INTRODUCTION TO ORGANISMS AND CLASSIFICATION

Two Major Domains: Archaea and Bacteria Prokaryotes Two Major Domains: Archaea and Bacteria Prokaryotes are single-celled organisms that do not have a membrane-bound nucleus, and can live in nearly every environment on Earth. Prokaryotes differ greatly in their genetic traits, their modes of nutrition, and their habitats. Based on genetic differences, prokaryotes are grouped in two domains: Domain Archaea and Domain Bacteria.

Three Domains of Living Organisms Prokaryotes Three Domains of Living Organisms

Prokaryotes Domain Archaea One of the ways in which archaea differ is the make up of their cell wall. Archaeal cells walls lack a protein-carbohydrate complex found in bacterial cell walls that make their cells walls rigid. (peptidoglycan). Archaea differ in the types of lipids in their cell membrane. Also, archaeal genes do not contain introns.

Domain Archaea, continued Prokaryotes Domain Archaea, continued Archaeal Groups (3) Archaeal groups include methanogens, halophiles, and thermoacidophiles.

Prokaryotes Domain Bacteria Bacteria occur in many shapes and sizes. Most bacteria have one of three basic shapes: rod-shaped, sphere-shaped, or spiral-shaped. Rod-shaped bacteria are called bacilli (singular, bacillus). Sphere-shaped bacteria are called cocci (singular, coccus).

Three Bacterial Cell Shapes Prokaryotes Three Bacterial Cell Shapes

Structure and Function, continued Biology of Prokaryotes Structure and Function, continued Prokaryotic Movement Many prokaryotes have long flagella that allow the prokaryotes to move toward food sources or away from danger.

VIRUSES

Characteristics of Viruses Viral Structure and Replication Characteristics of Viruses Are viruses alive? Viruses do not have all of the characteristics of life and are therefore not considered to be living. They are not on the phylogenetic “tree of life”

Viral Replication Replication in Viruses That Infect Prokaryotes Viral Structure and Replication Viral Replication Replication in Viruses That Infect Prokaryotes Bacteriophages are viruses that infect bacteria.

Viral Diseases Human Viral Diseases Viruses cause many human diseases, including the common cold, flu, hepatitis, rabies, chickenpox, certain types of cancer, and AIDS.

Prevention and Treatment Viral Diseases Prevention and Treatment Vaccinations (as a means of prevention) A vaccine contains a harmless version of a virus, bacterium, or a toxin that causes an immune response when introduced to the body. Vaccines have helped to greatly reduce certain viral diseases.

PROTISTS

A Diverse Group of Eukaryotes Characteristics of Protists A Diverse Group of Eukaryotes Protists are unicellular or simple multicellular eukaryotic organisms that are not plants, fungi, or animals.

Characteristics of Protists Classification Protists are classified by the characteristics that make them fungus-like, plant-like, or animal-like.

Characteristics Unicellular and Multicellular Characteristics of Protists Characteristics Unicellular and Multicellular Most protists are unicellular, but some form large, multicellular bodies. Mobility Protists use flagella, cilia, or pseudopodia for locomotion. Nutrition Protists can be heterotrophic or autotrophic

Reproduction Protists reproduce either asexually, sexually, or both. Characteristics of Protists Reproduction Protists reproduce either asexually, sexually, or both. Protists can reproduce either asexually by binary fission, multiple fission or sexually by conjugation.

Examples of Protists Paramecium Euglena Plasmodium (Causes malaria)

Protists and Health Malaria Protists and Humans Protists and Health Malaria Parasitic protists in the genus Plasmodium cause malaria, which is characterized by severe chills, headache, fever, and fatigue. Each year, nearly 3 million people die from malaria.

FUNGI

Overview of Fungi Characteristics Fungi are eukaryotic, nonphotosynthetic organisms that can be unicellular or multicellular in form. Most fungi are microscopic molds or yeasts. Molds that grow on bread and fruit are tangled masses of filaments. Yeasts are fungi whose colonies look similar to bacteria.

Characteristics Cell walls of chitin Decompose Overview of Fungi Characteristics Cell walls of chitin Decompose Cells are not completely divided

Examples of Fungi Bread molds Mushrooms Penicillin

Classification of Fungi Lichens Lichens represent symbiotic relationships between fungi and photosynthetic organisms, such as cyanobacteria or green algae. The algae makes sugar for the fungus and the fungus provides moisture, shelter and anchorage for the algae.

Section 3 Modern Classification Chapter 17 Six Kingdoms

Phylogenetic Diagram of Major Groups of Organisms Section 3 Modern Classification Chapter 17 Phylogenetic Diagram of Major Groups of Organisms

Plants

Eukaryotic, Multicellular Chloroplasts and starch granules in bryum moss

Autotrophic, Cell wall made of cellulose

Major

Animals Organelles? Cell walls? Unicellular? How do they eat? Eukaryotic No cell wall Multicellular Heterotrophic