Transcript Unit 2 Ecology Chp 3 Biosphere and Chp 4

UNIT 2: ECOLOGY
THE BIOSPHERE
Apollo 8
December 24, 1968
“Ecology”?
= The study of interactions among organisms and
between organisms and their environment
Levels of Ecology:
Populations
Biosphere
Put these in order (smallest  largest)
Ecosystems
Biomes
Species
Communities
Biosphere
8km Up
11km Down
At the core of every organism’s interaction with the environment
is its need for energy to power life’s processes
The flow of energy through an ecosystem is one
of the most important factors that determines
the system’s capacity to sustain life
Main
Source
“Autotrophs”
“Heterotrophs”
Autotrophs/ Producers (Photosynthetic and Chemosynthetic)
Heterotrophs/Consumers (Herb-/Carn-/Omn-ivores and Decomposers)
Energy flows through an ecosystem in one direction,
Sun or Inorganic compounds  Autotrophs (producers)  Heterotrophs (consumers)
Food Chains = a series of steps in which
organisms transfer energy by eating and
being eaten
Trophic Levels = each step in a food chain
or food web
Food Webs = links all the food chains in an ecosystem together
Producers?
First Order/Primary Consumers?
Second Order/Secondary Consumers?
Third Order/Tertiary Consumers?
Fourth Order/Quaternary Consumers?
Ecological Pyramid = a diagram that shows the relative amounts of energy
or matter contained within each trophic level in a food chain or food web
Energy Pyramids = represents the amount of energy that is transferred
from one trophic level to the next
Only about 10% of the energy available within one trophic level
is transferred to the next
What happens to the rest?
Life Processes and Heat
Biomass Pyramids = represent the amount of potential food that is
available for each trophic level in an ecosystem
Biomass is usually expressed in terms of grams of organic (living) matter
per unit area
Pyramid of Numbers = represents the numbers of individual organisms
at each trophic level in an ecosystem
Cycles
Don’t just need energy!
What else is needed?
More than 95% of the body is made
up of just four elements:
oxygen, carbon, hydrogen,
and nitrogen
Biogeochemical Cycles
Organisms don’t “use-up” matter,
they “transform” it
The Water Cycle
Nutrient Cycles
The Carbon Cycle
The Nitrogen Cycle
Proteins
78%
Nitrogen Fixation
The Phosphorous Cycle
DNA/ RNA/ ATP
Doesn’t enter the atmosphere
Primary Productivity = the rate at which organic matter is created by producers
Limiting Nutrient = a nutrient that is scarce or cycle slowly
Oceans = Nitrogen
UNIT 2: ECOLOGY
ECOSYSTEMS
AND
COMMUNITIES
1.
2.
3.
4.
The Role of the Climate
What Shapes an Ecosystem?
Biomes
Aquatic Ecosystems
1. THE ROLE OF CLIMATE
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What is Climate?
The Greenhouse Effect
The Effect of Latitude on Climate
Heat Transport in the Biosphere
What is Climate?
Weather = the day-to-day condition
of Earth’s atmosphere at a particular
time and place.
Climate = the average, year-after-year
conditions of temperature and precipitation
in a particular region.
What factors affect the climate?
The Greenhouse Effect
Greenhouse Effect = the natural situation in which heat is retained by
greenhouse gases (warming effect)
Carbon dioxide, methane, water vapor, and a few other atmospheric gases
Earth would be 30o C cooler than it is today if these gases weren’t present
The Effect of Latitude on Climate
Earth’s 23.5o tilt on its axis causes different parts of Earth to receive
different angles of solar radiation
This results in a difference in heat distribution with latitude
Three Main Climate Zones
Polar Zones = between 66.5o and 90o North and South latitudes
Temperate Zones = sit between the polar and tropical zones
Tropical Zones = between 23.5o North and 23.5o South of the Equator
Polar
Zones
Low Angle Sunlight
Cold
Temperate
Zones
Seasonal
Changing Angle
Tropical
Zones
Direct Angle
Constant
Heat Transport in the Biosphere
The unequal heating of Earth’s surface
drives winds and ocean currents, which
transport heat throughout the biosphere
Winds
Warm “Rises”
Pole-ward
Ocean Currents
Cold “Sinks”
Equator-ward
Mountains and the ”Rain Shadow” Effect
Ocean
Currents contribute for same reasons
2. WHAT SHAPES AN ECOSYSTEM?
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Biotic and Abiotic Factors
The Niche
Community Interactions
Ecological Succession
Biotic and Abiotic Factors
Biotic Factors = the biological influences on organisms within an ecosystem
Abiotic Factors = physical, or nonliving factors that shape ecosystems
Determine the survival and growth of an organisms and the productivity of the
ecosystem in which the organism lives
Habitat = the area where an organism lives (includes both biotic and abiotic factors)
The Niche
Niche = the full range of physical and biological conditions in which an organism
lives and the way in which the organism uses those conditions
Community Interactions
Community interactions can powerfully affect an ecosystem
1. Competition
Competition occurs when organisms of the same or different species attempt
to use an ecological “resource” in the same place at the same time
Often results in a winner and a loser (fails to survive)
Competitive Exclusion Principle = no two species can occupy the same niche
in the same habitat at the same time
CEP is a fundamental rule in ecology
2. Predation
Predation = an interaction in which one organism captures and feeds
on another organism (predator/ prey)
3. Symbiosis
Symbiosis = any relationship in which two species live
closely together (“living together”)
A. Mutualism
B. Commensalism
C. Parasitism
A. Mutualism = both species benefit
from the relationship
B. Commensalism = one member
benefits and the other is neither helped
nor harmed
C. Parasitism = one organism lives on or inside
another organism (the host) and harms it
Ecological Succession
Ecosystems and communities are always changing (abruptly or gradually) in
response to natural or human disturbances
Ecological Succession = this series of predictable changes that occurs in
a community over time
Mt. St. Helens May 1980
Lowered to 8,363 ft
Summit = 9,677 ft
As an ecosystem changes, older inhabitants gradually die out and new organisms
move in, causing further changes in the community
Primary Succession = succession (on land) that occurs on surfaces where
no soil exists (volcanic eruptions, glaciers, etc.)
Pioneer Species = the first species to
populate the area
Lichen = a symbiotic relationship
between a fungus and an
algae (protist)
Enchanted Rock (Fredericksburg)
Secondary Succession = succession that occurs when a disturbance of some
kind changes an existing community without removing the soil
Succession can even occur at the bottom of the oceans
3. BIOMES
• Biomes and Climate
• The Major Biomes
• Other Land Areas
Ecologists group Earth’s diverse environments into biomes
Biome = a complex of terrestrial communities that covers a large area and is
characterized by certain soil and climate conditions and particular assemblages
of plants and animals
World’s Major Biomes:
-Tropical Rain Forest
-Tropical Dry Forest
-Tropical Savanna
-Desert
-Temperate Grassland
-Temperate Woodland and Shrubland
-Temperate Forest
-Northwestern Coniferous Forest
-Boreal Forest
-Tundra
Each of these biomes is defined by a unique set of abiotic factors –
particularly climate- and a characteristic assemblage of plants and animals
Adaptations
Tolerance
The climate of a region is an important factor in determining which
organisms can survive there
Microclimate = the climate in a small area that differs from the climate around it
Some areas of land on Earth do not fall neatly into the major biome categories
Mountain Ranges
Abiotic and biotic conditions
vary with elevation
Polar Ice Caps
North Polar Region (thinner ice)
South Polar Region (thicker ice)
4. AQUATIC ECOSYSTEMS
Impacted by:
Depth
Flow
Temp
Chemistry of Water
Freshwater Ecosystems
3% of World’s Surface Water
Standing-Water
Flowing-Water
Flowing-Water Ecosystems:
(Rivers, Steams, Creeks, and Brooks)
Typically originate in mountains or hills,
often springing from an underground
water source
Plenty of dissolved oxygen but little plant life
Farther downstream, the water may
meander more slowly through flat areas
As the water flows downhill, sediments
build up and enable plants to establish
themselves
Standing-Water Ecosystems:
Lakes and ponds
In addition to the net flow of water in and
out of these systems, there is usually
water circulating (turning-over) within them
This circulation helps to distribute
heat, oxygen, and nutrients
Phytoplankton = single-celled
algae supported by nutrients
in the water
Plankton = tiny, free-floating or weakly swimming
organisms that live in both fresh/saltwater
Zooplankton = planktonic animals that
feed on the phytoplankton
Freshwater Wetlands:
Wetland = an ecosystem in which water either covers the soil or is present at
or near the surface of the soil for at least part of the year
“Biodiversity”
Bog
Marsh
Swamp
Estuaries
Estuaries = are wetlands formed where rivers meet the sea
fresh water and salt water (brackish)
Affected by the ocean tides
High
Productivity
Detritus = is made up of tiny pieces of
organic material that provide food for
organisms at the base of the estuary’s
food web
“Coastal Zone”
“Open Ocean”
Photosynthesis
(200 meters)
Chemosynthesis
Coral Reefs
Exists in warm, shallow water of tropical
coastal oceans
Among the most diverse and productive
environments on Earth
Named for the coral animals whose hard, calcium carbonate skeletons make
up their primary structure (Coral)
Symbiotic relationship with Algae
Algae: Photosynthesis
Coral: Waste