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Chapter 2: Ecosystems and Communities
Essential Questions:
Georgia Performance Standards:
•Determine how organisms depend
on one another and the flow of
energy and matter within their
ecosystems.
•
EQ: What happens to
the energy in an
ecosystem when one
organisms eats
another?
•
EQ: What happens
when nutrients are
depleted from
ecosystems?
•Arrange a food chain according to
energy flow.
•Compare the quantity of energy in
the steps of an energy pyramid.
•Explain the cycles of major
nutrients and the need for them
Prior Knowledge Assessment
• KWL Chart: Use the “What I Know” column to list the things you
know about ecology. Then list the questions you have about
ecology in the “What I Want to Find Out” column. At the end of
lecture, use the “What I Learned” column to list the information
you have learned about ecology.
K
What I Know
W
What I Want to Find Out
L
What I Learned
Chapter 2: WARM UP
What is ecology
• An ecosystem is a collection
of all the organisms that live
in a particular place,
together with their nonliving,
or physical, environment.
• Within an ecosystem, there
are several levels of
organization. Your school
and its grounds are similar
to an ecosystem.
1. What living things are found in
and around your school?
2. What nonliving things are found in
your school?
3. Into what large groups are the
students in your school divided?
4. Into what smaller groups are
these large groups divided?
5. Are these groups ever divided into
even smaller groups? If so, what
are these groups?
Chapter 2 Principles of Ecology
Section 1: Organisms and Their Relationships
Section 2: Flow of Energy in an Ecosystem
Section 3: Cycling of Matter
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
Ecology
 Scientific discipline in which the relationships
among living organisms and the interaction
the organisms have with their environments
are studied
 Ecologists observe, experiment, and model
using a variety of tools and methods.
What types of ecological Methods do
ecologists use to study the living world?
• Observing
• Experimenting
• Modeling
• All of these methods
rely on the application
of scientific methods to
guide ecological inquiry.
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
Levels of Organization: How are they related?
 Levels increase in complexity as the numbers
and interactions between organisms increase.
 Organism (species)
 population
 biological community
 ecosystem
 biome
 biosphere
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
 The lowest level of organization is the
individual organism itself.
 Organisms of a single species that share the
same geographic location at the same time
make up a population.
 A biological community is a group of interacting
populations that occupy the same geographic
area at the same time.
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
 An ecosystem is a biological community and
all of the abiotic factors that affect it.
 A biome is a large group of ecosystems that
share the same climate and have similar types
of communities.
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
The Biosphere
 A thin layer around Earth
 Extends several kilometers above the
Earth’s surface
 Extends several kilometers below the
ocean’s surface
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
The Biosphere
Chapter 2
Principles of Ecology
Check for Understanding
1.
List the six different levels of organization that ecologists
study, in order from smallest to largest.
2.
Describe the three basic methods of ecological research.
3.
Identify two ways in which you interact with each of the
three parts of the biosphere every day: land, water, and air.
4.
Suppose you wanted to know if the water in a certain
stream is safe to drink. Which ecological method(s) would
you choose, and why?
What Shapes an Ecosystem?
• Biotic and Abiotic Factors
• Niche
• Community Interactions
• Ecological Succession
Abiotic & Biotic Factors:
• Abiotic factors
are nonliving
factors
–
–
–
–
–
–
–
Temperature
Humidity
Precipitation
Wind
Nutrient availability
Soil type
Sunlight
• Biotic factors are
living factors
– Ecological community
– Ex: bull frog, what is
eats, other organisms
with which it interacts.
Abiotic & Biotic Factors:
• Together, biotic and abiotic factors
determine the survival and growth of an
organism and the productivity of the
ecosystem in which the organism lives.
Chapter 2
Principles of Ecology
2.1 Organisms and Their Relationships
 A habitat is an area where an organism lives. A
habitat includes biotic and abiotic factors.
 A niche is the role or position that an organism has in
its environment.
 The full range of physical and biological conditions
in which an organism lives and the way in which
the organism uses those conditions.
 Ex: an organisms place in the food web.
 Habitat is to address as niche is to occupation
Community Interactions
• Competition, predation, and various
forms of symbiosis, can powerfully affect
an ecosystem.
Competition
• Occurs when organisms of the same or different species
attempt to use an ecological resource in the same place at
the same time.
• Direct competition in nature often results in a winner and a
loser—with the losing organism failing to survive.
• Competitive exclusion principle - no two species can
occupy the same niche in the same habitat at the same
time.
Predation
• An interaction in which one organism
captures and feeds on another organism.
• Ex: Anglerfish on finding Nemo.
Symbiosis
• Any relationship in which two species live
closely together
– Mutualism – both species benefits
• Ex: bee and flower
– Commensalism- one species benefits and the other
is neither hurt nor harmed.
• Barnacles on whale
– Parasitism – one species benefits and the other is
harmed
• Flea on dog
Checkpoint!!!
• How are the three types of symbiotic
relationships different? How are they similar?
Homework
• Complete the KWL Chart (What I’ve
Learned Column).
• Complete Section 2.1 WS packet on
Organisms and Their Relationships
2.2: Flow of Energy in an Ecosystem
WARM UP
• Energy flows in one direction
through an ecosystem, from
the sun or inorganic
compounds to producers
(organisms that can make
their own food) through
various levels to consumers
(organisms that rely on other
organisms for food).
• Your body gets the energy
and materials it needs for
growth and repair from the
foods you eat.
•
Make a list of five foods that you
like to eat. Indicate whether the
food comes from a plant (producer)
or an animal (consumer).
•
Like many birds, chickens eat
grains, which are seeds. Where do
seeds come from?
•
Meat comes from beef cattle. What
do cattle eat?
•
Construct a diagram showing how
one of your favorite foods obtains
its energy. Include as many levels
as you can.
How does energy flow through the
biosphere?
• Sunlight is the main energy source for
life on Earth.
• Some types of organisms rely on the
energy stored in inorganic chemical
compounds
Energy Flow Through the Biosphere
• Autotrophs = Use energy from the environment to
make their own food. (Producers)
– Ex: plants, some algae and some bacteria.
– Photosynthesis = Adds oxygen to the environment and
remove carbon dioxide. Glucose is also produced.
• Chemosynthesis = when organisms use chemical
energy to produce carbohydrates.
Heterotrophs (Consumers)
• Organisms that rely on other organisms for
their energy and food supply
Types of Heterotrophs (Consumers):
• Herbivores = eat only plants
• Carnivores = eat animals
• Omnivores = eat both plants and animals
• Detritivores = eat plant and animal remains and
other dead matter (detritus)
• Decomposers = breaks down organic matter
What happens to the energy in an ecosystem when
one organisms eats another?
• Energy flows through an
ecosystem in one direction,
from the sun or inorganic
compounds to autotrophs
(producers) and then to
various heterotrophs
(consumers).
• Food chains = show oneway flow of energy
• Food webs = links food
chains
• Trophic levels = steps in
food chains or food webs.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Food Chains
 A food chain is a
simple model that
shows how energy
flows through an
ecosystem.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Food Webs
 A food web is a model
representing the many
interconnected food
chains and pathways
in which energy flows
through a group of
organisms.
Chapter 2
Principles of Ecology
Ecological Pyramids
• Diagram that shows the
relative amounts of
energy, biomass, or
numbers of organisms
(matter) at each trophic
level in an organism in
an ecosystem
• Only 10% of the
energy available
within one trophic
level is transferred to
organisms at the next
trophic level.
Chapter 2
Principles of Ecology
2.2 Flow of Energy in an Ecosystem
Types of Ecological Pyramids
Check for Understanding:
• What are the two main forms of energy that power
living systems?
• Briefly describe the flow of energy among
organisms in an ecosystem
• What proportion of energy is transferred from one
trophic level to the next in an ecosystem?
Class Activity
• Constructing Ecological Pyramid Models
2-3 Cycles of Matter:
• Georgia Performance
Standards:
• Determine how organisms
depend on one another
and the flow of energy and
matter within their
ecosystems.
• Explain the cycles of major
nutrients and the need for
them.
Essential Questions:
• How does matter cycle
among the living and
nonliving parts of an
ecosystem?
• What would happen to a living
system that was nutrient
deficient?
• How does the availability of
nutrients affect the
productivity of ecosystems?
It’s Raining, It’s Pouring
• How many times have you
had to change your plans
because of rain? It probably
didn’t help if someone tried
to cheer you up by saying,
“But we really need the rain.”
• However, rain is important. If
it didn’t rain, how would living
things on land get water?
•
When rain falls on the ground, it
either soaks into the soil or runs
across the surface of the soil. When
rainwater runs across the land, what
body of water might collect the rain?
•
From here, where might the water
flow?
•
After the rain, the sun comes out and
the land dries. Where does the water
that had been on the land go?
•
Construct a diagram that would
illustrate all the places a molecule of
water might go. Begin with a raindrop
and end with a cloud.
Recycling in the Biosphere:
• Unlike the one-way flow of energy, matter is
recycled within and between ecosystems.
• Biological systems do not use up matter, but
transform it.
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
The Water Cycle
Chapter 2
Principles of Ecology
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
 Approximately 90 percent of water vapor
evaporates from oceans, lakes, and rivers; 10
percent evaporates from the surface of plants
through a process called transpiration.
 Freshwater constitutes only about 3 percent of
all water on Earth.
 About 69 percent of all freshwater is found in ice
caps and glaciers.
Nutrient Cycles:
• Every living organism
needs nutrients to build
tissues and carry out
essential life functions.
• Like water, nutrients are
passed between organisms
and the environment
through biochemical
cycles.
• Video clip
• Carbon Cycle
• Nitrogen Cycle
• Phosphorus Cycle
The Carbon Cycle:
• Biological processes, such
as photosynthesis,
respiration, and
decomposition of plants
and animal
• Geochemical processes,
such as the release of
carbon dioxide (CO2) gas
to the atmosphere by
volcanoes
• Mixed biogeochemical
processes, such as the
burial of carbon-rich
remains of organisms and
their conversion into coal
and petroleum (fossil fuels)
by the pressure of the
overlying earth
• Human activity, including
mining, the burning of fossil
fuels, and the cutting and
burning of forests.
Chapter 2
Principles of Ecology
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
 Carbon and oxygen often make up molecules
essential for life.
 Carbon and oxygen recycle relatively quickly
through living organisms.
Chapter 2
Principles of Ecology
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
Long-term Cycle
 Organic matter converted to peat, coal, oil, or
gas deposits (carbon)
 Calcium carbonate (carbon and oxygen)
Short-term Cycle
 Burning fossil fuels (carbon)
Nitrogen Cycle
• All organisms require nitrogen
to make amino acids, which in
turn are used to build proteins
• nitrogen fixation
– A mutualistic relationship
between bacteria and the roots
of legume plants.
– The bacteria convert nitrogen
gas into ammonia so plants
can use it to make proteins
– The plants provide a habitat
for the bacteria
• Takes nitrogen from
atmosphere
• Denitrification
– Other soil bacteria convert
nitrates into nitrogen gas
– Puts nitrogen into the
atmosphere
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
The Nitrogen Cycle
 The capture and
conversion of
nitrogen into a form
that is useable by
plants is called
nitrogen fixation.
The Nitrogen Cycle
N2 in Atmosphere
NH3
NO3and NO2-
Chapter 2
Principles of Ecology
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
 Nitrogen enters the food web when plants
absorb nitrogen compounds from soil.
 Consumers get nitrogen by eating plants or
animals that contain nitrogen.
Phosphorus Cycle
• Phosphorus is essential to living organisms
because it forms part of important life-sustaining
molecules such as DNA and RNA.
• Phosphorus does not enter the atmosphere like
oxygen, carbon and nitrogen
• phosphorus remains mostly on land in rock and
soil minerals, and in ocean sediments
Phosphorus Cycle
• When plants absorb
phosphate from the soil or
from water, the plants bind
the phosphate into organic
compounds.
• Organic phosphate moves
through the food web, from
producers to consumers,
and to the rest of the
ecosystem.
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
The Phosphorus Cycle
Chapter 2
Principles of Ecology
Chapter 2
Principles of Ecology
2.3 Cycling of Matter
Short-term Cycle
 Phosphorus is cycled from the soil to
producers and then from the producers
to consumers.
Long-term Cycle
 Weathering or erosion of rocks that contain
phosphorus slowly adds phosphorus to the
cycle.
Nutrient Limitation
• Primary productivity – rate at which organic
matter is created by producers
– Controlled by the amount of available nutrients
– Limiting nutrient – when an ecosystem is limited
by a single nutrient that is scarce or cycles very
slowly.
Checkpoint!!!!
1. How does the way that matter flows through an
ecosystem differ from the way that energy flows?
2. Why do living organisms need nutrients?
3. Describe the path of nitrogen through its
biogeochemical cycle.
4. Explain how a nutrient can be a limiting factor in an
ecosystem.
Nutrient Cycle Activity
• Bio Zone