Transcript American

Arthropods are different from all other animals
because they are eucoelomates with a hard,
segmented body. The phylum Arthropoda
(jointed-foot) consists of most of the known
animals and many are enormously abundant as
individuals. The general characteristics of the
arthropods include a hard exoskeleton called a
cuticle made up of chitin and proteins. This hard
exoskeleton gives the organism’s segmented
body protection and a place for muscle
attachment. Arthropods also have jointed
appendages that allow for specialized functions.
They have an organ system level or organization
and they are triploblastic. There are five
subphyla: Trilobita, Checlicerata, Crustacea,
Myriapoda, and Hexapoda.
Subphylum: Trilobita
This subphylum (like other
arthropods) have paired
appendages.
They are segmented
without any specialization.
This subphylum are all
extinct (Permian era –
250 mya)
Subphylum: Cheliceriformes
Cheliceriformes all have 6 pairs of
appendages. The first pair is modified into
chelicerae. The next pair are modified into
pedipalps. The last 4 pairs are walking
legs. These animals have one or two body
regions (cephalothorax and abdomen).
These animals do not have a mandible or
any antennae.
Class: Eurypterids
The Eurypterids
or water
scorpions are
animals that are
now extinct. They
were normally
marine and
freshwater
predators.
Class: Merostomata
These organisms
(horseshoe crabs) are
found in shallow coastal
waters. The first pair of
appendages are modified
into chelicerae but the
second pair is not
modified into pedipalps
like other cheliceriformes.
The Horseshow crab’s
larvae look similar to the
extinct trilobites.
Class: Pycnogonida
These organisms (sea
spiders) are usually found
in shallow coastal waters
and many polar oceans.
These animals often have
eight legs (like true
spiders) but may have
extra legs from their
segments being
duplicated.
These organisms include
spiders, scorpions, ticks,
and mites. Spiders
contain modified
chelicerae which are
used as fangs to inject
poison. They also have a
special gland that can
produce silk used for
webs, eggs, escape, and
courtship. Scorpions are
the first terrestrial
invertebrates. Their
pedipalps are modified
into pinchers and their tail
is modified into a stinger.
Ticks and mites are
parasitic.
Class: Arachnida
Subphylum: Crustacea
Crustacea have two pair of antennae.
Each appendage is biramous (two main
branches). They have mandibles. These
animals have two or three body regions
(cephalothorax and abdomen or head,
thorax, and abdomen). These animals are
mostly marine.
Isopoda
The isopods are the
most diverse
crustaceans. These
animals are found in
terrestrial, freshwater,
and saltwater
habitats.
Decapoda
The decapods
include many of
the familiar
crustaceans.
They are
mostly aquatic
species.
Copepoda
The copepods are
animals that are
among the most
numerous members
of the marine and
freshwater plankton
community.
Cirrepedia
Barnicles are animals
that are exclusively
marine, and tend to
live in shallow and
tidal waters, typically
in erosive settings.
Subphylum: Myriapoda
Myriapods all have appendages that are
uniramous (one main branch). The body is
long with a distinct head. The have one
pair of antennae. These animals also have
a mandible.
Class: Chilopoda
These organisms are
centipedes. They
have one pair of
jointed legs per
segment. They have
poison claws and are
predators.
Class: Diplopoda
These organisms are
millipedes. They have
two pair or jointed
legs per segment.
(Two segments have
fused together). They
are herbivores.
Subphylum: Hexapoda
Hexapods all have 6 appendages, each
pair are attached to a segment of the
thorax. The body consists of a distinct
head, thorax, and abdomen. They have
one pair of antennae. These animals also
have a mandible.
Class: Insecta
Insects are the
most diverse of
all arthropods.
They may have
been the cause
of angiosperm
diversity. Know
the orders that
are
demonstrated
here.
Arthropoda
Level of Organization
Tissue Layers
Digestive System
Excretory System
Circulatory System
Respiratory System
Nervous System
Body Cavity
Asexual Reproduction
Sexual Reproduction
Organ-system
Triploblastic
Alimentary Canal with
modified mouth parts
Nephridia
Open system with heart
Skin, gills, tracheae or book
lungs
Dorsal brain with ring
connected to ventral cords
True
Budding in some
Usually Dioecious
Phylum: Echinodermata
The word Echinodermata means “spiny skin”.
These animals demonstrate secondary radial
symmetry as adults (evolved from bilateral
symmetry back to radial symmetry) while the
larvae stage still exhibits bilateral symmetry.
They are probably more closely related to the
vertebrates because of their deuterostome
development. Unique to echinoderms is the
water vascular system used for locomotion,
feeding and food exchange.
Echinoderm Structures
(P 126 Figure 7.100)
Oral Side: Side with mouth
Arboral Side: side without mouth
Madreporite: opening into water vascular
system
Ambulacral Grooves: Radiating grooves that
contain tube feet
Pedicellariae: pincer-like organs on surface
(see compound microscope)
Papillae: skin gills
Echinodermata Classes
Class
Characteristics
Examples
Asteroidea
Pentaradial
symmetry
Sea stars
Ophiuroidea
Pentaradial
symmetry
Disk-shaped, no
arms, spines
Brittle stars
Holothuroidea
Cucumbershaped, no arms,
no spines
Sea cucumbers
Crinoidea
Sessile, arms
used for filterfeeding
Sea lillies
Echinoidea
Sea urchin
Class: Asteroidea
Sea stars have five
arms that radiate from
a central disc. They
have an open
ambulacral groove.
The madreporite is on
the aboral side. They
contain both
pedicellariae and
dermal branchiae.
Class: Ophiuroidea
They have five thin
arms radiating from a
central disc. They
have a closed
ambulacral groove.
The madreporite is on
the oral side. They do
not have pedicellariae
or dermal branchiae.
The Sea urchins have no
arms but have five rows
of tube feet. They contain
moveable spines. They
have closed ambulacral
grooves. They
madreporite is on the
aboral side. They contain
pedicellariae and dermal
branchiae. They have
specialized jaw-like
structures called an
Aristotle’s lantern.
Class:
Echinoidea
Class:
Holothuroidea
Sea cucumbers are
soft bodied animals
with ambulacral areas
with tube feet. They
have an internal
madreporite. They
have no pedicellariae
or dermal branchiae.
The sea lilies are
attached to the
substrate with
many branched
arms. They have
open ambulacral
grooves. They
have no
madreporite,
pedicellariae or
dermal branchiae.
Class:
Crinoidea
Bipinnaria Larvae
The larvae form is
evidence that this
phyla has evolved
radial symmetry from
a bilateral ancestor.
The larvae form is
used for dispersal.
Echinodermata
Level of Organization
Tissue Layers
Digestive System
Excretory System
Circulatory System
Respiratory System
Nervous System
Body Cavity
Asexual Reproduction
Sexual Reproduction
Organ-system
Triploblastic
Alimentary canal
Absent
Reduced if at all
Dermal branchiae, tube
feet, respiratory tree
No brain, nerve ring with
radial nerves
True
Regeneration
Dioecious
Phylum: Chordata
The Phylum Chordata
include animals that
sometime in their life
cycle have a notochord
(for muscle attachment),
a hollow dorsal nerve
cord (to send nervous
signals), pharyngeal slits
(various functions) and a
post-anal tail
(movement). The three
subphyla are
Urochordata,
Cephalochordata, and
Vertebrata.
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Subphylum: Urochordata
The Tunicates or
Sea Squirts contain
only the pharyngeal
slits as an adult.
They are usually
sessile and use the
pharynx for filter
feeding.
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Subphylum: Cephalochordata
The Lancelets contain
all four chordate
characteristics as an
adult. They are usually
found buried in the
sand off our coast.
They are considered to
be the closest relative
to vertebrates.
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Subphylum: Vertebrata
The Vertebrates are
animals with
backbones. They
contain all four
chordate
characteristics as an
adult with some
modifications. They
are free-living.
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What is a Fish?
Fish are aquatic
vertebrates that are not a
mammal, bird, or reptile
(It isn’t a monophyletic
group).
There are the five major
living groups of fish:
Hagfish (jawless)
Lamprey (jawless)
Cartilaginous Fish
Lobe-finned Fish
Ray-finned Fish
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Superclass: Agnatha
The agnatha are animals
without jaws and most lack
paired appendages.
Hagfishes may also lack
eyes and a stomach. They
are scavengers that enter
natural openings on living
and dead fish and
mammals. Hagfish find their
prey by a sense of smell.
Hagfish can secrete large
quantities of slime or mucus
and can tie themselves into
a knot which can also help
release the slime.
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Superclass: Agnatha
The agnatha are animals
without jaws and most lack
paired appendages. The
adult lamprey feeds by
attaching its mouth to a fish,
secreting an anticoagulant
into the host, and feeding
on the blood and tissues of
the host.
Lamprey swim upstream to
spawn. They are called
ammocoetes as larva and
are found in burrows. The
larva must go through a
metamorphosis to become
adults where the entire
digestive system must be
restructured.
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Superclass: Gnathostomata
This superclass contains jaws which evolved
from skeletal supports of the pharyngeal
slits.
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Class: Chondrichthyes
The class chondrichthyes all
lack true bone and have a
skeleton made of cartilage
which is not a primitive
characteristic. Their tough
skin is covered with placoid
scales. Males have a
structure called claspers
which aren’t seen in females.
The two subclasses in this
class are Elasmobranchii (the
sharks, skates, and rays) and
the Holocehphali (the ratfish)
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Shark Reproduction
Male and female sharks can
easily be told apart. Male sharks
have claspers which are
extensions of the pelvic fins used
to transfer sperm. There is also
three different types of shark egg
development. They are:
Viviparity: the mother
feeds the “babies” by a
placenta
Oviparity: the mother
deposits eggs in the
ocean
Ovoviviparity: the eggs are
retained in mom but without
any nourishment from the
mother.
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Order: Selachiformes
Great White Sharks
The Great White Shark
measures up to 20 feet and
can weigh up to 4200 lbs.
They usually eat large bony
fish, smaller sharks,
dolphins, seals, and sea
lions. They are found in
almost all coastal and
offshore waters between 54
to 75 degrees F. The Great
White has been labeled a
“man eater” but in the last
100 years more people
have been killed by dogs in
the U.S. than this shark.
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Order: Selachiformes
Leopard Sharks
The Leopard Shark
measures up to 6.5 feet and
can weigh up to 40 lbs.
They usually eat bony fish,
crustaceans, worms, and
clams. They are found
along the coast from
Oregon to Baja California.
The leopard shark is
spotted as a juvenile in the
shallows but usually lose
their spots as they get
larger and move to deeper
water.
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Order: Selachiformes
Whale Sharks
The Whale Shark is the
largest fish in the ocean
and measures up to 66
feet and can weigh up to
7500 lbs. They usually
are filter feeders eating
enormous amounts of
plankton. They are found
in along the coast from
Oregon to Baja
California. The Whale
shark can filter 6000
liters of water an hour.
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Order: Selachiformes
Hammerhead Shark
The Hammerhead shark
measures up to 18 feet and
can weigh up to 1000 lbs.
They usually eat fish, rays,
other sharks, cephalopods
and crustaceans. They are
found in tropical and
subtropical waters along the
shorelines. The shape of
the head is thought to
spread their receptors
across a larger area making
them 10 times more likely to
detect prey.
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Order: Batiformes
Skates and Rays
Both skates and rays are
flat bottom-dwelling
organisms.
Skates have a tiny caudal
fin with no stinging
spines, each pelvic fin is
divided into two lobes and
lay egg cases.
Rays have a slender
whip-like tail with stinging
spines, each pelvic fin
contains one lobe and
give live birth.
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Broad Skate
The broad skate is
known to grow to be
just under a meter in
length. It is a deepwater skate found in
the central and
northern Pacific
ocean. They feed on
mollusks,
crustaceans and
fishes.
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Manta Ray
The manta ray is the largest
of the rays, with the largest
known specimen having
been about 7.6 m (about 25
ft) across. It ranges
throughout all tropical
waters of the world, typically
around coral reefs. Manta
rays are believed by some
to have evolved from
bottom-feeding ancestry,
but have adapted to
become filter feeders in the
open ocean
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Guitarfish
The guitarfish are
mainly found in tropical
and temperate waters,
traveling in large
schools. Most adult
guitarfishes reach five
or six feet in length.
These fish are bottom
feeders, preferring
small crustaceans.
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Order: Chimaeriformes
Chimaeras
Chimaeras differ from sharks in
that their upper jaws are fused
with their skulls; they have
separate anal and urogenital
openings; and they lack the
many sharp and replaceable
teeth of sharks, having instead
a few large permanent grinding
tooth plates. They are often
called ratfish or rabbit fish.
They are found in cold water
often at great depths. The diet
consists primarily of benthic
invertebrates. The tooth plates
are used to crush hard-bodied
prey such as crabs, clams, and
echinoderms.
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The “Osteichthyes” all have a
skeleton made of true bone.
Their skin is covered with
ctenoid scales. They also
have an operculum (a hard
covering over the gills), which
helps them breathe without
having to swim. They also
have a swim bladder which
helps the body create a
neutral balance between
sinking and floating. There
are two classes in this group:
the Class: Sarcopterygii, the
Lobe-finned fish and the
Class: Actinopterygii the Rayfinned Fish
Osteichthyes
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Sarcopterygii – Lobe-finned Fish
Subclass: Coelacanthimorpha
Coelocanths are lobe-finned fish
with the pectoral and anal fins on
fleshy stalks supported by
bones, and the tail is divided into
three lobes. Coelacanths also
have a special electroreceptive
device called a rostral organ in
the front of the skull, which
probably helps in prey detection.
Coelacanth populations have
been found near Indonesia and
South Africa. Coelacanths are
opportunistic feeders, hunting
cuttlefish, squid, snipe eels,
small sharks, and other fish.
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Sarcopterygii – Lobe-finned Fish
Subclass: Dipnoi
Lungfish are fresh water lobefinned fish. Lungfish are bestknown for retaining primitive
characteristics, including the
ability to breathe air, Today, they
live only in Africa, South
America, and Australia. African
and South American lungfish are
capable of surviving seasonal
desiccation of habitats by
burrowing into mud and
estivating throughout the dry
season. They have a diet of fish,
insects, mollusks, worms,
crustaceans, and plant material.
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Infraclass:
Holosteri
In this infraclass, all of
the fish are considered
to be primitive fish.
They are found in
brackish conditions.
They can use their
swim bladders to obtain
extra oxygen
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Infraclass: Holosteri
Order: Lepisoteriformes
Gars inhabit fresh, brackish, and
occasionally marine, waters of
eastern North America, Central
America, and the Caribbean
islands. They have a swim
bladder that opens to the
pharynx that can function as a
lung and most gars surface
periodically to take a gulp of air,
doing so more frequently in
stagnant or warm water when
the concentration of oxygen in
the water is low
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Infraclass: Holosteri
Order: Amiiformes
Amia's are also called Bowfin or
Dog fish. Amia’s distribution is
restricted to eastern North
America. Amia's swim bladder
functions much like a lung,
allowing this fish to gulp air when
dissolved oxygen levels become
dangerously low in the weed
beds where it lives.
They are primarily fish eaters,
although crayfish can make up a
substantial proportion of the diet,
and frogs are also consumed.
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