arthropods - mrs. borgie's...

ArthropodsArthropods

Ch. 13, pg. 374Ch. 13, pg. 374--382382

ArthropodsArthropods

Insects

Arachnids

Centipedes and Millipedes

Crustaceans

Characteristics of ArthropodsCharacteristics of Arthropods

�� Arthropods have jointed Arthropods have jointed appendagesappendages and and

include include legs, antennae, claws, legs, antennae, claws, and and

pincers.pincers.

�� Arthropod appendages are adapted for Arthropod appendages are adapted for

capturing prey, feeding, mating, and capturing prey, feeding, mating, and

sensing their environment.sensing their environment.

Characteristics of ArthropodsCharacteristics of Arthropods

�� Arthropods have:Arthropods have:

–– Bilateral symmetryBilateral symmetry

–– Segmented bodesSegmented bodes

–– An exoskeletonAn exoskeleton

–– A body cavityA body cavity

–– A digestive system with two openingsA digestive system with two openings

–– Nervous systemNervous system

Segmented BodiesSegmented Bodies

�� The bodies of arthropods are divided into The bodies of arthropods are divided into

segmentssegments..

�� Some arthropods have many segments. Some arthropods have many segments.

Others have segments fused together to Others have segments fused together to

form body regions, such as those of form body regions, such as those of

insects, spiders, and crabs.insects, spiders, and crabs.

ExoskeletonsExoskeletons

�� All arthropods have a hard outer covering All arthropods have a hard outer covering

called an called an exoskeletonexoskeleton..

�� Exoskeletons Exoskeletons cover, supportcover, support, and , and

protect protect the internal body and provides the internal body and provides

place for muscles to attach.place for muscles to attach.

ExoskeletonExoskeleton

�� An exoskeleton cannot grow as the animal An exoskeleton cannot grow as the animal

grows.grows.

�� From time to time, the exoskeleton is shed From time to time, the exoskeleton is shed

and replaced by a new one in a process and replaced by a new one in a process

called called moltingmolting..

InsectsInsects

�� There are more than 700,000 species of There are more than 700,000 species of

insects.insects.

�� Insects have three body regionsInsects have three body regions——a a head, head,

a thorax, and an abdomen.a thorax, and an abdomen.

InsectsInsects-- HeadHead

�� A insects head has a pair of A insects head has a pair of antennae, antennae,

eyes, and a mouth.eyes, and a mouth.

�� The antennae is used for The antennae is used for touch and touch and

smellsmell..

Insect Insect --HeadHead

�� The eyes are The eyes are simple simple or or compoundcompound..

–– Simple eyes detect Simple eyes detect light and darknesslight and darkness..

–– Compound eyes have many lenses and detect Compound eyes have many lenses and detect

colors and movementscolors and movements..

�� The mouthparts of insects vary.The mouthparts of insects vary.

InsectsInsects-- ThoraxThorax

�� An insectAn insect’’s thorax contains s thorax contains three pairs of three pairs of

legslegs and and one or two pairs of wingsone or two pairs of wings (if (if

the insect has wings).the insect has wings).

�� Insects are the only invertebrate animal Insects are the only invertebrate animal

that can fly.that can fly.

�� Flying allows insects to Flying allows insects to find places to find places to

livelive, , food sourcesfood sources, and , and matesmates..

InsectInsect-- AbdomenAbdomen

�� An insectAn insect’’s abdomen contains reproductive s abdomen contains reproductive

structures.structures.

�� Females lay thousands of eggs, but only a Females lay thousands of eggs, but only a

fraction develop into adults.fraction develop into adults.

Insect CharacteristicsInsect Characteristics

�� Insects have an Insects have an open circulatory open circulatory

systemsystem that carries digested food to cells that carries digested food to cells

and removes wastes.and removes wastes.

�� Insect blood does not carry oxygen Insect blood does not carry oxygen

because it does not contain hemoglobin.because it does not contain hemoglobin.

�� Insects have openings called Insects have openings called spiraclesspiracles on on

the abdomen and thorax through which the abdomen and thorax through which

gas exchange occurs.gas exchange occurs.

Insect Life CycleInsect Life Cycle

�� MetamorphosisMetamorphosis is is a process in which a process in which

many insect species change their many insect species change their

body form to become adultsbody form to become adults..


�� Metamorphosis can be Metamorphosis can be completecomplete and and

incompleteincomplete. .

�� Complete metamorphosis includes 4 Complete metamorphosis includes 4

stages: stages: egg, larva, pupa, and adultegg, larva, pupa, and adult..


�� Insects that undergo complete Insects that undergo complete

metamorphosis are: butterflies, beetles, metamorphosis are: butterflies, beetles,

ants, bees, moths, and flies.ants, bees, moths, and flies.


�� Incomplete metamorphosis includes 3 Incomplete metamorphosis includes 3

stages: stages: egg, nymph, and adultegg, nymph, and adult..

�� Examples include: grasshoppers, silverfish, Examples include: grasshoppers, silverfish,

lice, and crickets.lice, and crickets.

InsectsInsects-- Obtaining FoodObtaining Food

�� Insects feed on plants, the blood of Insects feed on plants, the blood of

animals, nectar, decaying materials, wood animals, nectar, decaying materials, wood

in houses, and clothes. in houses, and clothes.

�� Mouthparts are very diverse. Mouthparts are very diverse.

InsectsInsects-- Obtaining FoodObtaining Food

�� Grasshoppers and ants have large Grasshoppers and ants have large

mandibles for chewing plant tissue.mandibles for chewing plant tissue.

�� Butterflies and honeybees have siphons Butterflies and honeybees have siphons

for lapping up nectar in flowers.for lapping up nectar in flowers.

�� Mosquitoes have mouths that are adapted Mosquitoes have mouths that are adapted

for piercing skin and sucking blood.for piercing skin and sucking blood.

Insect SuccessInsect Success

�� Insects are extremely successful because Insects are extremely successful because

of their of their tough, flexible, waterproof tough, flexible, waterproof

exoskeletonsexoskeletons; ; their ability to flytheir ability to fly; ;

rapid reproductive cyclesrapid reproductive cycles; and ; and small small

sizessizes..

ArachnidsArachnids

�� Examples of Arachnids include: scorpions, Examples of Arachnids include: scorpions,

spiders, mites and ticks.spiders, mites and ticks.

ArachnidsArachnids

�� Arachnids have two body regionsArachnids have two body regions——a a head head

and a region called the and a region called the cephalothoraxcephalothorax..

�� Arachnids have 4 pairs of legs and no Arachnids have 4 pairs of legs and no

antennae.antennae.

�� Many arachnids are adapted to kill prey Many arachnids are adapted to kill prey

with with poisenpoisen glands, stingers or fangs.glands, stingers or fangs.

ScorpionsScorpions

�� Scorpions are Scorpions are arachnids that have a arachnids that have a

sharp, poisonsharp, poison--filled stinger at the end filled stinger at the end

of their abdomenof their abdomen..

�� Scorpions have a pair of wellScorpions have a pair of well--developed developed

appendagesappendages——pincerspincers–– with which they with which they

grab their prey. grab their prey.

SpidersSpiders

�� Spiders cannot chew their food, so they Spiders cannot chew their food, so they

release enzymes into their prey that help release enzymes into their prey that help

digest it.digest it.

�� Gases are exchanged in Gases are exchanged in book lungsbook lungs. .

Openings in the abdomen allow the gases Openings in the abdomen allow the gases

to move into the book lungs.to move into the book lungs.

MitesMites

�� Most mites are plant and animal parasites.Most mites are plant and animal parasites.

�� However, some are not parasites. Some However, some are not parasites. Some

mites live in the follicles of human mites live in the follicles of human

eyelashes.eyelashes.

�� Most mites are so small that they look like Most mites are so small that they look like

tiny specs of dust. tiny specs of dust.

TicksTicks

�� All ticks are All ticks are parasitesparasites. .

�� Ticks attach to their hosts through Ticks attach to their hosts through

specialized mouthparts.specialized mouthparts.

�� Ticks often carryTicks often carry bacteriabacteria and and viruses viruses

that can cause disease in other animals. that can cause disease in other animals.

Centipedes and MillipedesCentipedes and Millipedes

Centipede

Millipede


�� Centipedes and Millipedes have Centipedes and Millipedes have

–– long bodies with many segmentslong bodies with many segments

–– ExoskeletonsExoskeletons

–– Jointed legsJointed legs

–– AntennaeAntennae

–– Simple eyesSimple eyes


�� They can be found in damp environments, They can be found in damp environments,

including including wood pileswood piles, , under under

vegetationvegetation, and , and in basementsin basements..

�� Centipedes and millipedes reproduce Centipedes and millipedes reproduce

sexually.sexually.

�� They make nests for their eggs and stay They make nests for their eggs and stay

with them until they hatch.with them until they hatch.


�� Centipedes hunt for prey, which include Centipedes hunt for prey, which include

snails, slugs, and worms.snails, slugs, and worms.

�� Millipedes feed on plants and decaying Millipedes feed on plants and decaying

material.material.

CrustaceansCrustaceans

�� Crustaceans include Crustaceans include crabs, crayfish, crabs, crayfish,

shrimp, barnacles, pill bugs, and shrimp, barnacles, pill bugs, and

water fleas.water fleas.

Water Flea Barnacle Pill Bug


�� Crustaceans have Crustaceans have one or two pairs of one or two pairs of

antennae and mandiblesantennae and mandibles, which are , which are

used for crushing food.used for crushing food.

�� Most crustaceans live in water, except for Most crustaceans live in water, except for

pill bugs, which live in damp soil.pill bugs, which live in damp soil.


�� Crustaceans have five pairs of legs.Crustaceans have five pairs of legs.

–– The first pair are The first pair are claws to catch and hold claws to catch and hold

food.food.

–– The other four pairs are The other four pairs are walking legswalking legs..


�� Crustaceans have 5 pairs of appendages Crustaceans have 5 pairs of appendages

calledcalled swimmerets..

–– Swimmerets help with movement and Swimmerets help with movement and

reproduction.reproduction.

�� Crustaceans have Crustaceans have feathery gillsfeathery gills for gas for gas

exchange.exchange.

�� Crustaceans can also regenerate Crustaceans can also regenerate

appendages.appendages.

Value of ArthropodsValue of Arthropods

�� Arthropods are a source of food for many Arthropods are a source of food for many

animals.animals.

�� Insects pollinate crops which help produce Insects pollinate crops which help produce

food for humans.food for humans.

�� Arthropods produce products for humans Arthropods produce products for humans

like silk and honey.like silk and honey.

Harmful ArthropodsHarmful Arthropods

�� Arthropods can be pests and destroy food, Arthropods can be pests and destroy food,

clothing and property.clothing and property.

Harmful ArthropodsHarmful Arthropods

�� Many arthropods such as mosquitoes, Many arthropods such as mosquitoes,

tsetse flies, fleas, and ticks carry diseases.tsetse flies, fleas, and ticks carry diseases.

Controlling InsectsControlling Insects

�� One common way to control insects is One common way to control insects is

insecticides. insecticides.

–– However many insecticides kill helpful insects However many insecticides kill helpful insects

as well as harmful ones.as well as harmful ones.

–– Insecticides can also pollute the environment.Insecticides can also pollute the environment.

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