward right in northern
hemisphere and left in southern
Convection cells of rising moist air and sinking
cool, dry air
VI.
El-Nino Southern Ocillation – ENSO – (Major topic- study)
OVERVIEW
El-Nino- Effect Global Weather and Climatic Patterns
a) Characterized by unusually warm ocean temp in Equatorial Pacific Ocean.
b) Causes trade winds to relax in central and western Pacific.
c) The trade winds reverse normal patternNormal-trade winds flow from a westerly direction
El-nino-trade winds flow from a easterly direction
Climate change: wetter conditions promote transmission of disease by:
1. Increasing the regions where mosquitoes breed-some mosquitoes are carriers of
diseases such as malaria, dengue fever, or yellow fever.
2. Causing flooding, causing a problem because of sanitation (e.g., contamination of
water sources with bacteria that may promote the spread of cholera, amoebic
dysentery, giardia).
Climate change: warmer water promotes transmission of disease because:
1. Warmer water allows for increased growth of phytoplankton and zooplankton
2. Bacterial growth increases in warm water
3. Increased temperatures may mean increased breeding of insects
Climate change: higher air/land temperatures promote transmission of disease because:
1. Higher temperatures give insects (such as mosquitoes) a longer window of
reproduction ties
2. Increased temperatures may mean increase breeding and feeding of insects
3. Higher wintertime temperatures may mean insect populations that carry disease
are increased since not as many will be killed by freezes
Climate change: slightly drier conditions promote transmission of disease by:
1. Causing streams to become stagnant, resulting in standing ponds of water that are
conductive to increased mosquito populations. (One of the biggest outbreaks of
dengue fever in Fiji occurred during the last major ENSO event when Fiji was
unusually dry.)
Climate change: drought promotes transmission of disease by causing:
1. Deterioration in fresh water supplies (shortage of potable water; concentration of
pollutants in shallow ponds) increases the probability of diseases such as cholera
and other diarrheal diseases in places such as Papua New Guinea
Problems with climate change:
1. People most affected by the link between El Nino and disease are those where the
weather/climate changes are most extreme and health care and sanitation are
marginal (developing countries)
Diagram of Normal and El-Nino Conditions
ENSO may cause
Warming water
(Primarily ocean)
Problems (e.g.)
Habitat Destruction
Increased algal blooms
Coral Bleaching
Disruption of migration
No Upwelling of nutrient-rich
waters
Die-off of species that cannot
tolerate the warmth
Lowered water-solubility of CO2
gas
Increased storms/shift of zones
where storms form.
Increase in greenhouse gases
cause more frequent/stronger el
nino.
Depression of thermocline
Suppression of upwelling
Disruption of migration
Destruction of habitat
Flooding
Mudslides
Erosion
Nutrient Leaching.
Across Southern US (Flooding)
Across Peru (Flooding)
Drought/lack of water for living
organisms
Increased risk of fires
Less plant growth
Species unable to adapt
Drought
Effects (e.g.)
Starvation/die-off of species.
Changes in ocean currents
Disruption of migration
Disruptions of food webs
Flooding
Loss of habitat
Contaminated water supplies
Nutrient leaching from soils
Health- Causes septic tanks, city
sewer systems, and animal waste
from agribusiness; mix with
floodwaters – distributing
coliform bacteria.
Increased risk of fires
Lack of water for living
organisms
West Pacific (Brush fires in
Australia)
Flooding
Increased coastal erosion by
waves
Species die-offs
Reduced potable water
Poor/no plant growth
Movement of warm ocean
waters/increasing depth of warm
surface water
Increased rainfall
Decreased Rainfall
Increased land temperature
Drought
Increased storms (number,
frequency, or strength)
Loss of food for higher trophic
levels.
Disruption of food webs.
Loss of biodiversity.
Nutrient-rich waters not available
for fish
Loss of food
Starvation/die-off of species.
Habitat destruction
Plants unable to grow/loss of
food production
Starvation/die-offs
Habitat destruction
Habitat destruction
Starvation/die-offs
Habitat destruction
Decreased food
Starvation/die-offs
Habitat destruction.
La-Nina- opposite of El-Nino
a) Characterized by unusually cold ocean temp in the Equatorial Pacific
b) Usually, (but not always) occurs after an El-Nino year
Weather:
1. Warm winters in S.E. U.S.
2. Colder winters from great lakes to Pacific N.W.
3. Mixture of bad/good in N.E. and Middle Atlantic states
VII Continental Drift Theory: - Approx. 225 MYA one super-continent existed. It was called
Pangaea meaning “all lands”. 135 Million years ago Pangaea broke apart – the southern half was
called Gondwanaland and the Northern portion was called Laurasia. 65 MYA the 7 major
continents formed and moved into the locations we see on maps today. (Pg. 106)
1. Plate tectonics - the study of the movement of the Earth’s crust. There are 20
lithospheric plates. 7 major plates, (continents) and 13 minor plates.
2. Lithosphere – crust and upper portion of the mantle
3. Athenosphere – lower mantle. ( lithosphere floats on the athenosphere)
4. Convection currents – produced from the intense heat of the inner core, are the driving
force behind seafloor spreading
5. Seafloor spreading- Hess, 1962, mapping ocean floor, searching for mineral deposits, mapped
the largest underwater mountain chain on the planet. Called the Mid Atlantic ridge. Seafloor is
thin layer of Basalt, magma pushes to the surface and moves the plates apart – divergent plate
boundary. Plates come together – Convergent plate boundary –builds mountains. Subduction
Zone – two plates come together and one plate subducts or goes under the other plate and its
material is remelted into the magma – Pacific Ocean. California is made of several small pieces
of plates that jammed together- Thus earthquakes – occur at all plate boundaries. Rate of
movement at the MAR –2-3 cm per year.
6. In 1912 Alfred Wegener, proposed the theory of Continental Drift –( Continents move) –
scientific community thought his theory was incorrect. Not until we understood convection
currents and seafloor spreading did this get proven:
Evidence :
1. plates fit together like a puzzle
2. fossil record
3. convection currents and seafloor spreading
VIII BIOMES: CLIMATE & LIFE ON LAND
Why are there different organisms in different places?
a) differences in climate
b) results from differences in average temp. & precip.
Biome – terrestrial regions with characteristic types of natural, undisturbed ecological
communities adapted to the climate of the region.
For plants, precip. Is the limiting factor which determines if a region is going to be a desert,
grassland, or forest.
Average annual precip, temp, & soil type determine the type of biome.\
Biomes are not uniform – consists of a patchwork of different ecological communities, all with
similiarities unique to that biome.
Climate & biomes vary with latitude, ( distance from equator), and altitude, (elevation above sea
level).
From equator towards poles climates - colder
Why do plant sizes, forms, & survival strategies differ?
Main determining factors are : climate & soil type
Types:
a) Succulent ( fleshy) plants, such as the saquaro cactus – most surfaces on the plant
have vertical orientation – limits amount of direct sun. no leaves, the ability to store
food & water in the fleshy parts of the plant, open the pores, (stomata) only at night
to take in CO2.
b) Broadleaf evergreen plants – keep most of their broadleaves year round, large
surface of area of leaves help in photosynthesis & radiate out heat during the day.
c) Broadleaf deciduous plants – shed their leaves to survive cold & drought, become
dormant during these periods , oak, maple
d) Coniferous Evergreen plants – Canada, northern regions, keep some of their narrow
pointed leaves (needles) all year, leaves have a waxy covering that slows down heat
loss & water evaporation, contain cones which bear seeds
Keystone species – Species that play roles affecting many other organisms in an ecosystem.
Indicator species – Species that serve as early warnings that a community or an ecosystem is being
degraded.
Immigrant species or non-nativespecies – species that migrate into an area or are accidentally
introduced by humans.
Native species – species that usually live & thrive in a particular ecosystem
IX.
Desert Biome:
Desert- an area where evaporation exceeds precipitation.
Facts: a) covers 30% land- 30% N/S equator
b) largest desert- located on interior of continent
3 types:
Tropical desert
high temp year round
little rain
driest place on earth, few plants
Temperate desert
daytime temp are high in summer and low in winter
there is more precipitation then in tropical deserts
Cold deserts
winters are cold
summers are warm or hot
precipitation is low
How do Desert Animals and Plants Survive
wax coating on leaves prevents H2O loss
deep tap roots- plants
dormant during dry periods
animal hide deep burrows
thick outer skin- consumes H2O
DRAW A TYPICAL DESERT FOOD WEB.
X. Grassland, Tundra, and Chaparral Biomes
A) What are the Major Types of Grasslands?
Grasslands- regions with enough average annual precipitation to allow grass to
prosper but with precipitation so erratic that drought and fire prevent large stands
of trees from growing.
1.) Grasslands persist because of:
a) seasonal drought
b) grazing by large herbivores
c) occasional fires
2.) Three types:
a) tropical
b) temperate
c) polar
d)
B) What are Tropical Grasslands and Savannas?
1. Tropical grasslands are found in areas with:
a) high temperatures
b) low to moderate precipitation
c) a prolonged dry season
d) A type of tropical grassland, called a savanna usually has:
1) warm temperatures year round
2) two prolonged dry seasons
3) abundant rain the rest of the year
largest savannas are in central and southern Africa, but they are also
found in central South America, Australia, and Southern Asia.
e) African tropical savannas contain enormous herds of:
1) Grazing animals – grass eating herbivores
2) Browsing animals - twig and leaf nibbling
a) example:
1) giraffes eat leaves and shoots from the tops of trees
2) elephants eat leaves and branches further down
3) Thompson’s gazelles and wildebeests prefer short grass
4) Zebras graze on longer grass and stems
5)
C)
What are Temperate Grasslands?
Temperate grasslands cover vast expanses of plains and gently rolling hills in the
interiors of North and South America, Europe, and Asia.
Characteristics:
1) winters are bitterly cold
2) summers are hot and dry
3) annual precipitation is fairly sparse and falls unevenly thought the
year.
a) Types of temperate grasslands:
1) Tall-grass prairies and short- grass prairies of the Midwestern and western
United States and Canada.
2) South American pampas
3) African veldt
4) Steppes of central Europe and Asia
D. Polar Grasslands
Or Arctic tundra, occur just south of the arctic polar ice cap.
Most of the year these treeless plains are:
a) bitterly cold
b) swept by frigid winds
c) covered by ice & snow
d) carpeted with a thick spongy mat of low growing plants. Primarily grasses,
mosses, and low shrubs
e) Plants grow close to the ground – some evergreens – waxy coating on leaves
f) Permafrost – frozen layer of the soil – prevents water from seeping into
ground
g) Brief summer – soil remains waterlogged – bogs
h) Caribou, reindeer, wolf, ground squirrels, snowy owl
Survive the extreme cold by:
a) Do not hibernate – summer to short to store fat
b) Burrow underground
c) Thick coats of fur or feathers
d) Compact bodies to limit exposure
E. Alpine Tundra
Occurs above the limit of tree growth but below the permafrost line on high
mountains. The vegetation is similar to the arctic tundra, but get more sunlight. No
permafrost layer
F. Chaparral
Also known as a temperate shrubland. This biome occurs along coastal areas with
what is called a Mediterranean climate – mild winters, moderately rainy, long, hot, dry
summers. Pacific coast of North America, southern Texas, Chilie, Southwest africa
a) dominated by dense growth of low growing evergreen shrubs
b) leathery leaves – resist water loss, large underground root system
c) prone to fires – brittle vegetation in summer
d) some plants store food reserve in fire resistant roots
e) have seeds that only sprout after a fire
G. Human impact on Grasslands:
f) Conversion of savanna and temperate grasslands to cropland
g) Release of CO2 to atmosphere from burning and conversion to cropland
h) Overgrazing of tropical and temperate grasslands by livestock
i) Damage to fragile arctic tundra by oil production, air and water pollution,
and vehicles. – long time to recover
XI. Forest Biomes:
Undisturbed area with moderate to high average precipitation.
a) Three major Types:
1. Tropical
2. Temperate
3. Boreal (polar)
A. Tropical Rain Forest:
A type of broadleaf evergreen forest found near the equator.
1. has a warm annual mean temperature – varies little year-round
2. high humidity
3. heavy – daily rainfall
4. most diversity on Earth
5. rainforest area - covers about 2% of earth
6. habitats for 50 – 80 % of earth’s terrestrial species
7. Canopy layer – top – sunny –insects, birds
8. Diagram Pg. 137 - layers
B. Tropical Deciduous Forest:
Characteristics –
1. warm year round
2. get most of their rainfall during the wet (monsoon) season
3. lower canopy than tropical rain forest
4. deciduous trees – loose leaves to survive dry season
5. evergreen trees – retain leaves year-round
C. Temperate deciduous Forest :
1. grow in areas with moderate average temperatures
2. long warm summers –cold –not severe winters
3. abundant precipitation spread evenly throughout the year
4. broadleaf deciduous plants – oak, hickory, maple
5. become dormant in winter –shed leaves
6. eastern U.S.
D. Evergreen Coniferous Forests:
1. Aka boreal Forest or Taiga
2. Found south of arctic tundra in regions across north America, Europe, Asia
3. Subarctic climate – long winters, dry & cold, sunlight 6-8 hrs day, short summers
4. Cone bearing trees, needle shaped leaves, waxy covering, low plant diversity
5. Nutrient poor soil – acidic
E. Temperate Rain Forest:
1. Along coastal areas with ample rainfall
2. Dense conifers –Douglas fir, redwoods
3. Canada and northern Calif.
F. Human Impacts on the World’s Forest:
1. Clearing and degradation of tropical forests for agriculture, livestock, grazing, and timber
harvesting.
2. Clearing of the Temperate deciduous forest in Europe, Asia, and North America for timber,
agriculture and urban development
3. Clearing of the evergreen coniferous forest in North America, Finland, Sweden, Canada, Siberia,
Russia
4. Conversion of forest to tree farms
XII. Mountain Biomes:
1. Make up 20% of the earth’s land surface
2. Dramatic changes in altitude, climate, soil, and vegetation take place over a short distance
3. Above the snow line the mountain is always covered by snow
4. Ecological roles of mountains:
a) Contain the majority of the worlds forests – habitats
b) Help regulate the earth’s climate – reflect solar radiation –snow – top
c) Hydrologic cycle
Human Impacts on Mountain biomes:
1.
2.
3.
4.
5.
6.
7.
Landless poor migrating uphill to survive
Timber extraction
Mineral resource extraction
Increasing tourism
Hydroelectric electric dams
Air pollution from industry
Increased exposure to UV radiation –O3 depletion