SIX KINGDOMS & DOMAINS Section 9.1 cont….

The Kingdoms of Life The Greek philosopher Aristotle, divided all living things into two large groups, known as kingdoms: Plantae & Animalia.

Along Came The Microscope Classifying organisms became more difficult after the microscope was invented. The new tool revealed a previously unknown world of living things. Some microscopic organisms have characteristics of both plants and animals.

Protista In 1866, the German biologist Haeckel proposed classifying microorganisms that are neither animals nor plants into a third kingdom: Protista. EuglEEna

Fungi – The Fourth Kingdom As biologists learned more about the structure and way of life of different organisms, they added more kingdoms. Fungi, originally in the plant kingdom, do not carry out photosynthesis. They obtain food by absorbing materials into their bodies.

Eubacteria Eubacteria consist of very small cells that differ in appearance from the cells of the other kingdoms. Bacteria lack a nucleus and other organelles. They are classified in a fifth kingdom: Eubacteria.

Archaebacteria During the 1990s, there was growing interest in certain types of bacteria found in extreme environments, such as salt lakes or hot, acidic springs. New studies found that these bacteria were very different from other bacteria. The new data led scientists to rename and reclassify these microorganisms into a sixth kingdom: Archaebacteria.

Prokaryotes & Eukaryotes The study of cells is an important first step in understanding the diversity of life.

Prokaryotic Cells Eukaryotic Cells Eubacteria, archaebacteria Protists, plants, fungi, animals Small Large DNA circular, not bounded by membrane DNA in nucleus bounded by membrane Genome: 1 chromosome Genome: Many chromosomes Cell Division not by mitosis/meiosis Cell Division: mitosis/meiosis Asexual reproduction common Sexual reproduction common Multicellular forms are rare Most are multicellular Mitochondria and other membrane-bound organelles are absent Mitochondria and other organelles present Many are anaerobic Most are aerobic

Fossil Evidence The first forms of life were prokaryotic organisms similar in appearance to bacteria. First prokaryotes appear: 3.5 billion years ago. First eukaryotes appear: 1.5 billion years ago. First multicellular organisms appear: 700 million years ago.

The Three Domains Recent research on the cell has shown that living prokaryotes are far more diverse than anyone had previously suspected. This research led to a new level of classification above kingdoms, known as domains. The domain system better reflects the evolutionary history of life. The three domains are: Eubacteria, Archaebacteria and Eukaryota.

Domain Eukaryota Kingdoms: Protista, Fungi, Plantae and Animalia. The greatest biological diversity occurs within the Kingdom Protista. For example, there is a much greater genetic difference between some species of protists than there is between, for example, corn and humans.

Eukaryota Domain Kingdom Protista Fungi Plantae Animalia # of Cells Eubacteria Archae-bacteria Eukaryota Kingdom Protista Fungi Plantae Animalia # of Cells Unicellular Uni Mostly uni Mostly multi Multi Nucleus No Yes Cell Wall Some Nutrition Autotroph and Heterotroph Heterotroph Autotroph Reproduction Asexual Asexual and Sexual Sexual

Homework: P. 334 #5,6