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Animal Unit. November 8, 2010. Multicellular Organisms. Animals are multicellular organisms. Cells. In multicellular organisms, different cells have different jobs.
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Animal Unit November 8, 2010
Multicellular Organisms • Animals are multicellular organisms.
Cells • In multicellular organisms, different cells have different jobs. • In a multicellular organism the cells are organized in ways that enable them to survive and reproduce. (In a single-celled organism, all the functions of life are performed by one cell.)
Cells are Specialized For Example • Blood cells carry oxygen • Nerve cells send and receive signals • Skin cells provide protection • Muscle cells produce movement
Tissue • Cells that work together to carry out a job are organized into tissue.
Tissue • Cells of the same type are organized into tissue. • Tissue is a group of cells that work together. For Example A muscle is muscle tissue that is made up of many muscle cells.
Organs • Tissues are organized into organs. Each organ has a particular function (job).
Organs • Organs are structures that are made up of different tissues. Organs have particular functions. For Example The heart is an organ that functions as a pump. It has muscle tissue, which pumps the blood, and nerve tissue, which signals when to pump.
Organ System • Organs are part of different organ systems that meet specific needs of the organism.
Organ systems and the Organism • Different organ systems take care of specific needs. For Example Nervous System –enables a response to changing conditions. Muscular System – produces movement and supplies heat. Respiratory Systems – takes in oxygen and releases carbon dioxide.
Circulatory System – delivers oxygen and removes carbon dioxide. • Digestive System – breaks down food int a usable form. Organ systems allow multicellular organisms to obtain large amounts of energy, process large amounts of materials, respond to changes in the environment, and reproduce.
Organism • Together, cells, tissues, organs, and organ systems form an organism.
Levels of Complexity This organization is called the levels of complexity. Cells→Tissue→Organs→Organ System
****** Specialized structures perform specific functions at all levels of complexity. For Example: Leaves on trees Wings on birds
Animals • All animals need energy, materials, and living space. • Animal get energy and materials from food. • Animals have different adaptations and behaviors for meeting their needs. • Animals are consumers (they get food from their environment). • Most animals have body systems, including tissues and organs. • Animals interact with the environment and other animals.
Invertebrates • Most animals are invertebrates (animals that do not have backbones). • Most invertebrate animals are small. • Invertebrates can be found just about everywhere (from frozen tundra to tropical forests). Some invertebrates live in water and others survive in deserts. • Many organism live inside other organisms.
Animals That Are Invertebrates • Crickets • Oysters • Sea stars • Earthworms • Ants • Spiders • Sponge Where do they live?
Large Invertebrates • Even though most invertebrates are small a Giant Squid can grow to 18 meters long and can weigh over 450 kilograms.
Six Groups of Invertebratespage 124 • Sponges (the simplest animals on Earth). p125 • Cnidarians (have a central opening surrounded by tentacles). p128 • Worms (soft, tube-shaped bodies and a distinct head). p132 • Mollusks ( Have a muscular foot, most have shells – Example: clams, snails, octopuses). Include bivalves, gastropods, and cephalopods.p136 • Echinoderms (water animals that have a central opening for taking in food, have a water vascular system and tube feet – Example: sea stars, sand dollars).p139 • Arthropods ( have legs, some have wings, are found on land in air and in water – Example: insects, spiders, crabs millipedes). Includes insects, crustaceans, and arachnids.p142
Vocabulary • Invertebrate • Sponge • Sessile • Larva • Cnidarian • Tentacles • Mobile • Mollusk • Gill • Lung
Vocabulary • Echinoderm • arthropod • Radial symmetry • Bilateral symmetry • Exoskeleton • Molting • insect • Metamorphosis • segmented
Questions to Consider • Which group of animals are most abundant? • Is a spider an insect? • How are all invertebrates alike? • What is the process called when arthropods shed their exoskeleton? • Which invertebrate always have three body segments: a head, a thorax, and an abdomen?
Answers • 1. Arthropods are the most abundant group of animals. • 2. A spider is an arachnid. Insects, arachnids, and crustaceans are examples of a larger group of invertebrates called arthropods. • 3. All invertebrates lack a backbone. • 4. As arthropods grow, the y shed their exoskeleton in a process called molting. • 5. Adult insects always have a head, thorax, and adomen.