Invent an Insect

Students will:

1. recognize what makes an insect an insect by identifying the common structures and characteristics of insects.
2. explore examples of insect adaptations and infer how they fit the insect’s habitat or lifestyle.
3. appreciate the diversity of insects.

1. Print Insect Diagram and Invent an Insect sheets, one each per student.
2. Print and cut out Insect Habitat cards, one card per group.
3. (optional) Print Arthropods pictures or set up as a slideshow.

1. What is an insect? Discuss as a class what makes an insect. Be sure to specify what makes an insect different from other arthropods: they have three body segments, two antennae, and six legs. You can use the PDF Arthropods to show different arthropods, including insects, as examples or you can have students try to figure out if the arthropod is an insect or not. Teacher tip: this PDF may either be printed out or shown as a slideshow for the whole class.
    
2. Insect Anatomy Pass out one Insect Diagram handout for each student. Have students work in groups to try to fill out the sheets first, then have a class discussion about what each part is and what they think it does. Teacher tip: Try to allow students to share definitions in their own words before giving the class the formal definitions.
    
3. Adaptation Introduce the essential question: “How can there be so many similarities among living things, yet so many different species of plants and animals?” Discuss and define the term “adaptation.” Use the arthropods in the PDF as examples and have students try to point out adaptations they see on their bodies or behaviors they know the animals have.

1. Have each group present their insect to the class and state what habitat they were given. Have students share at least one adaptation they gave their insect and why.
    
2. As a class discuss how each groups’ insect was similar and different. Did any two have similar adaptations? Did any two have similar habitats, but different adaptations?
    
3. Reflect and try to answer the essential question: “How can there be so many similarities among living things, yet so many different species of plants and animals?”

Arthropods:

Scientists classify animals according to how their bodies have evolved. Animals with similar characteristics are grouped together. Insects belong to a very large group of animals called arthropods. Spiders, crabs, centipedes, ticks, scorpions, shrimp, also belong to the arthropod group. The characteristic that defines an arthropod is an exoskeleton, or an external, jointed skeleton that provides structure and protection for the animal’s softer insides. The plates of exoskeleton may overlap but have flexible joints in between, allowing’ different body parts to move independently of the rest, much like animals with internal skeletons.

Defining Characteristics of Insects:

Three Body Segments All insects have segmented bodies. Insect bodies are divided into three segments – the head, the thorax and the abdomen. With some insects, it’s difficult to tell exactly where one segment stops and another begins. But there is a fool-proof way to tell which part is which. First, look for the eyes and antennae; they’re always located on the head. Next, locate the legs; they’re always connected to the thorax. All that remains on the body is the abdomen, located on the opposite end as the head!

Six Legs All adult insects have six legs. Insects who undergo complete metamorphosis (meaning they change from an egg to a larva to a pupa to an adult) lack legs entirely during the first phases of their lives. By looking at an insect’s legs, you can usually tell what type of environment it lives in. For example, many insects that live in the water, such as water boatmen, have flattened oar-like legs to help them paddle through the water. Other insects may have legs suited for running, or climbing, or jumping great distances.

Antennae Adult insects also come equipped with a pair of sensitive antennae on their heads. These sensory organs are used to feel, smell, and sometimes hear. Antennae come in a wide range of shapes and sizes, depending upon how they are used. Scientists use antennae to help identify different types of insects because they are very particular to individual species of insects.

Wings All but our most “primitive” orders of insects possess wings. Even in ants and termites the reproductive members of the colony possess wings. Typically, insects have two sets of wings that move together in unison. In beetles, the front pair of wings has been modified to form a protective casing for the hind wings called elytra. True flies appear to have only two wings. This is because the hind wings have been modified into halteres, which resemble small knobbed structures that act as a counterweight to the front wings, helping stabilize the insect’s flight.

Insect Ecology

Insects occur in abundance everywhere on our planet, except in oceans and the polar regions. These places aside, wherever entomologists have looked, they have found a great diversity of insect species, each suited to the environment they live in. This includes extreme environments like mountain tops, deserts and frozen fresh water.

Not only have insects filled practically every habitat on Earth, but within each, they’ve filled nearly all ecological roles, from scavengers, to primary consumers, to predators, to parasites, and so on. Insects are not only well adjusted to the environments in which they live, but also their role within that environment, which is largely defined by what they eat. Plants, fungus, other insects, decaying matter, blood, and fecal matter have all been exploited by insects as sources for food. In order to eat, and sometimes catch, their food, insects have developed specialized body parts specific to each.

How we’ve come to have so many different types of insects filling so many roles is a matter of time and evolution. As far as we can tell, insect have been around for 325 million years, during which they have had plenty of opportunity to evolve and diversify. [Grimaldi, D., & Engel, M, 2005.]

Adaptation in Insects

Adaptation is the process whereby a group of organisms becomes better suited to its environment over the course of many generations. This fundamental concept of evolution shapes not only where an organism lives, but how it lives as well. Through a process of trial and error (error in this case meaning death without successful reproduction), combined with random genetic variations, populations of organisms and their descendants slowly become better adapted to the conditions around them.

Animals may adapt to their environment with changes in their behavior (e.g. a bumble bee flies further south to find plants in bloom during an atypically cold spring). They also adapt with changes in body structure. Every aspect of an insects’ body may be explained as an adaptation to some environmental factor. See page 4 for some examples of insect adaptations.

Disciplinary Core Ideas

• LS1.A: Structure and Function: Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.
• LS4.C: Adaptation: For any particular environment, some kinds of organisms survive well, some survive less well, and some cannot survive at all.
• LS4.D: Biodiversity and Humans: There are many different kinds of living things in any area, and they exist in different places on land and in water.

Crosscutting Concepts

• Structure and Function: The shape and stability of structures of natural and designed objects are related to their function(s). (K-2)
• Cause and Effect: Cause and effect relationships are regularly used to explain change. (Grade 3)

Related Performance Expectations

• K-2-ETS1-2. Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem.
• 3-LS4-3. Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all.
• 4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.
• 3-5-ETS1-2: Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.