Bio150 Chapter 01 - An Invisible World Flashcards
“Microorganisms or microbes”
Very small organisms; many types are too small to see without a microscope, although some parasites and fungi are visible to the naked eye.
Ötzi the Iceman
5300yr old mummy preserved in ice in Alps. Infected with eggs of the parasite Trichuris trichiura. Also found evidence of Borrelia burgdorferi, a bacterium that causes Lyme disease
Trichuris trichiura
Parasite that lays eggs causing abdominal pain and anemia. Ötzi had this.
Borrelia burgdorferi
Bacterium that causes Lyme disease. Ötzi had this.
Fomitopsis betulinus
Fungus that has laxative and antibiotics. Ötzi was carrying this and was thought to be using it to treat his infections.
Cloaca Maxima
A giant sewer system in ancient Rome to help remove waste. Was thought to aide in reducing waterborne epidemics.
Hippocrates
Greek physician (460-370BC) “Father of Western Medicine.” Rejected idea of illnesses caused by supernatural forces. Posited that they were naturally caused.
Thucydides
Greek philosopher (460–395 BC) “Father of Scientific Theory.” Advocated for evidence-based analysis of cause-and-effect. Observed that survivors of the Athenian plague, which killed 1/3 of the population, were unaffected by those who were actively sick. This shows an early understanding of immunology.
Marcus Terentius Varro
Roman writer (116–27 BC) who proposed things we cannot see can cause diseases. “Stay away from neighborhood swamps, they’ll make you sick.”
Antonie van Leeuwenhoek
Dutch (1632–1723) was first to develop lens strong enough to see microbes. Observed ‘animalcules’ which we now know were protists.
Golden Age of Microbiology
Spawned a host of new discoveries between 1857 and 1914
Louis Pasteur
French chemist (1822–1895) , showed that individual microbial strains had unique properties and demonstrated that fermentation is caused by microorganisms. He also invented pasteurization, a process used to kill microorganisms responsible for spoilage, and developed vaccines for the treatment of diseases, including rabies, in animals and humans
Robert Koch
German physician (1843–1910), was the first to demonstrate the connection between a single, isolated microbe and a known human disease. Discovered the bacteria that cause anthrax, cholera, and tuberculosis
Bacillus anthracis
Bacteria that causes anthrax
Vibrio cholera
Bacteria that causes cholera
Mycobacterium tuberculosis
Bacteria that causes tuberculosis
Taxonomy
classification, description, identification, and naming of living organisms
Carolus Linnaeus
Swedish (1701–1778). In 1735 published Systema Naturae, an 11-page booklet in which he proposed the Linnaean taxonomy, a system of categorizing and naming organisms using a standard format so scientists could discuss organisms using consistent terminology
Linnean taxonomy
This divided the natural world into three kingdoms: animal, plant, and mineral (the mineral kingdom was later abandoned). Within the animal and plant kingdoms, he grouped organisms using a hierarchy of increasingly specific levels and sublevels based on their similarities. The names of the levels in Linnaeus’s original taxonomy were kingdom, class, order, family, genus (plural: genera), and species.
Phylogenies
taxonomies that took into account the evolutionary relationships
Today, phylogenic analyses include what comparisons?
genetic, biochemical, and embryological comparisons
Linnaeus’s tree of life contained just two main branches for all living things:
Animal and Plant Kingdoms
Ernst Haeckel
German who proposed another kingdom, Protista, for unicellular organisms. Later proposed a fourth kingdom, Monera, for unicellular organisms whose cells lack nuclei, like bacteria.
Robert Whittaker
American, (1920–1980) who proposed adding another kingdom, Fungi, in his tree of life. Whittaker’s tree also contained a level of categorization above the kingdom level, the empire or superkingdom level to distinguish between organisms that have membrane-bound nuclei in their cells (eukaryotes) and those that do not (prokaryotes)
Empire Prokaryota contained:
Only Kingdom Monera.
Empire Eukaryota contained:
The other four kingdoms: Fungi, Protista, Plantae, and Animalia.
Viruses are not found in any of these trees because?
They are not made up of cells and thus it is difficult to determine where they would fit into a tree of life.
Modern taxonomy relies heavily on?
Comparing the DNA, RNA, or proteins from different organisms. The more similar the nucleic acids and proteins are between two organisms, the more closely related they are considered to be.
Carl Woese discovered what?
What appeared to be a “living record” of the evolution of organisms. He and his collaborator George Fox created a genetics-based tree of life based on similarities and differences they observed in the gene sequences coding for small subunit ribosomal RNA (rRNA) of different organisms. In the process, they discovered that a certain type of bacteria, called archaebacteria (now known simply as archaea), were significantly different from other bacteria and eukaryotes in terms of their small subunit rRNA gene sequences.
Archaebacteria is also known as?
Archaea
To accommodate this difference in gene sequences coding for rRNA, what was created?
A tree with three Domains above the level of Kingdom: Archaea, Bacteria, and Eukarya
Analysis of small subunit rRNA gene sequences suggests archaea, bacteria, and eukaryotes all evolved from a common ancestral cell type. The tree is skewed to show a closer evolutionary relationship between?
Archaea and Eukarya than they have to Bacteria.
Horizontal gene transfer
When a gene of one species is absorbed into another organism’s genome. This is especially common in microorganisms and can make it difficult to determine how organisms are evolutionarily related. Consequently, some scientists now think in terms of “webs of life” rather than “trees of life.”
Binomial nomenclature
A two-word naming system for identifying organisms by genus and specific epithet
Bergey’s Manual
Standard references for identifying and classifying different prokaryotes. Without easily observable macroscopic features like feathers, feet, or fur, scientists must capture, grow, and devise ways to study their biochemical properties to differentiate and classify microbes. Because so many bacteria look identical, methods based on nonvisual characteristics must be used to identify them
Within one species of microorganism, there can be several subtypes called
Strains. While different strains may be nearly identical genetically, they can have very different attributes. Think “E. coli”
An object must measure about how many micrometers (μm) to be visible without a microscope
100 micrometers (μm)
