Transcript Diagram to Review 33

Phylum Cnidaria: Cnidarians have radial symmetry, a
gastrovascular cavity, and cnidocytes
Two layers of cells that form TISSUES - cells that act as a functional unit
Gastrovascular cavity that allows for extracellular digestion - large food particles broken down so
that the gastrodermis can do intracellular digestion.
Simple nerve net forms nervous system - no brain
1. Phylum Platyhelminthes: Flatworms are
acoelomates with gastrovascular cavities
• There are about 20,000 species of flatworms
living in marine, freshwater, and damp terrestrial
habitats.
– They also include many parasitic species, such as the
flukes and tapeworms.
• Flatworms and other bilaterians are triploblastic,
with a middle embryonic tissue layer, mesoderm,
which contributes to more complex organs and
organs systems and to true muscle tissue.
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Two way gut
ventral nerve cords
Cephalization - brain, eye spot at head
gastrovascular cavity
acoelomate
5. Phylum Mollusca: Mollusks have
a muscular foot, a visceral mass,
and a mantle
• The phylum Mollusca includes 150,000 known species
of diverse forms, including snails and slugs, oysters and
clams, and octopuses and squids.
• Most mollusks are marine, though some inhabit fresh
water, and some snails and slugs live on land.
• Mollusks are soft-bodied animals, but most are protected
by a hard shell of calcium carbonate.
– Slugs, squids, and octopuses have reduced or lost their shells
completely during their evolution.
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Mantle secretes
the shell
Radula is used
for rasping food
off of surfaces,
but can be
modified to bore
holes or tear
apart tough
animal tissue
Has trochophore
larvae a type of
ciliated larvae
They lack true
segmentation
Gastropoda is
the largest
molluscan class
During
embryonic
development it
undergoes
torsion which
results in its
asymmetrical
shape
bivalves
Annelids have a true
coelom - which allows for
easier fluid movement
between organs
They have body
segmentation - each
segment can become
specialized
closed circulatory system
with hearts- blood with
hemoglobin
excretory tubes called
metanephridia collects
wastes from the blood
through a funnel called a
nephrostome and dumps
it outside through
nephridia pores.
Phylum Nematoda: Roundworms are nonsegmented
pseudocoelomates covered by tough cuticles
complete digestive tract
BLASTULA
invagination
GASTRULA
Forms mouth
in
protostomes
NEURULA
Arthropods are segmented coelomates with
exoskeletons and jointed appendages
The diversity and
success of
arthropods is
largely due to three
features: body
segmentation, a
hard exoskeleton,
and jointed
appendages.
Crustaceans
Spiders have
cheicerae - piercing
mouth parts
a pair of appendages
called pedipalps used for
sensing or feeding
four pairs of walking legs
book lungs used for gas
exchange
Insecta is the largest class
3 body parts with 3 pairs of
legs
two pair of wings
nitrogenous waste excreted
through Malpighian tubules
gas exchange through tracheal
tubes
mandibles (jaws)
Echinoderms
Coelomates
Echinoderms have water entering
into a madreporite down a water
vascular system that operates
tube feet
Deuterostomes
Radial
Symmetry
They are
capable of
everting their
stomach
through their
mouth - either
dumping the
contents or
digesting
something
outside of its
body
• The phylum Chordata includes three subphyla, the
vertebrates and two phyla of invertebrates, the
urochordates and the cephalochordates.
Fig. 34.1
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1. Four anatomical features
characterize the phylum Chordata
• Although chordates vary widely in appearance,
all share the presence of four anatomical
structures at some point in their lifetime.
– These chordate
characteristics are
a notochord; a dorsal,
hollow nerve cord;
pharyngeal slits;
and a muscular,
postanal tail.
Fig. 34.2
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Ectoderm
will
invaginate
to form the
spinal cord
and brain
Cells from the
neural crest may
form bone and
cartilage of the
skull
Notochord will
evolve into the
vertebrae of the
backbone
SuperClass Agnatha
Brain and cranium evolved
notochord will evolve into vertebrae of backbone
Jawless fish - mud suckers, suspension feeders or
parasitic
no paired fins
include lamprey and hagfish
Jaws and paired fins were major evolutionary breakthroughs
Jaws evolved from a pair of gill support bars
A jawed fish can exploit food supplies that were unavailable to earlier
agnathans
The Devonian period (about 360 to 400 million years ago) has been
called the “age of fishes”.
Chondircthyes
Sharks and rays have cartilaginous
endoskeleton
Jaws
gill slits
paired fins
The intestine of shark is a spiral valve, a corkscrew-shaped
ridge that increases surface area and prolongs the passage of
food along the short digestive tract.
The lateral line system, a row of microscopic organs
sensitive to pressure changes, can detect low frequency
vibrations
•The ancestors of Chondrichthyes had bony skeletons.
•The cartilaginous skeleton evolved secondarily.
Osteichthyes
Bony or calcified endoskeleton with skull (During the development of most vertebrates, the
skeleton is first cartilaginous and then becomes ossified as hard calcium phosphate matrix
replaces the rubbery matrix of cartilage)
operculum covers the gills
swim bladder controls the bouyancy swim bladder evolved from balloonlike lungs that may
have been used to breath air when dissolved oxygen levels were low in stagnant shallow waters
ray finned fish, lobe finned fish, lung fish
•Traditionally, all bony fishes were combined
into a single class, Osteichthyes, but most
systematists now recognize three extant classes:
the ray-finned fishes, the lobe-finned fishes, and
the lungfishes.
Amphibians adaptations for terrestrial living included
hard endoskeleton for support
a three chambered heart for more efficient circulation
lungs for breathing air
legs for movement on land
They are not true terrestrial organisms because:
the sideward limbs (not under body) did not support their weight
their skin dried out and their gametes and eggs dried out
The amnion provides a protective fluid environment for the embryo to develop in
Reptiles can lay eggs in very dry environments
Aves probably
arose from a
reptile
An ancestral
amniote gave rise to
Reptiles, Aves and
Mammals
Reptiles are true terrestrial organisms because they have:
scales on their skin to prevent dessication
internal fertilization
leathery or hard shell to prevent the eggs from drying out
amniotic eggs
Low pressure to
body
High
Mammalian Characteristics
• Evolved from
therapsids
• Hair (made of keratin)
• Mammary Gland
• Endothermic (active)
• diaphragm
• 4 chambered
heart/high metabolism
• most placental
Evolutionary Trends from Ape To
Humans
• Jaw became shorter and teeth
smaller
• Point of attachment of the
vertebra to the cranium
shifted from the rear to the
bottom-for bipedal walking
• Braincase became larger
• Feet Flattened and arch
developed
• Big toe moved in line
• Reduced Size Differences
Between the Sexes. In
hominoids, a size difference between
females and males is a major feature of
sexual dimorphism.
Evolutionary Trends from Ape To
Humans
• Eyebrow ridges and
other keels on the
skull were reduced
• Nose becomes more
prominent
• Arms become shorter