Download What Is an Arthropod?

Biology
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Copyright Pearson Prentice Hall
28-1 Introduction to the
Arthropods
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
What Is an Arthropod?
What are the main features of
arthropods?
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
What Is an Arthropod?
What Is an Arthropod?
1. have a segmented body, a tough
exoskeleton made of chitin, and jointed
appendages.
(Arthropods include insects, crabs, centipedes,
and spiders.)
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28-1 Introduction to the Arthropods
Evolution of
Arthropods
Evolution of Arthropods
Fossilized Trilobites
2. Led to:
*fewer body segments
*highly specialized
appendages
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
3.Feeding
(Arthropods include herbivores, carnivores, and
omnivores. There are filter feeders, detritivores,
and parasites.)
*mouthparts are adapted to the type of food it eats.
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
4. Respiration
Most aquatic,
breathe through
featherlike gills
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
5. Circulation
open circulatory
system.
(The heart pumps blood
through arteries that
branch and enter the
tissues. Blood collect in
large sinus around the
heart and re-enter it)
Heart
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
6. Excretion
diffusion moves wastes from the body into the
surrounding water.
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
Brain
7. Response
a. Most have a welldeveloped nervous
system.
b. All arthropods have a
brain that connects to a
ventral nerve cord
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
c. Most have
sophisticated sense
organs such as
compound eyes.
Form and Function in
Arthropods
Compound eyes
(Compound eyes may
have more than 2000
separate lenses and can
detect color and motion
very well.)
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
8. Movement
well-developed groups of muscles that are
coordinated and controlled by the nervous system.
(Muscles generate force by contracting and then
pulling on the exoskeleton.)
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
(At each body joint, different muscles either flex
(bend) or extend (straighten) the joint.)
Flexed
Extended
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Form and Function in
Arthropods
9. Reproduction
Aquatic- may have internal or external fertilization.
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Growth and Development
in Arthropods
What happens when an arthropod
outgrows its exoskeleton?
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Growth and Development
in Arthropods
Growth and Development in Arthropods
10. When they outgrow their exoskeletons,
arthropods undergo periods of molting.
(During molting, an arthropod sheds its
entire exoskeleton and manufactures a larger
one to take its place. )
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Copyright Pearson Prentice Hall
28-1 Introduction to the Arthropods
Growth and Development
in Arthropods
(Molting is controlled by the arthropod's endocrine
system.
Most arthropods molt several times.
The arthropod is vulnerable to predators while its
shell is soft.)
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28-1 Introduction to the Arthropods
Growth and Development
in Arthropods
(Skin glands digest the inner part of the exoskeleton,
and other glands secrete a new skeleton.
When the new exoskeleton is ready, the animal pulls
itself out of what remains of the original skeleton.)
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28–1
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28–1
The mouthparts of arthropods are
a. similar in all species.
b. adapted to enable different species to eat
different foods.
c. adapted to enable different species to
respire in different ways.
d. useful for locomotion as well as feeding.
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Arthropods have open circulatory systems,
which means that blood
a. leaves the blood vessels, flows through
sinuses, and then returns to the heart.
b. flows from the heart directly into sinuses and
then returns to the heart.
c. never leaves the circulatory system.
d. vessels open to the external environment.
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Characteristics which define the arthropods
include
a. an endoskeleton made of chitin and jointed
appendages.
b. an endoskeleton made of chitin and six pairs
of appendages.
c. an exoskeleton made of chitin and jointed
appendages.
d. an exoskeleton made of chitin and
Malpighian tubules.
Copyright Pearson Prentice Hall
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What type(s) of fertilization do terrestrial
arthropods have?
a. internal
b. external
c. both internal and external
d. hermaphroditic
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What happens to the exoskeleton of an
arthropod as the animal grows?
a. It remains soft until the animal reaches
adulthood.
b. It develops additional body segments.
c. It softens and stretches to a larger size.
d. It is discarded and replaced by a new, larger
exoskeleton.
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