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Arthropods!. Do Now: Turn in Earthworm dissection. Phylum Arthropoda. Biggest phylum of animals currently alive and extinct. Several MILLION different species Exist in every environment, in almost every ecosystem on Earth.
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Arthropods! Do Now: Turn in Earthworm dissection
Phylum Arthropoda • Biggest phylum of animals currently alive and extinct. • Several MILLION different species • Exist in every environment, in almost every ecosystem on Earth. • By any measure, the most “successful” animal phylum. ¾ of all known species of animal are arthropods.
What Makes an Arthropod? • Exoskeleton: • Hard, protective outer “shell.” • Used for movement • Made with chitin, a polysaccharide.
Exoskeleton for Muscle Attachment • Your muscles are attached to an endoskeleton. • An exoskeleton serves the same purpose
What Else Makes an Arthropod? • Bilateral symmetry
Segmented body plan • Each segment has at least 1 pair of appendages. • Legs, antenae, flipers, claws, etc. are all appendages. • Some segments may be fused together.
3 Main Body Sections • Called tagmata: Some may be fused
Recap: Arthropod Characteristics • EXOSKELETON • Bilateral symmetry • Segmented body plan (3 main sections: head, thorax, abdomen) • Jointed appendages (many pairs). Note: arthropod means “jointed foot.”
Arthropod Circulatory System • Open circulatory system with heart.
Arthropod Respiration • Gills/book lungs: oxygen diffuses into blood • Trachea: air moves into insect directly
Types of Arthropods • Domain: Eukyra • Kingdom: Animalia • Phylum: Arthropoda • Classes: Crustacea, Insecta, Arachnida (+ Myriapoda
Class Crustacea: The Crustaceans • Only arthropod class with 2 pairs of antennae.
Class Crustacea: The Crustaceans • Includes crabs, lobsters, shrimp, as well as pillbugs.
Crustacean Orders • “True” Crustaceans = Order Decapoda • 5 pairs of thorasic legs • 2 tagmata • Cephalothorax • Abdomen • “Pillbugs” = Order Isopoda • 7 pairs of thorasic legs • 3 tagmata
Class Insecta • 1 pair of antennae • 3 pairs of legs • 3 tagmata • Wings or wingless
Insect Diversity • Biggest order of animal on Earth • Over 900,000 documented species. • Highest estimates suggest up to 30,000,000 species may exist.
Class Arachnida: Spiders, Ticks, Scorpions, Mites, etc. • No antennae • 4 pairs of legs
Arachnids Trilobites = Extinct Arachnids
Centipedes And Millipedes: Class Myriapoda • One pair of antennae. • Two tagmata: head and trunk 1 pair of legs per segment centipede subclass chilopoda 2 pairs of legs per segment Millipede subclass diplopoda
Recap: Arthropod Family Tree Phylum Arthropoda Class Crustacea Class Insecta Class Arachnida Class Myriapoda many orders many orders, including extinct trilobites Chilopoda Deca-poda diplopoda Iso-poda