November 8, 2010

 Animals are multicellular organisms.

 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.)

For Example  Blood cells carry oxygen  Nerve cells send and receive signals  Skin cells provide protection  Muscle cells produce movement

 Cells that work together to carry out a job are organized into 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.

 Tissues are organized into organs. Each organ has a particular function (job).

 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.

 Organs are part of different organ systems that meet specific needs of 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.

 Together, cells, tissues, organs, and organ systems form an organism.

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

 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.

 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.

 Crickets  Oysters  Sea stars  Earthworms  Ants  Spiders  Sponge Where do they live?

 Even though most invertebrates are small a Giant Squid can grow to 18 meters long and can weigh over 450 kilograms.

 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

 Invertebrate  Sponge  Sessile  Larva  Cnidarian  Tentacles  Mobile  Mollusk  Gill  Lung

 Echinoderm  arthropod  Radial symmetry  Bilateral symmetry  Exoskeleton  Molting  insect  Metamorphosis  segmented

1. Which group of animals are most abundant? 2. Is a spider an insect? 3. How are all invertebrates alike? 4. What is the process called when arthropods shed their exoskeleton? 5. Which invertebrate always have three body segments: a head, a thorax, and an abdomen?

 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.