Download Invertebrates

Classification
The three-domains
Bacteria
Archaea
Eukarya
The six-kingdom system
Bacteria
Archaea
Protista
Plantae
Fungi
Animalia
Fungi
Animalia
The traditional five-kingdom system
Monera
Protista
Plantae
(Forams and Radiolarians) Rhizarians
Rhodophyta
CHLOROPHYTA
AMOEBOZOANS
Alveolates
Stramenopile
Euglenozoa
Evidence indicates that animals evolved
from choanoflagellates (protists) ~ 570 mya
•
•
•
•
Single cells
Often clonal
Heterotroph
No
specialization
or coodination
between cells
Animal Classification
1. DNA sequencing
2. Body Symmetry
3. Presence or absence of body cavity
4. Embyonic Development
Symmetry
Body Cavity
Most bilateral animals have body cavities
– Body cavities are fluid-filled cavities
between the digestive tube and the outer
body wall
– Functions:
• skeleton, providing support for the body and a
framework against which muscles can act
• protective buffer between the internal organs
and the outside world
• They can allow organs to move independently
of the body wall
Body Cavity?
epidermis
A No coelom
(acoelomate animal)
gut
cavity
organs packed between
gut and body wall
Fig. 25-4a, p. 405
Body Cavity?
epidermis
B Pseudocoel
(pseudocoelomate animal)
gut
cavity
unlined body cavity around gut
Fig. 25-4b, p. 405
Body Cavity?
epidermis
C Coelom
(coelomate animal)
gut
cavity
body cavity with a lining (dark
blue) derived from mesoderm
Fig. 25-4c, p. 405
Embryonic Development
Protostomes
Blastopore forms
mouth first
Deuterostomes
Blastopore forms
anus first
Porifora - sponges
• Sessile (Larva motile)
• No true tissues or organs
• Exhibit asymmetry or radial
symmetry
• Filter feeders
Sponge Anatomy
epithelial
cell
spicules
(water flow out
of the sponge)
pore
(water flow into
the sponge)
amoeboid
cell
pore cell
collar cell
(water flow)
Fig. 23-5
Sponge filtration/feeding
Collar Cell
Collar Cell
http://www.youtube.com/
watch?v=T7E1rq7zHLc&feat
ure=player_embedded
http://www.youtube.com/watch?v
=29W77870BgE&list=PLVN5247pO
BYcE1Mn_pWHIL9l0sMIx19TI
Figure 23-4 The diversity of sponges
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Cnidaria – Sea Anemone
• Radial symmetry
• Two tissue layers
• Filled with water–
supports body
• Nerve net
• Nematocysts -stinging
organelles that release
toxins
Cnidarian Weaponry: The Cnidocyte
trigger
filament
trigger
nuclei
(b) Cnidocytes
Fig. 23-8
Cnidaria: Symbiosis
Coral is a mutualism between photosynthetic
dinoflagellates (protist) and a cniderian (animal)
• Algae in coral called zooxanthelle
In many coral species polyps form colonies
Cnideria
video
Colonial polyps secrete
a hard external
skeleton of calcium
carbonate
The skeleton remains
after the polyp dies
New polyps build on
the skeletal remnants
of earlier generations
Figure 23-6a Anemone
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Figure 23-6b Sea jelly
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Figure 23-6c Coral
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Figure 23-7a Polyp
mouth
lining of
gastrovascular
cavity
tentacle
body wall
gastrovascular
cavity
foot
(a) Polyp
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Medusa
lining of
gastrovascular
cavity
gastrovascular
cavity
body wall
tentacle
mouth
(b) Medusa
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Nematoda - round worms
• Exoskeleton (molts)
• Unsegmented
• Psuedocoelom (false body
cavity)
• Bilateral worms
• 3 tissue layers
• Parasites and decomposers
A freshwater nematode
posterior
end
intestine
anterior
end
ovary
vagina
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eggs
mouth
cuticle
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Platyhelminthes - flatworms
• Bilateral symmetry
• 3 tissue layers
• Cephalization (nerve
mass)
• True organs and organ
systems
• Aceolomate (no body
cavity)
• Parasitic forms but
some free living
Figure 23-9 Flatworm diversity
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Figure 23-17 The exoskeleton allows
precise movements
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Figure 23-18 The exoskeleton must be
molted periodically
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antennae
head
thorax
abdomen
compound eye
mouth parts
wing
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Figure 23-21a Aphid
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Figure 23-21b Ant
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Figure 23-21c Beetle flying
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The diversity of myriapods
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Figure 23-24c Hermit Crab
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Figure 23-24d Barnacles
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Figure 23-24b Sowbug
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Annelida - segmented worms
Polychaetes- many hairlike chetae
12,000 species
Mostly marine
Oligochaets- few or no chetae
Earthworms
10,000 species
Aquatic or terrestrial decomposers
Hirudinia- leeches
700 species
coelom
nephridia
intestine
excretory
pore
ventral
nerve cord
anus
coelom
brain
mouth
pharynx
ventral
vessel
hearts esophagus
ventral nerve cord
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crop
gizzard
intestine
Diverse annelids
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Mollusca
(clams, snails, slugs, octopuses & squids)
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unsegmented
bilateral symmetry
coelomates
aquatic & terrestrial
possess all organ systems
Figure 23-14 The diversity of
gastropod mollusks
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The diversity of bivalve mollusks
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Figure 23-16a Octopus
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Squid
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Figure 23-16c Nautilus
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Figure 23-27a Sea cucumber
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Figure 23-27b Sea urchin
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Figure 23-27c Sea star
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