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

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

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

4. 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.

5. 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

6. 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.

7. 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.

8. 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

9. 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.

10. 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

11. Video Clip Elaboration
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12. 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

13. 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.

14. 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.

15. What type of Metamorphosis is this?
Grasshopper
Incomplete

16. What type of Metamorphosis is this?
Mosquito
Complete

17. What type of Metamorphosis is this?
Butterfly
Complete

18. What type of Metamorphosis is this?
Ladybug
Complete

19. What type of Metamorphosis is this?
Fly
Complete

20. What type of Metamorphosis is this?
Milkweed Bug
Incomplete

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