INVERTEBRATES INVERTEBRATES CH. 24-27 CH. 24-27
Mar 27, 2015
INVERTEBRATESINVERTEBRATES
CH. 24-27CH. 24-27
Kingdom AnimaliaKingdom AnimaliaMajor Characteristics= eukaryotic, multi-cellular, heterotrophic, lack a cell wall
Invertebrates◦Include 95-97% of all animal species
◦Without a backbone
ExoskeletonExoskeleton
Hard, tough outer covering that provides framework and support
Made of chitin
EndoskeletonEndoskeleton
Internal skeleton
EndodermEndoderm
Inner layer of cells in the gastula
Develops into tissues and organs of the digestive tract
EctodermEctoderm
Outer layer of cells in the gastula
Develops into skin and other body coverings and the nervous system
MesodermMesoderm
Between the endoderm and ectoderm
Develops into skeletons and muscles
CoelomCoelom
Fluid filled cavityProvides open space inside of body
Coelom
SegmentationSegmentation
“put together”Sectionsmultiple body components
CephalizationCephalization
Animals with anterior (head) & posterior (tail)
Tendency to concentrate nervous and sensory organs at the anterior
Development of a specialized head
AsymmetryAsymmetry
Irregular shapeEx. Sponge
Radial symmetryRadial symmetry
Body plan in which parts repeat around an imaginary line drawn through the center
Ex. Cnidarians (jellyfish)
Bilateral SymmetryBilateral Symmetry
Body plan in which left and right sides are identical when an imaginary line is drawn through the center
Ex. Flatworm
SpongesSponges
• Sessile: live entire adult life attached to a single spot • Very simple: no mouth, no organ systems• Rely on the movement of water through their bodies for respiration, circulation, and excretion• Based on their shape, what is their symmetry?
CnidariansCnidarians
• Soft-bodied, carnivorous, stinging tentacles• Simplest animals to have body symmetry and specialized tissues• Based on their shape, what is their symmetry?
Platyhelminthes Platyhelminthes (Flatworms)(Flatworms)
• Soft, flattened worms• Simplest organisms to have cephalization• Based on their shape, what is their symmetry?
Nematoda Nematoda (Roundworms)(Roundworms)
• Unsegmented worms• Have pseudocoeloms and digestive systems with two openings• Many are predators• Some act as parasites that affect humans• Based on their shape, what is their symmetry?
MolluscaMollusca
• Soft-bodied• Usually have an internal or external shell• Based on their shape, what is their symmetry?
Annelida (Segmented Annelida (Segmented Worms)Worms)
• Worms with segmented bodies• Have a true • Based on their shape, what is their symmetry?
ArthropodaArthropoda
Have a segmented body, tough exoskeleton, jointed appendages
Exoskeleton◦Hard, tough outer covering that provides framework and support
◦Made of chitin
Arthropoda - Arthropoda - CrustaceansCrustaceans
• Two pairs of antennae, and two or three body sections• Have chewing mouthparts called mandibles• Based on their shape, what is their symmetry?
Arthropoda – Arachnids Arthropoda – Arachnids (Chelicerates)(Chelicerates)
• Have mouthparts called chelicerae• Two body sections• Nearly all have four pairs of walking legs• Based on their shape, what is their symmetry?
Arthropoda - InsectsArthropoda - Insects
• Jaws• One pair of antennae• Three-part bodies
• head, thorax, abdomen• legs attached to thorax
• Based on their shape, what is their symmetry?
EchinodermataEchinodermata
Sea Cucumber
Sea Urchin
• Spiny skin• Internal skeleton• Water vascular system• Suction-cup “feet” • Based on their shape, what is their symmetry?
Circulatory Circulatory SystemsSystemsOpen circulatory system- a system in which blood vessels from the heart are not contained in blood vessels
Circulatory Circulatory SystemsSystemsClosed circulatory system- a system in which blood is confined to vessels as it moves through the body