What are they and how are they grouped? Animals What are they and how are they grouped?

What is an Animal? Body Structure Obtaining Food and Oxygen Keeping Conditions Stable Movement Reproduction

Structure of Animals Animals are composed of many cells (multicellular). Cell: The basic unit of structure for all living things. The cells of MOST animals are organized into higher levels of structure, including tissues, organs, and systems.

Tissues, Organs, and Systems Tissue: A group of similar cells that perform a specific function. Example: Nerve cells working together to transport electrical signals through the body. Organ: A group of several different tissues working together. Example: A frog’s thigh bone is composed of bone tissue, nerve tissue, and blood. System: Groups of structures performing the broadest functions in an organism.

Functions of Animals From tiny worms to giant whales, animals are diverse. Despite their differences, however, all animals carry out the same basic functions. The major functions of animals are… Obtain food and Oxygen Keep internal conditions stable Move Reproduce

Obtaining Oxygen and Food An animal cannot make its own food, it must obtain it from eating other organisms (heterotroph). Food provides animals with raw materials for growth and with energy for their bodies activities. All animals body cells need oxygen to release energy from food. Some animals get oxygen from the air and some from water.

Keeping Conditions Stable Animals must maintain a stable environment within their bodies. When balance is lost, animals do not survive very long. For example, cells that get too hot start to die. Animals have adaptations that allow them to stabilize their bodies in the environment they live in. Homeostasis: Keeping internal conditions stable.

Movement All animals move in some way at some point in their lives. Most move freely their whole lives by swimming, running, hopping, flying, etc. Some, like oysters or barnacles, only move from place to place at the earliest stages of their lives. Animal movement is usually related to their needs of survival and reproduction.

Reproduction Because individual animals cannot live forever, they must reproduce. MOST animals reproduce sexually. Sexual Reproduction: The process by which a new organism develops from the joining of 2 sex cells --- a male sperm cell and a female egg cell.

Reproduction (cont.) Fertilization: The joining of a sperm and egg cell. New individuals resulting from sexual reproduction have a combination of characteristics from both parents. Some animals can reproduce asexually as well as sexually.

Asexual Reproduction Asexual reproduction: The process by which a single organism produces a new organism identical to itself. For example, animals called sea anemones sometimes split down the middle, producing two identical organisms.

Classification of Animals Scientists have identified more than 1.5 million species of animals!!! Animals have been classified into roughly 35 major groups of animals (35 phylum). Animals are classified according to how they are related to other animals. These relationships are determined by an animal’s body structure, the way the animal develops and its DNA.

The 2 biggest groupings… Invertebrates: All animals without backbones. Vertebrates: All animals with backbones. We will be spending much of our time studying the vertebrates, but roughly 97% of animals on Earth are invertebrates!!!

Recap All animals: Are made of cells, most are grouped into tissues, organs and systems. Are heterotrophs and need oxygen to survive. Are adapted to keep their internal conditions stable in whatever environment they live in. Move at least sometime during their lives. Reproduce. Most sexually, some can perform asexual as well. Are classified according to how closely they are related to other animals