Transcript Section 28.1 Summary – pages 741 - 746

Section Objectives: 28.1
• Relate the structural and behavioral
adaptations of arthropods to their ability
to live in different habitats.
• Analyze the adaptations that make
arthropods an evolutionarily successful
phylum.
• A typical _______ is a segmented,
_______ invertebrate animal
with________ symmetry, an exoskeleton,
and jointed structures called appendages.
• An _______ is any
structure, such as a
leg or an antenna,
that grows out of the
body of an animal.
• Arthropods are the earliest known
_________ to exhibit jointed appendages.
• Joints are advantageous because they allow
more flexibility in animals that have hard,
rigid __________.
• Joints also
allow powerful
movements of
appendages,
and enable an
appendage to be
used in many
different ways.
• The exoskeleton is a hard, thick, outer
covering made of ______ and ____ (KI tun).
• In some species, the exoskeleton is a
continuous covering over most of the body.
• In other species, the exoskeleton is made of
separate ______ held together by hinges.
• The exoskeleton protects and supports
internal tissues and provides places for
attachment of _______.
• In many aquatic species, the exoskeletons
are reinforced with ________ ____.
• _________ have their disadvantages.
• First, they are relatively _____ structures.
The larger an arthropod is, the ______ and
heavier its exoskeleton must be to support
its larger muscles.
• A second and more important disadvantage
is that exoskeletons cannot _____, so they
must be ___ periodically. Shedding the old
exoskeleton is called _______.
• When the new ________ is ready, the
animal contracts muscles and takes in air
or water.
• This causes the animal’s body to swell
until the old exoskeleton splits open,
usually along the back.
• Before the new exoskeleton hardens, the
animal puffs up as a result of increased
_______ circulation to all parts of its body.
• Thus, the new exoskeleton hardens in a
________ size, allowing some room for the
animal to continue to grow.
• Most arthropods ____ four to seven times in
their lives before they become adults.
• When the new exoskeleton is soft,
arthropods cannot _____ themselves from
danger because they move by bracing
muscles against the _____ exoskeleton.
• In most groups of arthropods, segments have
become fused into three body sections—_____,
_____, and ______.
• In other groups,
even these
segments may
be fused.
• Some
__________
have a head and
a fused thorax
and abdomen.
• In other groups, there is an abdomen and a
fused head and thorax called a
________________.
• Fusion of the body segments is related to
movement and protection.
• ________ have efficient respiratory
structures that ensure rapid oxygen
delivery to cells.
• This large oxygen demand is needed to
sustain the high levels of ________
required for rapid movements.
• Three types
of respiratory
structures
have evolved
in arthropods:
____, ___
tubes, and
____ lungs.
• _____
arthropods
exchange gases
through _____,
which extract
oxygen from
water and release
carbon dioxide
into the water.
• Land arthropods have either a system of
______ tubes or _____ lungs.
• Most insects have _______ tubes, branching
networks of hollow air passages that carry air
throughout the body.
• Muscle activity helps pump the air through
the ______ tubes.
• Air enters and leaves the tracheal tubes
through openings on the thorax and
abdomen called _______.
• Most _____ and their relatives have book
lungs, air-filled chambers that contain leaflike
plates.
• The stacked plates of a ____ lung are arranged
like pages of a book.
• Movement, sound, and chemicals can be
detected with great sensitivity by ______,
stalk-like structures that detect changes in the
environment.
• Antennae are also used for ____ and ____
communication among animals.
• Have you ever watched as
a group of ants carried
home a small piece of
food?
• The ants were able to work together as a
group because they were communicating
with each other by ______, chemical odor
signals given off by animals.
• _________ sense the odors of pheromones.
• Accurate vision is also important to the
active lives of arthropods.
• Most arthropods have one pair of large
_________eyes and three to eight ______
eyes.
• A simple eye is a visual structure with only
one ____ that is used for detecting light.
• A ________ eye is a visual structure with
many lenses.
• Each lens registers light from a tiny
portion of the field of view.
• The total image that is formed is made up
of thousands of parts.
• The nervous system consists of a double
_______ nerve cord, an _____ brain, and
several ______.
• Arthropods have ganglia that have become
fused. These ganglia act as control centers for
the body section in which they are located.
• Arthropod blood is pumped by a heart in an
_____ circulatory system with vessels that
carry blood away from the heart.
• The blood flows out of the ______, bathes the
tissues of the body, and returns to the heart
through open body spaces.
• Arthropods have a complete _______ system
with a mouth, stomach, intestine, and anus,
together with various glands that produce
digestive ________.
• The mouthparts of most arthropod groups
include one pair of jaws called ___________.
• The mandibles, together with other mouthparts
are adapted for holding, chewing, sucking, or
biting the various foods eaten by arthropods.
• Most ______ arthropods excrete wastes
through _______ tubules.
• In insects, the tubules are all located in the
_______ rather than in each segment.
• Malpighian tubules are attached to and empty
into the _______.
• Another well-developed system in
arthropods is the ______ system.
• In an arthropod limb, the muscles are
attached to the inner surface of the
___________.
• An arthropod muscle is attached to the
exoskeleton on both sides of the joint.
• Most arthropod species have separate males
and females and reproduce _______.
• Fertilization is usually _______ in land
species but is often _______ in aquatic
species.
• Some species, including bees, ants, aphids,
and wasps, exhibit ______________, a form
of asexual reproduction in which a new
individual develops from an unfertilized
egg.
Section Objectives: 28.2
• Compare and contrast the similarities and
differences among the major groups of
arthropods.
• Explain the adaptations of insects that
contribute to their success.
• ___ and ____ differ from spiders in that
they have only one body section.
tick
• The head, thorax, and abdomen are
completely fused.
• Ticks feed on ____ from reptiles, birds,
and mammals.
• ___ feed on fungi, plants, and animals.
• They are so small that they often are not
visible to the unaided human eye.
• Like ticks, mites can transmit ______.
• _______ are easily
recognized by their
many abdominal body
segments and enlarged
________.
• They have a long tail
with a _______
stinger at the tip.
• ______ (krus TAY
shuns) are the only
arthropods that
have two pairs of
antennae for
sensing.
• All crustaceans have ________ for
crushing food and typically have two
compound eyes.
• Unlike the up-and-down movement of
your jaws, crustacean mandibles open
and close from ____ to _____.
• Many crustaceans have ____ pairs of
walking legs.
claw
legs
• The first pair of walking legs are often
modified into strong ______ for defense.
• Members of the class _______ include crabs,
lobsters, shrimps, crayfishes, water fleas, pill
bugs, and barnacles.
• Most crustaceans are _____ and exchange
gases as water flows over feathery ____.
• __ bugs and ___bugs, two of the few
land crustaceans, must live where there
is _______, which aids in gas exchange.
• Like spiders, ______ and ______ have
Malpighian tubules for excreting wastes.
• In contrast to spiders, centipedes and
millipedes have _______ tubes rather than
book lungs for gas exchange.
• Centipedes are ___________ and eat soil
arthropods, snails, slugs, and worms
• The ____ of some centipedes are painful
to humans.
• A millipede eats mostly plants and dead
material on damp forest floors.
• _______ do not bite, but they can spray
foul-smelling fluids from their defensive
_____ glands.
• __________ crabs are members of the class
__________.
• Horshoe crabs are considered to be living
fossils; Limulus fossils have remained
relatively unchanged since the ______
Period about 220 million years ago.
• Horseshoe crabs are heavily protected by an
extensive __________ and live in deep coastal
waters.
• They forage on sandy or muddy ocean
bottoms for algae, _______, and mollusks.
• Flies, grasshoppers, lice, butterflies, bees, and
beetles are just a few members of the class
_______.
• Insects have ____ body segments and ___
legs.
• There are more ______ of insects than all
other classes of animals combined.
• Insects usually mate _____ during their
lifetime.
• The eggs usually are ______ internally.
• Some insects exhibit ___________,
reproducing from unfertilized eggs.
• Most insects lay a
____ number of
eggs, which increase
the chances that
some offspring will
survive long enough
to reproduce.
• After eggs are laid, the insect _______
develops and the eggs hatch.
• In some _______ insects development is
direct; the eggs hatch into miniature forms
that look just like tiny adults.
Nymph
Molt
Eggs
Nymph
Molt
Adult
• These insects
go through
successive
___ until the
adult size is
reached.
• In some cases,
the adult insect
bears little
resemblance to
its ________
stage.
Adult
Egg
Pupa
Larva
• This series of changes, controlled by
chemical-substances in the animal, is
called _______________.
• Insects that undergo metamorphosis usually
go through four stages on their way to
adulthood: ___, _____, ____, and ______.
• Other insects that undergo complete
metamorphosis include ants, beetles, flies,
and wasps.
• Many insect species, as well as other
arthropods, undergo a gradual or incomplete
metamorphosis, in which the insect goes
through only _____ stages of development.
• These three stages are ___, ______, and adult.
Nymph
Molt
Eggs
Nymph
Molt
Adult
• A _____, which
hatches from an
egg, has the
same general
appearance as
the adult but
is smaller.
• ________ cannot reproduce.
• As the nymph eats and grows, it molts several
times. With each _____, it begins to resemble
the adult more.
• Gradually, the nymph becomes an adult.
• Grasshoppers and cockroaches are insects that
undergo ________ metamorphosis.
Incomplete metamorphosis of a harlequin bug
• The success of arthropods can be attributed
in part to their varied life cycles, high
reproductive output, and structural
adaptations, such as small size, a hard
exoskeleton, and jointed appendages.
• Arthropods most likely evolved from an
ancestor of the _______.
• Segments in arthropods are more complex than
in annelids, and arthropods have more
developed _____ tissue and sensory organs,
such as eyes.
• The exoskeleton of arthropods provides
_______ for their soft bodies.
• Muscles in arthropods are arranged in _____
associated with particular segments and
portions of appendages.
• The circular muscles of _______ do not
exist in arthropods.
• Because arthropods have many hard parts,
much is known about their evolutionary
history.