By: Brianna Cremard And Silvia God Domain Archae By: Brianna Cremard And Silvia God

Domain Archae - Kingdom Archaebacteria Archaebacteria often inhabit but are not restricted to extreme and stressful environments on earth. Archaebacteria of Domain Archae may be the oldest forms of life on earth. Includes all Prokaryotes Prokaryotes - Species with cells lacking membrane-bound organelles. The Archae are grouped into three general categories based on the environments in which they live or on their specialized metabolic pathways: 1. Methanogens 2. Extremophiles 3. Nonextreme Archae

Kingdom Archaebacteria Methanogens They obtain their energy by using hydrogen gas (H2) to reduce carbon dioxide (CO2) to methane gas (CH4). They are poisoned if exposed to oxygen. They live in swamps, marshes, and the intestines of mammals. They release about 2 billion tons of methane gas into the atmosphere each year.

Methanogen

Kingdom Archaebacteria Extremophiles They are able to grow under conditions that are extreme to us. There are several types: Thermophiles – They live in temperatures ranging from 60º to 80º Celsius (C). Cold-adapted – They live in glacier ice and alpine lakes. Halophiles – They live in very salty environments including the Great Salt Lake and the Dead Sea. They require water with a salinity of 15% to 20%. pH-tolerant – They grow in highly acidic (pH = 0.7) or highly basic (pH = 11) environments. Pressure-tolerant – They are found in the ocean depths. They require at least 300 atmosphere (atm) of pressure to survive and can withstand up to 800 atm. Note – To experience 300 atm of pressure you would need to dive 3000 m below the surface of the ocean. The record for the deepest dive is 127 m.

Thermophiles

Halophiles Salt Loving Bacteria

Pressure-Tolerant Deep Sea Archae

Kingdom Archaebacteria Extremophiles cont. Pressure-tolerant – They are found in the ocean depths. They require at least 300 atmosphere (atm) of pressure to survive and can withstand up to 800 atm. Note – To experience 300 atm of pressure you would need to dive 3000 m below the surface of the ocean. The record for the deepest dive is 127 m. Nonextreme They grow in the same environments as bacteria.

Non-Extreme

Kingdom Archaebacteria Cellular Structure Cell walls - They lack peptidoglycan, which is an important component of the cell walls of bacteria. Lipids – The lipids in the cell membranes of archae have a different structure from those in all other organisms. Archae have distinctive ribosomal RNA sequences.