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Structures of Life, Crayfish Habitat Page 1 of 23
Daily Lesson PlanSuzanne Parry
Subject: Science Topic: Structures of Life, Crayfish Habitat Grade: 3 rd – 4th
Allocated Time: 45 minutes
Student Population: 24 Students (14 Girls / 10 Boys)
1 Student w/ Hearing Impairment
2 Students w/ a Visual Impairment
3 Gifted Students
1 ELL Student
State Standards:
Specific Number: Exact wording:
3.1.3.A.1:Describe characteristics of living things that help to identify and
classify them.
3.1.3.A.2:Describe the basic needs of living things and their dependence on
light, food, air, water, and shelter.
3.1.3.A.3:Illustrate how plants and animals go through predictable life cycles
that include birth, growth, development, reproduction, and death.
6.2.3.A:Identify goods, services, consumers, and producers in the local
community
Structures of Life, Crayfish Habitat Page 2 of 23
Goal for Understanding: Crayfish have particular requirements for life, including clean, cool
water; food; and shelter. A habitat is where an animal lives.
Guiding Question: What does a crayfish need to survive in a habitat?
Student Measurable Objectives
Students will be able to…
Predict requirements
for life of a crayfish.
Define “habitat.”
Set up two crayfish
habitats based on the
requirements for life
of a crayfish and learn
to care for and feed
the crayfish in the
classroom.
Sources of Evidence
Students will set up a
crayfish habitat and
learn to care for and
feed the crayfish in
the classroom.
Criteria for Evaluation
Teacher observation
Student Sheet No. 13
Crayfish Log (see
Attachment 1 and
Attachment 2)
A final portfolio for the
unit; Student Sheet No.
17 (see Attachment 3 and
Attachment 4)
Structures of Life, Crayfish Habitat Page 3 of 23
Science Concept Background Information
The consequence of structure is function, from the intracellular level to organisms’
niches in ecosystems. The crayfish provides observable interesting and entertaining
adaptations for demonstrating the roles of the structures of life to students while engaging
students in inquiry learning about aquatic animals, habitats, and behavior.
Crayfish, also known as crawfish, crawdads, and freshwater lobsters, are typical
shrimplike crustaceans characterized by a joined head and thorax, or midsection, and a
segmented body. The crayfish head has two pairs of sensory antennae and one pair of
moveable eye stalks. The appendages, or peripods, along the crayfish thorax include four pairs
of walking legs which also serve to probe cracks and crevices during searches for food. Crayfish
also have several pairs of food handling “legs,” bailers to cycle water over the gills, and five
pairs of swimmerets under the abdomen. Perhaps the most fascinating anatomical crayfish
feature to students is the pair of claw bearing chelipeds that extend in front of the crayfish
body. The strong pincers are specialized for defense, cutting, capturing food, and attack
(Crayfish Corner, n. d.). All of these appendages can be regenerated if detached (Crayfish Corner,
n. d.).
Structures of Life, Crayfish Habitat Page 4 of 23
Crayfish are usually about 7.5 cm (3 inches) long (Crayfish Corner, n. d.). “Among the
smallest is the 2.5-centimetre-long Cambarellus diminutus of the south-eastern United States.
Among the largest is Astacopsis gouldi of Tasmania; its length may reach 40 cm and its weight
about 3.5 kg (8 pounds)” (Crayfish Corner, n. d.).
They are members of order decapoda and share phylum arthropoda with centipedes,
insects, millipedes, mites, scorpions and spiders (Crayfish Corner, n. d.). More than 500 species
of crayfish exist, over half of which are found in North America (Crayfish Corner, n. d.).
Antarctica and Africa are the only continents on which crayfish are not found (Arne, 2013).
Generally crayfish are found in fresh water streams, rivers, ponds, swamps, and marshes; they
are found in almost any wetland, including drainage ditches (Helfrich & DiStefano, 2009).
Structures of Life, Crayfish Habitat Page 5 of 23
Because crayfish require an abundant oxygen supply, most live in rivers and streams where
water flows; however, some species have adapted to living in standing water such as ponds
(Helfrich & DiStefano, 2009). Although most species are strictly aquatic, some are semi-aquatic,
burrowing tunnels to the water table where they have a water supply even during droughts
(EnchantedLearning.com (Helfrich & DiStefano, 2009).
A hard outer shell provides protection but limits crayfish growth. As a result crayfish
must molt, shedding their exoskeletons, thereby allowing room for new growth. Molting is
stressful for the crayfish, occasionally resulting in death; therefore, classroom crayfish that have
molted should be quarantined from other potentially predatory crayfish and students for about
four days after the molt. The exoskeleton will be consumed by the newly molted crayfish,
providing nutrients for rebuilding a new hard shell. After three days, any unconsumed
exoskeleton should be removed from the crayfish habitat to prevent rotting. Crayfish molt six
to 14 times throughout their first year due to rapid growth (Helfrich & DiStefano, 2009)
Molting slows to one to three times per year as they grow older (Helfrich & DiStefano, 2009).
Most crayfish live only two to four years with the exception of some species, such as the
Tasmanian crayfish, which can live 20 years (Helfrich & DiStefano, 2009). The short lifespan of
most crayfish requires rapid sexual maturity and abundant egg production for survival of the
species (Helfrich & DiStefano, 2009). Females carry their fertilized eggs by attaching them to
small appendages under their abdomens (Helfrich & DiStefano, 2009). A female carrying a
bunch of eggs is said to be “in berry” because the eggs resemble blackberries (Helfrich &
DiStefano, 2009). Depending on the species and water temperature a female may carry 20 to
Structures of Life, Crayfish Habitat Page 6 of 23
700 eggs for two to ten months, using her tail to protect and aerate them (Helfrich & DiStefano,
2009). After hatching the young remain attached and close to the female for two weeks to
four months for safety and protection until they become independent (Helfrich & DiStefano,
2009).
Crayfish are well known for their ability to hide, using elements of their habitats, such as
rocks, twigs, logs, and plants, for concealment (crayfishfacts.net). Numerous predators
including alligators, fish, turtles, otters, and birds, combined with limited self-defense, make
hiding a key to crayfish survival (crayfishfacts.net).
Being opportunistic, nocturnal feeders, crayfish eat nearly any dead or alive plant or
animal, using their antennules to feel and taste for food (Helfrich & DiStefano, 2009). Although
adults are generally herbivores, young crayfish seem to prefer a carnivorous diet, feeding on
aquatic insects, tadpoles, snails, fish and salamanders (Helfrich & DiStefano, 2009). Both young
and adult crayfish are cannibalistic (Helfrich & DiStefano, 2009). Their vast, omnivorous diet is
the basis for the role crayfish play in the ecosystem by allowing broad adaptability, creating an
important means of energy transfer up the food chain, and improving water quality (Helfrich &
DiStefano, 2009).
The ecological significance of crayfish lies in their link in the aquatic food chain. They
clean the water by eating algae, water weeds, and dead plant and animal matter; in turn,
crayfish are eaten by over 240 species of wild animals (Helfrich & DiStefano, 2009). Nearly 75%
of the diets of small mouth bass and bullfrogs consist of crayfish (Helfrich & DiStefano, 2009).
Debris from crayfish crushing and chewing provides readily available organic materials as a food
Structures of Life, Crayfish Habitat Page 7 of 23
source for smaller aquatic animals (Helfrich & DiStefano, 2009). The role of crayfish in the
aquatic food chain extends to an economic role when considering trophic levels and game
fishing:
“The importance of the crayfish in a game fish's diet can be played up or down
depending on one's point of view. Down: Studies show that trout eat more aquatic
insects than any other item. Up: Biological studies also show that stream-living trout will
select the largest prey items that they can swallow. When crayfish are available, they
will be eaten!
Regardless of your perspective, crayfish can't be overlooked because of their size and
nutritional value. Can you imagine how many ants or mayflies a trout would have to eat
to equal the food value gained from one average-sized crayfish? Then factor in how
much energy the fish would have to expend to feed on those hundreds of tiny insects.
The same principle would hold true for bass.
My sporadic (I usually release my catch) inspection of trout stomach contents frequently
turns up crayfish. I found crayfish, usually in several pieces, in trout as small as 7.5
inches. Several times I removed parts of more than one crayfish from a single stomach.
Although anglers seemingly in-the-know favor the "just molted" soft-shelled "crabs" for
bait, all of the consumed crayfish that I examined were "hard-shells."
Structures of Life, Crayfish Habitat Page 8 of 23
What does all of this tell the serious angler? Crayfish are eaten by trout and bass. Fish
can't afford to pass up such a large meal. They do make an effective bait” (Nale, By Mark
A., n.d.).
Crayfish are important indicators of water quality, providing an opportunity for
educators to address the “Science, Technology, and Society” theme in social studies standards.
Their sensitivity to water pollution provides a tool for scientists to monitor water quality,
presenting the opportunity to address the “Time, Continuity, and Change” social studies
standard: “[They] can be used as biological monitors to forecast present and historical water
quality conditions” (Helfrich & DiStefano, 2009).
Estimates indicate that 65 of the crayfish species in North America are endangered, and
195 native species need protection (Helfrich & DiStefano, 2009). Unfortunately, the exact
status of crayfish endangerment and extinction rates is limited since very few distribution and
population surveys have been conducted (Helfrich & DiStefano, 2009).
Habitat loss is the leading cause of population decline for crayfish, followed by the
introduction of nonnative crayfish (Helfrich & DiStefano, 2009). Nonnative crayfish cause
declines in native aquatic plants and animals through introduction of diseases (such as the
fungal infection, the crayfish plague), predation, and competition for food and habitat (Helfrich
& DiStefano, 2009). Including classroom discussion and activities concerning habitat loss
provides the opportunity to visit the social studies standards theme of “People, Places, and
Environment.”
Structures of Life, Crayfish Habitat Page 9 of 23
Although small, unimposing, and, to some individuals, adorable, crayfish are considered
a cash crop with economic impact (H., 2013). As mentioned previously, the trophic level of the
crayfish impacts game fishing. In addition to their value in the ecosystem, they have value as
bait and as a delicacy:
“Crayfish are very popular in French cooking where they’re called écrevisses. In the US,
harvest comes from the waters of the Mississippi basin, and many Louisianans call their
state the ‘crawfish capital of the world.’ Crayfish can be prepared in most manners
appropriate for lobster and, like lobster, turn bright red when cooked. They're usually
eaten with the fingers, and the sweet, succulent meat must be picked or sucked out of the
tiny shells” (Crayfish Corner, n.d.).
Sold in fish markets throughout the world, crayfish are a nutritious and valuable human food.
Approximately 75,000 tons are produced in the United States annually via trapping or farming
(Helfrich & DiStefano, 2009). Louisiana, Mississippi, Alabama, and Texas are the main
producers of crayfish, selling them as food or fish bait, (Helfrich & DiStefano, 2009), inviting
reference to the “Culture” theme of the social studies standards:
http://1.bp.blogspot.com/_2YyC3TFfR24/TSMrWfbO3dI/AAAAAAAAAh0/cZ0bWOe47_g/s1600/RA_0707_08A.jpg
http://www.goscandinavian.com/2012/08/08/crayfish-festival-day-8th-of-august/
http://www.veronicadelbianco.com/2011/05/23/eat-crawfish-sustainable-for-earth-and-your-girth/
Structures of Life, Crayfish Habitat Page 10 of 23
“Crawfish also are cultivated for food in Texas,
Arkansas, Mississippi, Alabama, South Carolina and North Carolina, and are consumed in
these and many other states. However, there is no place where crawfish have had more
impact on the economy of a region than in Louisiana, where the industry contributes
well in excess of $150 million to the state’s economy annually”( McClain & Romaire,
2007).
Globally, invasive crayfish cause destruction, inviting the opportunity to discuss
“Production, Distribution, and Consumption” and “Global Connections” themes of the social
studies standards:
“Finally, invasive crayfish and fish species inflict a great deal of damage on human well-
being. The types of damage they can cause have not been well studied but range from
indirect damage (e.g. the loss in crayfish production following the pan-European spread
of the plague) to direct damage (e.g. the destruction of crops, such as rice, by P. clarkii
in Portugal). There can also be substantial indirect costs to society, for example:
– £100,000 and £190,000, respectively, for the eradication of P. leniusculus in Scotland
(25)
– US$4.5 million for the reintroduction of P. fortis in California (references in 25)”
(Gherardi, F., 2010).
Structures of Life, Crayfish Habitat Page 11 of 23
The FOSS Structures of Life Teaching Kit
This unit consists of four parts, focusing on physical structures and functions and
behaviors of crayfish. The “Teacher’s Notes” included in the kit explain that Part 1 will take
about 40-50 minutes for two days. Part 2 should be scheduled later the same day or the next
day and will consume approximately 45 minutes. Part 3, a one-day session, should be
conducted a few days after the crayfish have settled into their habitats. Part 4 will take one
session to introduce, 5-minute daily observations for 4 days or more, and one 20-minute wrap-
up. The Crayfish Habitat lesson is to take place on the third day of the unit plan, after students
have performed Day 1 and Day 2 lessons, and before the last three lessons in the unit.
A Brief Review of the Unit:
DAY 1: Read engaging scenario and review clues.
Write a Focus Question
Writes a Prediction
DAY 2: Collects Data – Crayfish Structures
DAY 3: Collects Data – Crayfish Habitat (there will be numerous observations for 4
weeks)
DAY 4: Collects Data - Crayfish Behaviors
DAY 5: Collects Data - Crayfish Territories (introduction, 4 observations, summary)
DAY 6: Making Meaning Conference
Writes Claims and Evidence
Writes Conclusions
Reflection
Structures of Life, Crayfish Habitat Page 12 of 23
Foss Structures of Life Unit, Meet the Crayfish, Part 2: DAY THREE, Crayfish HabitatEstimated
Time:
5-10 minutes
15 – 20 minutes
Teaching to the Objective
Introduction/Motivation/Prior Knowledge Begin by starting PowerPoint slides. Open the session by discussing the care of the crayfish by asking:
What do we need to know about crayfish in order to keep them here in our classroom?
Write student ideas on the board. (K-W-L chart may be used if preferred). Students will probably come up with: Feeding - what, how much, how often? Water - how deep, what temperature, and when to change? Air – crayfish get oxygen from the water (tie in with water). Space - do the crayfish need hiding places or rocks? Togetherness - should the crayfish live together?
Play video clip about crayfish habitat.
Developmental Activities: Continue to the correct PowerPoint slides. Introduce the crayfish habitat. State that the place where an animal
lives is called a habitat. Hold up a bus tray and tell the students that you have two big trays for crayfish habitats. Half of the crayfish will live in one and the other half in the other.
State - In their natural habitat, crayfish find their own food and shelter. But in the classroom, they must be fed and given a safe place to live.
Discuss the feeding and cleaning needs of the habitat. Be sure to cover:
Keeping the water cool (no direct sunlight) Keeping the water clean Providing aquatic plants as a food source all of the time. Using additional basins for feeding the protein-based cat
food. Use the transparency or PowerPoint slide of the Crayfish Log student
sheet that will be posted near each crayfish habitat (see Attachment
Differentiation: Required for each Section.
Student with Hearing Impairment Teacher wears microphone /
speaks clearly Student sits near teacher to be
able to read lips Written handouts for
directions / vocabulary (word wall)
Teacher checks for understanding often
Student with Visual Impairment Printed handouts with darker
ink and larger font Additional natural and
classroom lighting Teacher checks often for glare
on Smart Board, etc. Teacher checks for
understanding often
Gifted Students Ask more difficult questions Give additional assignments Offer additional computer
technology for research
ELL- Bilingual Handouts: KWL charts,
directions, etc. Spanish/English Dictionary
Structures of Life, Crayfish Habitat Page 13 of 23
10 minutes
1). The log includes basic care information at the top and spaces for
the group to record what they have to do and observe each day. A different group will make the observations for each day. The log might continue for a couple of months.
Assign four groups to each bus tray. Give each group a date to take care of the habitat. Write the group’s name or number on the Crayfish Log sheet for that date.
Word Wall: Habitat (see Attachment 6) Bring out the gravel. Let the students divide it equally and spread it
out on the bottoms of the two bus trays. Pour water from the individual basins or from the aged water supply into the trays about 4 - 6 cm deep or just enough to cover the backs of the crayfish.
Note: Crayfish are agile climbers. Do not place rocks or any objects near the sides of the tray. The crayfish will use them as stepping stones to get out of the trays!
Introduce the Elodea (food) and crayfish houses (shelter). Let the students put half of the Elodea and four of the houses into one bus tray and the other half into the other tray. Transfer the crayfish to the habitats.
Have the students make a sketch of the habitat where they placed their crayfish in their science notebooks under the heading of “Crayfish Habitat.” Share a few.
Tell the students that he crayfish will be moved to the smaller basins to eat their cat food. Cat food can never be placed in the habitat container. Keep the two feeding basins near the crayfish. Use any remaining water to water some plants. Rinse and dry the basins.
Ask students what would happen if crayfish couldn’t find all the requirements for life in their habitats.
Ask students what some reasons would be for a crayfish’s inability to find what it needs to stay alive.
Choose a few students (or the teachers) to be labeled with one of the following:
Role play musical chairs with each chair labeled one of the following (see Attachment 5a): Food
and Flashcards available
Structures of Life, Crayfish Habitat Page 14 of 23
5 – 10 minutes
Water (Oxygen) A Place to Hide
Choose a few students (or the teachers) to be labeled with one of the following (see Attachment 5b): Pollution Invasive Species
Play musical chairs and during every round of the game have “Pollution” remove a chair and “Invasive Species” join the game.
As students are called “out” from lack of a chair, replace their labels with pollution or invasive species labels and allow them to rejoin the game.
Assessment: Teacher observation Formative with use of Student Sheet #13 (see Attachments 1 and 2);
(4 to 5 week investigation) A final end of unit portfolio; Student Sheet #17 (see Attachment 3
and Attachment 4)
Closure: Close by stating that when we observe the crayfish for the next
several weeks. We will observe what they do. This is called observing their behaviors.
Word Wall: Elodea (see Attachment 6) Word Wall: Behavior (see Attachment 6)
Structures of Life, Crayfish Habitat Page 15 of 23
Follow-up:
Class observations of the crayfish over the next several weeks.
Move on to part three of this lesson.
Materials:
For each group of four students:
1 basin
1 crayfish
4 Student sheet No. 13 Crayfish Log
For the class:
2 bus trays
2 bags gravel
8 crayfish houses
1 bag dry cat food
1 bag Elodea
aged water
1 pitcher
PowerPoint slide of Student Sheet No. 13 Crayfish Log (see Attachment 1)
Student Sheet No. 13 Crayfish Log (see Attachment 1)
Structures of Life, Crayfish Habitat Page 16 of 23
Resources:
Amsel, Sheri. “Crustaceans.” Crayfish. Exploring Nature Educational Resource. © 2005 - 2013. April
3, 2013. <http://exploringnature.org/db/detail.php?dbID=43&detID=1136>
Arne. (2013). Trapper Arne’s 2013 crayfish page. Retrieved from http://www.trapperarne.com/.
Crayfish Corner. (n.d.). Retrieved from http://www.mackers.com/crayfish/
Gherardi, F. (2010). Invasive crayfish and freshwater fishes of the world. Rev. sci. tech. Off. int.
Epiz., 29 (2). Retrieved from http://www.oie.int/doc/ged/D7610.PDF
H., Kevin H., (2013). Procambarus clarkii/Cambarus aculabrum, the crayfish. Retrieved from
http://www2.chccs.k12.nc.us/education/components/scrapbook/default.php?
sectiondetailid=61020&
Helfrich, Louis A., & DiStefano, Robert J. ( 2009, May 1). Sustaining America's Aquatic Biodiversity -
Crayfish Biodiversity and Conservation, Virginia Cooperative Extension, Virginia Tech, and
Virginia State University. Retrieved from http://pubs.ext.vt.edu/420/420-524/420-524.html
McClain, W. Ray, & Romaire, Robert P. (2007, September). Procambarid crawfish: Life history and
biology. Retrieved from http://www.ca.uky.edu/wkrec/CrawfishBiologyHistory.pdf
Nale, By Mark A. (n.d.). Crayfish as fishfood. Retrieved from
http://www.mackers.com/crayfish/info.htm.
Technology:
Computer
PowerPoint
Video
Structures of Life, Crayfish Habitat Page 21 of 23
Food
Water
Shelter
Attachment 5a
Structures of Life, Crayfish Habitat Page 22 of 23
Pollution
Invasive Species
Crayfish
Attachment 5b