1. The passage discusses the anatomy and characteristics of various invertebrate phyla, including Arthropods, Nematodes, and Myriapods. 2. It describes the adaptations of spiders, including their ability to produce silk from specialized abdominal glands to construct webs and lines. 3. The passage also discusses parasitic nematodes that infect humans, including the life cycle of the Trichinella spiralis worm which can be contracted by eating undercooked pork.

1. r;;==; face area of these respiratory organs is a structural adaptation by
Calcarea and Silicea Although defined primarily
that enhances the exchange of O2 and CO 2 between the he-
Cmdana molecular evidence, the dade
planet and many onts features. These free-living worms
Biology II - Zoology
important role in decomposition and nutrient cycling, b
molymph and air.
Lopholnxhowa
Ecdysozoa includes catch animals is known about most species. One species of soil nem
Invertebrates
A unique adaptation of many spiders is the ability toPoison
Ecdysozoa
insects by constructing webs of silk, a liquid tough external coat
Deuterostorma that shed a protein produced
gland Caellorhabditis elegalls, however, is very well studied a
by specialized abdominal glands. The silk isthey grow; in fact,
(cuticle) as spun by organs
Arthropods into fibers that then solidify. Each spider en- become a model research organism in biology (see Chap
called spinnerets
the group derives its name fromitsthis process, which is called
gineers a web characteristic of species and builds it perfectly Myriapods
Ongoing studies on C. elegans are revealing some of the
molting,on the first try. This complex behavior is of about eight animal
or ecdysis. Ecdysozoa consists apparently inherited. anisms involved in aging in humans, among other findin
Various spiders also use silk species than droplines for
phyla and contains mOTe knownin other ways: asall other protist, Phylum Nematoda includes many significant agric
s All living myriapods are terrestrial. The myriapod head has
rapid escape, as a cover for eggs, and even as Pedipalp for food
fungus, plant, and animal groups Chelicera combined. Here we'll focus
that males offerSperm during courtship. Many small spiders
females
pests that attack the roots ofplants. Other species of nem
Silk gland
a pair of antennae and three pairs of appendages modified
on the two extrude silkreceptacle air and let themselves be transported and
also largest e<dysozoan phyla, the nematodes
into the parasitize animals. Humans are hosts to at least 50 nem
arthropods, which are among the most successful and abun- ... Figure :n.:n A including various pinworms and hookworms. O
3.32 Anatomy of a a behavior known as
by wind, spider. species, millipede.
dant of all animal as mouthparts, including the jaw-like mandibles. spiralis, the worm that
groups. torious nematode is Trichinella
Myriapods trichinosis (Figure 33.26). Humans acquire this nemat
tained
Nematodes and centipedes belong to the subphylum Myriapoda,
ve sur-
Millipedes eating raw or undercooked pork or other meat (includin
tation the myriapods. All living myriapods are terrestrial. The myria- game such as bear or walrus) that has juvenile worms en
Some
he he- ofpod head has aubiquitous animals, nematodes (phylum
the most pair of antennae and three pairs of appendages
in the muscle tissue. '(!ithin the human intestines, the ju
Nematoda), or roundworms,including the in most aquatic habitats,
modified as mouthparts, are found jaw-like mandibles.
develop into sexually mature adults. Females burrow i
in the soil, in the moist tissues of plants, and in the bodyof
catch Millipedes (class Diplopoda) have a large number fluids
duced legs, though fewer than the thousand their name implies intestinal muscles and produce more juveniles, whic
and tissues of animals.Eachcontrast to annelids, nematodes do
organs (Figure 33.33).
In trunk segment is formed from two
through the body or travel in lymphatic vessels to other
der en-havefused segmentsbodies. The cylindrical bodies ofeat
not segmented and bears two pairs of legs. Millipedes nema-
including skeletal muscles, where they encyst.
rfectly range fromleavesthanother plant matter. than a meter in length,
todes decaying less and 1 mm to more They may have been
erited.
often tapering to aearliesttip at the posterior end mosses andmore
among the
fine animals on land, living on and to a
1 leg pair /
Parasitic nematodes have an extraordinary mo
nes for
2 leg pairs / segment
primitive vascular plants.
or food tip at Unlike millipedes, centipedes (class Chilopoda) are carni-body
blunt the anterior end (Figure 33.25). A nematode's segment
toolkit that enables them to redirect some of the cellula
tions of their hosts and thus evade their immune sy
is covered by a tough cuticle; centipede's trunkgrows,has periodically
piders vores. Each segment ofa as the worm region it one pair
ported its oflegs (Figureand secretes a new, larger one. Nematodes
Plant-parasitic nematodes inject molecules that indu
sheds old Figure :n.:n A millipede. have poison claws on their
cuticle 33.34). Centipedes
...
Millipede
foremost trunk segment that paralyze prey and aid in defense.
have an alimentary canal, though they lack a circulatory system. ... Centipede
Figure 33.34 A centipede.root cells, which then supply nutrients
development of
parasites. Trichinella controls the expression of s
(Class Diplopoda)
Nutrients are transported throughout the body via fluid in the
pseudocoelom. The body wall muscles are all longitudinal, and
(Class Chilopoda)
muscle-cell genes that codeInvertebrates 687 make the ce
CHAPTER THIRTY·THREE for proteins that
apoda, April 13, 2010
Tuesday, tic enough to house the nematode. Additionally, the in

2. r;;==; Although defined primarily by
Calcarea and Silicea
Cmdana molecular evidence, the dade
planet and many onts features. These free-living worms
Biology II - Zoology
important role in decomposition and nutrient cycling, b
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma Invertebrates
that shed a tough external coat Caellorhabditis elegalls, however, is very well studied a
Arthropods (cuticle) as they grow; in fact, become a model research organism in biology (see Chap
the group derives its name from this process, which is called Insects
Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal anisms involved in aging in humans, among other findin
phyla and contains mOTe known species than all other protist, Phylum Nematoda includes many significant agric
fungus, plant, and animal groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
on the two largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least 50 nem
Insects and their relatives (subphylum Hexapoda)
arthropods, which are among the most successful and abun- species, including various pinworms and hookworms. O
are more species-rich than all other forms of life
dant of all animal groups. torious nematode is Trichinella spiralis, the worm that
trichinosis (Figure 33.26). Humans acquire this nemat
combined. They live in almost every terrestrial habitat
Nematodes eating raw or undercooked pork or other meat (includin
game such as bear or walrus) that has juvenile worms en
Nematoda), or roundworms, are found in most aquatic habitats, insects fill the air. Insects
and in fresh water, and flying
Some of the most ubiquitous animals, nematodes (phylum
in the muscle tissue. '(!ithin the human intestines, the ju
develop into sexually mature adults. Females burrow i
are of animals. though annelids, absent, in marine habitats, where
rare, In contrast to not nematodes do
in the soil, in the moist tissues of plants, and in the body fluids
and tissues
intestinal muscles and produce more juveniles, whic
crustaceans are the dominant arthropods.
not have segmented bodies. The cylindrical bodies of nema-
through the body or travel in lymphatic vessels to other
including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
Parasitic nematodes have an extraordinary mo
often tapering to a fine tip at the posterior end and to a more
toolkit that enables them to redirect some of the cellula
blunt tip at the anterior end (Figure 33.25). A nematode's body
tions of their hosts and thus evade their immune sy
is covered by a tough cuticle; as the worm grows, it periodically
Plant-parasitic nematodes inject molecules that indu
sheds its old cuticle and secretes a new, larger one. Nematodes
development of root cells, which then supply nutrients
have an alimentary canal, though they lack a circulatory system.
parasites. Trichinella controls the expression of s
Nutrients are transported throughout the body via fluid in the
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall muscles are all longitudinal, and
Tuesday, April 13, 2010 tic enough to house the nematode. Additionally, the in

3. r;;==; Calcarea and Silicea
Cmdana
Although defined primarily by
molecular evidence, the dade
planet and many onts features. These free-living worms
Biology II - Zoology
important role in decomposition and nutrient cycling, b
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma that shed a tough external coat Invertebrates
Caellorhabditis elegalls, however, is very well studied a
Arthropods (cuticle) as they grow; in fact, become a model research organism in biology (see Chap
the group derives its body has three regions: head,
The insect
name from this process, which is called Insects
Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal
thorax, and abdomen. The segmentation anisms involved in aging in humans, among other findin
of the thorax and abdomen are obvious,
phyla and contains segmentsknown speciesare fused. other protist,
but the mOTe that form the head than all Phylum Nematoda includes many significant agric
fungus, plant, and animal groups combined. Here we'll focus
Abdomen Thorax Head
pests that attack the roots ofplants.nerve species of nem
Cerebral ganglion. The two Other
cords meet in the head, where the
.. ...............
on the two largest e<dysozoan phyla, the nematodes and Heart. The parasitize animals. Humans are hosts to at least 50 nem
insect heart ganglia of several anterior segments
Compound eye
drives hemolymph are fused into a cerebral ganglion
arthropods, which are among the most successful and abun- through an open species, including variouswhite below). The hookworms. O
(brain, colored pinworms and
circulatory system. antennae, eyes, and other sense
dant of all animal groups. organs Trichinella spiralis,
torious nematode isare concentrated on the head.the worm that
trichinosis (Figure 33.26). Humans acquire this nemat
Nematodes eating raw or undercooked pork or other meat (includin
Anus
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
Malpighian tubules. in the muscle tissue. '(!ithin the human intestines, the ju
Nematoda), or roundworms, are foundVagina
Metabolic wastes are in most aquatic habitats,
develop into sexually mature adults. Females burrow i
in the soil, in the moist tissues the plants, and in the body fluids
removed from
of
organs called by contrast
hemolymph Malpighian intestinal muscles and produce more juveniles, whic
and tissues of animals. In which are to annelids, nematodes do
tubules, through the body or travel in lymphatic vessels to other
not have segmented bodies.of the cylindrical bodies of nema-
out-pocketings The
digestive tract. including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
Parasitic nematodes have an extraordinary mo
often tapering to a fine tip Tracheal tubes. Gas exchange and to is more
at the posterior end in insects a Insect mouthparts are formed from
Nerve cords. The insect enables pairs of modified appendages. of the cellula
toolkit that several them to redirect some
blunt tip at the anterior end accomplished by athat infiltrate theofbody and
tracheal system branched.
(Figure 33.25). A nematode's body nervous system
chitin-lined tubes
tions of their The mouthparts include for chewing.
mandibles,
hosts and thus evade their immune sy
is covered by a tough cuticle; as oxygen directlygrows,The periodically consists nervepair of
carry the worm to cells. it tracheal
system opens to the outside of the body ventral
of a
cords
which grasshoppers use
through spiracles, larger one. control air Plant-parasitic nematodes inject are
with several
In other insects, mouthparts molecules that indu
new, pores that can closing .
sheds its old cuticle and secretes awater loss by opening orNematodes segmental ganglia.
flow and
specialized for lapping, piercing,
development ofsucking.cells, which then supply nutrients
or root
have an alimentary canal, though they lack a circulatory system.
... Figure 33.35 Anatomy of a grasshopper, an insect. parasites. Trichinella controls the expression of s
Nutrients are transported throughout the body via fluid in the
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall muscles are all longitudinal, and
Insects
Tuesday, April 13, 2010 tic enough to house the nematode. Additionally, the in

4. r;;==; Although defined primarily by
Calcarea and Silicea
Cmdana molecular evidence, the dade
planet and many onts features. These free-living worms
Biology II - Zoology
important role in decomposition and nutrient cycling, b
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma that shed a tough external coatInvertebrates
Caellorhabditis elegalls, however, is very well studied a
Arthropods (cuticle) as they grow; in fact, become a model research organism in biology (see Chap
the group derives its name from this process, which is called Insects
Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal anisms involved in aging in humans, among other findin
phyla and contains mOTe known species than all other protist, Phylum Nematoda includes many significant agric
Oldest insect fossils: Devonian (~416 Ma)
fungus, plant, and animal groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
on the two largest e<dysozoan phyla, the Carboniferous and Permia
Evolution of insect flight: nematodes and parasitize animals. Humans are hosts to at least 50 nem
arthropods, which are among the most successful and abun- species, including various pinworms and hookworms. O
dant of all animal groups. explosion in insect diversity. torious nematode is Trichinella spiralis, the worm that
trichinosis (Figure 33.26). Humans acquire this nemat
Jurrassic beetle
Nematodes eating raw or undercooked pork or other meat (includin
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
Carboniferous dragonfly
in the muscle tissue. '(!ithin the human intestines, the ju
Nematoda), or roundworms, are found in most aquatic habitats,
develop into sexually mature adults. Females burrow i
in the soil, in the moist tissues of plants, and in the body fluids
intestinal muscles and produce more juveniles, whic
Fossil record of insect mouthparts indicates specialized feeding on
and tissues of animals. In contrast to annelids, nematodes do
not have segmented bodies. The cylindrical bodies of nema-
through the body or travel in lymphatic vessels to other
gymnosperms and other Carboniferous plants contributed to early
todes range from less than 1 mm to more than a meter in length,
including skeletal muscles, where they encyst.
Parasitic nematodes have an extraordinary mo
adaptive radiations
often tapering to a fine tip at the posterior end and to a more
blunt tip at the anterior end (Figure 33.25). A nematode's body
toolkit that enables them to redirect some of the cellula
tions of their hosts and thus evade their immune sy
is covered by a tough cuticle; as the worm grows, it periodically
Plant-parasitic nematodes inject molecules that indu
Major increase in insect diversity stimulated by the evolutionary
sheds its old cuticle and secretes a new, larger one. Nematodes
have an alimentary canal, though they lack a circulatory system.
development of root cells, which then supply nutrients
expansion of flowering plants during the mid-Cretaceous (~ 90 Ma).
Nutrients are transported throughout the body via fluid in the
parasites. Trichinella controls the expression of s
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall muscles are all longitudinal, and
Tuesday, April 13, 2010 tic enough to house the nematode. Additionally, the in

5. r;;==; Although defined primarily by
Calcarea and Silicea
Cmdana molecular evidence, the dade
planet and many onts features. These free-living worms
Biology II - Zoology
important role in decomposition and nutrient cycling, b
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma that shed a tough external coatInvertebrates
Caellorhabditis elegalls, however, is very well studied a
Arthropods (cuticle) as they grow; in fact, become a model research organism in biology (see Chap
the group derives its name from this process, which is called Insect flight
Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal anisms involved in aging in humans, among other findin
phyla and contains mOTe known species than all other protist, Phylum Nematoda includes many significant agric
•one key to great success ofand insects
fungus, plant, and animal groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
•facilitates escape successful and abun-
on the two largest e<dysozoan phyla, the nematodes parasitize animals. Humans are hosts to at least 50 nem
arthropods, which are among the most from many predators species, including various pinworms and hookworms. O
• animal groups.
dant of all facilitates discovery of food and mates torious nematode is Trichinella spiralis, the worm that
Nematodes•facilitates dispersal to new habitats trichinosis (Figure 33.26). Humans acquire this nemat
eating raw or undercooked pork or other meat (includin
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
•one or two pairs of wings emerging from the dorsal side of
Nematoda), or roundworms, are found in most aquatic habitats,
in the muscle tissue. '(!ithin the human intestines, the ju
develop into sexually mature adults. Females burrow i
the thorax
in the soil, in the moist tissues of plants, and in the body fluids
and tissues of animals. In contrast to annelids, nematodes do
intestinal muscles and produce more juveniles, whic
through the body or travel in lymphatic vessels to other
not have segmented bodies. The cylindrical bodies of nema-
including skeletal muscles, where they encyst.
•because wings are extensions of the cuticle and not true
todes range from less than 1 mm to more than a meter in length,
often tapering to a fine tip at the posterior end and to a more
Parasitic nematodes have an extraordinary mo
appendages, insects can fly without sacrificing any walking
blunt tip at the anterior end (Figure 33.25). A nematode's body
toolkit that enables them to redirect some of the cellula
tions of their hosts and thus evade their immune sy
legs
is covered by a tough cuticle; as the worm grows, it periodically
Plant-parasitic nematodes inject molecules that indu
sheds its old cuticle and secretes a new, larger one. Nematodes
development of root cells, which then supply nutrients
have an alimentary canal, though they lack a circulatory system.
parasites. Trichinella controls the expression of s
Nutrients are transported throughout the body via fluid in the
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall muscles are all longitudinal, and
Tuesday, April 13, 2010 tic enough to house the nematode. Additionally, the in

6. r;;==; Calcarea and Silicea
Cmdana
Although defined primarily by
Biology II - Zoology
molecular evidence, the dade
planet and many onts features. These free-living worms
important role in decomposition and nutrient cycling, b
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma that shed a tough external coat Invertebrates Caellorhabditis elegalls, however, is very well studied a
Arthropods (cuticle) as they grow; in fact, become a model research organism in biology (see Chap
the group derives its name from this process, which is called
Exploring Insect Diversity Insects Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal anisms involved in aging in humans, among other findin
phyla ,and contains mOTe known species than all other protist, Phylum Nematoda includes many significant agric
Approximate
fungus, plant, and animal groups combined. Here we'll focus
Order Number of Main Characteristics attack the roots ofplants. Other species of nem
pests that
Examples
on the two largest e<dysozoan phyla, the nematodes and
Species parasitize animals. Humans are hosts to at least 50 nem
arthropods, which are among the most successful and abun- species, including various pinworms and hookworms. O
dant of8lattodea groups. 4,""
all animal Cockroaches ha'c a dorso'entrally torious nematode is Trichinella spiralis, the worm that
body, with lqs
modified for rapid running. Forewings hen present, are leath·
ery, ",ilereas hind wings are fan6J.:e. F trichinosis (Figure 33.26). Humans acquire this nemat
w than 40 cockroKh German
cockroach
Nematodes habitUs raw or undercooked pork or other meat (includin
§Ilt'cies moe in houses; the rest exploit eating r.lnging from
forest floors to caves and descn.s.
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
in the muscle tissue. '(!ithin the human intestines, the ju
Nematoda), or roundworms, are found in most aquatic habitats,
Coleoptera 350.000 BcrtIcs comprise the most specks-rich Ofdcr of ins«u.sexually mature adults. Females burrow i
develop into Thq-
in the soil, in the moist tissues of plants, and in''''-0 pairs of ",;ngs, one of.....hich is thick and stiff, the
ha'e the body fluids
intestinal muscles and produce more juveniles, whic
and tissues of animals. In contrast to annelids,membranous. lbty h;l'e an armomi nosktltton and
other nematodes do
mouthPMU adapled for biting and ehe",;ng. BertIes undergo or travel in lymphatic vessels to other
through the body
not have segmented bodies. The cylindrical bodies of nema-
complete metamorphosis.
including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
Parasitic nematodes have an extraordinary mo
often tapering to a fine tip at the posterior end and to a more
DermaptcnII 1.200 Earwigs are generally nocturnal Ka'mgers. Sotmo species are them to redirect some of the cellula
toolkit that enables
blunt tip at the anterior end (Figure 33.25).'oingless, while others ha...e Iwo p,airs of"'ings, one of ....hich is
A nematode's body
tions of their hosts and thus evade their immune sy
is covered by a tough cuticle; as the worm grows, itkoathery, the other membranous. EalVoigs have biting
thick and periodically
Plant-parasitic nematodes inject molecules that indu
mouthparts and large posterior pincer" They undergo incom-
sheds its old cuticle and secretes a new, larger one. Nematodes
plete metamorphosis. Earwig
development of root cells, which then supply nutrients
have an alimentary canal, though they lack a circulatory system.
parasites. Trichinella controls the expression of s
Nutrients are transported throughout the body via fluid in the
Diptera 151,000 Diptl"I'1UIS ha.T one pair of ..... ings;!.he muscle-cell genes that code for proteins that make the ce
SCCOlld pair has be<:OITK'
pseudocoelom. The body wall muscles are modined into balancing organs called haltcrtS. Their mouth-
all longitudinal, and
Tuesday, April 13, 2010 tic enough to house the nematode. Additionally, the in
pam are adapll'd for sucking, piercing. or lapping. Dipll."rans

7. r;;==; Although defined primarily by specks-rich Ofdcr and many onts features. These free-living worms
Calcarea and Silicea 350.000
Coleoptera
Cmdana Biology II - Zoology
BcrtIcs comprise the most
ha'e ''''-0 pairs of dade
planet of ins«u. Thq-
molecular evidence, the",;ngs, one of.....hich is thick and stiff, the decomposition and nutrient cycling, b
important role in
Lopholnxhowa other membranous. lbty h;l'e an armomi nosktltton and
Ecdysozoa mouthPMU adapled for biting and ehe",;ng. BertIes undergo
includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma tough metamorphosis.Invertebrates
that shed a completeexternal coat Caellorhabditis elegalls, however, is very well studied a
Arthropods Insect Diversity in fact,
Exploring (cuticle) as they grow; become a model research organism in biology (see Chap
the group derives its name from this process, which is called
DermaptcnII 1.200 Insects
Earwigs are generally nocturnal Ka'mgers. Sotmo species are C. elegans are revealing some of the
Ongoing studies on
molting, or ecdysis. Ecdysozoa consists of 'oingless,eightothers ha...e Iwo p,airs of"'ings, involved in aging in humans, among other findin
, about while animal anisms one of ....hich is
Approximate thick and koathery, the other membranous. EalVoigs have biting includes many significant agric
phyla and contains mOTe known species than all other protist,
mouthparts and large posterior pincer" Phylum Nematoda
Order Number of Main Characteristics incom-
plete metamorphosis.
They undergo
Examples
Earwig
fungus, plant, and animal Species
groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
on the two largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least 50 nem
Cockroaches ha'c dorso'entrally species, including various pinworms and hookworms. O
arthropods, which are among4,"" most successfulha.T oneapair of .....ings;!.he SCCOlldbody,has be<:OITK'
the Diptl"I'1UIS and abun-
8lattodea with lqs
Diptera 151,000 pair
modified for rapid running. Forewings hen present, are leath·
dant of all animal groups. modined into balancing organs called haltcrtS. nematode is Trichinella spiralis, the worm that
torious Their mouth- German
ery, ",ilereas hind wings are fan6J.:e. F w than 40 cockroKh
pam are adapll'd for sucking, piercing. or lapping. Dipll."rans cockroach
trichinosis (Figure 33.26).Horsefly
§Ilt'cies moe in houses; the rest exploit habitUs r.lnging from
undergo complete metamorphosis. Flies and mosquitoes are Humans acquire this nemat
forest floors to caves and descn.s.
Nematodes eating raw or undercooked pork or other meat (includin
among the best·known dipterans, which live as scavengers.
predators. and parasites.
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
Coleoptera 350.000 BcrtIcs comprise the most specks-rich the muscle tissue. '(!ithin the human intestines, the ju
in Ofdcr of ins«u. Thq-
Nematoda), or roundworms, are found in most aquatic habitats, of.....hich is thick and stiff, the
ha'e ''''-0 pairs of ",;ngs, one
Hemiptera 85,000 develop bed sexually mature adults. Females burrow i
Hemipterans are so-called "true bugs; includingintobugs, u·
otherthe body fluids h;l'e an armomi nosktltton and
membranous. lbty
in the soil, in the moist tissues of plants, and in bugs, and chinch bugs. ([nsects in other orders are some·
sassin Leaf-
times erroneously called bugs.) Hemipterans have muscles and produce more juveniles, whic
intestinal t.....o pairs of
mouthPMU adapled for biting and ehe",;ng. BertIes undergo
and tissues of animals. In contrast to annelids, nematodes do
complete metamorphosis. footed
wings, one pair partly leathery. the other membranous. Theyor travel in lymphatic vessels to other
through the body bog
not have segmented bodies. The cylindrical bodies of sucking mouthparts and undergo incomplete
have piercing or nema-
metamorphosis. including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
DermaptcnII 1.200 Parasitic nematodes have an extraordinary mo
Earwigs are generally nocturnal Ka'mgers. Sotmo species are
often tapering to a fine tip at the posterior end and to others ha...e Iwo p,airs of"'ings, one of ....hich is
'oingless, while a more
toolkit that enables them to redirect some of the cellula
125,000 A nematode's theare membranous. EalVoigs have biting
at the anterior end (Figure 33.25). Ants, and koathery, body generally highly social insects. They
blunt tipHymenopten thick
bees, and wasps
other
mouthparts and large posterior pincer" They undergo incom- and thus evade their immune sy
tions of their hosts
is covered by a tough cuticle; as the worm grows,metamorphosis.
it periodically
have two pairs of membranous wings. a mobile head. and
plete Earwig
Plant-parasitic nematodes inject molecules that indu
chewing or sucking mouthparts. The females of many spe<ies
sheds its old cuticle and secretes a new, larger one. Nematodes
have a posterior stinging organ. Hymenopterans undergo com-
development of root cells, which then supply nutrients
have an alimentary canal, though they lack a plete metamorphosis.
circulatory system. Cicad<l-killer wasp
Diptera 151,000 parasites. Trichinella controls the expression of s
Diptl"I'1UIS ha.T one pair of ..... ings;!.he SCCOlld pair has be<:OITK'
Nutrients are transported throughout the body viainto balancing organs called haltcrtS. Their mouth-
modined fluid in the
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall 2,"" muscles are all longitudinal, andsocialpiercing.thatlapping. Dipll."rans
pam are adapll'd for sucking, or
Horsefly
Termites complete metamorphosis. tic enough to house the nematode. Additionally, the in
are Widespread
lsoptcra
Tuesday, April 13, 2010 undergo Flies produce enormous
ins«ts and mosquitoes are

8. r;;==; Hemiptera
Calcarea and Silicea
Cmdana
85,000 Hemipterans are so-called "true bugs; including bed bugs, u·
Although defined primarily by ([nsects in other orders are some· features. These free-living worms
Biology II - Zoology
sassin bugs, and chinch bugs.
times erroneously dade
planet and many onts
important role in of
Leaf-
molecular evidence, the called bugs.) Hemipterans have t.....o pairs decomposition and nutrient cycling, b
footed
Lopholnxhowa wings, one pair partly leathery. the other membranous. They bog
Ecdysozoa have piercing or sucking mouthpartsis known about most species. One species of soil nem
includes animals
Invertebrates
and undergo incomplete
Ecdysozoa
metamorphosis.
that shed a tough external coat Caellorhabditis elegalls, however, is very well studied a
Deuterostorma
Arthropods
Exploring Insect Diversity in fact,
(cuticle) as they grow; become a model research organism in biology (see Chap
Hymenopten Ants, bees, and wasps are Insects
the group derives its name from this process, which is called generally Ongoing studies on C. elegans are revealing some of the
125,000 highly social insects. They
molting, or ecdysis. Ecdysozoa consists of about eightofanimal
, have two pairs membranous wings. a mobileinvolved in aging in humans, among other findin
anisms head. and
Approximate chewingother mouthparts. The females of many spe<ies
or sucking
phyla and contains mOTe known species than all posterior protist,organ. Hymenopterans undergo com- includes many significant agric
Phylum Nematoda
have a stinging
Order Number of Main Characteristics Examples
fungus, plant, and animal Species groups combined. Here we'll focus
plete metamorphosis. pests that attack the roots ofplants. Other species of nem
Cicad<l-killer wasp
on the two largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least 50 nem
8lattodea 4,"" Cockroaches ha'c a dorso'entrally species, including various pinworms and hookworms. O
arthropods, which are among2,"" most successful and abun-social ins«ts that produce enormous
the body, with lqs
lsoptcra Termites are Widespread
modified for rapid running. Forewings hen present, are leath·
dant of all animal groups. colonies. It has been estimated that F w are 700 kg oftet'mites Trichinella spiralis, the worm that
ery, ",ilereas hind wings are fan6J.:e. torious nematode is
there
than 40 cockroKh German
for every per50Il on Earth! Some termites ha,'e t"'·o pairs of cockroach
Approximate membranous ....ings, .....the rest exploit ....ingless.r.lnging from 33.26). Humans acquire this nemat
§Ilt'cies moe in houses;
hile others aretrichinosis (Figure
habitUs
They f«d on
forest floors to caves and descn.s.
Nematodes Order Number of eating raw
aid of microbial symbionts carried in spe<ial.izcd Examples
.....ood. ....ith the Main Characteristics or undercooked pork orTerrmte meat (includin other
Species chambers in their hindgut.690
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
Coleoptera 350.000 BcrtIcs comprise the most specks-rich the muscle tissue. '(!ithin the human intestines, the ju
in Ofdcr of ins«u. Thq-
Nematoda), or roundworms, 120.000
Lepidoptera are found in most aquatic habitats, amOllg the best-knownstiff, the
ha'e ''''-0 pairs of ",;ngs, one of.....hich is thick and insects.
Butterflies and moths arc
other membranous. of ""ings covered ....ith tinyinto sexually mature adults. Females burrow i
They have two J»irslbty develop SQlI('$. To
in the soil, in the moist tissues of plants, andfeed, the body illfluids h;l'e an armomi nosktltton and
in they uncoil long proboscis. Most ft'rd on n«ur, but
mouthPMU adapled for biting and ehe",;ng. BertIes undergo and produce more juveniles, whic
intestinal muscles
and tissues of animals. In contrast to annelids, species feed on other substan<:es. including animal
$Orne nematodes do
complete metamorphosis.
blood or tears. through the body or travelSwallowtaIl
in lymphatic vessels to other
not have segmented bodies. The cylindrical bodies of nema- butterfly
690 UNIT fiVE The Evolutionary History of Biological Diversity including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
DermaptcnII 1.200 Parasitic nematodes have an extraordinary mo
Earwigs are generally nocturnal Ka'mgers. Sotmo species are
often tapering to a fine tip at the posterior end and to others ha...e Iwo p,airs of"'ings, one of ....hich is
'oingless, while a more
toolkit that enables them to redirect some of the cellula
thick and koathery, the other membranous. EalVoigs
blunt tipOdonalaanterior end (Figure 33.25). A nematode's body han' two J»irs of large. have biting
at the 5.000 Dragonflies and damselflies
nous '>lings. and large posterior pincer" They undergo incom- and thus evade their immune sy
mouthparts They N'''' an dongakdtions of Large. com-
abdomen. their hosts
is covered by a tough cuticle; as the worm grows,metamorphosis. mouthparts. They undcrgo
plete
pound it periodically
and cheo.ooing Earwig
Plant-parasitic nematodes inject molecules that indu
sheds its old cuticle and secretes a new, larger one. Nematodes and arc active predators.
incompktt metamorphosis
development of root cells, which then supply nutrients
Dragoofty
have an alimentary canal, though they lack a circulatory system.
Diptera 151,000 parasites. Trichinella controls the expression of s
Diptl"I'1UIS ha.T one pair of ..... ings;!.he SCCOlld pair has be<:OITK'
Nutrients are transported throughout the body viainto balancing organs called haltcrtS. Their mouth-
modined fluid in the
muscle-cell genes that code for proteins that make the ce
Grasshoppers. crickcu. and piercing. or alt' mostly herbr.'O-
pseudocoelom. The body wall13.000 muscles are all longitudinal, and their rdatin'$ lapping. Dipll."rans
pam are adapll'd for sucking,
Horsefly
Tuesday, April 13, 2010 rous. They have Large hind Iq;s adapted enough to house the nematode. Additionally, the in
undergo complete metamorphosis. tic for jumping. '....0 are
Flies and mosquitoes pairs

9. r;;==; Calcarea and Silicea Although defined primarily by covered ....ith tiny SQlI('$. To onts features. These free-living worms
They have two J»irs of ""ings
Biology II - Zoology
planet and many
feed, they uncoil ill long proboscis. Most ft'rd on n«ur, but
molecular evidence, the on other substan<:es. including animalin decomposition and nutrient cycling, b
$Orne species feed dade
Cmdana important role
Lopholnxhowa SwallowtaIl
Ecdysozoa blood or tears. animals
includes is known about most species. One species of soil nem
Invertebrates
Ecdysozoa butterfly
Deuterostorma that shed a tough external coat Caellorhabditis elegalls, however, is very well studied a
Arthropods Insect Diversity in fact,
Exploring (cuticle) as they grow; become a model research organism in biology (see Chap
Odonala 5.000 Insects
the group derives its name from this process, which isdamselflies han' two J»irs of large.
Dragonflies and called Ongoing studies on C. elegans are revealing some of the
molting, or ecdysis. Ecdysozoa consists of about eight animal dongakdanisms involved in aging in humans, among other findin
, nous '>lings. They N'''' an abdomen. Large. com-
Approximate than all other protist,mouthparts. They undcrgoNematoda includes many significant agric
pound and cheo.ooing
phyla and contains mOTe known species incompktt metamorphosis and arc active predators. Phylum
Order Number of Main Characteristics Examples
fungus, plant, and animal Species groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
Dragoofty
on the two largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least 50 nem
8lattodea 13.000 Cockroaches ha'c a dorso'entrally species, including various pinworms and hookworms. O
arthropods, which are among4,"" most successful and abun- their rdatin'$ alt' mostly herbr.'O-
the Grasshoppers. crickcu. and body, with lqs
modified for rapid running. Forewings hen present, are leath·
rous. They have Large hind Iq;s adapted for jumping. '....0 pairs
dant of all animal groups. ery, ",ilereas hind wings aremembnnous), than nematode is Trichinella spiralis, the worm that
torious 40 cockroKh
of.... ings (one leathery, one fan6J.:e. F w and biting orcbew-
German
§Ilt'cies moe in houses; commonly make courtship sounds by 33.26). cockroach acquire this nemat
trichinosis (Figure
ing mouthparts. Malesthe rest exploit habitUs r.lnging from Humans
rubbing forest floors to palU. and descn.s. on their hind legs.
togelht-r body caves such as ill ridge
Nematodes Orthopterans undergo incomplete mrtamorphosis.
eating raw or undercooked pork or other meat (includin
Katydid
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous animals, nematodes (phylum
Coleoptera 350.000 BcrtIcs comprise the most specks-rich the muscle tissue. '(!ithin the human intestines, the ju
in Ofdcr of ins«u. Thq-
Nematoda), or roundworms, are found in most aquatic habitats, of.....hich is thick and stiff, the
Phasmalodea Stick inserts and leaf insects are exquisite mimics of plants.
ha'e ''''-0 pairs of ",;ngs, one
develop into sexually mature insect Females burrow i
l"he eggs of some sjX'Cies e"en mimic seeds nosktltton and
other membranous. lbty h;l'e an armomi orthe plants on Stick adults.
in the soil, in the moist tissues of plants, and in the insects live. Their body iscylindrkal or natlenro
....hich the body fluids
mouthPMU adapled for biting and ehe",;ng. BertIes undergo and produce more juveniles, whic
intestinal muscles
dorsoventrally. They lack foreWings but have fanlike hind
and tissues of animals. In contrast to annelids, nematodes do
complete metamorphosis.
dngs. Their mouthparts arc adapted for biting or chewing. or travel in lymphatic vessels to other
through the body
not have segmented bodies. The cylindrical bodies of nema-
including skeletal muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length,
DermaptcnII 1.200 Parasitic nematodes have an extraordinary mo
Earwigs are generally nocturnal Ka'mgers. Sotmo species are
often tapering to a fine tip at the posterior end and called sucking lice, these insects spend their entire
Phthiraplcr<i 2.400 Commonly to a more
'oingless, while others ha...e Iwo p,airs of"'ings, one of ....hich is
life as an ectoparasite feeding on thetoolkit that enables them to redirect some of the cellula
hair or feathers of a single
thick and koathery, the other membranous. EalVoigs have Human
blunt tip at the anterior end (Figure 33.25). A nematode's body with clawlike tarsi, are adaptedbiting
host. Their legs, equipped for
mouthparts and large posterior pincer" They undergo incom- and body evade their immune sy
tions havetheir hosts
of reduced eyes. thus
is covered by a tough cuticle; as the worm grows,metamorphosis. They lack wings and
plete it periodically
clinging to their hosts. louse Earwig
Plant-parasitic nematodes inject molecules that indu
Sucking lice undergo incomplete metamorphosis.
sheds its old cuticle and secretes a new, larger one. Nematodes ,
development of root cells, which then supply nutrients
have an alimentary canal, though they lack a circulatory system.
Diptera 151,000 parasites. Trichinella controls the expression of s
Diptl"I'1UIS ha.T one pair of ..... ings;!.he SCCOlld pair has be<:OITK'
Nutrients are transported throughout the body are bloodsucking ectoparasites on birds and mammals.
Siphonaplel'll 2.400 fleas via fluid in the
modined into balancing organs called haltcrtS. Their mouth-
muscle-cell genes that code for proteins that make the ce
Their body is Wingless and laterally compressed. Their legs are
pseudocoelom. The body wall muscles are all longitudinal, and hosts and or lapping. Dipll."rans
pam are adapll'd for sucking, piercing.
modified for clinging to their for long-distance jump- Horsefly
Tuesday, April 13, 2010 undergo complete metamorphosis. tic enough to house the nematode. Additionally, the in
Flies and mosquitoes are

10. r;;==; Phasmalodea and Silicea
Calcarea
Cmdana
Stick inserts and leaf by
Although defined primarilyinsects are exquisite mimics of plants. onts features. These free-living worms
Biology II - Zoology
planet and many
molecular evidence,some sjX'Cies e"en mimic seeds orthe plants on decomposition and nutrient cycling, b
l"he eggs of the dade important role in Stick insect
Lopholnxhowa ....hich the insects live. Their body iscylindrkal or natlenro
Ecdysozoa dorsoventrally. animalsforeWings butknown about most species. One species of soil nem
includes They lack is have fanlike hind
Ecdysozoa
Deuterostorma Invertebrates
that shed a toughTheir mouthparts arc adapted for biting or chewing.
dngs. external coat Caellorhabditis elegalls, however, is very well studied a
Arthropods Insect Diversity in fact,
Exploring (cuticle) as they grow; become a model research organism in biology (see Chap
Phthiraplcr<i 2.400 Insects
the group derives its name from this process, which is called lice, theseOngoing studies on C. elegans are revealing some of the
Commonly called sucking insects spend their entire
molting, or ecdysis. Ecdysozoa consists of about eight animal on theanisms involved in aging in humans, among other findin
, life as an ectoparasite feeding hair or feathers of a single Human
Approximate host. Their legs, equipped with clawlike tarsi, are adapted for
phyla and contains mOTe known species than all other protist, lack wings and have reduced eyes. body
Phylum Nematoda includes many significant agric
Order Number of clinging to their hosts. They
Main Characteristics louse Examples
fungus, plant, and animal Species groups combined. Here we'll focus
Sucking lice undergo incomplete metamorphosis. attack the roots ofplants. Other species of nem
pests that ,
on the two largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least 50 nem
8lattodea the Cockroaches ha'c a dorso'entrally species, including various pinworms and hookworms. O
arthropods, which are among4,"" most successful and abun- body, with lqs
Siphonaplel'll 2.400 fleas are bloodsucking ectoparasites on birds and mammals.
modified for rapid running. Forewings hen present, are leath·
dant of all animal groups. ery, ",ilereas hind wings arelaterally compressed. Their legs are Trichinella spiralis, the worm that
Their body is Wingless and
fan6J.:e. F w than nematode is
torious 40 cockroKh German
modified for clinging to their hosts and for long-distance jump-
trichinosis (Figure 33.26). cockroach acquire this nemat
§Ilt'cies moe in houses; the rest exploit habitUs r.lnging from
ing. They undergo complete metamorphosis. Humans
forest floors to caves and descn.s.
Nematodes Flea
eating raw or undercooked pork or other meat (includin
game such as bear or walrus) that has juvenile worms en
Some of the most ubiquitous 450 animals, nematodes small, Wingless insects with a nauenM body and
Silverfish arc (phylum
Coleoptera 350.000 BcrtIcs comprise the most specks-rich the muscle tissue. '(!ithin the human intestines, the ju
in Ofdcr of ins«u. Thq-
reduced eycs. They live inleaflittl'l" or under Inri:. Theyan
Nematoda), or roundworms, are found in most aquatic habitats, of.....hich is thick and stiff, the
ha'e ''''-0 pairs of ",;ngs, one
also infest buildings, whl'l"e they candevelop into sexually mature adults. Females burrow i
become pests.
in the soil, in the moist tissues of plants, and in otherthe body fluids h;l'e an armomi nosktltton and
membranous. lbty
mouthPMU adapled for biting and ehe",;ng. BertIes undergo and produce more juveniles, whic Silverfish
intestinal muscles
and tissues of animals. In contrast to annelids, nematodes do
complete metamorphosis.
through the body or travel in lymphatic vessels to other
not haveTrichapten bodies. The cylindrical bodies of nema- in streams, ,,'here they make
segmented 7.100 The larvae of caddistlies lin'
including skeletal
house'S from sand gr;AiRS•..-ood fragments. or ot.hef material muscles, where they encyst.
todes range from less than 1 mm to more than a meter in length, haw f',Hl pairs of hairy wings and
held tosether by silk. Adults
DermaptcnII 1.200 Parasitic nematodes have an extraordinary mo
Earwigs are generally nocturnal Ka'mgers. Sotmo species are
often tapering to a fine tip at the posterior end and lappingmore Iwo p,airs of"'ings, one of ....hich is
chOling or to a mouthpalU. They undtrgo complete meta-
'oingless, while others ha...e
morphosis. toolkit that enables them to redirect some of the cellula
Caddisfty
blunt tip at the anterior end (Figure 33.25). A nematode's body membranous. EalVoigs have biting
thick and koathery, the other
mouthparts and large posterior pincer" They undergo incom- and thus evade their immune sy
tions of their hosts
is covered by a tough cuticle; as the worm grows,metamorphosis.
plete it periodically Earwig
Plant-parasitic nematodes inject molecules that indu
sheds its old cuticle and secretes a new, larger one. Nematodes
development of rootlHIUl·TllIIU Invertebrates nutrients
cells, which then supply 691
have an alimentary canal, though they lack a circulatory system.
Diptera 151,000 parasites. Trichinella controls the expression of s
Diptl"I'1UIS ha.T one pair of ..... ings;!.he SCCOlld pair has be<:OITK'
Nutrients are transported throughout the body viainto balancing organs called haltcrtS. Their mouth-
modined fluid in the
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The body wall muscles are all longitudinal, and piercing. or lapping. Dipll."rans
pam are adapll'd for sucking,
Horsefly
Tuesday, April 13, 2010 undergo complete metamorphosis. tic enough to house the nematode. Additionally, the in
Flies and mosquitoes are

11. r;;==; Calcarea and Silicea
Cmdana
Although defined primarily by
Biology II - Zoology
molecular evidence, the dade
planet and many onts features. These free-living worms
important role in decomposition and nutrient cycling, b
Crustaceans
Lopholnxhowa
Ecdysozoa includes animals is known about most species. One species of soil nem
Ecdysozoa
Deuterostorma Invertebrates
Vhjle arachnids and insects thrive on a tough external coat
that shed land, crustaceans, for the
most part. have remained in marine and freshwater environ-
Caellorhabditis elegalls, however, is very well studied a
(cuticle) as they grow; in fact, become a model research organism in biology (see Chap
ments. Crustlre.ms
the group derives itsappendages. Lobsters process, which instance.
specialized name from this and crayfIShes, for is called Crustaceans
Crustlce,) typically M" highly
Ongoing studies on C. elegans are revealing some of the
molting, live marine of 19 pairs of appendages about eight animal
• oranteriormost and freshwater of crustaceans areThe
ecdysis. Ecdysozoa consists environments; typically have highly specializedin humans, among other findin
have a toolkit 33.29). anisms involved in aging appendages
phyla andanteriormost known are antennae; antennae; crustaceans are the only arthropods with two pairs agric
appendages species than
contains mOTe appendages are all other protist, the
• only arthropods with two pairs. Three or more pairs of ap- Phylum Nematoda includes many significant
fungus, plant, and animal groups combined. Here we'll focus pests that attack the roots ofplants. Other species of nem
pendages are modified as mouthparts. including the hard
on the Three or more pairs of appendages are modified as mouthparts, including the hard mandibles 50 nem
twomandibles. Walking legs are present on the thorax, and, unlike
largest e<dysozoan phyla, the nematodes and parasitize animals. Humans are hosts to at least
arthropods, insects, crustaceans alsothe most successful and and, unlike insects, including various pinworms and hookworms. O
Walking legs among regenerated at nextthorax, abun-
which are are present on theon their abdomen.
have appendages species, crustaceans also have appendages
A lost groups. (a) Ghost crabs live on sandy ocean beaches worldwide. Pnmarily
dant of all animalappendage can beA lost appendage can be regenerated atnematode is burrows dunng the day_ the worm that
on their abdomen.
molt.
nocturnal. they take shelter In Trichinella spiralis,
torious next molt.
Small crustaceans exchange gases across thin areas of the
cuticle; larger species have gills. Nitrogenous ....'astes also dif-
trichinosis (Figure 33.26). Humans acquire this nemat
Nematodes through thin areas of the cuticle. but a pair of glands reg-
fuse eating raw or undercooked pork or other meat (includin
the ulates the salt balance of the hemolymph. game such as bear or walrus) that has juvenile worms en
Some of the mostare separate in most crustaceans. In the case of lob-
on- Sexes ubiquitous animals, nematodes (phylum
in the muscle tissue. '(!ithin the human intestines, the ju
Nematoda), sters and crayfish. theare foundain most aquatic habitats,
hly or roundworms, male uses specialized pair of abdomi-
develop into sexually mature adults. Females burrow i
in the soil, in the moist tissues of plants, and reproductive pore of
ce.
nal appendages to transfer sperm to the in the body fluids
the female during copulation. Most aquatic crustaceans go intestinal muscles and produce more juveniles, whic
The tissues of animals. In contrast to larval stages.nematodes do
and through one or more swimming
annelids,
through the body or travel in lymphatic vessels to other
the have segmented bodies. groups cylindrical bodies of nema-
not One ofthe largest The ofcrustaceans (numbering about
ap-
including skeletal muscles, where they encyst.
todes range from less than the isopods, which includemeter in length,
IO,lXX') species) is 1 mm to more than a terrestrial. fresh·
Parasitic nematodes have an extraordinary mo
often tapering to and marine species. Some isopodend and to a more
ard water, a fine tip at the posterior species are abundant
ike tip at thehabitats at the bottom of the deep ocean. Among thebody
in ter· toolkit that enables them to redirect some of the cellula
blunt anterior end the pill bugs. or wood lice. common on the
restrial isopods are
(Figure 33.25). A nematode's
en. tions of their hosts and thus evade their immune sy
is covered by a tough of moistsandyand worm grows, it periodically
undersides cuticle;logs the leaves.
(a) Ghost crabs live on
as ocean beaches worldwide. Pnmarily
(b) Planktonic crustaceans known (el The injectappendages
Plant-parasitic nematodes JOinted molecules that indu
Lobsters. crayfishes. crabs.new, larger one. Nematodes
cuticle they take shelter and shrimpsare all day_ large
sheds its oldnocturnal. and secretes a In burrows dunng the as I:::rin are consumed In vast prOjectlng from the shells
the crust:aceanscalleddecapods (Figure 33.38a). Thecuticleofde- development of root cells, which thencapture nutrients
quantities by some whales. of these barnacles supply
have an alimentary canal, though they lack a circulatory system.
dif- organISms and organic
capods is hardened by calcium carbonate; the portion that cov- parasites. Trichinella controls the expression of s
partlCles suspended in
Nutrients are transported ofthe cephalothorax body a shield called the
eg- ers the dorsal side throughout the forms via fluid in the the water.
muscle-cell genes that code for proteins that make the ce
pseudocoelom. The Most decapod species are marine. Crayfishes, how-
carapace. body wall muscles are all longitudinal, and
• Figure 33.38 Crustaceans. the nematode. Additionally, the in
Tuesday, April 13, 2010
ever, live in fresh water, and some tropical crabs live on land. tic enough to house

12. Sea stars, sea urchins, and other spiny, and derma, skin) are slow-moving or sessile mar
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology
imals. A thin epidermis covers an endoskeleton of h
dermata) may seem to have lit- careous plates. Most echinoderms are prickly from
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Invertebrates
bumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
vertebrates-animals that have a backbone. In fact, however, Echinoderms
extensions called tube feet that function in locomotio
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
deuterostome mode of development, such as radial cleavage echinoderms usually involves separate male and fema
and formation of the mouth at the end of the embryo opposite viduals that release their gametes into the water.
Echinoderms are deuterostomes.
the blastopore (see Figure 32.9). Molecular systematics has re- The internal and external parts of most adult echin
inforced Deuterostomia as a clade of bilaterian animals. But radiate from the center, often as five spokes. However
molecular evidence also indicates that some animal phyla with oderm larvae have bilateral symmetry. Furthermore, th
Molecular systematics has reinforced Deuterostomia as a
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
clade of bilaterian animals. But molecular evidence also
cluding ectoprocts and brachiopods, are not in the deutero-
stome dade (see Chapter 32). Hence, despite its name, the clade
the opening (madreporite) ofa sea star's water vascular
is not central but shifted to one side.
indicates that some animal phyla with members that have
deuterostome developmental features, including ectoprocts and
brachiopods, are not in the deuterostome clade. Hence, despite
The surface of a sea star is
its name, the cladedigestive tract runs from theis defined primarily by DNA
Ashort
Deuterostomia covered by spines that help
defend against predators, as
similarities, not developmentalcentral
mouth on the bottom of the similarities. small gills that
well as by
provide gas exchange.
disk to the anus on top of the disk.
Central disk. The central disk
Tuesday,a nerve ring and nerve
has April 13, 2010
r

13. Sea stars, sea urchins, and other spiny, and derma, skin) are slow-moving or sessile mar
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology
imals. A thin epidermis covers an endoskeleton of h
dermata) may seem to have lit- careous plates. Most echinoderms are prickly from
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Invertebrates
bumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
vertebrates-animals that have a backbone. In fact, however, Echinodermata
extensions called tube feet that function in locomotio
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
deuterostome mode of development, such as radial cleavage echinoderms usually involves separate male and fema
and formation of the mouth at the end of the embryo opposite viduals that release their gametes into the water.
the blastopore (see Figure 32.9). Molecular systematics has re- The internal and external parts of most adult echin
inforced Deuterostomia as a clade of bilaterian animals. But radiate from the center, often as five spokes. However
molecular evidence also indicates that some animal phyla with oderm larvae have bilateral symmetry. Furthermore, th
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
cluding ectoprocts and brachiopods, are not in the deutero- the opening (madreporite) ofa sea star's water vascular
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
(a) Asea star (class Asteroidea) (b) Abrittle star (class Ophiuroidea)
The surface of a sea star is
covered by spines that help
Ashort digestive tract runs from the defend against predators, as
mouth on the bottom of the central well as by small gills that
disk to the anus on top of the disk. provide gas exchange.
Central disk. The central disk
Tuesday,a nerve ring and nerve
has April 13, 2010
r
«) Asea urchin (class E(hinoidea) (d) Afeather star (class Crinoidea)

14. spiny, and derma, skin) are slow-moving or sessile mar
Sea stars, sea urchins, and other
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology
imals. A thin epidermis covers an endoskeleton of h
careous plates. Most echinoderms are prickly from
dermata) may seem to have lit-
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Invertebrates
bumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
vertebrates-animals that have a backbone. In fact, however, Echinodermata
extensions called tube feet that function in locomotio
«) Asea urchin (class E(hinoidea) ing, and gas exchange (Figure 33.39). Sexual reprodu
echinoderms and chordates share features characteristic of a (d) Afeather star (class Crinoidea)
deuterostome mode of development, such as radial cleavage echinoderms usually involves separate male and fema
and formation of the mouth at the end of the embryo opposite viduals that release their gametes into the water.
the blastopore (see Figure 32.9). Molecular systematics has re- The internal and external parts of most adult echin
inforced Deuterostomia as a clade of bilaterian animals. But radiate from the center, often as five spokes. However
molecular evidence also indicates that some animal phyla with oderm larvae have bilateral symmetry. Furthermore, th
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
cluding ectoprocts and brachiopods, are not in the deutero- the opening (madreporite) ofa sea star's water vascular
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
The surface of a sea star is
(e) Asea cucumber (class Holothuroidea) (f) A sea daisy (class Con(entricycloidea)
covered by spines that help
.. Figure 33.40 Echinoderms. Ashort digestive tract runs from the defend against predators, as
mouth on the bottom of the central well as by small gills that
disk to the anus on top of the disk. provide CHECK 33.5
CONCEPT gas exchange.
Chordales
1. Describe how sea star tube feet attach to substrates.
Phylum Chordata consists of m'o subphyla of invertebrates as 2. Are characteristics shared by a sea star and a sea daisy
r
well as the hagfishes and the vertebrates. Chordates are bilat-
erally symmetrical coelomates with segmented bodies. The
dose relationship between echinoderms and chordates does
Central disk. The central diskevolved from the other. In fact,
not mean 13, 2010 and nerve
Tuesday,a nerve ring phylum
has April that one
homologous or analogous? Explain.
3. •i,il:O'I,. The insect Drosophila me/anogasler and
the nematode Caenurhabditis e/egans are prominent
model organisms. Are these species the most appro-

15. spiny, and derma, skin) are slow-moving or sessile mar
Sea stars, sea urchins, and other
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology
imals. A thin epidermis covers an endoskeleton of h
careous plates. Most echinoderms are prickly from
dermata) may seem to have lit-
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Invertebrates
bumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
Echinoderms
vertebrates-animals that have a backbone. In fact, however, Echinodermata
extensions called tube feet that function in locomotio
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
deuterostome mode of development, such as radial cleavage echinoderms usually involves separate male and fema
Class and
and formation of the mouth at the end of characteristics
Main the embryo opposite viduals that release their gametes into the water.
Examples
the blastopore (see Figure 32.9). Molecular systematics has re- The internal and external parts of most adult echin
inforced Deuterostomia as a clade of bilaterian animals. But radiate from the center, often as five spokes. However
molecular evidence also indicatesStar-shaped body with multipleoderm larvae have bilateral symmetry. Furthermore, th
Asteroidea that some animal phyla with arms; mouth directed to substrate
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
Ophiuridea
cluding ectoprocts and brachiopods, are not in thedisk; long, flexible opening (madreporite) ofa sea star's water vascular
Distinct central deutero- the arms; incomplete digestive system
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
Echinoidea Roughly spherical or disk-shaped; no arms; five rows of tube feet,
enabling slow movement; mouth ringed by complex, jaw-like structure
Crinoidea Feathered arms surrounding upward-pointing mouth; suspension feeders
The surface of a sea star is
Holothuroidea Cucumber-shaped body; five rows covered by spines that feet around the
of tube feet; tube help
Ashort digestive tract runs from the tentacles; against predators, as
mouth are bottom of the central
modified as feeding defend reduced skeleton;
mouth on the well as by small gills that
no spines
disk to the anus on top of the disk. provide gas exchange.
Concentri- Armless, disk-shaped body ringed with small spines: incomplete digestive
r
cycloidea system; live on sub- merged wood
Central disk. The central disk
Tuesday,a nerve ring and nerve
has April 13, 2010

16. and formation of the mouth at the end of the embryo opposite
spiny, and derma, skin) are slow-moving or sessile mar
Sea stars, sea urchins, and other The internal and external parts of most adult echinoderms
Biology II - Zoology
the blastopore (see Figure 32.9). Molecular systematics has re-
! e<hinoderms (phylum
Cmdana Deuterostomia as a clade of bilaterian animals. But
inforced
molecular evidence also indicates that some animal phyla with
radiate from the center, often epidermis However, echin-
imals. A thin as five spokes. covers an endoskeleton of h
oderm larvae have bilateral symmetry. Furthermore, the sym-
Lopholrochozoa dermata) may seem to have lit- metry ofcareous plates. not truly echinoderms are prickly from
Most radial. For example,
Invertebratesnetwork of hydraulic canals branch
members that have deuterostome developmental features, in-
Ecdysozoa adult echinoderms is
Deuterostomia
brachiopods, are not the deutero- bumps and spines. Unique to echinoderms is the
cluding ectoprocts andtle in common inwith phylum the opening (madreporite) ofa sea star's water vascular system
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
Chordata, which includes the vascular system, a
Echinoderms
vertebrates-animals that have a backbone. In fact, however, Sea star tube feet that function in locomotio
extensions called
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
The surface of a sea star is
deuterostome mode of development, such as radial cleavage covered by spines that help usually involves separate male and fema
echinoderms
Ashort digestive tract runs from the defend against predators, as
and formation of the mouth at the endmouth on the bottom ofopposite
of the embryo the central well as by small gills that release their gametes into the water.
viduals that
provide gas exchange.
the blastopore (see Figure 32.9). Molecularthe anus on top of the disk.
disk to
systematics has re- The internal and external parts of most adult echin
inforced Deuterostomia as a clade of bilaterian animals. But radiate from the center, often as five spokes. However
has a nerve ring and nerve
r
molecular evidence also indicates that some animal phyla with
members that have deuterostome developmental features, in-
Central disk. The central disk
cluding ectoprocts and brachiopods, are not in the deutero-
cords radiating from the ring
into the arms.
oderm larvae have bilateral symmetry. Furthermore, th
metry of adult echinoderms is not truly radial. For ex
the opening (madreporite) ofa sea star's water vascular
Madreporite. Water
can flow in or out
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted vascular side.
of the water to one
system into the
surrounding water
through the
madreporite.
Digestive glands secrete
digestive juices and aid in the
absorption and storage
of nutrients.
The surface of a sea star is
covered by spines that help
Ashort digestive tract runs from the defend against predators, as
mouth on the bottom of the central well as by small gills that
/
disk to the anus on top of the disk.
Radial canal. The water vascular
provide gas exchange.
Each tube foot consists of a bulb-like ampulla and a podium (foot
system consists of a ring canal in the portion). When the ampulla squeezes. water is forced into the podium,
central disk and five radial canals, which expands and contacts the substrate. Adhesive chemicals are then
r
each running in a groove down the secreted from the base of the podium, attaching it to the substrate. To
entire length of an arm. Branching detach the tube foot, de-adhesive chemicals are secreted and muscles
from each radial canal are hundreds in the podium contract, forcing water back into the ampulla and
of hollow, muscular tube feet filled shortening the podium. As it moves, a sea star leaves an observable
with fluid. Nfootprint of adhesive material on the substrate.
H
Central disk. The Figure 33.39 Anatomy of a sea star, an echinoderm.
... central disk
Tuesday,a nerve ring and nerve
has April 13, 2010

17. Sea stars, sea urchins, and other spiny, and derma, skin) are slow-moving or sessile mar
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology
imals. A thin epidermis covers an endoskeleton of h
dermata) may seem to have lit- careous plates. Most echinoderms are prickly from
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Invertebrates
bumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
vertebrates-animals that have a backbone. In fact, however, Chordates
extensions called tube feet that function in locomotio
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
deuterostome mode of development, such as radial cleavage echinoderms usually involves separate male and fema
and formation of the mouth at the end of the embryo opposite viduals that release their gametes into the water.
Chordates are bilaterally symmetrical coelomates
the blastopore (see Figure 32.9). Molecular systematics has re-
inforced Deuterostomia as a clade of bilaterian animals. But
The internal and external parts of most adult echin
radiate from the center, often as five spokes. However
with segmented bodies. The close relationship
molecular evidence also indicates that some animal phyla with oderm larvae have bilateral symmetry. Furthermore, th
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
between echinoderms and chordates does not
cluding ectoprocts and brachiopods, are not in the deutero- the opening (madreporite) ofa sea star's water vascular
mean that one phylum evolved from the other. In
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
fact, echinoderms and chordates have evolved
independently of one another for at of a sea star500 The surface least is
covered by spines that help
million years. on the bottom of thefrom the defend by small predators, as
Ashort digestive tract runs
mouth central well as
against
gills that
disk to the anus on top of the disk. provide gas exchange.
Central disk. The central disk
Tuesday,a nerve ring and nerve
has April 13, 2010
r

18. Sea stars, sea urchins, and other spiny, and derma, skin) are slow-moving or sessile mar
! Cmdana
Lopholrochozoa
e<hinoderms (phylum Biology II - Zoology imals. A thin epidermis covers an endoskeleton of h
dermata) may seem to have lit- careous plates. Most echinoderms are prickly from
Ecdysozoa
Deuterostomia
tle in common with phylum
Chordata, which includes the
Chordatesbumps and spines. Unique to echinoderms is the
vascular system, a network of hydraulic canals branch
Echinodermata
vertebrates-animals that have a backbone. In fact, however, extensions (sister group to chordates) that function in locomotio
called tube feet
echinoderms and chordates share features characteristic of a ing, and gas exchange (Figure 33.39). Sexual reprodu
ANCESTRAL
-
deuterostome mode of development, such as radial cleavage
DEUTEROSTOME
Cephalochordata
echinoderms usually involves separate male and fema
(Iancelets) 9
o
and formation of the mouth at the end of the embryo opposite viduals that release their gametes into the water. a
Urochordata •
Not"h;
the blastopore (see Figure 32.9). Molecular systematics has re-
inforced Deuterostomia as a clade of bilaterian animals. But
Common
The internal and external parts of most adult echin
(tunicates)
radiate from the center, often as five spokes. However
ancestor of - Myxini
molecular evidence also indicates that some animal phyla with
chordates (haglishes)
oderm larvae have bilateral symmetry. Furthermore, th
members that have deuterostome developmental features, in- metry of adult echinoderms is not truly radial. For ex
cluding ectoprocts and brachiopods, are not in the deutero- H:t Petromyzontida
(lampreys)
the opening (madreporite) ofa sea star's water vascular
Phylogeny of living
stome dade (see Chapter 32). Hence, despite its name, the clade is not central but shifted to one side.
Chondrichthyes
chordates. This Vertebral COI± (sharks. rays, chimaeras) "..",.,..
phylogenetic Actinopterygii ..-....
hypothesis shows Jaws. mineralized skel± (ray·finned fishes)
the major clades of Actinistia ..
chordates in relation lungs or lung deriva± The surface of a sea star is
(coelacanths) ..
covered by spines that help
to the other main Ashort digestive tract runs from the against predators, as ,
defend Dipnoi •
deuterostome clade, mouth on the bottom of the central well as by small gills that
disk to the anus on top of the disk.
Echinodermata. For selected clades, - provide gas exchange.
Amphibia
salamanders) '.-Q
some of the derived characters are •
.. Figure 34.2 Phylogeny of living chordates. This
:t - !
r
listed; for example all chordates, and of chordates in
phylogenetic hypothesis shows the major clades Reptilia _
(turtles. snakes, ••
relation to the other main deuterostome clade. Echinodermata (see
only chordates, have aselected clades. some 01 the derived characters ,
3
Chapter 33). For notochord. crocodiles. birds)
are listed; for example. all chordates. and only chordates. have 'j; +
Am"ioti' Mammalia
o·
;
•
a notochord. Milk (mammals)
Central disk. The central disk
Tuesday,a nerve ring and nerve
has April 13, 2010