Friday
(February 18, 2011)
4/13/2015
Today’s Agenda:
(1) Journal Question: What is a biome?
*(2) Lecture III: Ecosystems & Responses
to a Changing Environment (slide 33)
(3) Begin working on Biome Project
a. Select a biome
b. Follow the instructions in your unit
packet
(4) Homework: Each group member
should do some research on their biome
for Wednesday
1
-Read Chapter 22 (pp. 414 – 435)
Lecture III:
Ecosystems &
Responses to a
Changing
Environment
By Dr. Rick Woodward
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Food Chains
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Species
A. The first step in
investigating a biotic
community may be
simply to catalogue
all the species
present.
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(You will be doing this for
your group biome project
today)
4
Recall: Taxonomy
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Species
B. Species are the different kinds
of plants, animals, and microbes
in the community.
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Species
C. The biological definition of a
species is the entirety of a
population that can
interbreed to produce fertile
offspring, whereas members
of different species
generally do not interbreed.
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Speciation
A. Two species arise from one.
(1). Allopatric
 Speciation that occurs when 2 or more populations
of a species are geographically isolated from one
another
 The allele frequencies in these populations change
 Members become so different that that can no no
longer interbreed
(2). Sympatric
 Populations evolve with overlapping ranges
 Behavioral barrier or hybridization or polyploidy
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Speciation
Northern
population
Early fox
population
Spreads
northward
and
southward
and
separates
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Southern
population
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Gray Fox
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
9
Populations
A. Each species in a biotic
community is represented by a
certain population; that is, by
a certain number of individuals
that make up the
interbreeding, reproductive
group.
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10
The Ecosystem Concept
A. Ecosystems join together the
biotic community (fish) and
the abiotic conditions (salt
water) that it lives in.
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11
The Ecosystem Concept
C. Examples of ecosystems:
1. Polar
2. Tundra
3. Coniferous Forest
4. Deciduous Forest
5. Grassland
6. Tropical Rain Forest
7. Temperate Rain Forest
8. Ocean (Marine); Coral Reefs
9. Freshwater Biome (Lakes,
Ponds, Rivers, Streams)
(Biome Project Presentations)
(1) Terrestrial Biomes –on land.
(2) Aquatic Biomes –water.
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-You select one of the above for your
project. (pp. 767-776)
12
Ecology
B. The study of ecosystems and
the interactions that occur
among organisms and their
environment belongs to the
science of ecology.
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13
An Ecotone
A. Ecosystems are not
isolated from one another.
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14
An Ecotone
B. One ecosystem blends into the
next through a transitional
region called an ecotone.
C. An ecotone contains many
species common to both
systems.
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Ecosystem Boundaries: Ecotones
Land zone
Transition zone
Aquatic zone
Number
of species
Species in land zone
Species in aquatic zone
Species in transition
zone only
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The Biosphere
A. All the species on Earth, along
with all their environments, make
up one vast ecosystem, often
called the biosphere.
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17
Overlapping of the Spheres
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Ecosystem Organization
Biosphere






Organisms
 Made of cells
 Eukaryotic vs Prokaryotic
Species
 Groups of organisms that resemble one
another in appearance, behavior, and
genetic make up
 Sexual vs Asexual reproduction
 Production of viable offspring in nature
 1.5 million named; 10-14 million likely
Populations
 Genetic diversity
Communities
Ecosystems
Biosphere
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Ecosystems
Communities
Populations
Organisms
Fig. 4.2, p. 19
66
Sustaining Life on Earth…



One way flow of
high quality energy
The cycling of
matter (the earth is
a closed system)
Gravity

Causes
downward
movement of
matter
Biosphere
Carbon
cycle
Phosphorus Nitrogen
cycle
cycle
Water
cycle
Oxygen
cycle
Heat in the environment
Heat
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Heat
Heat
20
Community
Association of different
populations of organisms that
live and interact together in the
same place at the same time.
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Responses to a Changing Environment
A. Organisms are able to survive
within a wide range of
environmental conditions.
(1) Temperature Conditions
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Responses to a
Changing Environment
B. Tolerance Curve
(1) A graph or performance
versus values of an
environmental variable, such as
temperature, is called a tolerance
curve.
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Acclimation
A. Some organisms can
adjust their tolerance
to abiotic factors
through a process of
acclimation.
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Acclimation
B. Spending a few weeks at a high
elevation, you will acclimate to
reduced oxygen levels, or “thin
air.” –over time the number of
red blood cells in your body
will increase.
(i.e. training for a marathon)
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Control of Internal Conditions
A. Ways an organism deals with
changes to its environment:
(1) Conformers
(2) Regulators
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Conformers
A. Conformers are organisms
that do not regulate their
internal conditions; they
change as their external
environment changes.
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Conformers
(1) Example: The body
temperature of desert
lizards rises and falls with
the temperature of the
lizard’s environment.
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Regulators
A. Regulators are organisms that use energy to
control some of their internal conditions.
(1) Regulators can keep an internal condition
within the optimal range over a wide variety
on environmental conditions.
-Example: Humans –Our body temperature
remains constant throughout the day.
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29
Escape from Unsuitable Conditions
1. Dormancy
2. Migration
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30
Dormancy
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A. Entering into a state of
reduced activity is called
dormancy.
(1) During the winter
many reptiles and
amphibians survive by
hiding underground and
becoming dormant until
spring.
31
Migration
A. Moving to a more favorable habitat with
better climate conditions is referred to as
migration.
(1) A familiar example of migration is the
seasonal movements of birds, which
spend spring and summer in cooler
climates and migrate to warmer climates in
the fall.
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Stop Here!

Group Project Today
-Work in groups of four
-Select a biome
-Draw pictures to describe your selected
biome
1. List and draw 4-8 animals.
2. List and draw 4-8 plants.
3. List climate conditions and the location of
your specific biome.
-Present your poster to the class.
a. Take notes in your composition book on
your classmates biomes.
(You will be tested on your classmates
projects)
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