Comparing Insect Life Cycles Ask: What does metamorphosis mean? It is a transformation, a change in form. Metamorphosis Comparing Insect Life Cycles

Insects are Everywhere Look around you. Chances are, there is an insect nearby. Ask: Do you see any insects now?

Metamorphosis As you have learned previously, insects go through a life cycle.

Metamorphosis Metamorphosis means "change of form." It’s the way insects grow and mature. Their lives are divided into separate stages for resting, growing and reproducing. Gradual growth vs. growth in stages Humans grow gradually. You began life as a baby and grow a little at a time until you’re an adult. While you’re growing, the basic plan of your body doesn’t change. You have the same body your whole life. Insects grow in stages. The cycle of stages is called metamorphosis. For many insects, the stages are so different from one another that you might not recognize them as the same animal. http://exhibits.pacsci.org/insects/metamorphosis.html

Complete Metamorphosis Some insects change drastically …. Egg to larva Adult lays eggs Ask: What does drastically mean? Do you remember the names of some of these stages? Larva to pupa Pupa to adult

Complete Metamorphosis Complete metamorphosis is the way butterflies, bees, flies, beetles and many other insects develop. Complete metamorphosis has four stages: egg, larva, pupa and adult.   Egg Larva Pupa Adult Every insect begins life as an egg. The egg is the embryo stage. The larva hatches from the egg. The larva is the eating and growing stage. Some insects don’t eat at all after this stage. Larvae don’t look like adults. Caterpillars, grubs and maggots are larvae that grow up to be butterflies, beetles and flies as adults. A larva’s exoskeleton can’t stretch or grow, so the larva sheds its skin, or molts, several times as it grows. When a larva has finished growing, It forms a pupa (plural: pupae). The pupa is the insect’s trans- forming stage. Outside, the pupa looks as if it’s resting. But inside, the entire body is rearranging. New organs, muscles and body parts develop. When it has finished changing, the pupa molts one last time, emerging as an adult. The adult is the repro-ductive stage. The adult has all the identifiable insect features: three body sections, six legs, two antennae and usually wings. http://exhibits.pacsci.org/insects/metamorphosis.html

Complete Metamorphosis Highlights Insects that undergo complete metamorphosis have four distinct life cycle stages: egg, larva, pupa, and adult. During the insect’s larva stage, it grows and stores up energy needed for the next developmental stage (pupa), by eating large quantities of food. As an insect enters its pupa stage, it forms a harder outer shell for protection. The insect will remain as still as possible, in order to use its energy toward the transformation process into an adult. The adult insects no longer grow in size, but focus their energy on gathering food and reproduction.

Incomplete Metamorphosis …while others just grow larger. Adult Lays Eggs Nymph to Adult Ask: Do you remember the names of some of these stages? Egg to Nymph

Incomplete Metamorphosis Some insects, such as grasshoppers, dragonflies and cockroaches, develop by incomplete metamorphosis. Incomplete metamorphosis has three stages: egg, nymph and adult. Egg Nymph Adult Early, basic development happens in the egg. The nymph is the eating and growing stage. Nymphs often look like smaller versions of adults, without wings. The nymph’s exoskeleton can’t grow or stretch, so the nymph needs to shed its skin, or molt, in order to grow. At each stage, the nymph looks a little more like the adult form. Wing buds form and grow on the nymph’s back. The adult is the reproductive stage. The nymph emerges from its final molt as an adult. In species that have wings, the wings don’t fully appear until this stage. Adults mate, females lay eggs, and the cycle begins again. http://exhibits.pacsci.org/insects/metamorphosis.html

Incomplete Metamorphosis Highlights Insects that undergo incomplete metamorphosis have three distinct life cycle stages: egg, nymph, and adult. Nymphs often closely resemble the adult, but are smaller in size and lack wings. Nymphs shed their exoskeleton as they grow, and do not develop wings until they are adults. Adult insects focus their energy on survival and reproduction. Images courtesy of Clip Art

Video Clip Elaboration http://www.harcourtschool.com/activity/science _up_close/315/deploy/interface.html http://glencoe.mheducation.com/sites/dl/free/0 078617022/167348/00076710.swf

So, What’s the Difference? Complete Metamorphosis Both Incomplete Metamorphosis 4 stages – larva, pupa, adult, egg egg 3 stages- nymph, adult, egg pupa is called a chrysalis or cocoon adult   larva look different than the adult adults usually have wings nymphs look like wingless adults darkling beetle life cycle cockroach moth praying mantis bee grasshopper

Sort these phrases into a Tree Map… Phrase sort Draw a Tree Map in your notebook with the following categories: Complete Metamorphosis Both Incomplete Metamorphosis Sort these characteristics into the correct place on the tree map. Don’t glue them until your class checks your answers.

Sort these phrases into a Tree Map… Phrase sort Draw a Tree Map in your notebook with the following categories: Complete Metamorphosis Both Incomplete Metamorphosis It has a larva stage. It has a total of 4 stages. It has a pupa stage. There is usually a dormant stage. It starts with an egg. It has an adult stage. The adult lays the eggs. The cycle repeats itself. The adult may have wings. It has a total of 3 stages. It has a nymph stage. The adult looks like the stage before it.

What type of Metamorphosis is this? Grasshopper Incomplete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

What type of Metamorphosis is this? Mosquito Complete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

What type of Metamorphosis is this? Butterfly Complete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

What type of Metamorphosis is this? Ladybug Complete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

What type of Metamorphosis is this? Fly Complete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

What type of Metamorphosis is this? Milkweed Bug Incomplete http://www.entm.purdue.edu/entomology/outreach/insectivity/beehive/metamorphan.pdf

Using the pictures in your group, sort the cycles into incomplete & complete metamorphosis