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A Three Day Lesson Plan
Udhrain, Adam, and William Farris
Crocodiles are remarkable reptiles that have survived since the
age of the dinosaurs. These voracious predators of land and water,
have been able to adapt to their environment over millions of years
due to superb design and superior intelligence.
There are 3 crocodilian subspecies: Alligatorinae, Crocodylinae
and Gavialinae and all of these contain 23 species, crocodylinae
containing 13. These long live reptiles are also widespread throughout
the world. Although, they are a very hardy species, many have become
endangered due to human activities such as over-hunting, pollution
DAY 1: On this day the students will be introduced to the subject
of crocodiles by dividing them into small groups of 2 or 3 and doing
prepared research at the school library. Upon returning the completed
assignment the teacher will then give them each a "chocodile."
DAY 2: On this day the students will begin by watching "The Ultimate
Guide: Crocodiles," a 30 minute video. Afterwards, the teacher will
assess the students knowledge of the material presented in the video
by engaging in a class discussion. This should take up the rest
of the class time.
DAY 3: The lesson plan for the day will be introduced with a short
lecture/question review of the information that has already been
covered. After the lecture/question review is complete, the students
will receive a handout with the outline of a crocodile and the internal
organs. They will be required to label, color and know the function
of specific organs.
DAY 4: Crocodiles evolved 200 million years ago and have outlived
the dinosaurs. when they first evolved they had longer legs and
shorter snouts and lived on land. They evolved to have short legs,
long snouts and live in water. With changes in environment and human
acitivty, what could be next? Today the students will work together,
3-4 to a group, to brainstorm as to why crocodiles are such successful
animals. Have them discuss and possibly draw how they think crocodiles
will look like in 200 million years from today.
DAY 5: To assess their knowledge of the material taught in the
last four days, students will be given a unit quiz. Along with the
in class activities, there will be homework assignments and opportunities
for extra credit. This lesson plan allows students to learn for
themselves through various activities, where crocodiles are found
in the world and what their habitats are like, with map and geographical
activities. Another activity will help students learn what characteristics
have helped them survive while other species have become extinct,
through small group brainstorm discussions. Along with that, they
can discover their anatomy and specialized structures through lecture,
pictures, articles to be read, and videos. These acitvities would
involve brainstorming in groups and allow them to express the knowledge
they have learned in creative ways.
|Grade Levels: 6-8th grade
á The ideal class size for this lesson plan is anywhere from 10-30
description or introduction
The scientific principles
that the activity is founded on.
|This lesson is aimed at educating
young people about animal behavior, archaeology, biology, genetics,
evolution, nature, wildlife and conservation of animals and environment.
These topics will be taught, discussed and learned through lectures,
media and most importantly hands on activities presented in this outline.
INTRODUCTION: Crocodiles evolved around 200 million years ago (humans
evolved about 1 million years ago). They used to be strictly land
animals, and had longer legs and shorter snouts than they do today.
Around 65 million years ago, at the end of the Mesozoic Era, many
land animals became extinct. One species that survived were the
crocodilians. Today crocodiles are found in the warm regions of
Africa, Asia, Australia and North and South America.
CLASSIFICATION: There are 3 subspecies of crocodles, Alligoritinae,
Crocodylinae, and Gavialinae. Each of these contain 23 species.
Crocodiles have a large pointy snout with 2 sharp pointy teeth pointing
up from the bottom of its mouth. Alligators have a round snout and
its 2 prominent teeth are hidden. Members of the subspecies Gavialinae
are characterized by their long slender snout. The following discusses
4 of the most common of the species. Saltwater Crocodiles(Crocodylus
porosus) is found on the northern coast of Australia through Indonesia
to southern India. Primarily found in estuaries but have been seen
far out at sea. They can grow to 8 meters in length however most
are around 4 meters long. Saltwater crocs are very aggressive and
will attack people. Nile Crocodiles live in large numbers in African
river basins, lakes and water holes and are also found in Madagascar.
They grow to 5 meters and weigh more than 2,000 pounds. Despite
their size, they are very agile in the water. Chinese Alligators
are found in eastern China in the Yangtze River. They grow to almost
2 meters in length. Chinese alligators hibernate in the winter in
holes dug out of the river banks. American Alligators inhabit the
southeastern U.S. rivers, lakes and swamps. They can reach lenghts
of 6 meters, but more commonly are about 4 meters long.
DIET: Crocodiles are carnivores. Their diet depends on their size
and what is available around them. Hatchlings and young animals
eat insects, snails, small fish and crustaceans. They grow fast
and must eat often. As they grow larger, their prey and time between
meals does also. They go from eating large fish and reptiles to
mammals of all size, monkeys and buffalo to zebras and snakes. They
generally eat the larger mammals as they come to the water to drink
or cross rivers, during the dry season or migration. Since this
is seasonal, crocodiles eat large amounts and can go for a year
between meals. The crocs teeth are big and sharp, but are not used
to chew. Instead they use them for snatching and grasping prey,
which is then taken under and drowned. Chunks of flesh are twisted
off and swallowed whole.
REPRODUCTION: Mating takes place in the water and the mother then
lays between 20 and 80 eggs on a hard nesting area on the shore.
Incubation takes up to 3 months and the nest is guarded fiercely
by the female. The hatchlings are oviporous, meaning they are perfectly
formed, but stay with their mother for 3 years before they are weened.
Sexual maturity is reached at a certain length anywhere from 5 to
15 years of age.
HABITS: Crocodiles are cold blooded, and spend a lot of time in
the water, which helps them to maintain a constant body temperature.
Generally, they will spend the night in the water and the day basking
in the sun. Crocs cannot sweat and during hotter months can be seen
with their mouths open, panting like dogs, to stay cool. Crocodiles
are usually found in large groups that are controlled by a dominat
male who is very territorial. Crocs make a variety of sounds, from
grunts and hisses to chirps and growels. This helps them to communicate
messages to each other. Crocs can walk and even gallop on land but
are more adept to the water. They propel themselves using their
large, powerful tails.
PROBLEMS: Although crocodiles,date back some 200 million years,
many species of crocodiles have become endangered in the last century.
Once revered and even worshipped by such groups as the Egyptians,
Phillipinos, and Australian Aborigines, crocodiles are now hunted
primarily for their skins. In 1929, 190,000 alligator skins were
sold in America. It is estimated that if the government, in 1944,
had not stepped in, they would be extinct. The Nile Crocodile has
also been hunted, and has disappeared from many of its northern
habitats. The Indian gharial may already be extinct in the wild;
In 1973 only 6 were found along 5000 km of waterway, where they
were once overcome with animals. In South America an estimated 1
million caimans are killed each year. These are sad trends in population
decline, showing the desparate need of conservation of the species.
INTERESTING FACTS: Crocodiles are the largest, most intelligent
reptiles in the world. They can live for up to a century and can
wait a year between meals. Crocodiles have many specialized structures
that have helped them to evolve to what they are today. Crocodile's
jaws are capable of producing 16 tons of crushing force! Another
interesting feature on the jaws,is a unique structure on young hatchlings
jaws, an "egg tooth", which is located on the tip of their snout.
It is used to penetrate the membrane of the egg during hatching.
The "egg tooth" is then gradually enveloped and disappears in an
adult crocodile. They also have a unique feature to keep water from
going down their throat while submerged underwater, a Palatal Valve.
Since their mouths allow water in even when closed, the Palatal
Valve covers the opening to the trachea and esophagus. Crocodiles
also have a very complicated heart. It can actually bypass the lungs
and pump oxygenated blood to the brain and other organs while underwater.
This allows them to stay submerged for long periods of time, voluntarily
up to 30 min, when pressed though they have been known to stay submerged
for 2 hours or more! Crocodiles also have some sensory cells, ISO
cells, which help them to detect vibrations under water. This helps
them to locate prey in murky conditions. They are also thought to
be chemoreceptors, which help them sense changes in salinity of
the water. Crocodiles are amazing creatures which have survived
since the dinosaurs and should be preserved for another 200 million
for the activity
|This is our original activity. The
credit for this activity goes to Ashish Udhrain, Adam, and William
time to do the activity
|This unit involves 5 class
periods. á Day one of the lesson plan will take nearly 45-50 minutes.
á Day two of the lesson plan will conclude after 50 minutes. á Day
three will also take up to 50 minutes. Day four - 50 minutes Day five
- 50 minutes
|To introduce the students to wildlife
| To distinguish between crocodiles
|To help the students understand
Darwin's theory of evolution.
Science Education Standards. (NSES)
content standards that this lesson plan covers:
|Student knows about the diversity
and unity that characterize life: á Through this lesson plan, students
will observe ways in which living things can be classified (e.g.,
taxonomic groups of various crocodile; groups based on the details
of an organism's internal and external features). á The activity will
reveal to the students that crocodiles have a great variety of body
plans and internal structures that serve specific functions for survival
(e.g., digestive structures, reproductive structures, etc.).
|Student understands how species
depend on one another and on the environment for survival: á The activity
will illustrate how the crocodile's ability to regulate its internal
environment enables it to obtain and use resources, grow, reproduce,
and maintain stable internal conditions while living in a constantly
changing external environment. á Students will observe ways in which
these species interact and depend on one another in an ecosystem (e.g.,
predator/prey interactions, competitive as well as mutualistic interactions).
Pre-quiz, as many copies as needed and hand out for web resources.
Video "The Ultimate Guide: Crocodiles," index cards, pushpins and
DAY 3: Ditto with outline of crocodile and internal organs, coloring
devices (crayons, coloring pencils, markers, etc).
DAY 4: Piece of paper, writing utensils and thinking cap.
Prepared quiz and appropriate number of copies.
Engage: The engagement activity is the first activity of
the first day of this unit. It is designed to elicit prior knowledge
that students have regarding crocodiles, as well as capture the
students interest of crocodiles. In order to assess the students
previous knowledge, a pre-quiz will be given (the questions in the
pre-quiz are mentioned in the section below titled "Step-by-Step
Procedure for the Activity"). The students will not know most answers
but the questions will be worded in a way as to grab their interest.
Following the quiz, they will work in small groups doing research
to further their knowledge of crocodiles by answering the questions
they answered incorrectly on the pre-quiz. This will take place
in the school library through periodicals and the internet, if accessible.
Upon completion of the assignment the students will be rewarded
with a "chocodile."
DAY 1: Prepare the pre-quiz. Reserve library.
DAY 2: Have video ready. May take a week or so to order. Reserve
VCR and TV.
DAY 3: Prepare ditto with the crocodile outline and internal organs
and have appropriate number of copies.
DAY 4: Make sure to understand the concepts of evolution.
DAY 5: Prepare quiz in advance and make sure to have appropriate
number of copies. Bring in drinks, cups, napkins, plates, etc. for
Procedure for the Activity
DAY 1: See "Engagement Acitivty."
Questions for the pre-quiz:
- What type of animal is a crocodile?
- What is the general habitat in which crocodiles live?
- What are the two distinguishing factors between crocodiles and
- How many species of crocodiles are there?
- Give the names of two species.
- What must crocodiles do in order to digest their food?
- Crocodiles spend a lot of time under water, what specific organkeeps
them from drowning?
- What is special about the crocodile heart?
- What special feature helps crocodiles hatch from their eggs?
- How does the mother crocodile protect her young before and after
they have hatched?
Answers to pre-quiz:
- Marine: River, Swamps, Lakes (Saltwater Crocodiles are often
times found in oceanic waters.
- Crocodiles have a long pointy snout and two prominent bottom
teeth can be seen protruding from their mouths; whereas, alligators
have a shorter more round snout and non protuding teeth.
- acutus, cataphractus, intermedius, johnstoni, mindornsis, moretelli,
niloticus, novaeguineae, palustris, porosus, rhombifer, slamensis,
- Swallow a stone or wood
- Palatal Valve
- .It can bypass the lungs and send blood directly to the brain
and other vital organs while the crocodile is underwater.
- She protects the nest before they hatch and after they hatch
she carries them in her mouth to the water. She then continues
to protect them until they are three years old.
After the students complete the pre-quiz, collect them from the
students so the teacher can evaluate how much prior knowledge the
students have of crocodiles. After collection, break the students
up into small groups of 2-3 (depending upon number of computers
and other resources available). Each group will be given another
copy of the pre-quiz to take with them and to be filled out at the
library. Make sure to tell the students which resources are appropriate
to search for the answers.
Also mention the names of the websites which are appropriate if
access to the internet is available: http://school.discovery.com
While the students are performing their research make sure to grade
their pre-quizes. When the students complete their research and
turn in the completed forms reward each child with a "chocodile."
DAY 2:When the students arrive in class review the information
from the previous day. Answer any question the students may have
on the information discussed so far. View video. Discuss the information
provided in the video and ask if the students have any further questions.
Homework Assignment:(Due by Friday) Divide the students into groups
of three. Have each group research one of the species of Crocodylidae
to locate where each species lives. On an index card they should
record the name, habitat, diet, size and notable fact of each species
and post a picture (if available). Use a world map and pushpins
to then identify the area in which each species lives: you can use
pins of different colors for each species. Post the index card around
the map connecting each card to a pushpin with thin pieces of ribbon
or coordinating numbers.
DAY 3:When students arrive in class, review the information which
has been discussed up to date. Students will then be given a handout
containing a diagram with the outline of a crocodile and the internal
organs. Hand out crayons to the students and then instruct them
to color each organ a specific color, eg. the stomach can be colored
red. Tell them to also make a key off to the side. So "red" will
match up with "stomach." Then after the coloring is complete, break
them up into groups of three and assign each group an organ. Have
each group then brainstorm as to what the function of their assigned
organ is. Give them roughly 10-15 minutes. At the end of this time
period have each group come up to the front of the room and present
the function of the organs to the class. Make sure to tell the students
that when they are not up in front of the class that they should
be taking notes on the other organs. Homework Assignment: (Due Friday)
Have the students go home and create the outside and interns of
the crocodile, which they learned that day in class, completely
out of food. Usually candy and cakes work well for this activity;
however, most "fun" foods will work. Tell the students to try to
use different food items that they believe to be appropriate for
each organ. For instance, licorice for the esophogus, it is long
narrow and hollow. Tell the students that this will be do on Friday
and that they will explain their designs and reason for each food
item after the quiz and then when they have all explained their
designs they will then be able to eat each others edible crocodiles
during the party.
DAY 4:Discuss how crocodiles evolved 200 million years ago and
have outlived the dinosaurs. When they first evolved they had longer
legs and shorter snouts and lived on land. They evolved to have
short legs, long snouts and live in water. With changes in environment
and human acitivty, what could be next? Today the students will
work together, 3-4 to a group, to brainstorm as to why crocodiles
are such successful animals. Have them discuss and possibly draw
what they think crocodiles may look like in 200 million years from
today. Homework Assignment: Complete the crocodile food sculpture,
the group geopgraphy/information cards and also remind them to study
for the quiz tomorrow.
DAY 5: Upon arriving have the students hand in their geography/information
card assignments and place their food sculptures on a table off
to the side of the room. Then have them get in their seats for the
quiz. After the quiz the students will then explain their food crocodile
sculptures and the class will party. Homework Assignment: NONE!
Have a great weekend. :)
work sheets, additional web pages
for discussion or conclusion
|What are the two main distinctions
between crocodiles and alligators?
|What special features help
to protect crocodiles when they dive underwater?
|Why is a crocodile's heart
considered so specialized?
|How long ago did crocodiles
|Mainly the students will be
assessed on the difference in their performance from the pre-quiz
to their performance on the final quiz given on DAY 5. The students
will also be evaluated by their participation in class activities,
their in-class as well as homework assignments.
activities which relate to and extend the complexity of the experiment.
|To get the students
thinking about conservation biology, homework can be assigned requiring
students to write a one page (hand-written) essay in which they would
answer the following questions: How would the extinction of crocodiles
affect us? What can we do to help prevent the extinction of crocodiles?
Have students contact the education department of a local zoo or animal
conservation organization to find out what activities are most harmful
to crocodiles within the U.S. as well as around the world. Have them
find out what actions are being taken to help preserve and restore
crocodile populations. Two internet sources are as follows: "Crocodile
Specialists Groups" "Crocodiles: Natural History and Conservation"
A web address with information on the topic of the activity.
|Video: Discovery Channel Presents...