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Mollusks, Arthropods, and Echinoderms 7th Grade Science
Chapter 10 Mollusks, Arthropods, and Echinoderms 7th Grade Science
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Mollusks __________ - invertebrates with soft unsegmented bodies that are often protected by a harder outer shell _________ - a thin layer of tissue that covers the internal organs – produces the hard shell _______ - crawling, digging, or catching prey Examples of Mollusks – clams, snails, scallops, oysters Mollusks Mantle foot
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Characteristics of Mollusks
_____________ - bilateral symmetry and a digestive system with __________. Body parts are not repeated as in segmented worms – instead organs are located in one area. _________________ - blood is not always inside blood vessels – blood sloshes over the organs and returns to the heart. Body Structure Two openings Open circulatory system
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Obtaining oxygen ____ - mollusks that live in water obtain oxygen through _______ and __________ _____ - hair-like structures that move back and forth making the water flow over the gills Gills remove oxygen from the water and passes it into the bloodstream Wastes are also removed through the ______ into the water gills cilia Blood vessels cilia gills
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Three Main Groups Mollusks are classified into three main groups based on _______________ Three main groups of mollusks are: ___________ - single external shell or no shell __________ - two shells held together by hinges ___________ - ocean dwelling – foot adapted to form tentacles around its mouth Physical characteristics gastropods bivalves cephalopods
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Gastropods ___________of mollusks Examples: _____________
Live nearly everywhere on earth Some are ________, _________, and ________ ________ - organ that is a flexible ribbon of tiny teeth to obtain food Movement – creeping along on a broad _____ Largest group Snails and slugs herbivores carnivores scavengers radula foot
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Bivalves Oysters, clams, scallops, and mussels
Found in ________________ ____________ - strain their food out of water as it flows over their gills __________ Movement - _____ float or swim, adults attach themselves to hard surfaces or use their ____ to move slowly Water environments Filter feeders omnivores larva foot
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Cephalopods Octopuses, squids, cuttlefish
Only mollusks with a __________________ _________ - captures prey using muscular tentacles. ________ - uses to cut the flesh of its prey ___________ - most complex of all invertebrates, large eyes and excellent vision, large brains and ability to remember learned items. Movement - ____________ Closed circulatory system carnivores radula Nervous system Jet propulsion
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Arthropods ___________ - spider, grasshopper, crabs, lobsters, centipedes and scorpions. Classified into 4 major groups: __________ ___________________ ____________ arthropods crustaceans arachnids Centipedes and millipedes insects
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Arthropods Body Structure
Arthropods are __________ that have: _______________ ___________ - jointed attachments “arthros” – Greek for ______ “podos” – Greek for __________ Bilateral symmetry ______ circulatory system and a digestive system with ___________ Reproduce sexually invertebrates External skeleton A segmented body Appendages joint Foot or leg open Two openings
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Outer Skeleton ___________ - waterproof outer covering
Exoskeleton _________ the animal and prevents __________ Arthropods occasionally shed their exoskeleton and grow new ones that are larger. __________ - the process of shedding the exoskeleton exoskeleton protects Evaporation molting
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Segmented Body Segmented bodies similar to an earthworm
Easy to see segments in _________ and __________. An arthropod may have up to three segments: _________ ___________ Segments are _________ looking centipedes millipedes head Mid-section Hind section identical
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Jointed Appendages ________ in ___________ give the animal ____________ and enable it to ________ ______________________ tools for moving, eating, reproducing, and sensing the environment ________ - an appendage that is attached to the _____ that contains sense organs. ____ and _____ are also appendages Joints appendages flexibility move Appendages are highly specialized antenna head legs wings
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Diversity Scientists have identified more species of arthropods – over a million – than all other species of animals combined!
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Crustaceans ___________ - shrimp, crab, and pill bugs
Crustaceans thrive in ________, ______, or ___________ ___________ - two or three body sections, five or more pairs of legs, and two pairs of antenna ______ - most have gills to obtain oxygen ____ - scavengers, predators, herbivores crustaceans freshwater oceans Damp places Body structure oxygen food
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Life Cycle of Crustaceans
Life cycle for many varieties begins as _______ ______________ - a process in which an animal’s body undergoes dramatic changes in form during its life cycle. _________ develop into adults through ____________. larvae metamorphosis larvae metamorphosis
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Arachnids ________ - spiders, mites, ticks, and scorpions
Arachnids are _________ with two body sections, four pairs of legs, and no antennae ____________ - combined head and midsection _____________ - hind section called the ________ ___________ - contains the reproductive organs and part of the digestive system. arachnids arthropods First body section Second body section abdomen abdomen
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Spiders / Mites/ Scorpions/Ticks
All spiders are ________ and most eat _______. Adaptations include _____ - used to inject venom and sucks in food _______ and chiggers are _________ __________ - adaptation is a _____ at the end of its abdomen to inject venom into prey. ______ - parasites that live on the outside of hosts bodies predators insects fangs parasites Mites stinger scorpions ticks
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Math / Analyzing Data pg. 341
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Centipedes and Millipedes
Centipedes and millipedes are _________ with ____________ and _____________. First body section has a _____ with one pair of _________ The second body section has a long _________ with many body segments ___________ have one pair of legs attached to each segment arthropods Two body sections Many pairs of legs head antennae abdomen centipedes
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Centipedes and Millipedes Continued
Centipede means ______________ Centipedes are very fast _______ that inject venom into their ____. ____________ - have more than 80 segments have _____ pairs of legs on each segment. Millipede means _____________ - they do not have that many Millipedes are _________ “ one hundred feet” predators prey Millipedes two “thousand feet” scavengers
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Section 2 Assessment Page 342 (1 and 2)
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Insects ________ - caterpillars, plant hoppers, dragonflies, and bees
Insects are ___________ with all of the following: _________________ ________ ________________ insects arthropods Three body sections Six legs One pair of antennae Two pairs of wings
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Body Structure The three body sections are:
________ - most of the insects sense organs, two large compound eyes – keen at sensing movement. Simple eyes distinguish between light and darkness. _______ - midsection where wings and legs are attached. Insects are the only invertebrates that can fly _________ - contain the internal organs head thorax abdomen
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Obtaining food Insects feed on all of the following depending on their specialized and adapted _________: _________________________ __________________________________ ______________________________________ mouthparts Parts of plants – leaves or nectar Products that are made from plants – book lice Animal – fleas and mosquitoes feed on the blood of living animals Animal droppings – dung beetle Decaying bodies of dead animals – burying beetles
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Life Cycle Insects are born from tiny, hard shelled ___________
After they hatch, insects begin a process of ____________ (either complete or gradual) before becoming an _____insect. __________________ - four stages _______ ______ - specialized for eating and growing ______ - enclosed in a protective covering _______ - beetles, butterflies, flies and ants Fertilized eggs metamorphosis adult Complete metamorphosis egg larvae pupa adult
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Gradual Metamorphosis
________________ - no distinct larval phase. Egg hatches into a stage called a _____ _________ - looks like an adult insect without wings Grasshoppers, termites, cockroaches and dragonflies. Gradual metamorphosis nymph nymph
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Insect Ecology ___________ - series of events in which one organism eats another and obtains energy. __________ - the study of food chains and other ways that organisms interact with their environment All food chains begin with the ____ Next a _________ - an organism that makes its own food – grass and other plants. Food Chain ecology sun producer
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Insects and the Food Chain
___________ - producers are the food that provides energy. Some consumers also eat other _________. ___________ - breaks down the wastes and dead bodies of other organisms Insects can either be _________ or _________ in the food chain Insects can be ______ for other consumers consumers consumers decomposers consumers decomposers prey
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Insects as Consumers, Prey, and Decomposers
Insects eat about ____ of the crops grown by humans as well as wild plants. Caterpillars ________ plant materials Caterpillars and other insects are _______ for other types of animals such as birds and fish. Insects such as the carrion beetle are __________ - feed on the tissues of dead birds. 20% consume prey decomposers
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Pollen and Disease Carriers
_________ - an animal that carries pollen among plants. Examples of insects as pollinators are _______________. Without pollinators some plants would not be able to _________ Insects that carry diseases often have ______________ that pierce the skin of their prey that provides an opening for the disease to enter the organisms body - ______ pollinators Bees, beetles, and flies reproduce Sucking mouth parts malaria
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Controlling Pests _________ - use of chemicals to control pests
Pesticides have also killed _________ Humans have also used ____ and other __________ (such as other insects) to control pests. _______________ - a natural predator or disease released into an are to fight a harmful insect. pesticides pollinators traps Living things Biological control
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Echinoderms _____________ - invertebrates with an internal skeleton and a system of fluid filled tubes. All echinoderms live in ________ The internal skeleton of the echinoderms is called an __________ - made up of hard plates which give the animal a bumpy texture. ______________ usually in multiples of 5 Echinoderms Salt water Endoskeleton Radialy symmetrical
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Movement _________________ - the internal system of fluid-filled tubes
The water vascular system contracts and forces water into the _______ - the ends of the tube feet are sticky and they act like suction cups. The ________ and __________ allow the echinoderms to grip the surface beneath them Water vascular system Tube feet suction stickiness
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Reproduction and Life Cycle
_____ are usually fertilized in the ______ Fertilized egg develops into a swimming ______ . ______ undergo ___________ and become ______ echinoderms. 4 major groups of echinoderms: __________, __________, _________, __________ eggs water larvae larvae metamorphosis adult Sea stars Brittle Stars Sea Urchins Sea Cucumbers
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