View
236
Download
5
Category
Tags:
Preview:
Citation preview
Invertebrate Zoology
Animals without Backbones
Patterns of the Invertebrate
• Symmetry- orientation around a central axis
• Germ Layers- embryonic tissue
• Deuterosome vs Protostome
• Body openings and digestion
• Coelom development
Deuterostomes
• Indeterminate cleavage
• blastophore becomes anus/second opening becomes mouth
• radial cleavage-cells of cleavage are aligned
Protostomes
• Determinate cleavage in most ( fate fixed early)
• blastophore develops into a mouth first
• Spiral cleavage-cells do NOT line up
Symmetry• ( a ) radial- can be
divided along any plane, through a central axis into roughly equal halves
• ( b ) bilateral- can be divided down it’s length only one way into similar right and left halves
• (not shown asymmetry-irregular in shape
Germ Layers
1. Ectoderm- outermost germ layer (forms skin, nerves )
2. Mesoderm- middle germ layer ( forms muscle, kidney, liver etc.)
3. Endoderm- innermost germ layer ( forms digestive and reproductive tract )
1.
2
3
Mesoderm forms as an outpocketing from endoderm
ectoderm
endoderm
Coelom
• Coelomate- has a true coelom CAVITY WITHIN A BODY
• Acoelomate- lacks a true coelom
• Pseudocoelomate- false body cavity ( no mesodermal connection )
Body Cavity
• COELOM- true cavity within a body
• Acoelomate- lacks a true body cavity
• Pseudocoelomate- has a false body cavity ( cavity develops with no mesodemal connection )
• Coelomate- true body cavity developing from out pockets of the mesoderm
SUMMARYGERM LAYERS
1. Ectoderm- outermost germ layer (forms skin, nerves )
2. Mesoderm- middle germ layer ( forms muscle, kidney, liver etc.)
3. Endoderm- innermost germ layer ( forms digestive and reproductive tract )
BODY SYMMETRY
• Symmetry- orientation around a central axis• ( a ) radial- can be divided along any plane,
through a central axis into roughly equal halves
• ( b ) bilateral- can be divided down it’s length only one way into similar right and left halves
• (not shown asymmetry-irregular in shape
Invertebrate Phyla
Porifera
Parazoa-lacking true tissue
Filter feeders- incurrent and excurrent pore ( osculachoanocytes- collar cells that create currentamoebocytes- capture food by phagocytosis
Spicules- silica or calcium carbonate skeletal structuresSpongin- protein in some species for support
Hermaphrodites contain both male and female sex organsBEHAVE LIKE A COLONY
Cnidarians
Eumetazoan- have true tissuesRadial symmetryacoelomate- lack a coelomdiploblastic- only two germ layersAlternation of generationpolyp- plant likemedusa- free swimming ( jelly fish like
Digestive traffic-two way, gastrovascular cavity-no separate
circulatory/digestive system
Nematocyst- stinging cell
Sea Anemone
Phylum Cnidaria
Class HydrozoahydraClass Scyphozoajelly fishClass Anthozoasea anemone
BUD-----
nematocyst
Platyhelminthes
Planaria
Nematoda
• Three germ layers
• Pseudocoelomate
• One-way digestive pattern
• Little need for resp. or digestive system
• Separate sexes
• Parasitic and free-living
ectoderm
endoderm
mesoderm
Rotifera• Mostly freshwater
• Pseudocoelom with several organ systems
• Crown of cilia around mouth
• Both sexual and asexual reproduction
S- SYMMETRY assymetryGL-GERM LAYERS noneBO-BODY OPENINGS manyBC-BODY CAVITIES acoelomateDT-DIGESTIVE TRAFFICnone, filter feeds cells digestCS-CIRCULATORY SYSTEMnone, filter water to remove water
phylum sym germ layeropen cav diges circporifera asy nonemany acoel none nonecnidaria rad 2 1 acoel two gastrovascular cavityplaty bil 3 1 acoel twonematoda bil 3 2 pseudo one noneannelida bil 3 2 coelom one closed with 5 heartsmollusca bil 3 2 coelom one bivalves-open, ceph-closedechinodermatarad 3 1 coelom water vascular systemarthropoda bil 3 2 coelom one open system
digestive traffic is direction of digestive system
characteristic inse
cta
arac
hnid
a
chio
poda
dipl
opod
a
crus
tace
a
segments A.orB.A C C Aappendages H, K. DOP K,G F E jointedlocomotion Z, K. D G F Efeeding N N,O N N Nnervous sys K.,L. K.,L. K.,L. K.,L.K.,L. sensoryrespiration V V V V X gas exchangereproduction Y Y Y Y Yexcretion R R R R Q. eliminate nitrogen waste
circulation S S S S S
Recommended