Transcript Energy and Nutrients

13-1 “Ecology: Studying
Nature’s Houses”
 Objective:
 Define the term ecology.
 Explain ecology’s importance
as a scientific field of study.
Ecological Research

Ecology is:
Study of interactions between
organisms
 Study of interaction between
organisms and their environment
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Observations
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Advantages: Often lead to valuable
understanding of situations and
phenomena; Often suggest connections
between various events in nature.
Disadvantage: Alone cannot prove those
links.
Experiments
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Advantages: Allow control of variables
and the chance to manipulate each
variable.
Disadvantage: In the lab it’s difficult to
recreate complex relationships found in
nature.
Why Study Ecology?

Gives us information necessary to
understand and resolve many of
the environmental and ecological
issues that confront us.
Web of Interdependence
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Living things affect each other in many
ways.
The process of acquiring energy and
nutrients joins all life together.
Organisms need energy to power life’s
processes and raw materials to build and
maintain living tissue.
13-2 Ecology & Energy:
Essential for Life’s Processes

Objective:
 Describe how energy flows through
the biosphere & different trophic
levels.
 Define the terms consumer,
producer, heterotroph, autotroph,
carnivore, omnivore, parasite &
decomposer.
Energy From the Sun
What organisms can harness
energy from sunlight?
 Green Plants, Algae, some
Bacteria
 By what process?
 Photosynthesis
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Primary Producers

Autotrophs
 “self-feeders”
 Create food from water, CO2
and sunlight
 Produce all of the food for all
organisms
Consumers
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Heterotrophs
 “different food”
 Must consume food produced by
the producers
Heterotrophs
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Herbivores obtain energy by eating
autotrophs (mostly plants)
Carnivores obtain energy by eating
other animals (meats)
Omnivores are animals who eat both
plants and animals.
Heterotrophs
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Parasites are organisms that live in or on
other organisms and obtain their
nutrients from their living host.
Decomposers feed on the dead bodies of
animals and plants or on their waste
products.
Energy Flow Through the
Biosphere
Energy can neither be created
nor destroyed!
(Law of Thermodynamics)
Energy Flow Through the
Biosphere
•Energy flows from the sun to
producers to consumers.
•All energy on Earth comes
from the sun.
Trophic Levels Fig. 13-6, p.288
Each step in a food chain or food web
 More levels = less energy
 90% of energy is lost at each level
 Usually no more than 5 trophic levels
 Decomposers fit in everywhere
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Ecological Pyramids
Fig. 13-7, p.290
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Diagram how energy and nutrients
decrease as you move up the trophic
levels.
13-3 Nutrients: Building Blocks
of Living Tissue

Objectives:
 What are nutrients?
 Describe how nutrients are re-cycled in
the biosphere. (Water, Nitrogen and
Carbon)
 Nutrient Limitation
What are nutrients?
The chemical building blocks of
life.
 The substances that organisms use
to build living tissues and to grow.

How do autotrophs obtain
nutrients?

Autotrophs make complex
substances such as carbohydrates,
fats, and proteins from simple
nutrients that they can easily get
from their environment

(ex. Water, carbon dioxide, nitrogen,
phosphorus, and potassium).
How do heterotrophs obtain
nutrients?
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Heterotrophs must eat other organisms
to obtain nutrients.
Fats and carbohydrates provide
immediate energy or are stored in the
animal’s body.
Proteins are broken down into amino
acids, which are used to build the
animal’s proteins.
Where does all energy on Earth
come from?
Light energy from the sun.
How do heterotrophs release
energy?
Heat energy.
Nutrient Cycles
Matter can not be created nor
destroyed.
 We only have what is present on
the Earth.
 Nutrients must be recycled.
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Examples of Nutrient Cycles
Water
 Carbon
 Nitrogen
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Water Cycle
Carbon
Cycle
Nitrogen Cycle
N2 in Atmosphere
NH3
NO3and NO2-
Nutrient Limitation
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The size of a community depends on
the amount of food produced by the
autotrophs.
Certain nutrients are scarce, so they
limit plant growth.
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This is why farmers use fertilizer.
13-4 Food Webs: Who Eats
Whom?
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Describe a food web.
Food Chains and Webs
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Food chain – simple diagram showing
who eats who
Food web – combination of all food
chains in a community
 Shows complexity of feeding
relationships
Coastal Salt
Marsh Food
Web
13-5 The Carbon Cycle: A
Closer Look
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The Greenhouse Effect
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The increase in warming effect on Earth.
Greenhouse gases (ex. Carbon dioxide) trap energy
in the atmosphere as heat.
Later heat radiates back into outer space.
BUT carbon dioxide and other gases absorb some
of this heat energy forming a “heat trap” around the
Earth.
4 Major Carbon Pathways
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1. Biological Pathways
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2. Geochemical Pathways
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Photosynthesis, respiration, and death and decay of
plants and animals.
Release of carbon dioxide to atmosphere by
volcanic activities, weathering of rocks, and
exchange of carbon dioxide between the ocean and
atmosphere.
3. Biogeochemical Pathways
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Burial and conversion of carbon from dead
organisms into coal and petroleum.
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4. Human-initiated Pathways
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Mining, burning of fossil fuels, and cutting and
burning of forests.
Experimental Data
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Carbon flows between 3 major carbon reserviors.
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Oceans, atmosphere, and deposits in the Earth.
Although the amount of carbon entering the
atmosphere as a result of human activity is
relatively small, its cumulative effect in the future
can be significant.
Atmospheric Carbon Dioxide
Levels
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Gradual increase in atmospheric carbon dioxide
levels is probably due to human activity.
As the insulating layer of carbon dioxide gets
thicker, it could have a warming effect on Earth.