TAXONOMY:
Taxonomy is the classification of living organisms. The biologists divide the whole world of living things into six kingdoms.
THE SIX KINGDOMS
1- A) The arrangement of all six kingdoms from the simplest to the most complex:
One: Archaeobacteria
Two: Eubacteria
Three: Protista
Four: Fungi
Five: Plantae
Six: Animalia
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| Six kingdom classification of life |
B) The Kingdoms that meet the criteria for
Microorganisms are:
One: ArchaeobacteriaTwo: Eubacteria
Three: Protista
Four: Fungi
C) There are two Kingdoms that do not qualify as Microorganisms, they are Plantae and Animalia.They do not fit the criteria to quality as an Microorganism.
D) The two characteristics that disqualify each kingdom
as Microbes are:
1) Plantae and Animalia Kingdoms have tissue differentiation.
2) Plantae and Animalia can be seen with the unaided human eye while the microbes can be seen only through the lenses of a microscope.
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| The various cells of the human body |
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| Plant tissue system |
DIVERSITY OF MICROBIAL LIFE
(Why Microbes cannot fit into a single group or Kingdom)
2- A) Two characteristics Eubacteria and Archaea share are that both are prokaryotic and single celled organisms. Also, they both lack membrane bound organelles such as nuclei and mitochondria. Both of them are also characterized by having a single chromosome and asexual reproduction by binary fission. Therefore both are denominated bacteria in general.
B) The estimated average sizes of Archaea and Bacteria are 0.2 micrometer in diameter and 2-8 micrometer in length.
3. To characteristics that differentiate the Kingdoms Archaea and Animalia from Eubacteria are the following:
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EUBACTERIA
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ARCHAEA
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ANIMALIA
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Organism
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Bacteria, Cyanbacteria, Actinobacteria
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Methanogens, Halophiles,
Thermophiles
Psychrophiles
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Amoebia
SpongeMammals Reptiles |
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Cell Type
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Prokaryotic
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Prokaryotic
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Eukaryotic
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Metabolism
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Anaerobic
Aerobic
Facultative |
Aerobic
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Aerobic
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Nutritional Acquisition
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Absorption
Photosynthesis Chemosynthesis
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Absorption
Non-photosynthesis Photophosphorylation
Chemosynthesis
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Reproduction
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Asexual
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Asexual
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Sexual
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C). The estimated average sizes of human and animal cells differ in many ways and from organ to organ. In Humans, the estimated average sizes and shapes vary. The average cell is between 10 to 100 micrometers. This diversity is due to the cell's primary function. Some cells, for example the nerve cells, are long and can measure up to a meter long while others like a cheek cell is about 50 micrometers or 0.05 millimeters in size. In Animals, most cells range in size between 1 and 100 micrometers and are visible only with the aid of a microscope.
4-A) The two kingdoms Fungi and Plantae share the following characteristics: both fungi and plants are eukaryotic, the are multicellular, they possess a cell wall, they produce spores and they are non-motile.
B)
Fungi and Plants are not grouped into the same Kingdom because they differ in the way the take nutrients. Plants are autotrophs which means that they produce their own food from photosynthesis, while the Fungi are hetertrophs: they take food from other organisms through metabolism.
C) Estimate the average sizes of Plant & Yeast Cells is as follows:
The estimated size of a Plant cell is between 10 μm and 100 μm while the size of a yeast cell is 2-10 µm.
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| Plant cell: size 10 to 100µm |
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| Yeast cells of the species Saccharomyces cerevisiae (credit: Jef D. Boeke and Sarah Richardson, Johns Hopkins University) |
KINGDOM: PROTISTA
Protista share many characteristics with the other kingdoms
but they remain unique.
5- A) The characteristics of the Kingdom Protista are the following:
The protists belong to the Kingdom Protista which are eukaryotic organisms found in aquatic
habitats. Although they are mostly unicellular microscopic organisms or microorganisms, they
can also be multicellular or colonial. Some have complex life cycle involving
multiple organisms. Some are sexual or asexual, some reproduce by mitosis and
meiosis. Protista motility happen thanks to their use their flagella (tail-like whip), their cilia which are extremely thin filament (hair-like projections) and some of these microorganisms are pseudopods, which means the possess (false feet).
B) Some Protista that look like Fungi are better known as molds. There are two major mold groups, Slime Molds and Water molds. Slime molds are fungus-like protista that grow as slimy masses on decaying matter. They play an important role in the recycling of nutrients by digesting decayed organic materials. Now let’s move on to Water Molds. Water Molds resembles white fuzz growing on the surface of dead fish, usually in fresh water. They depend on dead and decaying organic matter in the water to survive. Water molds or Oosmycota are decomposers. They reproduce both sexually and asexually; sexual reproduction takes place in specialized structures that are formed by hyphae. Antheridium produces male nuclei and oogonium produces female nuclei. Fertilization takes place and spores form a new organism or asexually: asexual reproduction involves hyphae (thin filaments) which develop into zoosporangia (spore cases) flagellated spores swim away in search of food. Spores develop into hyphae when they find food and grow into a new organism.
C) Several Protista are Animal-like, these protists are unicellular eukaryotic microorganisms. The fact the they do not have chloroplasts or chlorophyll make them separate from plants. They are called protozoa. Proto-meaning first and zoa- meaning animal: thus the protists are a primitive form of life. These tend to be found around freshwater areas. There are four groups of protista. Ciliophora (cilia bearing), zoomastigina (flagella bearing), sporozoa (in fluids as parasites), and sarcodina (with pseudopods).
(D) Plant-like Protista can be described as an unicellular algae. They contain chlorophyll and are able to carry out photosynthesis. There are four phyla: Euglenophytes, chrysophytes, diatoms, and dinoflagellates. These algae usually have different colors due to the fact that they have accessory pigments which assist them to absorb light. Euglenophytes reside in water. They have flagella which allows motility (ability to move autonomously). They do use chloroplast to perform photosynthesis, but they can become heterotrophs if left in the dark for an extended period of time.
THE REAL VIRUSES
Unlike every other life-form, Viruses are not classified in any
Kingdom; there are even
questions about whether they are living things!
6-A) Microbiology defines a Virus by many ways. First, a virus is not visible to the unaided human eye. It is so small that it cannot be seen even with a light microscopy. One needs an electron microscope to see the virus. A virus is an infective agent that typically consists of nucleic acid molecule in a protein coat. Unlike bacteria, a virus can only multiply within the living cells of a host, thus it is a parasitic microorganism.
B) By what criteria are Viruses living things?
Let us first define "living things". A living thing is an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction. As stated above, the only way a virus can replicate or better said reproduce is in living cells within a host. Hence viruses cannot really reproduce without the help of cells. In a host virus cells start chemically reacting and more viruses start to come up once a the host's cell is infected. Due to the fact that they to reproduce with the help of cells, that would almost make the virus to be considered "living".
Let us first define "living things". A living thing is an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction. As stated above, the only way a virus can replicate or better said reproduce is in living cells within a host. Hence viruses cannot really reproduce without the help of cells. In a host virus cells start chemically reacting and more viruses start to come up once a the host's cell is infected. Due to the fact that they to reproduce with the help of cells, that would almost make the virus to be considered "living".
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| Life diversity |
References:
Case, T. F. (2014). Microbiology: an introduction. (11th ed.). Boston: Pearson.
Kadner, R. J. (2013, September 12). Diversity of structure of bacteria. Encyclopædia Britannica, Inc., Retrieved January 28, 2014, from http://www.britannica.com/EBchecked/topic/48203/bacteria/39334/Diversity-of-structure-of-bacteria
Davidson, M. W. (1995 - 2013). Introduction to cell and virus structure. Florida State University. (© 1995-2013), Retrieved January 28, 2014, from http://micro.magnet.fsu.edu/cells/index.html
Koning, R. E. (1994). Kingdom archaea. Plant Physiology Information Website, Retrieved January 29, 2014, from http://plantphys.info/organismal/lechtml/archaea.shtml
Kaiser, G. E. (1994). The prokaryotic cell: Bacteria. Doc Kaiser's Microbiology Home Page, Retrieved January 29, 2014, from http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/shape/shape.html
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The Five Kingdoms Of Life. (n.d.).Kingdoms Of Life. Retrieved January 30, 2014, from http://waynesword.palomar.edu/trfeb98.htm
The Six Kingdoms. (n.d.). The Six Kingdoms. Retrieved January 28, 2014, from http://www.ric.edu/faculty/ptiskus/Six_Kingdoms/Index.htm
The Six Kingdoms of Life. (n.d.). The Kingdoms. Retrieved January 28, 2014, from http://www.paec.org/biologypartnership/assets/classification/6%20Kingdoms.pdf
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