7th grade ch. 2 sec. 3 insects
TRANSCRIPT
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
Camouflage Activity
Table # Total # # of green
1 31 4
2 26 4
3 25 2
4 26 5
5 45 9
6 23 4