Transcript Unit 4.2
Chapter 7 UNIT 4.2 Classification of Living Things TYPES OF LIVING THINGS Living things are classified by similar characteristics. Each different type of organism is called a species. It is estimated that there are over ten million different species on Earth. All of the same kind of dust mite are members of a single species. KINGS PLAY CHESS ON FINE GRAIN SAND I N G D O M H Y L U M L A S S R D E R A M I L Y E N U S P E C I E S CLASSIFYING LIFE One system of classification groups all living things into one of six kingdoms: • Archaea • Bacteria • Protista Fungi Plantae Animalia ARCHAEA Contains unicellular organisms that are similar to bacteria, BUT have a different cell structure Can be spherical, rod, spiral, or irregular in shape. Some exist as single cells, others form filaments or clusters. Until the 1970s this group of microbes was classified as bacteria. Can live in extreme environments BACTERIA Unicellular organisms with no nucleus usually grouped into three types: rod-shaped (bacilli), spherical (cocci), or curved/helical (spirilla) Some bacteria can produce their own food. Others break down food and absorb it. PROTISTA Includes organisms that are not easily classified as animals, plants, or fungi. They are either unicellular or simple multicellular organisms Have nuclei Amoeba are classified as Protista FUNGI Includes mushrooms, molds, and yeasts Fungi are important because they break down rotting things and return the nutrients to the soil. PLANTAE made up of multicellular organisms whose cells have a nucleus. Includes plants, such as trees, grass, and moss In photosynthesis, plants convert energy from the sun and store it in the form of molecules Producers Divided into terrestrial (on land) and aquatic (water-dwelling) Terrestrial is divided into seed bearing (seeds) and non-seed bearing (spores) ANIMALIA Includes animals, from lions and tigers and bears to ants and tiny mites. Beetles, worms, snakes, and birds are classified into the Kingdom Animalia. Animals are multicellular organisms with cells that have a nucleus. CLASSIFYING LIFE To classify a living thing into one of the kingdoms, scientists ask 3 questions: 1. Does it have prokaryotic (simple) cells or eukaryotic (complex) cells? 2. Is it unicellular (single-celled) or multicellular (many-celled)? 3. Does it get energy by making its own food (as a producer) or by getting food from other organisms (as a consumer)? PLANT AND ANIMAL KINGDOMS- COMPARED CLASSIFYING LIFE Taxonomy is the process of identifying and classifying living things. A Swedish scientist and explorer named Carolus Linnaeus (1707–1778) developed a system of classification in the 1700s. There are currently seven levels of classification. LEVELS OF CLASSIFICATION Organisms with shared characteristics are grouped together. What characteristic do these organisms share? LEVELS OF CLASSIFICATION For animals, the levels of classification are: kingdom, phylum, class, order, family, genus, and species. •At what level are these two animals classified differently? SCIENTIFIC NAMES A scientific name is the two-part, scientifically recognized name given to an organism, consisting of its genus and species. SCIENTIFIC NAMES You may have a difficult time understanding scientific names because they are usually in Latin or Greek. Felis is Latin for “cat” and domesticus is Latin for “domesticated.” DICHOTOMOUS KEYS A dichotomous key is a tool that helps its user identify natural objects like birds, trees, rocks, fungi, and insects. Dichotomous means "divided into two parts.” WHAT IS IT? The ghost plant (Monotropa uniflora) lacks the green pigment chlorophyll, which gives most plants their color. How should we classify this species? DICHOTOMOUS KEYS It is difficult to create a key for the kingdoms because there are so many organisms to consider. DICHOTOMOUS KEYS A dichotomous key turns questions into paired statements. DICHOTOMOUS KEYS Most dichotomous keys are designed to identify small groups like trees, butterflies, and song birds. Can you suggest a way to tell these arthropod classes apart? DICHOTOMOUS KEYS Here is one solution… ECOLOGY CONNECTION Discovering a New Species There are still remote regions on Earth, even though it may seem like humans have been everywhere. ACTIVITY Making a Dichotomous Key Scientists who study the characteristics of organisms and their relationships to other organisms are called taxonomists. Make a dichotomous key to identify your classmates’ shoes.