Transcript Chapter 3 Notes

Chapter 3 Notes
The Biosphere
3-1 What is Ecology

A. Interactions and Interdependence
– 1. Ecologists study interactions among
organisms and between organisms and
their environment
– 2. Earth’s organisms live in the biosphere
(land, water, air, atmosphere)

B. Levels of Organization
– 1. Individual
– 2. Population- group of individuals, of the same
species, that live in the same area
– 3. Community- populations that live together in a
defined area
– 4. Ecosystem- community and its nonliving matter
– 5. Biome- ecosystems that have the same climate
and dominant communities
– 6. Biosphere- all the parts of the planet where life
exists
3-2 Energy Flow

A. Producers
– 1. All organisms need to get energy from
their environment in order to survive.
– 2. Sunlight is the major source of energy
for life on Earth
– 3. Only plants, some algae, and certain
bacteria are producers
– 4. Autotrophs (producers)- captures energy
from sunlight or chemicals and uses that
energy to produce food.

a. the process of autotrophs using light energy to
make food is called photosynthesis
CO2 + H2O  Carbohydrates + O2

b. the process of autotrophs using chemical energy
to make carbohydrates is called chemosynthesis

B. Consumers
– 1. Heterotrophs (consumer)- organisms that
rely on other organisms for their food.
a. Herbivore- eat only plants
 b. Carnivore- eat animals
 b. Omnivore- eat plants and animals
 c. Detritovore- feed on dead stuff
 d. Decomposer- break down organisms

C. Feeding Relationships
-1. Energy flows through an ecosystem in one
direction
Sun/inorganic compoundsAutotrophsHeterotrophs
– 2. Food Chain- Series of steps where
organisms transfer energy by eating and
being eaten
– 3. Food Web- links together all food chains in
an ecosystem
– 4. Each step in a food chain or web is called a
trophic level
a. consumers make up higher trophic levels,
producers make up lower levels
 b. each consumer depends on the trophic level
below it for energy


D. Ecological Pyramids
– 1. Energy Pyramid- shows how much
energy is available at each trophic level
(only 10% of the energy is transferred up
to the next level)
– 2. Biomass Pyramid- shows the amount
of living matter at each trophic level
– 3. Pyramid of Numbers- shows the
number of organisms at each trophic
level
3-3 Cycles of Matter

A. Recycling in the Biosphere
– 1. Matter is recycled within and between
ecosystems
– 2. Matter is transformed into tissue or
passed as waste
– 3. Biogeochemical cycles- elements,
chemical compounds and other forms of
matter are passed from one organism to
another and one part of the biosphere to
another

B. Water Cycle
– 1. Evaporation- water changes from liquid to
atmospheric gas
– 2. Transpiration- water from leaves of plants
enters atmosphere as gas
– 3. Condensation- atmospheric gas cools and
condenses into liquid droplet form
– 4. Precipitation- when the
liquid droplets become large
enough to return to Earth

C. Nutrient Cycles
– 1. Organisms need nutrients to build tissues
and carry out life functions

a. Nutrients pass through biogeochemical cycles too
– 2. Carbon Cycle
Processes that use or produce carbon:
Biological- photosynthesis, respiration,
decomposition
Geochemical- erosion, volcanic activity
Biogeochemical- burial, decomposition,
conversion
Human actions- mining, cutting, burning
forests and fossil fuels


3. Nitrogen Cycle
– a. Nitrogen fixation- the conversion from
nitrogen gas into ammonia by bacteria and
then into nitrates and nitrites
a. once in this form, producers use them to make
proteins
 b. consumers eat producers and reuse the
nitrogen

– b. Denitrification- releases nitrogen into
atmosphere by conversion by bacteria

4. Phosphorus Cycle
– a. All organisms use phosphorous for
synthesizing phospholipids, NADPH, ATP, DNA
and RNA
– b. Remains in rock & soil minerals, and ocean
sediments as inorganic phosphate
– c. weathering and soil erosion sends
phosphates into streams and rivers, then
oceans
– d. plants help cycle phosphorous rapidly
through an ecosystem

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Limiting nutrient- any essential
resource which, in short supply, limits
population growth
Examples: food, minerals of certain
types, refuge from predators, a
pollution-free environment,
competition for resources
Checkpoint

You have a small garden in your
backyard. What are some limiting
nutrients (factors) that will affect the
success of your garden?