METAMORPHOSIS Comparing Insect Life Cycles I NSECTS ARE

METAMORPHOSIS Comparing Insect Life Cycles

I NSECTS ARE E VERYWHERE Look around you. Chances are, there is an insect nearby.

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

M ETAMORPHOSIS 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

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

C OMPLETE M ETAMORPHOSIS H IGHLIGHTS 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.

I NCOMPLETE M ETAMORPHOSI S …while others just grow larger. lt u d A to Egg h p Nym s y a L s g g E Nymph t to Adul

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

I NCOMPLETE M ETAMORPHOSIS H IGHLIGHTS 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.

V IDEO C LIP E LABORATION http: //www. harcourtschool. com/activity/science _up_close/315/deploy/interface. html http: //glencoe. mheducation. com/sites/dl/free/0 078617022/167348/00076710. swf

sis oh S O, W HAT’S THE D IFFERENCE? pr om at e. M et elp m oc n. I 4 stages – larva, pupa, adult, egg 3 stagesnymph, adult, egg hto pupa is called a chrysalis or cocoon adult larva look different than the adults usually have wings nymphs look like wingless adults darkling beetle life cycle cockroach moth praying mantis bee grasshopper B

Phrase sort S ORT THESE PHRASES INTO A T REE M AP… 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.

Phrase sort S ORT THESE PHRASES INTO A T REE M AP… Draw a Tree Map in your notebook with the following categories: Complete Metamorphosis • It has a larva stage. • It has a total of 4 stages. • It has a pupa stage. • There is usually a dormant stage. Both Incomplete Metamorphosis • 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.

Grasshopper W HAT TYPE OF M ETAMORPHOSISIS THIS? Incomplete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

Mosquito W HAT TYPE OF M ETAMORPHOSISIS THIS? Complete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

Butterfly W HAT TYPE OF M ETAMORPHOSISIS THIS? Complete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

Ladybug W HAT TYPE OF M ETAMORPHOSISIS THIS? Complete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

Fly W HAT TYPE OF M ETAMORPHOSISIS THIS? Complete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

Milkweed Bug W HAT TYPE OF M ETAMORPHOSISIS THIS? Incomplete http: //www. entm. purdue. edu/entomology/outreach/insectivity/beehive/metamorphan. pdf

U SING THE PICTURESIN YOUR GROUP, SORT THE CYCLES INTO INCOMPLETE& COMPLETEMETAMORPHOSIS