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Invertebrates. Invertebrate. - Organism without a backbone. 3 Main Body Plans. 1. Bilateral. 2. Radial. 3. Asymmetrical. Bilateral. - Two sides of the body mirror each other. Radial. - Symmetry is found all around the center point. Asymmetrical. - There is no line of symmetry.
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Invertebrate - Organism without a backbone 3 Main Body Plans 1. Bilateral 2. Radial 3. Asymmetrical Bilateral - Two sides of the body mirror each other Radial - Symmetry is found all around the center point Asymmetrical - There is no line of symmetry
Invertebrate Characteristics Ganglion - Concentrated mass of nerve cells - Nerves allow animal to sense environment - All animals except sponges have nerves Gut - A pouch used to break down food Coelom - Space surrounding the gut - Can have other organs within
Sponges - Asymmetrical - Simplest invertebrates - Live in water - Can regenerate broken or missing parts Regeneration - Ability to grow back a body part -Holes on the outside of body -Water brings in food and oxygen Pores Osculum -Hole on top of sponge that allows water to leave
Cnidarians - Radial symmetry -complex tissue and a gut -simple nerve cells -stinging cells - Ex: Jellyfish, Anemones - Two body forms: Medusa or Polyp - Swims through water Medusa - Usually attach to a surface Polyp
Classes of Cnidarians Hydrozoans -common cnidarians -live in both fresh and salt water -most spend lives as polyps Jellyfish -use tentacles to catch food -spend most of lives as medusas -brightly colored -spend lives as polyps Sea anemones Coral -polyps -brightly colored -made of calcium carbonate -live in colonies -build reefs
Round Worms - Bilateral symmetry - Simple nervous system - Brain is a ring of ganglia • Many are parasites Trichinella spiralis • Some infect humans pinworms and hookworms • decomposers
Flatworms - Bilateral symmetry - Clearly defined head - Two large eyespots - Cannot see through eyespots, but sense light • Some can be parasitic • 3 main type Planarian -Live in freshwater -predators -well developed nervous system Flukes -parasites -no eyespots -contain suckers and hooks to attach to other animals
Tapeworm -parasites -no gut or eyespots -attach to the intestines of other animals Absorb nutrients -can infect humans
Mollusks -Most live in the ocean -some live in freshwater and land -complex ganglia -contain a circulatory system -Bodies are made of : • -Muscular foot-used for movement • -Visceral mass- contains gut, gills, • and other organs • -Mantle-covering used for protection • if no shell • -Shell-hard covering used for protection
3 Classes of Mollusks -slugs and snails Gastropods -eat by using a radula tongue with curved teeth Bivalves - 2 shells -clams and other shellfish -use gills to filter food from water Cephalopods -Octopus and squid -use tentacles to get food and a powerful jaw to eat it -contain large brain connected to ganglia
Annelid Worms -segmented worms -bodies are in segments identical repeating body parts -bilateral symmetry -circulatory system -Complex nervous system with brain -Live in salt water, freshwater or on land -3 major groups Earthworms -most common -decomposers -leave casting in soil produce rich soil Use stiff hairs or bristles to move
-Colorful -Live in ocean Marine Worms -Polychaetes covered in bristles -Eat mollusks or filter water for food -Parasites that suck blood produces a chemical that thins blood can be used medically Leeches -Scavengers that eat dead animals
Four Characteristics Shared by Arthropods 1. Segmented and specialized body 2. Jointed limbs - Body parts bend at joints 3. External Skeleton (Exoskeleton) 4. Compound Eyes Exoskeleton - Hard covering of the body Antennae - Feelers that sense touch, taste, and smell Compound Eye - Several identical light-sensitive units
Mandible - Mouthparts that can pierce objects Crustaceans - Have gills, antennae, and mandibles - Have compound eyes Ex: Shrimp, Crab, Lobster
Arachnids - 2 body parts: Cephalothorax and Abdomen - 4 pairs of legs - Simple eyes -spiders, scorpions, mites, ticks
Insects - Largest group of arthropods - Six legs - 3 main body parts 1. Head 2. Thorax 3. Abdomen
Metamorphosis - Change from young to adult - Organism goes through a complete change CompleteMetamorphosis - No major changes in organism IncompleteMetamorphosis - Grows from smaller youth to larger adult
Echinoderms - Means “spiny skinned” - Radial symmetry - Simple nervous system - contains a mouth Sea stars, Sand Dollars Endoskeleton - Internal bones and cartilage
- System of canals WaterVascularSystem - Circulates water - Used to move, eat, sense environment, breathe
Types of Echinoderms Brittle Stars Basket Stars -long slim arms -smaller than sea star Sea Urchins Sand Dollars -round with no arms -shell-like structure -use spines and tube feet to move Sea Lilies Feather Stars -have multiple feathery arms Sea Cucumbers -no arms and worm-shaped