Chapter 3: The Biosphere

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Chapter 3 The Biosphere
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• Objectives
• Identify the levels of organization
• Describe the methods used to study ecology
• Identify the source of energy for life processes
• Trace the flow of energy through living systems
• Describe how matter cycles among the living and
  nonliving parts of an ecosystem.
• Explain why nutrients are important in living
  systems.

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What is Ecology?

• Ecology is the scientific study of interactions
  among organisms and between organisms and their
  environment.
• What does this mean?
• How do we study these interactions?

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• We have to ask questions about events and
  organisms that range in complexity from a single
  individual to the entire biosphere.

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Levels of Organization
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Organism
An individual living thing
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Population

• Members of one species that interbreed and live
  in the same place at the same time.

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Population

• Compete for
• Food
• Water
• Shelter
• Mates

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Community

• Different populations that live together in a
  defined area.
• Several populations interacting together.

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Ecosystem

• A collection of all of the organisms that live in
  a particular place, together with their
  nonliving, or physical environment.

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Ecosystem

• Biotic Factors living organisms within an
  ecosystem
• Abiotic Factors nonliving factors that help
  shape an ecosystem

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Biomes

• A group of ecosystems that have the same climate
  and similar dominant communities.

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Biosphere

• The highest level of organization that ecologists
  study is the entire biosphere itself.
• The portion of
• the Earth that
• supports life.

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BIOSPHERE
BIOME
ECOSYSTEM
COMMUNITY
POPULATION
ORGANISM
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Ecological Methods

• Ecologists use a wide range of tools and
  techniques to study the living world.
• Apply the scientific method to do ecological
  research
• Observing
• Experimenting
• Modeling

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Interactions Between Organisms

• All organisms depend upon other living things
  and nonliving things to meet their needs, such
  as
• Food
• Shelter
• Reproduction
• Protection
• Thus, an interdependence exists among organisms
  and the environment

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Energy Flow

• All living things need ENERGY to survive.
• Where does this energy ultimately come from?

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Autotrophs

• Organisms that capture energy from sunlight or
  chemicals and use that energy to produce food.
• Ex. Bacteria,
• plants, and algae
• Also called producers

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Heterotrophs

• Rely on other organisms for
• their energy and food supply
• Also called consumers

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Types of Consumers

• Herbivores
• Carnivores
• Omnivores
• Detritivores
• Decomposers

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Herbivores
Heterotrophs that eat plants (1st order consumers)
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Carnivores

• Heterotrophs that eat animals
• They come in many sizes!

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Omnivores
Eat both plants and animals Ex humans,
raccoons, bears
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Detritivores
Animals that feed on animal remains and dead
matter (collectively called detritus) EX
mites, earthworms, snails, crabs
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Decomposers
Break down decaying matter Ex bacteria and
fungi
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Feeding Relationships

• What happens to the energy in an ecosystem when
  one organism eats another?
• The energy moves along a one-way path.
• Energy flows through an ecosystem in one
  direction, from the sun to autotrophs and then to
  various heterotrophs

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Food Chains

• The energy stored by producers can be passed
  through an ecosystem along a food chain, a series
  of steps in which organisms transfer energy by
  eating and being eaten.

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A food chain shows how matter and energy move
through an ecosystem
Each organism represents a trophic level, a step
in the food chain.
Natural Food Chain
Sun Grass Rabbit
Snake Hawk
The arrows show the direction that energy is
transferred
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Food Web

• Shows all of the possible feeding relationships
  at each trophic level in the community.

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Tertiary consumers
Secondary consumers
Primary Consumers- herbivores
Producers
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Ecological Pyramids

• A diagram that shows the relative amounts of
  energy or matter contained within each trophic
  level in a food chain or food web.
• 3 types
• Energy pyramids
• Biomass pyramids
• Pyramids of numbers

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Energy Pyramid

• Only part of the energy that is stored in one
  trophic level is passed on to the next level.
  why?
• Organisms use much of the energy that they
  consume for life processes (reproduction,
  respiration, and movement).

• Only 10 of the energy available within one
  trophic level is transferred to organisms at the
  next trophic level.

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Biomass Pyramid

• The total amount of living tissue within a given
  trophic level is called biomass.
• A biomass pyramid represents the amount of
  potential food available for each trophic level
  in an ecosystem.

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Pyramid of Numbers

• Pyramid based on the numbers of individual
  organisms at each trophic level.

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Matter also is moved throughout an ecosystem...
Water
Carbon
Nitrogen
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Water

• The water cycle is the continuous movement of
  water between Earth and its atmosphere.

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Carbon Cycle

• Carbon is an essential component of proteins,
  fats, and carbohydrates
• The carbon cycle is a process by which carbon is
  cycled between the atmosphere, land, water, and
  organisms.

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Carbon Cycle

• Four processes
• Respiration (adds)
• Combustion (adds)
• Decomposition (adds)
• Photosynthesis (removes)

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Carbon Cycle

• The carbon cycle has been operating to keep the
  amount of carbon dioxide in balance between the
  atmosphere and Earth.
• HOWEVER, the burning of fossil fuels has added
  more carbon dioxide than can be removed by plants
  during photosynthesis.

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Carbon Cycle

• Carbon dioxide is considered a greenhouse gas it
  traps heat on Earth.
• This contributes to global warming, which has led
  to an overall increase in the Earths average
  temperature.

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Nitrogen Cycle
78 of the atmosphere is composed of
nitrogen Living things cannot use nitrogen in
the atmospheric form Lightening and some
bacteria convert nitrogen to usable forms, then
producers use them to make proteins. Consumers
then eat the producers and reuse the nitrogen to
make their own proteins! When organisms die,
decomposers return nitrogen to the soil and it is
either reused or converted into nitrogen gas and
returned to the atmosphere.
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Nutrient Limitation
Primary Productivityrate at which an organic
matter is created by producers Process can be
limited by a lack of nutrients
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A polar bear, its fur stained with algae, stands
in its cage at Higashiyama Zoo in Nagoya, central
Japan, Saturday, Sept. 6, 2008. Three polar bears
at the zoo changed their colors in July after
swimming in a pond with an overgrowth of algae,
prompting many questions from visitors concerned
about whether the animals are sick or carrying
mold, a zoo official said. Credit AP Photo/Kyodo
News, Shuzo Shikano