The Science of Sytematics
Systematics- the science of phylogeny (all species are related due to evolutionary relationships.
There are 8 categories of life.
”Genus” and “species” produce the scientific names of animals.
Rules to scientific names: Genus and species are always italicized. First letter of Genus is capitalized while species is left in lower case.
Aristotle was the first to attempt to classify animals.
Karl von Linnaeus used a Latin system of classification of animals ( Based on resemblance to other life forms.)
Charles Darwin demonstrated that all organisms are related by common systems.
Similarity of DNA helps to clarify not classify organisms.
Before 1970 all forms of
Chapter 19
Diversity of Viruses:
Host specific, reproduce in the host’s cells (not cellular), nucleic acids wrapped in a protein coat of its own DNA or rNA, extremely small, cannot grow, cannot reproduce, spreads to other organisms, multitude of shapes.
Bacteriophage- virus that attacks bacteria
Viruses will attack specific types of cells and can also mutate. (AZT limits the replication of HIV viral agents)
Viroids- do not have a protein coat, they are unique to plants (citrus)
Prions- neural wasting disease, loss of bodily function, smallest known infectious agents. Only protein based. Only found in neural tissues.
Gram-Stain Sample Test- differentiates possible domain of viral agents based on cell wall structure.
Prokaryotes can be rod, corkscrew, or spherical shaped. They have flagella. Form bio-films to adhere to surfaces which protects against antibiotics.
Prokaryotes can endure extremes of climate change and varying atmospheric pressures. (Extremophiles)
Many prokaryotes can go dormant for years. They go into a non-functioning state. Diverse metabolism, anaerobic or aerobic. (Causes tetanus).
A few bacteria are photosynthetic (cyanobacteria) like plants.
Endospores- resistant structures that help bacteria to survive. Helps in dormancy (Anthrax)
Most endospores are virulent, easily dispersed, and enclosed in resistant enclosures for protection.
Conjugation- cell membranes of two bacteria bridge together to have DNA exchange (Parasexual Reproduction)
Nitrogen fixation captures nitrogen and affixes it to hydrogen to create (NH4) “ammonia”
Rhizobium spores are an example of Nitrogen fixation.
Nitrogen gas is fixated into soil due to lightning strikes.
Pathogenic Bacteria
Skin is the first line of defense against bacterial agents. Open wounds make infection more possible.
Black Death (Yersinia pestis) killed half of Europe. This bacteria is non-fatal if treated in early stages. Today there are approximately 2000-300 killed per day from the Black Death.
Streptococcus pneumonia causes debilitating symptoms by stimulating an allergic reaction that clogs the lungs with fluid.
E. coli (Mad Cow Disease) is another pathogenic bacteria.
Protists- any eukaryotic organism that is not a plant, animal or fungus. (60,000 varieties approx.)
Photosynthetic protests are –algae
Non-Photosynthetic protests are- protozoa
Chromists- oomycetes (water mold)
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