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Brief Description: Students will research a topic by using multiple sources as well as mathematical functions, comparing and contrasting, and following verbal directions. Students will learn and understand the concept of life cycles, and recognize the similarities and differences in living organisms regarding their life stages and spans.
Focus Areas: Animal Life Styles; Science, Math, Language Arts
Focus Skills: researching a topic using multiple sources, using mathematical functions, comparing and contrasting, following verbal directions
Objectives
- To understand the concept of life cycles
- To recognize that among living organisms there are similarities and differences in regard to life stages and life spans
- To increase ability in the use of mathematical data to create reasonable explanations
Essential Questions
- What is a living organism’s life span?
- What are the life stages of a living organism?
- How do life stages and life spans differ among living organisms?
Essential Understandings
- Animals have life cycles that begin with birth and end with death.Animals can survive only in those environments that provide for their basic needs.
- The life spans of living things differ in length.
- Living things develop and change in a series of stages.
- The life stages differ in length from species to species.
- Mathematical computation is often needed in scientific inquiry.
Background
All living things develop in a series of stages, which begin with birth and end at death. These stages involve both growth and change. In the insect world, these stages, called metamorphosis, involve dramatic changes in structure and appearance. Some insects, like dragonflies, go through three stages, called incomplete metamorphosis. Others, like butterflies, experience four stages, called complete metamorphosis.
The four stages of a monarch butterfly’s development are egg, larva, pupa, and adult. Eggs laid in the spring and summer by multiple generations of adult monarchs hatch in about 4 days and a caterpillar, the larval stage, emerges. For approximately two weeks, this tiny insect larva feeds on its surrounding environment, beginning with its own shell and continuing through multiple meals of the milkweed plant on which the egg was laid. The larva’s size increases from 1/16 of an inch to 2 inches, and it’s mass by approximately 4,500 times in 9 to 14 days. As the caterpillar grows, it molts 5 times. Each molt results in a larger instar or growth stage of the caterpillar. The last molting ushers in the pupa or resting stage. The larva attaches itself head down to a sturdy twig or branch, its skin splits, and a chrysalis appears. Monumental changes then occur. Multiple legs become six, chewing mouth parts are replaced with a proboscis, and wings form. Within 8 to 13 days, a butterfly, the high fashion model of the insect world, emerges. Blood from the engorged abdomen is pumped into the flattened wings. Within approximately 30 minutes the wings become rigid, and the adult exoskeleton hardens. Because this final stage of a monarch’s life span is beautiful but brief, the monarch takes flight and mates within 3 to 8 days.
Females may mate several times and lay as many as 700 eggs of the next generation over the next few weeks. Each egg is laid singularly and attached to the underside of a milkweed leaf. Even with the care that mom takes to provide a safe and tasty environment for her offspring, only a very small percentage will survive until the pupal stage, and these will be orphans. Only the final generation of adult butterflies born each year lives longer than 2 to 6 weeks after emerging from the chrysalis stage. This generation, usually the fourth in the Northeast and Canada, emerges in the late summer and early fall. Although in all appearances they look like their parents, grandparents, and even great grandparents, these monarchs are unique and have a life span measured in months, not weeks. (See Unit 3, Section 1, Lesson 2, Migration Relay for further information.)
Vocabulary
chrysalis the inactive third stage, or pupa, in a butterfly’s metamorphosis
cocoon the case that contains the pupal stage of some insects during metamorphosis
egg the first stage in the process of metamorphosis
generation the time lapse between the birth of maternal parents and the birth of the first child
instar one stage of a caterpillar’s growth, beginning with one molt and ending with the next
larva the second developmental stage of some insects (Example: caterpillar)
life span the average time between birth and death of an organism
life stage a period of time during which specific physiological changes occur
metamorphosis a series of changes through which insects go from egg to adult
offspring an immature animal resulting from the mating of two adult animals
pupa the third stage of many insects’ metamorphosis
sibling offspring of the same parents
Logistics
Time: two 45 minute time blocks and an additional 30 minutes for Follow Through
Group Size: 5 to 30
Space: an area for comfortable seating
Materials
- Handout 1 “Monarch Life Cycle Research” *
- Handout 1 Answer Key *
- Rubric for Individual Work *
- Animal Babies and Adults Picture Card Set *
- black/white board or chart paper
- multiple computers with Internet access or an
- LCD projector
- assorted print materials on monarch butterflies
* single copy provided
Preparation
- Read the Background section.
- Make copies of Handout 1, “Monarch Life Cycle Research.”
- Arrange time in the computer lab or procure an LCD projector.
- Collect print material on monarch butterflies, focusing on their life cycle.
- Preview and select monarch websites for children’s use.
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Grade Span |
Maine Learning Results |
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Grades 3-5 |
ELA – C. Research C1. Students create, identify, and answer research questions by gathering information from print and non- print sources and communicating findings. c. Collect, evaluate, and organize information for a specific purpose. d. Communicate findings from a variety of print and non-print sources. MA – A. Number Grade 4 – A3. Students understand and use procedures to multiply and divide whole numbers by two-digit numbers. Grade 5 – A2. Students multiply and divide numbers up to four digits by numbers up to two digits, and by tens, hundreds, and thousands and interpret any remainders. A3. Students solve problems requiring multiple operations (addition, subtraction, multiplication, and division) and use the conventions of order of operations (no exponents expected). SCI – E. The Living Environment E1. Biodiversity – Students compare living things based on their behaviors, external features, and environmental needs. a. Describe how living things can be sorted in many ways, depending on which features or behaviors are used to sort them, and apply this understanding to sort living things. b. Describe the changes in external features and behaviors of an organism during its life cycle.
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