Unit 4 Lesson 1 How Are Living Things Grouped? Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Why Classify? Scientists use classification to organize living things into similar groups. Domains and kingdoms are the broadest levels of classification. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Why Classify? Scientists classify organisms so that they can understand how organisms are related. Cell type, cell structure, and genetic information are used to classify organisms. Shape, size, and symmetry are also used to classify organisms. A dichotomous key is a chart with many choices that guide you to the name of what you want to identify. Copyright © Houghton Mifflin Harcourt Publishing Company

Classifying Living Things Unit 4 Lesson 1 How Are Living Things Grouped? Classifying Living Things Organisms are classified into one of three domains. A domain is the broadest level of classification. Organisms are separated into domains by their cell structures. Organisms are more closely related to each other as you continue down each level of classification. Copyright © Houghton Mifflin Harcourt Publishing Company

Classifying Living Things Unit 4 Lesson 1 How Are Living Things Grouped? Classifying Living Things Kingdoms are the first level of classification. Organisms in kingdoms are grouped into phyla. A phylum can be broken into classes. The next level is order, which can be further divided into families. A genus is a subdivision of a family. Organisms are finally classified as species, or unique organisms. Copyright © Houghton Mifflin Harcourt Publishing Company

Plants and Animals There are more than 320,000 species of plants. Unit 4 Lesson 1 How Are Living Things Grouped? Plants and Animals There are more than 320,000 species of plants. Plants are made of many cells and use sunlight to make food. Plants are classified according to their structures and how they use those structures to live. Some plants have vascular tissue, which consists of long, narrow tubes that transport materials throughout the plant. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Plants and Animals Plants are also classified by how they reproduce. Some produce seeds in fruits, some produce seeds in cones, and some produce no seeds. Some plants use flowers to reproduce. Flowering plants make up the largest number of species in the plant kingdom. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Plants and Animals Most animals are made of multiple cells and cannot make their own food. Animals are divided into two groups. Vertebrates are animals with backbones, such as fish, birds, reptiles, amphibians, and mammals. Invertebrates are animals without backbones, such as insects, worms, jellyfish, and sponges. They make up about 95% of Earth’s animals. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Plants and Animals Some of the other factors used to classify animals include their body structures and how they take in oxygen and digest food. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Fungi and Protists Fungi do not make food from sunlight. Instead, they feed on dead or decayed materials. Mushrooms and yeasts are a type of fungus. Unlike mushrooms, yeasts are made up of only one cell. Some yeast cells can be seen only with a microscope. Scientists classify fungi according to size, shape, and the way they reproduce. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Fungi and Protists Kingdom Protista is very diverse. Protists may look or act like plants, fungi, or even animals. Most protists are made up of only one microscopic cell, but some protists live in large colonies that look like a single organism. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Fungi and Protists Protists can move by forming structures to drag themselves or by using hair-like structures to move in water. Many protists don’t move at all. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Fungi and Protists Scientists classify protists as plants, animals, or fungi. Plant-like protists use sunlight to make food and are classified according to size and color. Animal-like protists can move and capture prey. Fungus-like protists grow and feed like fungi. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Bacteria and Archaea Bacteria are microscopic and cover the surfaces of everything you see. Bacteria can cause disease and pollute lakes, but they can also be used to make foods, such as yogurt and cheese. Bacteria can even help us digest food. Bacteria are classified according to shape, size, how they get food, and whether or not they use oxygen. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 1 How Are Living Things Grouped? Bacteria and Archaea Archaea are single-celled organisms similar to bacteria. They are classified in separate domains because their structures and genetic materials differ. Archaea live in extreme environments, such as hot springs, where nothing else survives. Archaea get energy from unusual resources, such as ammonia or sulfur gas. Copyright © Houghton Mifflin Harcourt Publishing Company