Oh My! Mealworms

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Objective

SWBAT observe and identify the changes a mealworm goes through in the different stages of the life cycle.

Big Idea

The changes animals go through during their life form a pattern known as the life cycle.

Setting the Stage

Next Generation Science Standards:

This lesson addresses 2-LS4-1: make observations of plants and animals to compare the diversity of life in different habitats. Groups develop a model of a meal-worm habitat to describe how organisms have unique and diverse life cycles.  The meal-worm life cycle have birth, growth, reproduction, and death in common.

Science and Engineering Practices in the Next Generation Science Standards:

This lesson addresses SP 2: developing and using models. In grades K-2, students progress in building and revising simple models and using models to represent events and design solutions. Students collaborate in groups to build a habitat for meal-worms to describe phenomena.

Background Knowledge:

Certain generalizations can be made about the life cycles of specific animal groups even though the sequential stages of life cycles are different for different animals. The life cycle of birds, for example, always includes egg laying and hatching because that is the way in which birds have offspring. A bird’s life cycle may differ from one species to the next, depending on such things as nesting and feeding habits and how long the young are cared for. In contrast, mammals give birth to “live young” meaning that the egg develops inside the mother who gives birth to a fully developed offspring. A mammal’s life cycle may vary among species, but almost all mammals care for their young for a time. Life cycle findings are based on recognizing patterns that animals grow to resemble their parents and the life cycle begins again.

Guiding Question(s):

How will your meal-worms change?

How can you keep them healthy to observe those changes?

Materials:

 

Meal-worms can be purchased at a pet supply store or biological supply house. Cover the bottom of an open box with bran meal or wheat germ and place the meal-worms in it. Maintain a spray bottle of water next to the meal-worm “home.” Meal-worms are the larval stage of a beetle found in stored grain. If kept for several weeks, meal-worms will turn into pupa and then into adult beetles. You may wish to keep the meal-worms in an enclosed container so children can observe the beetle’s entire life cycle. Make a hand lens available for children to use while making their observations. Allow students to examine meal-worms for 15 minutes a day for one to two weeks

Engage

With the students at their desks, we play a game called, “Names of Young Animals.” I explain to the students that some young animals have special names, such as kittens and puppies. I write the following sentence frame on the board. A _________ is a young _________.  (Example: A cat is a young kitten.) Or (A frog is a young tadpole.) I give each student their own sentence strip, have them write the sentence frame onto their strips, and write words that complete the sentence.

This game identifies the correlation between how a young animal grows and changes through the life cycle process from a baby to an adult.

Explore

20 minutes

Students are placed in groups of 5. I assign the leader and I permit them to select who will record, report, manage, and measure. I assign the leader to a student that demonstrates leadership qualities. Occasionally, I will permit the other group members to select their roles. This is done so students can select a role in which they acknowledge as a strength.

Groups observe meal-worms as they go through their life cycle. First, I express the importance of how students must respect and care for these animals. I state to the students that part of the lesson focuses on what animals need to live: water, food, air and space. I also help students see the value in all animals. Therefore, I avoid referring to them as gross, ugly, yucky, or dirty. I also emphasize the importance of making careful observations using our four senses. This will be the basis of how students demonstrate the knowledge of the life cycle process.

The groups are given time to observe the meal-worms by placing them on a paper plate. As the groups observe the meal-worms, I provide opportunities for groups to share observations and predictions with their group members and during class discussions. Groups are made aware they should be respectful and safe. Groups have also previously used their hand lens’ and are prepared to use them correctly to have a more thorough and in-depth view of their meal-worms. After the groups examine the meal-worms, they are given a worksheet called, “Observing Meal-worm Larva” to utilize four of their five senses to write what they see, feel, smell, and hear. I provide the groups with the lab sheet after their observation so they can explore the meal-worms.  

Finally, I guide groups as we set-up their groups' plastic tubs to observe the meal-worms through their life cycle in our classroom for the next four weeks in 15 minute intervals. This process permits the groups to analyze and describe the sequence of events in the life cycle of a meal-worm. The groups examine the meal-worms at least twice a week. Teacher note- It takes about four weeks to observe a beetle. 

Here is a Meal Worm-Lab Sheet.

Observing meal-worms-October 27th

Observing meal worms- November 10th

We have a beetle-November 24th.

 

 

Evaluate

15 minutes

After two weeks of observing the meal worms....

With the students at their desks, they draw a picture of the life cycle of a meal-worm and label it using the vocabulary words. This enables the students the ability to communicate observations about animals' growth.

 After two weeks, we have a pupa.