Describe the bacteria classification based on nutrition and ecology . Bacterial cell requires nutrients necessary for growth and development and based on how they obtain the necessary nutrients , bacteria can be classified into three major groups . Classification Based on Nutrition . Phototrophs , these are bacteria that derive their energy from the sun and use it for growth and development . Chemotrophs , these are bacteria that uses energy from chemical derivatives for growth and development . Autotrophs , these are bacteria that uses carbon dioxide to manufacture it's own nutrients .
Heterophs , these are bacteria that are unable to fix carbon dioxide and hence they use organic compound as the source of energy .
Classification Based on Ecology . Bacterial classification Based on Ecology occurs on the basis of how it interacts with it's environment , these include tolerance to temperature , pH and also on the basis of gaseous requirements .
Based on temperature bacteria can be classified as psychrophiles which can tolerate low growth temperatures , mesophilles which grow batter at moderate temperatures and also thermophiles which can tolerate high levels to extreme temperatures .
Based on pH , bacteria can be classified as acidophiles capable of growing in acidic condition , alakalinophiles capable of tolerating basic condition and also neutrophils which only survive under neutral conditions .
Based on gaseous requirements , bacteria can be classified as obligate aerobes which can only grow in presence of oxygen , facultative anaerobes that can grow without oxygen and it's available they can still use it , obligate anaerobes which can only grow in absence of oxygen and lastly microaerophilic that only grow in presence of low levels of oxygen .