Download ARTHROPODS HAVE EXOSKELETONS & JOINTS

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Living things in culture wikipedia, lookup

Grasshopper wikipedia, lookup

Home-stored product entomology wikipedia, lookup

Entomophagy wikipedia, lookup

Insects in culture wikipedia, lookup

Horse-fly wikipedia, lookup

Transcript
Arthropods Have Exoskeletons
& Joints
• MOST INVERTEBRATES ARE
ARTHROPODS
– Most common type of invertebrate: arthropod =
invertebrate with segmented body covered by hard
outer skeleton; many pairs of legs; insects, crustaceans
& arachnids are arthropods
• INSECTS ARE SIX-LEGGED ARTHROPODS
• CRUSTACEANS LIVE IN WATER AND ON
LAND
• ARACHNIDS ARE EIGHT-LEGGED
ARTHROPODS
• MILLIPEDES AND CENTIPEDES ARE
ARTHROPODS
Arthropods: exoskeletons
• Exoskeleton made of hard “chitin”, like suit of armor
protecting it & keeping it moist (if on land).
• Joints (where chitin is thin & flexible) allow for
movement; muscles attach around joints for this.
• 3 main body parts: Head, Thorax, & abdomen
• Exoskeleton doesn’t grow, it molts (sheds old one
and grows new one); this is dangerous time because
new one stays soft for awhile.
Insect: 6 legged arthropods
• Arthropods have well-developed nervous & digestive
systems; open circulatory system with blood moving into
body without blood vessels; reproduce sexually; either
male or female parts.
• As adults have 3 body segments, pair of antennae, 6 legs
attached to thorax.
• If on land, have spiracles (openings in exoskeleton to bring
in oxygen).
• Many can blend in to environment, or have wings.
• Many are herbivores with designs for specific plants to eat
(butterfly has tube to reach nectar)
• Some are social insects (bee, termite, ant) living in groups;
work together to get food, maintain nest & care for
offspring; usually just one female (queen) lays eggs.
Insect=most common arthropod
• All insects reproduce sexually; female lays many eggs(often
with protective hard covering to keep from drying out)
• Insects undergo metamorphosis(3 stages of change): Egg
hatches into Larva= spends its time eating; Pupa=second
stage, insect body develops inside of protective casing;
Adult= final stage, insect able to reproduce now
• Some insects skip some of the metamorphic stages
• Many larval stages are common (caterpillar, inchworm);
often larva are very different (mosquito larva live in water &
feed on algae, pupa form on water surface & adult flies off to
feed on blood of animals & lay eggs in water again).
•
•
•
•
•
Crustacean
Arthropods
Most live in water; many used as
food source in important food
webs & by humans.
3 or more pairs of legs & 2 pair
sensory antennae
Most have heart but no blood
vessels like other arthropods
May eat plants/small animals, or
remains of other organisms
(barnacle is filter feeder)
Barnacle larva is free swimming,
then attaches as adult to hard
surface (rock/boat/mollusk shell)
& uses its tentacles to grab food
from surrounding water.
Arachnid- 8 legged arthropod
• Spiders, mites, ticks & scorpions are arachnids.
• Exoskeleton, jointed limbs, segmented bodies
(like all arthropods) but also have 4 pairs of legs
and only 2 body segments; no antennae
• Some are parasites(tics,chigger mites), others are
predators (spiders & scorpions). These get prey
by stinging, biting or injecting venom.
• Most arachnids are spiders. Make strong silk to
form webs to capture food. Spinnerets at rear of
abdomen spins strands of silk into web.
• Some arachnids have spiracles to get oxygen,
while others (some spiders) have “book lungs”
(moist folded pockets within abdomen).
Millipede & Centipede
Arthropods
• Both have long, segmented bodies with many
legs.
• Reproduce sexually, hatch from eggs.
• Millipedes have 2 pair of walking legs on each
body segment; move slowly & eat decaying
leaves & plant matter; may emit foul odor if
disturbed which may harm predators.
• Centipedes move quickly, have 1 pair of legs
per segment, have antennae & jaw-like
mouthparts. Many have pincers on rearmost
segment. Are predators that can paralyze prey.