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| Overview |
| Grade Level: 7-9 |
| Background Information:
The Intertidal Zone presents a unique set of challenges for the
organisms who live there. Extreme fluctuations in moisture level,
heat, salinity, and sunlight make it a habitat suitable for only
a few species. However, conditions change dramatically over a very
small area, going from only occasionally wet to usually submerged
in a matter of a few feet. Therefore, the intertidal zone contains
great diversity and has always been fascinating to children who
love to collect shells and see the sea creatures who live there.
The activities contained in this unit are designed to enable students
to investigate the creatures of intertidal zones and how they've
adapted to the conditions that they live in.
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| Content Standards |
| Related National Standards:
This lesson addresses the following National Content Standards
found at: http://books.nap.edu/html/nses
Content Standard F: As a result of their activities in grades
5-8, all students should develop understanding of:
- Biological Evolution
- The great diversity of organisms is the result of
more than 3.5 billion years of evolution that has filled
every available niche with life forms.
- Species evolve over time. Evolution is the consequence
of the interactions of (1) the potential for a species
to increase its numbers, (2) the genetic variability
of offspring due to mutation and recombination of genes,
(3) a finite supply of the resources required for life,
and (4) the ensuing selection by the environment of
those offspring better able to survive and leave offspring.
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Content Standard C: As a result of their activities in grades
5-8, all students should develop understanding of:
- Reproduction and Heredity
- The characteristics of an organism can be described
as a combination of traits. Some traits are inherited
and others result from interactions with the environment
- Regulation and Behavior
- All organisms must be able to obtain and use resources,
grow, reproduce, and maintain stable internal conditions
while living in a constantly changing external environment.
- Regulation of an organism's internal environment involves
sensing the internal environment and changing physiological
activities to keep conditions within the range required
to survive.
- An organism's behavior evolves through adaptation to
its environment. How a species moves, obtains food, reproduces,
and responds to danger is based in the species evolutionary
history.
- Diversity and Adaptations of Organisms
- Biological evolution accounts for the diversity of
species developed through gradual processes over many
generations. Species acquire many of their unique characteristics
through biological adaptation, which involves the selection
of naturally occurring variations in populations. Biological
adaptations include changes in structures, behaviors,
or physiology that enhance survival and reproductive
success in a particular environment.
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| Extension Web Sites
from PBS: |
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The
Living Edens - South Georgia Island
An ocean food web activity for middle school.
Secrets
of the Ocean Realm - In the School
This site contains a variety of hands-on activities for Middle School
students.
The
Living Edens - Etosha
This is a lesson plan to teach students about adaptations for survival.
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| Activity 1: Describing Organisms
- The Power of the Pen in Science |
| Time Allotted:
20 minutes
Materials:
A variety of shells (starfish, mussels, gastropods, limpets, etc.)
enough for one per student
Rulers
| Objectives: |
- Students will practice description skills using marine
organisms.
- Students will learn the difficulty of painting a verbal
picture.
- Students will develop an appreciation for the descriptive
skills necessary for a scientist.
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| Teacher Instructions: |
- Tell students to imagine that they are scientific explorers
from around 1750. They have gone on an expedition to an
uncharted part of the world and are seeing organisms that
no one from their society has ever seen before. They are
to try to write descriptions to illustrate the organisms
to the people back home.
- Explain to students that scientists have to rely on descriptive
skills when identifying organisms. Especially before the
widespread use of photography, biologists had to describe
the features of organisms to distinguish between species.
Today, careful description still is a foundation of scientific
research.
- Have the class divide in half. They should turn so that
half the class has their backs facing the other half of
the class. In other words, the two halves are back to back.
They will need a pencil and a piece of paper.
- Explain that they are to write a description of a shelly
organism so that another person can draw the organism. They
cannot use the name of the organism (like clam) or scientific
terms (e.g. muscle scar). You should encourage them to include
measurements and specific data about the size and shape.
Have a number of rulers handy so that they can measure their
shells if they choose to.
- Distribute a shell to each student. Try to have a variety
of types and sizes. Have them start writing.
- As students from the two opposing sides complete their
writing, swap papers and have the students attempt to draw
the shell from the verbal description. Be sure that all
students get a description to draw from. If you like, you
can make it a contest to see whose drawing most closely
resembles the original object.
Assessment Ideas
You may want to team with an English teacher to assess the
descriptive writing in this activity.
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Watch
the AFG Video Segment:

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Oregon
Tide Pools
Tidal
pools provide habitat for numerous marine species of plants
and animals, but unfortunately humans may be upsetting
their delicate balance. |
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| Activity 2: A Virtual Tour
of a Rocky Shore |
| Time Allotted:
15-30 minutes
Materials:
Infocus Machine
"Rocky Shore Tour" PowerPoint presentation
file (download zip file) or
Web Version of "Rocky Shore
Tour" (Note: You can use the web-based version if you do
not have access to PowerPoint)
| Objectives: |
- Students will use discussion to generate ideas about how
organisms adapt to their environment.
- Students will learn specific adaptations for the Rocky
Intertidal Zone.
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| Teaching Instructions: |
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Watch the AFG Video Segment:

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Northwest
Beach - Tide Pools
Pools
of thriving sea life are left behind when the tide recedes,
and mini-communities of marine plants and animals can
be observed. |
Ask your students to pay attention to specific information
regarding conditions in the rocky intertidal zone and to adaptations
organisms have for survival.
After watching, make a list of factors which might influence
your life if you live in a shoreline area. These might include:
salinity, heat, moisture, predation, finding food, sunlight,
staying put, etc.
Show the PowerPoint presentation 'A Virtual Tour of a Rocky
Shore'. Photos are accompanied by some background information
about each species and zone for your information. Encourage
students to use this presentation as a focus for discussion.
Given the conditions present in each zone, how do they think
organisms might survive. They should address the different
factors which they listed after watching the video above.
The objective of this exercise is for students to brainstorm
and to be creative in thinking about adaptations.
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| Activity 3: Adaptations to
Survival in the Intertidal Zone |
| Time Allotted:
15-30 minutes
Materials:
Marine shells - at least one per group of two or three students
| Objectives: |
- Students will consider the various abiotic influences
on organisms living at the edge of the ocean.
- Students will examine organisms to determine adaptations
for survival.
- Students will learn that organisms use different strategies
for survival.
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| Teaching Instructions: |
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Introduce the idea of adaptations. Ask students to look for
adaptations to survival while watching the video.
Watch the AFG Video Segment:

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Northwest
Beach - Tide Pools
Pools
of thriving sea life are left behind when the tide recedes,
and mini-communities of marine plants and animals can
be observed. |
- Brainstorm:
- Discuss factors that organisms living in the intertidal
zone have to contend with. Some abiotic factors include
changes in temperature, salinity, light, moisture, and
wave action. Biotic factors include finding food, avoiding
predation, and mating. List these factors on the board.
- Discuss some of the adaptations referred to in the
video
- Break students into groups of 2 or 3. 4.
- Provide each group with the shells of one or two marine
organisms.
- Ask students to think about the factors they heard about
in the clip and listed during the discussion. What special
features do they think this organism has that enable it
to survive in the intertidal zone.
- You may want to have students share their results with
the class. Ask them to choose one organism or one unique
adaptation to explain to the group
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Extension Activities:
Students might conduct research to discover more about the organisms
they have selected. For information regarding Intertidal Zone organisms,
try the following websites:
The
Tidepool Page
Enchanted
Learning: The Intertidal Zone
Exploring
the Intertidal - Online Field Guide
Spaceports:
Intertidal Life
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| Activity 4: Hold On to Your
Home |
| Time Allotted:
One 45-minute class period
Materials:
Student Instruction Sheet
Observation Worksheet
An assortment of rocks, big and small, enough for each group to
build a pile at one end of their tray
Sand
Small Trays with sides that allow them to hold sand 9x11 is a good
size
Small shells of different sizes and shapes or small objects like
paper clips, coins, toothpicks, marbles, and monopoly houses. Either
way, providing a small object with a suction cup will be useful
Large cups or beakers (100ml minimum) for creating storm waves
| Objectives: |
- Students will compare rocky substrates with sandy substrates
to determine the difficulties of living in each environment.
- Students will experiment with models to determine how
adaptations enable organisms to survive.
- Students will understand that organisms have a variety
of adaptations to protect them from a variety of influences.
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Background Information
Adaptations that are necessary for life on a sandy beach are different
from those necessary for life on a rocky coastline. In both areas,
one of the great challenges is to hold on but the techniques are
much different. In this activity, students will experiment with
sand, rocks, and water to determine some methods useful for "holding
on" in each environment.
Watch the AFG Video Segments:

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Chincoteague
Wildlife Refuge - Beach and Dunes
The
beach on the Atlantic side of Assateague Island is a great place
to find seashells and other evidence of marine life.
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Note: Start at the beginning and stop after hearing "very
common in the Atlantic Ocean offshore".
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Acadia
National Park, Maine - Tide Pools
The
shells that can be found along the tidal zone of Acadia National
Park offer evidence of thriving marine life.
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Note: You may choose to skip this video if you watched a
video clip as part of Activity 2.
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| Teacher Instructions: |
- Divide the class into groups of 3 or 4.
- Each group should get a tray with sand, some rocks, and
a variety (at least four or five) of small organisms or
objects representing organisms.
- Their goal is to experiment with the variety of organisms
on each of the different substrates to see what adaptations
might be useful for living on there.
- In the first part of the student instructions, they are
asked to brainstorm factors related to survival in a shoreline
area. If you have done Activity 2 in this lesson, they should
be able to do this on their own. If not, you may want to
do that part as a class after the video clip and before
having the students work on their own.
- Students will build models of the shoreline. They should
pile sand or rocks at one end of their tray and they should
fill the tray about half way with water at the other end
to represent the ocean. They will then experiment with the
different organisms as described in the student instructions.
They should then clean the sand out of the tray and repeat
with the rocks.
- Encourage them to try different methods to get organisms
to stick and be prepared to provide extra materials such
as tape or string. They might bury them, orient them differently,
tie them down, use tape, etc. Remind them that a sandy beach
often has thousands of feet of sand below it, so a limitation
of their model is that the tray has a bottom. They may not
use the bottom of the tray to attach their organisms.
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| Assessment:
Answers to the Analysis Questions:
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- On a sandy coast, the substrate is constantly shifting
while on a rocky coast it is not. However, on a sandy coast,
the sand is able to absorb some of the energy of the waves
while the rocks cannot.
- Answers will depend on the organisms you use. Things that
can stick will do better in rocky areas, things that can
dig will do better in sandy areas.
- Storm waves can wash away the sand or will increase the
energy present on the rocks, uncovering or unsticking many
organisms. This is often reflected by the increase in shells
at the beach after high waters.
- Answers will vary. For example: Once an organism can avoid
being washed away, it still has to deal with other influences.
For instance, if the students buried an organism, how does
it avoid predation? It won't be able to move quickly but
the fact that it is buried gives it some protection. It
might get food by sticking out a tongue-type organ that
allows it to filter the water. Etc.
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