7th grade ch. 2 sec. 3 insects

Ch. 2 Sec. 3

YouTube video-Bill Nye Insects song

Humans are definitely outnumbered!

• For every pound of humans, there are 300 pounds of insects! So if you weigh 50 pounds, your share of insects weighs 15,000 pounds! That's as much as 7 cars!  

• How much do you weigh in insects?

It's a good thing insects can't vote!

• If they could, they would rule the Earth!  There are a lot more insects than people!  If all the insects in the world were divided up, and you got your share, guess how many you would get.  

- InsectsInsect Body Structure• 3 body sections- head, thorax & abdomen

• 6 legs

• 1 pair of antennae

• usually 1or 2 pairs of wings

legs & wings attached to

thorax

Obtaining food

• insect’s mouthparts adapted for eating specific foods

•butterfly’s mouth- shaped like coiled tube- can be uncoiled like straw to suck up nectar

Some flies- sponge-like mouthpart to lap up decaying flesh

Ant- sharp edged chewing mouthparts

Leaf cutter ants

2 types of insect metamorphosis

• complete metamorphosis

• incomplete (gradual) metamorphosis

- Insects

complete metamorphosis• 4 different stages: egg, larva, pupa, & adult

Egg Larva Pupa Adult

Life cycle of the monarch butterflyLife cycle of the monarch butterfly

- Insectsgradual metamorphosis• no distinct larval stage

• egg hatches into a stage called a nymph, usually looks like adult insect w/out wings

Complete Metamorphosis

Adult insect

Egg

Larva

Pupa

- Insects

Insects and Metamorphosis

1. Name an insect that goes through complete metamorphosis, and an insect that goes through incomplete metamorphosis.

2. How are the 2 types of metamorphosis different? The same?

Insect defenses

• stinkbug- bad odor

• bees- sting

• camouflage= protective coloration

• mimic larger animals

moth caterpillar defendsitself by mimicking a snake

One of the most common defenses against predators is camouflage.

Can you find the creature?

Most insects are harmless or beneficial to people.

Controlling insect pests

• Insects can damage crops

• Pesticides

Insects do not have a backbone.

True or False

TRUEInsects are invertebrates. They have an exoskeleton instead of a backbone.

The three sections of an insect’s body are called the mandible,

the antenna, and the wing.

True or False

FALSE

How many different How many different species of insects are species of insects are

there?there?

• There are over a millionover a million species of insects. Insects outnumber all other animals at a rate of 4 to 1.

• The biggest group of insects are the beetles, numbering around 330,000 species.

Spiders are insects.Spiders are insects.

True or FalseTrue or False

FALSESpiders are arachnids. They only have 2 body sections, while insects have 3 body sections.

Insects live just about everywhere on earth.

True or False

TRUE

Insects do not spread disease.

True or False

FALSE

When an insect first comes out of its egg it is called a larva.

True or False

TRUE

larva

Camouflage Activity

Table # Total # # of green

1 31 4

2 26 4

3 25 2

4 26 5

5 45 9

6 23 4