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DO NOW. Pick up papers on the chair Read over the crayfish activity Answer on the Lab What is the difference between an arthropod and a mollusk? 10 o Clock Buddies. Agenda. Discovery Notes Tick Brochures (?). Crayfish. Dorsal Side. Ventral Side. Arthropods. Science 7 Mr. D.
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DO NOW • Pick up papers on the chair • Read over the crayfish activity • Answer on the Lab • What is the difference between an arthropod and a mollusk? • 10 o Clock Buddies
Agenda • Discovery • Notes • Tick Brochures (?)
Crayfish Dorsal Side Ventral Side
Arthropods Science 7 Mr. D
Arthropods • Characteristics – Phylum: Arthropoda • Largest group of animals • Have jointed appendages which include legs, antennae, claws, wings, and pincers • Have bilateral symmetry, segmented bodies, exoskeletons, a body cavity, a digestive system with two openings and a nervous system • Most have separate sexes and reproduce sexually • Open circulatory system • Use air tubes, book lungs, and gills to obtain oxygen
Arthropods • Body Segments • Bodies of these animals are divided into segments similar to segmented worms • Some have many segments, others have segments that are fused together to form body regions • Exoskeleton • A hard outer covering that supports and protects the internal body and provides places for muscle to attach. • Doesn’t grow as the animals does, it is shed and replaced during a process called molting
What are they • Crustaceans • Centipedes • Millipedes • Spiders and their relatives • Insects
Crustaceans • Have one or two pair of antennae and mandibles, which are used for crushing food. • Most live in water, but some live in moist environments on land—such as pill bug. • Have five pair of legs, first pair of legs are claws for catching and holding food.
Crustaceans • Swimmerets are appendages on the abdomen which help in movement and are used in reproduction; also force water over the gills used in O2 and CO2 exchange • If a crustacean loses an appendage it can regenerate it
Who are they? • Crabs • Lobsters • Barnacles • Shrimp
Centipedes & Millipedes • Have long bodies and many segments, exoskeleton, jointed legs, antennae and simple eyes. • Found in damp environments • Reproduce sexually • Make nests for eggs and stay with them until they hatch. • Centipedes are predators • Millipedes feed on decaying plant matter.
Meet the Arachnids • Spiders • Scorpions • Ticks • Mites
Arachnids • Have two body regions • Cephalothorax and an abdomen • Four pairs of legs and no antennae • Many are adapted to kill prey with poison glands, stingers, or fangs • Some are parasites
Arachnids • Scorpions • Have sharp, poison filled stinger at the end of abdomen. • Have a well-developed appendages which they can grab their prey. • Spiders • Can’t chew their food, release enzymes into prey to digest it—then suck the predigest liquid into its mouth. • Have book lungs where O2 and CO2 are exchanged.
Arachnids • Mites & Ticks • Most are parasites • Ticks have specialized mouthparts to remove blood from the host. • Ticks often carry disease such as Lyme disease.
Value of Arthropods • A source of food • Agriculture would be impossible without bee pollination • Useful chemicals are obtain from some arthropods • Important part of ecological community
Origin of Arthropods • Some fossils are more than 500 million years old • Scientist hypothesized that arthropods probably evolved from an ancestor of segmented worms because they have body segments • The hard exoskeleton and walking legs allowed arthropods to be among the first animals to live successfully on land
Video • http://www.youtube.com/watch?v=ySXCdcnKBgg# • http://www.youtube.com/watch?v=2N0lfprZ5iU
Activity • Design a series of signs to be used along hiking trails in national parks to remind hikers of ways to protect themselves from ticks
DO NOW • Take out your homework and Notesheet • Answer this question – How are arthropods different from sponges and cnidarians? • Agenda • Finish lecture • Insects • Zebra Mussels