Viruses, Bacteria, Protists, & Fungi (Part 1)

1. Viruses, Bacteria, Protists, & Fungi(Part 1)

2. Classification • One of the jobs Darwin had on his voyages was to record and classify any new species he encountered. • Scientists, like Darwin, had to figure out a way to classify organisms so they could be easily identified in the wild. • Classification – The process of grouping things based on their similarities. • The study of how things are classified is called taxonomy.

3. Classify yourself • How would you classify yourself? Write down qualities, descriptive features, or other modifiers that both make you unique and part of a larger group of people. (List at least seven different things.) • Mr. Huelsman • Science Lab (or) Bearded • St. Gabriel Brown eyes • Louisville Over 5ft • Kentucky Left handed • United States Extroverted • North America Male • Earth Human

4. Taxonomy of Life • In the 1750’s, a scientist by the name of Carolus Linnaeus devised a naming system for organisms called binomial nomenclature. • Binomial Nomenclature follows these rules: • All organism will receive a two-part ‘scientific name’. • All names will be given in Latin. (Why?) • The first part of an organism’s scientific name is its Genus. (This is always capitalized.) • The second part of an organism’s scientific name is its species. (This is always lower case.)

5. Classification beyond Genus • Species with similar evolutionary histories are often classified more closely together and share the similar Genus names. • Organisms that have characteristics in common beyond Genus share more general classification names. (ex: We are all Kentuckians, but are also US citizens.) • Today, scientists use 8-9 different levels of classification to group organisms. • These levels are determined by characteristics that are shared by a group of organisms.

6. Levels of Classification • From broadest to most specific: • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species • Subspecies • Dutch Kings Play Chess On Fine Green Silk Sometimes

7. Domains of Life • Currently, there are three accepted domains of life: • Archaea Domain • Single-celled, prokaryotic organisms that resemble the earliest forms of life. They can be either autotrophic or heterotrophic. • Many archaea live in ‘extreme’ environments. • Bacteria Domain • Single-celled, prokaryotic organisms that can be either autotrophic or heterotrophic. • Bacteria are classified in their own domain b/c their chemical makeup is different from that of archaea. • Eukarya Domain • Eukaryotic celled organisms that can be either autotrophic or heterotrophic. • Eukarya organisms can be unicellular or multicellular. • Currently divided into four ‘Kingdoms of Life’

8. Eukarya Kingdoms • There are currently four kingdoms in the Eukarya Domain: • Protist Kingdom • A group of eukaryotic organisms that can either be unicellular or multicellular. • They can be heterotrophic or autotrophic. • This kingdom is known as the ‘odds n’ ends’ kingdom. • Fungi Kingdom • Multicellular, eukaryotic organisms that resemble plants, but are heterotrophic instead of autotrophic. • Fungi feed on dead or decaying organisms. • Plant Kingdom • Multicellular, eukaryotic organisms that are autotrophic. • Plants feed almost all heterotrophic organisms on Earth. • Animal Kingdom • Multicellular, eukaryotic organisms that are all heterotrophic. • Animals have special adaptations that allow them to locate, capture, eat, & digest food.

9. Re-classifying Things • It was once taught that there are six kingdoms of life: • Archaebacteria Kingdom* • Eubacteria Kingdom* • Protist Kingdom* • Fungi Kingdom • Plant Kingdom • Animal Kingdom • All “living” things are classified into one of these kingdoms. (What about viruses?) • Occasionally, some organisms are moved from one kingdom to another; or a new kingdom forms if more information about that organism is discovered. • (ex: Plant/Fungi Kingdoms; Protozoa/Chromista Kingdoms; Protists/Monera Kingdoms; etc…) • The first three kingdoms listed above continue to be renamed and reclassified even to this day.

10. Viruses • Viruses are small, non-living particles that invade & then reproduce inside of a living cell. • Biologists consider viruses to be non-living b/c viruses do not have a cell structure. They also do not use energy to grow, nor do they respond to their environment. • The only thing viruses share in common w/ living organisms is genetic material, which both use for replication.

11. All viruses have two basic parts: • An outer protein coat that protects the virus • An inner core made of genetic material (Some viruses also have ‘legs’, which they use to attach to a host cell.) • Viruses must ‘infect’ a host cell in order to reproduce. They do this by attaching themselves to a cell and injecting their genetic material inside. This then takes over the cells functions and reprograms the cell to produce copies of the virus. • Many viruses instruct the cell to continue replication until the cell dies.

12. Active vs. Hidden Viruses • A unique feature of viruses are that they can sometimes ‘hide’ within a cell. • Hidden viruses do not immediately take over a cell’s functions, but rather become part of the cell’s genetic material for a period of time. (ex: cold sores, chicken pox, etc..) • These viruses then occasionally ‘activate’ themselves and begin replication. (ex: stress can trigger hidden viruses.) • Active viruses immediately take over a cell’s functions and begin making new copies of themselves.

14. Preventing Viral Infections • Since viruses are non-living, they cannot be treated w/ antibiotics. • Instead, white blood cells must physically digest or rip apart viruses for them to stop infecting new cells. • Your body can also produce chemicals that attach to viruses preventing them from infecting new cells. • In order to ‘train’ your body to start producing these chemicals, people are given a weakened or altered version of the virus called a vaccine. • When vaccines are introduced, your body is tricked into thinking it’s under attack and starts producing the chemicals necessary to prevent certain viruses from ever infecting your cells. • If the virus doesn’t evolve rapidly, one vaccine may be enough to prevent a viral infection. If the virus does evolve rapidly, then several doses may be necessary throughout your life.

15. Bacteria • Bacteria are prokaryotes, meaning that their genetic material is not contained in a nucleus. • Bacteria come in several different shapes and sizes. The three most common are spherical, rodlike, & spiral. • In order to move in their environment, some bacteria have whiplike structures called flagellum that spin in place like a propeller. • When bacteria have plenty of food, the right temperature, and other suitable conditions, they thrive and reproduce quickly forming, sometimes forming colonies.

16. Features of Bacteria • There are few interesting features that bacteria exhibit: • Binary fission – the process where a bacteria cell divides to form two identical cells • Conjugation – the process where bacteria transfer genetic material through thin, threadlike fibers. • If a bacteria is placed in an extreme environment, it can also form into an endospore. • Endospore – a small, rounded, thick-walled, resting cell that forms inside of a bacteria cell. • Endospores can allow a bacteria to survive freezing, heating, and drying sometimes for years. Some bacteria have been found to survive in space!

17. Roles of Bacteria w/ Humans • Bacteria benefit / “harm” the living world by: • Providing oxygen. • Providing food. • Examples include cheese, pickles, sauerkraut, yogurt, vinegar, sour cream, etc.. • Pasteurization is the process of heating foods to kill bacteria that would otherwise “spoil” some foods • Aiding in the digestion/recycling of materials found in nature. • This also provides fuel sources. (ex: methane gas) • Bacteria are sometimes used in chemical spills to eat toxins. • Converting nitrogen gas into nitrogen products that plants absorb in the soil.

18. Bacterial Health & Medicine • Bacteria are also a source of both disease and medicine in living things. • Helpful bacteria living on humans benefit you by: • Aiding in your digestion of certain foods • Creating certain vitamins for your body • Attacking harmful bacteria that invade your body • Genetically modified bacteria can also mass produce certain medicines or organic compounds. • Examples: Insulin, Human Growth Hormone, etc.. • Harmful bacteria can be killed by chemicals called antibiotics. (ex: penicillin, amoxicillin, etc..)