Transcript Introduction to ecology - the physical environment - Moodle

Introduction to Ecology:
Climates and Biomes
• Or: Why is it so darned cold here today!
Arlington, TX
Sioux City, IA
Fort Stewart, GA
Peachtree City, GA
Big Frog Mountain, GA
Oregon, WI
Key Concepts
Ecology’s goal is to explain the distribution and abundance of
organisms. It is the branch of biology that provides a scientific
foundation for conservation efforts.
Physical structure—particularly water depth—is the primary
factor that limits the distribution and abundance of aquatic
species. Climate—specifically, both the average value and annual
variation in temperature and in moisture—is the primary factor
that limits the distribution and abundance of terrestrial species.
Climate varies with latitude, elevation, and other factors—such as
proximity to oceans and mountains. Climate is changing rapidly
around the globe.
A species’ distribution is constrained by historical and biotic
factors, as well as by abiotic factors such as physical structure and
climate.
© 2011 Pearson Education, Inc.
Introduction to Ecology Topics
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Ecology defined
The Abiotic Environment
Properties of Water
Solar energy drives climate
Climate is a major determinant of
– distribution of organisms and
– adaptations to the physical environment
Two definitions of ecology:
(Oikos = house)
• Study of interactions between
organisms and their environment
–Biotic environment = living things
–Abiotic environment = non-living
things
• Study of the distribution and
abundance of organisms
Common Ground
• Interactions between organisms and
environment determine distribution
and abundance of organisms
• Ecological interactions are the
mechanisms by which differences in
survival and reproduction come about
• Recall the importance of environment
in natural selection – what is favored
depends on the specific environment
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
How Do Ecology and Conservation Efforts Interact?
• The four levels of ecological study are synthesized
and applied in conservation biology.
Ecologists study how interactions between
organisms and their environments result in
species’ distributions and abundances.
Conservation biologists apply these data to
preserve species and restore environments.
© 2011 Pearson Education, Inc.
Properties of water
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“Universal solvent”
Maximum density at 4C
High specific heat capacity
High heat of fusion
High heat of vaporization
Holds more O2 at lower temperatures
Higher density and viscosity than air
“Universal solvent”
• Biochemistry is Aqueous chemistry
• Most nutrients and many waste products
dissolve in water
– Aquatic animals tend to excrete more water soluble,
but also more toxic wastes (e.g., ammonia), while
terrestrial animals store and excrete insoluble and
less toxic wastes (e.g., uric acid)
• Plants obtain nutrients from solution in soil and
in aquatic habitats
• Organisms transport nutrients and wastes in
solution
Maximum Density at 4C
– Both warmer
and colder
water float on
top
– ICE FLOATS!
• Lakes do not
freeze solid!
High Heat of vaporization
• Heat of vaporization is the amount of
energy required to convert liquid to gas
• Water has the highest heat of vaporization
per gram of any molecular liquid (2257 J/g
at boiling point).
• There is a great deal of energy required to
convert the water to gas.
• Evaporative cooling is very effective
Water has a high specific heat capacity
• It takes a lot of energy to make its
temperature change.
• Water has to absorb 4.184 Joules of heat
for the temperature of one gram of water
to increase 1 degree celsius (°C).
– (it only takes 0.385 Joules of heat to raise 1
gram of copper 1°C.)
• Water can transfer large amounts of heat
from place to place.
• Aquatic habitats tend to be thermally
stable, as do nearby terrestrial habitats
High heat of fusion
• Heat of fusion is the amount of energy
required to convert solid to liquid
• So during the formation of ice water loses
a lot of heat, or requires a lot of cooling.
• Ice forms slowly and water temperature
does not change as it does so.
Cold water holds more O2
• Easier to
respire with
gills in cooler
water
High density and viscosity
• Water is dense, so it is buoyant,
– aquatic species need less support against
gravity than terrestrial ones
• Water is viscous, meaning it resists flow
– Easier to swim than to fly
• Aquatic organisms can use swimming to disperse
gametes and propagules
– But there is a premium on streamlining to
reduce drag
• Fusiform body shape common to swimmers
Solar energy drives all life, plus
hydrologic cycle, plus most aspects
of climate
• Intertropical
convergence
Heated air rises
over solar
equator
• → Hadley cells
• → wind toward
ITC & rain
• Adiabatic
cooling →
condensation
which dries air
• Adiabatic
heating:
falling air
dries as it
warms
• Bands of wet
(~0° & ~60°)
and dry (~30°)
climate
Fig. 58.3
Coriolis effect
causes winds to
“curve”
• Counterclockwise
flow in Southern
Hemisphere,
clockwise in
Northern
Hemisphere
• Trade winds and
doldrums
Winds drive major ocean currents
Winds and properties of water drive lake
turnover and upwelling in aquatic systems
• Stratification in summer and winter
• 4C (or coolest) water always at bottom
• Ice or warmest water always on top
• O2 greatest near surface
• Nutrients settle to bottom
Winds and properties of water drive lake
turnover and upwelling in aquatic systems
• Mixing in spring and fall when surface
temperatures shift past 4C
• Distributes nutrients and O2 throughout
water column
• Leads to spring bloom
Upwelling and El Niño
• Reversal of
flow in
southern
Pacific
stops
upwelling
• Rains start
• Fisheries
collapse
• Mudslides
Why Rain?
Wind currents over ocean and land
primary determinants of climate
• Onshore winds → rain
• Offshore winds → desert
• Mountain ranges → rain on windward side,
rain shadow on leeward side
Climate dictates biome type
• Biome = major patterns of vegetation
type
• E.g., Tropical rainforest, tallgrass
prairie, boreal forest
Rain shadow
Tilt of earth → seasons
Why is there tallgrass prairie
(Temperate grassland biome) here?
• Biomes = large scale ecosystem types
dictated primarily by climate
• Iowa: Midlatitude, midcontinental climate
• Modest precipitation, hot summer, cold winter
Fig. 58.8
A few of my favorite biomes
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Precipitation
(mm)
Temperature
(°C)
Mount Vernon, IA
J F MAM J J A SO N D
Month
We live in temperate grassland biome
at ~ 42°N, 91°W
Moderately hot, moderately dry
in summers with frequent droughts
Cold, dry winters
• “Walter
diagrams”
represent climate
in ecologically
relevant fashion
• 20mm rain/mo
needed for every
10ºC rise in
temperature
• 0º is approximate
limit of growing
season
The Iowa Connection: Tallgrass Prairie
• Deep rooted perennial plants adapted to
frequent fires
• Soils rich in organic material from accumulated
root biomass and minerals from ash
• In Iowa, further mineral nutrients from glacial
sediment deposits
Temperate grasslands
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High species richness, moderate productivity
Dominated by grasses, usually < 2m tall
Many perennial plants
Nutrients stored in rich organic soil 
conversion to agriculture
• Large grazers, many insect herbivores
• Fire-tolerant
• Grass height varies with precipitation balance
(shortgrass grades into desert at one
extreme, tallgrass into savannah, then forest
at the other)
Tallgrass Prairie
Shortgrass Prairie
Boreal Forest (e.g., Wilderness Field
Station)
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Precipitation
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Temperature
(°C)
Ely, MN
• 47°N, 91°W
• Colder and
drier than Mt
Vernon yearround
• Shorter
growing
season
Boreal Forest – Northern
Minnesota
Sampling tree diversity at the
Wilderness Field Station
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Precipitation (mm)
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Ely, MN
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Mount Vernon, IA
Temperature (°C)
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• Extreme seasonality,
short growing season,
harsh winters,
moderate-low rainfall
• Low species richness
moderate productivity
• Mostly conifers with
understory of shrubs
and some fast growing
deciduous trees
• Deep humus, acidic,
nutrient-poor soil
• Frost and fire tolerant
Seasonal tropical forest
(AKA Tropical dry forest)
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~10ºN, 85ºW
Precipitation (mm)
Temperature (°C)
Playa Grande, CR
• Hot year round
• Marked wet and dry
seasons (related to
seasonal rain shadow
effect in central
America)
• Many deciduous trees
shed leaves in dry
season
• Grades into tropical
savannah with fire
and grazing
Figure 5.22a
Fig. 58.7
Introduction to Ecology Topics
•
•
•
•
•
Ecology defined
The Abiotic Environment
Properties of Water
Solar energy drives climate
Climate is a major determinant of
– distribution of organisms and
– adaptations to the physical environment