Archaea Review Methanogens
Archaea is any of the unicellular microorganisms that are genetically distinct from bacteria and eukaryotes and often inhabiting extreme environmental conditions.
Although they are genetically distinct from bacteria, they look and act a lot like bacteria and until the late 1970’s scientist all over thought that Archaea was just a “weird” type of bacteria.
There are three different types of Archaea:
Crenarchaeota: Which are characterized on their ability to tolerate extreme temperature and acidity.
Euyarchaeota: Are methane-producers and salt-lovers.
Korarchaeota: A group for archaeans that scientists are unsure of.
These three main types of Archaea also have subtypes, which are:
Methanogens: Archaeans that produce methane gas as a waste product of their digestion, or their process of making energy.
Halophiles: Are archaeans that live in salty environments (halo= salt and phile= loving).
Thermophiles: Are archaeans that live at extremely hot temperatures (thermo= heat and phile= loving). Psychrophiles: Are archaeans that live in very cold temperatures. (psychro= cold and phile= loving)
Where do Archaea live?
There are over 200 Archaebacteria species, and they are found in many places around the world. But they are known to live in oxygen free environments like a volcano's vent or the bottom of the ocean.
When most people think or talk about Archaea they usually assume that they all live at the bottom of the ocean, which is not true. Archaea is found everywhere.
Halogens for example are found in waters that have a salt concentration several times the oceans.
Thermophiles grow in hot springs, geysers and near volcanoes. The can survive in environments of 100°C, which is the boiling point of water.
Methanogens are found inside termites, cows, humans and swamps. These Achaea help breakdown cellulose that is a tough carbohydrate made by plants and due to the niche of methanogens, they are a perfect fit. This allows termites to eat wood and cows to eat a lot of grass and plants.
Why is Achaea important?
Methanogens have a huge impact on our ecosystem. They can be found in the inside of a cow’s stomach which allows the cow to break down tough grass and plants. This is an example of a mutualistic relationship. Without the cow, this specific Archaebacteria would not have the food it needs to survive. Therefore, the cow could possibly end up dying if it wasn’t able to break down its food properly.
Phylogenetic Tree
Although many scientists thought that Archaea was just another type of bacteria, this phylogenetic tree of Achaebacteria shows that Archaea is more similar to eukaryotes then to bacteria. Which means that humans are closer to Archaea then bacteria are to Archaea. Scientist have also shown that Archaebacteria doesn’t react to the antibiotics they use on bacteria, but are sensitive to the antibiotics that affect Eukarya.

Characteristics of Archaea vs. Bacteria (similarities and differences)
Similarities
Differences
Prokaryotic Cells
More complex rRNA
Shape, size and appearance
Doesn’t react to some antibiotics that affect bacteria.

Asexual
Cell Wall is made without peptidoglycan

Unicellular
Have different membrane lipid bonding (ether bonds instead of ester bonds)

No nucleus or cell organelles

Multiply by binary fission and move primarily by means of flagella.

This table shows that mostly all of the differences between Archaea and bacteria are genetic, and mostly all of the similarities are physical.
Binary Fission
Archaea reproduces not by mitosis or meiosis but by binary fission. Archaea’s chromosomes are circular instead of linear as you can see in the diagram.
Step 1: The cell grows.
Step 2 - DNA replication: It will copy the genetic material.
Step 3 - Chromosome segregation: it will then split in half.
Step 4 – Cytokinesis: The two new