Transcript All insects develop from eggs.

Lesson 34
How do insects develop?
Insects are by far the largest single
group of invertebrates. Nearly one
million insect species have been
classified so far!
Scientists believe that there are as
many as 10 million insect species!
Each species probably contains
billions of members.
That is one heck of a lot of insects
crawling and flying around this
earth!
How do insects develop?
All insects develop from eggs.
When it hatches, it usually does not
look like the adult.
Insects grow into adults by means of
metamorphosis.
Metamorphosis means a change
into a new form.
There are 2 kinds of metamorphosis:
Complete
and
Incomplete
Complete Metamorphosis
You have seen
butterflies flying
around the flowers.
Just a short time before, that
butterfly was a caterpillar.
That caterpillar made a complete
body change to a butterfly.
It underwent a complete
metamorphosis.
Some insects that develop by
complete metamorphosis are
butterflies, mosquitoes, flies and
bees.
There are 4 stages to complete
metamorphosis.
Our butterfly started out as an egg.
It hatched, and it was in the larva
stage. (caterpillar)
After hanging out for a while as a
caterpillar, it rests in the pupa stage.
While it rests, its body makes a
complete change.
What comes out of the
cocoon is the adult
butterfly.
The adult looks nothing like the
larva, does it?
This is why it is called Complete
Metamorphosis.
Incomplete Metamorphosis
During incomplete metamorphosis,
the change from the young stage to
the adult stage is not so great.
There are only 3 stages of
incomplete metamorphosis.
Let’s look at the life of a
grasshopper.
Momma grasshoppers lay eggs in
the dirt.
Grasshopper eggs hatch into
nymphs.
The nymph looks an awful lot like
the adult, but not exactly.
The nymph has a large head and no
wings.
The wings develop as the nymph
grows.
As the nymph grows, it molts its
skin. Molt means to shed.
A nymph will molt its skin about 5
times as it grows. After the first
molt, small wings appear. Each time
it molts, its wings are bigger.