Transcript Chapter 3

Chapter 3
The Biosphere
3.1 What Is Ecology
Biosphere
Consists of all of the life on earth and parts
of the Earth where life exists
• Land, water, and atmosphere
• Bacteria underground to spores in the
atmosphere
• From 8 km above the Earth to 11 km below
surface of the ocean
3.1 What Is Ecology
Ecology
Scientific study of interactions among organisms
and between organisms and their physical
environment
Relationships
Eaten plants and animals
Competition
• Food
• Habitat
– Rainforest
Pollution
3.1 What Is Ecology
Levels of Organization
Individual organism
Population
Community
Ecosystem
Biome
Biosphere
3.1 What Is Ecology
FIGURE 3.1 on page 65
3.1 What Is Ecology
Biotic Factor
Any living part of the environment that an
organism might interact with
• Animals, plants, bacteria
Abiotic Factor
Any nonliving part of the environment
• Sunlight, heat, precipitation
3.1 What Is Ecology
3.1 What Is Ecology
List biotic and abiotic factors
3.2 Energy, Producers, and Consumers
Primary Producers
Living systems operate by expending energy
• Growth, reproduction, and metabolic processes
NO organism can make its own energy
• Sunlight is the ultimate source of energy for most life
on earth
• For some organisms, chemical energy stored in
inorganic compounds serves as the ultimate energy
source
3.2 Energy, Producers, and Consumers
Autotrophs
Use solar or chemical energy to produce food
• Assembling inorganic compounds into complex
organic molecules
Store energy in forms that make it available to
other organisms that eat them
“PRIMARY PRODUCERS”
3.2 Energy, Producers, and Consumers
Energy From the Sun
Photosynthesis
• Captures light energy and uses it to power chemical
reactions
– Converts CO2 and H2O into O2 and energy rich carbohydrates
– Makes Sugars and Starches
– Removes CO2 from the atmosphere and adds O2
3.2 Energy, Producers, and Consumers
Photosynthesis
3.2 Energy, Producers, and Consumers
Life Without Light
Chemosynthesis
• Producers harness chemical energy from
inorganic materials
– Hydrogen sulfide
• Uses this chemical energy to produce
carbohydrates
3.2 Energy, Producers, and Consumers
Chemosynthesis
3.2 Energy, Producers, and Consumers
Heterotrophs
Must acquire energy from other organisms
• By ingesting them in one way or another
Can not make own food
Called consumers
3.2 Energy, Producers, and Consumers
Types of Consumers
Carnivores
Herbivores
Omnivores
Scavengers
Decomposers
Detritivores
3.2 Energy, Producers, and Consumers
FIGURE 3.6
Page 71
3.2 Energy, Producers, and Consumers
3.3 Energy Flow in Ecosystems
Food Chain
Energy flows in a one way stream
• From primary producer to various consumers
Series of steps in which organisms transfer
energy by eating and being eaten
3.3 Energy Flow in Ecosystems
Food Web
Network of all
feeding interactions
In most ecosystems,
feeding relationships
are much more
complex
3.3 Energy Flow in Ecosystems
Trophic Levels
Each step in the food chain or food web
Primary producers always make up the first
trophic level
Each step is further removed from the
primary producer
3.3 Energy Flow in Ecosystems
Making a Food Web
Primary producers
are on the bottom
and carnivores are
on the top following
trophic levels
Arrows point in
direction of energy
flow
3.3 Energy Flow in Ecosystems
Pyramid of Energy
Shows the relative amount of
energy available at each
trophic level
Organisms expend much of
their energy
• Respiration, movement,
growth, and reproduction
Most of remaining energy is
lost as heat
Very little is stored
• Only about 10% is passed on
3.3 Energy Flow in Ecosystems
Why are food chains usually short?
3.3 Energy Flow in Ecosystems
3.3 Energy Flow in Ecosystems
Pyramid of Biomass and
Numbers
Pyramids of biomass
show the total amount of
living tissue at each
trophic level
A pyramid of numbers
shows the relative
numbers of organisms at
different trophic levels
3.4 Cycles of Matter
Energy
Passes through an
ecosystem
Gets use or released
as heat
Matter
Cycles through an
ecosystem
Constantly getting
reused
3.4 Cycles of Matter
Water cycle
Water moves between the ocean, the atmosphere, and land.
• Evaporation & Transpiration
• Condensation
• Precipitation
3.4 Cycles of Matter
Carbon Cycle
Carbon is a key ingredient
of all organic compounds
Adds CO2
• Burning
• Respiration
• Geologic activity
Removes CO2
• Photosynthesis
• Dissolves in rainwater
3.4 Cycles of Matter
Nitrogen Cycle
Nitrogen is needed by all
organisms to build proteins
• Nitrogen fixation
–
Converts nitrogen gas to ammonia
• Denitrification
–
Converts nitrates to nitrogen gas
• Primary producers use nitrogen to
make proteins and nucleic acid
• Consumers eat producers and
reuse nitrogen to make own
compounds
• Decomposers release nitrogen
back to soil
• Fertilizers add extra nitrogen to soil
3.4 Cycles of Matter
Phosphorus Cycle
Phosphorus is needed for
molecules such as DNA
and RNA
• Cycles among land, ocean,
and organisms
• Does not enter the
atmosphere in significant
amounts
• Fertilizers add extra
phosphorus to soil