Download Ch 3: The Biosphere

Ch 3: The
Biosphere
Studying Our Living Planet
Biosphere: all life on Earth
and all parts of the Earth in
which life exists
 Eco = oikos, meaning house
 Ecology: study of
interactions among &
between living organisms
and their physical
environment

Levels of Organization
 Ecologists
have organized the
interactions an organism takes part
in into different levels according to
complexity.
Ecological Levels of Organization
1st Level of Organization
Organism/Individual:
A living thing that is made
of cells, uses energy,
reproduces, responds,
grows, and develops—is
part of a species
 Species: group of similar
organisms that can breed
& produce fertile
offspring

2nd Level of Organization
 Population:
A group of
organisms, all
of the same
species, which
interbreed and
live in the same
place at the
same time.
3rd Level of Organization
 Biological
Community:
All of the
populations of
different
species that live
in the same
place at the
same time.
4th Level of Organization
 Ecosystem:
Populations of
organisms that
interact with each
other and with the
environment of a
given area.
5th level of Organization
-Biomes are a group of ecosystems with
similar climates and typical organisms.
6th Level: The Biosphere
Life is found in
air, on land, and in
fresh and salt
water.
 The BIOSPHERE
is the portion of
Earth that
supports living
things.

Biotic and Abiotic Factors
Biotic factor – living components of the
environment with which an organism may
interact; all of the biological influences on
organisms
--Ex: Plants, Animals, Fungi, Protists, Bacteria
 Abiotic factor – any nonliving part of the
environment that affects the organism
--Ex: Sunlight, heat, precipitation, humidity,
wind, water currents, soil type, etc.

Abiotic or Biotic?
Biotic
Abiotic or Biotic?
Abiotic
Abiotic or Biotic?
Abiotic
Abiotic or Biotic?
Biotic
Energy, Producers, & Consumers
Living systems operate by using energy
 Need energy for: growth, reproduction,
metabolism, etc.
 Organisms can only use energy from other
sources
 Where do you get your energy from??
 Where does the energy in food come from???

What is our Planet’s Energy
Source?
For
most life on Earth, sunlight is the ultimate
energy source
For some organisms energy stored in chemicals
in rocks, soil, etc., serves as their primary energy
source
Primary Producers (Autotrophs)

•
•
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Organisms that produce their own
food supply
Cells of most autotrophs contain
chlorophyll & can use energy
directly from the sun
Ex: plants, attached algae, freefloating algae (phytoplankton), &
some bacteria
May be photoautotrophs using
light energy (e.g. plants)
May be chemoautotrophs using
chemical energy (e.g. some
bacteria)
Photosynthesis
 Chemical
reaction
where producers use
water and carbon
dioxide to store the
sun’s energy as
glucose.
6H2O + 6CO2 + Sun  C6H12O6 + 6O2
20
Chemosynthesis
 Chemical
reaction
where producers
use chemicals and
carbon dioxide to
store energy as
glucose.
Consumers (Heterotrophs)

Eat other organisms to obtain energy.
Ex: animals, fungi, protists, & many bacteria
 Herbivores
--Eat only plant products (leaves, roots, seeds, or fruits)
--Ex: Cows, caterpillars, deer
 Carnivores
--Eat only other animals
--Ex: Snakes, dogs, cats, otters
 Omnivores
--Eat plant products & animals
--Ex: Humans, bears, pigs, raccoons
 Scavengers
--Eat carcasses of other animals killed by predators or died of natural causes
--Ex: Vultures
 Decomposers
--`feed’ by chemically breaking down organic matter; produces detritus (small
pieces of dead & decaying plant & animal remains)
--Ex: Bacteria & fungi
 Detritivores
--Consume detritus & the decomposers that live on/in detritus
--Ex: Earthworms, mites, snails, shrimp, crabs
Feeding Relationships
Energy flows through an
ecosystem in one direction:
from producers to various
levels of consumers
 Food Chain
 Series of steps in which
organisms transfer energy
by eating & being eaten
 Food Web
 More realistic path through
an ecosystem—made of
many food chains (because
organisms may eat more
than one kind of food!)
Food Webs
 Are
interconnected
food chains
 They show the
feeding
relationships in
an ecosystem
Food Chain
1st
Order
Consumer
Producer
(trapped sunlight
& stored food)
2nd Order
Consumer
3rd Order
Consumer
4th Order
Consumer
Trophic Levels
Levels through which energy flows in an
ecosystem
 Each step taken in a food chain or web is called
a trophic level
 1st level: Primary producers
 2nd level: Primary consumers
 3rd level: Secondary consumers
 4th level: Tertiary consumers

Food Chains Show Available Energy
What happens to the energy?

Most of the energy the primary consumer gets

Some of the energy moves into the atmosphere

Rule of 10: Only about 10% of energy is transferred
from one trophic level to the next. The rest is used for
life functions (growth, reproduction, etc)!
from the producer is used by the consumer
as heat.

Example:
 It takes 100 kgs of plant materials (producers) to support 10
kgs of herbivores
 It takes 10 kgs of herbivores to support 1 kg of 1st level
predator
Ecological Pyramids
Another way of
showing the relative
amount of energy or
matter contained in
each trophic level
 3 different types:
--Energy
--Biomass
--Numbers

Ecological Pyramids Show
Energy Pyramids:


Amount of available energy at each trophic level
Only 10% of energy is transferred from one level to the next.
Biomass Pyramids:

Amount of living organic matter available at each trophic level
(grams/kg)
Numbers Pyramids:

Number of individual organisms at each trophic level
(population size)
30
Ecosystem Recycling: Cycles of Matter
All ecosystems must have cycles of systems to
reuse raw materials (there is not an infinite
amount of resources!!!)
 Matter is recycled within & between ecosystems
 Biogeochemical Cycles: closed loops that
allow matter to be recycled through biological,
geological, & chemical (physical) processes
 Water Cycle
 Carbon Cycle
 Nitrogen Cycle
 Phosphorus Cycle

Water Cycle
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Evaporation
Transpiration
Precipitation
Runoff
Groundwater
Steps of the Water Cycle
Water vapor in the air condenses and falls as
rain or snow.
2A. Some rain/snow seeps into soil and becomes
part of groundwater.
2B. Most rain/snow falls into the ocean.
3A. Water is heated by the sun and evaporates.
3B. Plants absorb water that is in the ground.
4. After going through the plant, the sun and wind
pulls water out by evaporation – process called
transpiration.
1.
Nitrogen/Phosphorus Cycle
• Found in atmosphere, runoff, fertilizersdue to decomposition
• Nitrogen & phosphorus are used in the
synthesis of amino acids (proteins),
nucleic acids (DNA), & energy molecules
(ATP)
• Nitrogen/Phosphorus fixing (converting):
done by bacteria/fungi; change
nitrogen/phosphorus compounds into a
usable form for plants
• Nitrogen/Phosphorus in soil is then
absorbed by plants and becomes part of
the plant’s tissues
• Plants are consumed by herbivores or
omnivores & these organisms are then
consumed by another consumer or
decomposed of when they die
Carbon Cycle
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Combustion
Photosynthesis
Respiration
Decomposition
Fossil fuels
Steps of the Carbon Cycle
CO2 in the air is used by producers for
photosynthesis. They become part of the
producers in the form of sugar.
2A. Respiration – most organisms (plants,
animals, etc) breathe in O2 created by
producers. They breathe out CO2.
2B. Combustion – burning of fossil fuels
increase CO2 in the air.
2C. Decomposition – Decay of dead organic
wastes by bacteria/fungi create CO2.
1.
Nutrient Limitation
Primary Productivity: rate at which
organic material is produced by
autotrophic organisms
 With ample sunlight & water, primary
productivity may be limited by the
nutrients available
 Limiting nutrient: nutrient whose
supply limits productivity
 Limitations can occur in soil or in
aquatic habitats
