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

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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)

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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.).

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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).

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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

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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."

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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).

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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

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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 17 of 23

Attachment 1

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Attachment 2

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Attachment 3

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Attachment 4

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Food

Water

Shelter

Attachment 5a

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Pollution

Invasive Species

Crayfish

Attachment 5b

Structures of Life, Crayfish Habitat Page 23 of 23

HabitatThe area or environment

where an animal or community lives.

ElodeaAn aquatic freshwater

plant native to North America.

BehaviorThe actions of an

animal in response to its environment.

Attachment 6