What Is an Animal? Chapter 9 Section 1

Structure of Animals Composed of… ◦Cells ◦Cells: basic unit of structure and function of living things ◦Tissue ◦Tissue: group of similar cells that perform a specific function organs ◦Tissues combine to form organs, more complex job systems ◦Organs combine to form systems

Functions of Animals Obtaining food and oxygen Obtaining food and oxygen Keepings conditions stable Keepings conditions stable Movement Movement Reproduction Reproduction

Food and Oxygen Food Food provides animals with raw materials for growth and energy cavity Most animals take food into a cavity inside their bodies ◦It is then digested/broken down oxygen To release energy from food, the body’s cells need oxygen

Adaptations a structure or behavior that allows animals to perform basic functions in their environments

Movement Some animals move around their entire life Some animals move around their entire life ◦Humans, frogs, dogs (swim, walk, hop) Some animals move for part of their lives Some animals move for part of their lives ◦Oysters, barnacles Why do animals move? Why do animals move? ◦Obtaining Food ◦Reproducing

Reproduction Sexual Reproduction Sexual Reproduction ◦New organisms develops from the joining of two sex cells (male sperm cell and female egg cell) ◦Combination of both parents characteristics What is the joining of an egg cell and a sperm cell called? What is the joining of an egg cell and a sperm cell called?  Fertilization

Reproduction Continued Asexual Reproduction ◦Process by which a single organism produces a new organism identical to itself  Sea Anemones  Single-celled organisms such as the archaea, bacteria, and protists

Classification of Animals 1.5 million species phylum Biologists have classified animals into about 35 major groups called phylum single-celled ancestors Evidence suggests that all animals arose from single-celled ancestors When classifying, biologists consider ◦How it looks ◦How it develops ◦The content of its DNA

Vertebrate vs. Invertebrate Vertebrates Vertebrates ◦animals with a backbone Invertebrates Invertebrates ◦animals without a backbone ◦97%