The system that we still use today for giving scientific names to plants and animals has many founders, from the Greek philosopher Aristotle to the Swedish physician and botanist Carolus Linnaeus.
Carolus Linnaeus is considered as the father of Taxonomy.
Aristotle:
Taxonomy's first father was the philosopher Aristotle (384-322 BC), sometimes called the "father of science." It was Aristotle who first introduced the two key concepts of taxonomy as we practice it today:
i- Classification of organisms by type
ii- Binomial definition
Aristotle was the first to attempt to classify all the kinds of animals in his book on Animals (Historia Animalium in Latin).
He grouped the types of creatures according to their similarities: animals with blood and animals without blood, animals that live on water and animals that live on land.
Abu Usman Umer Aljahiz:
He was the first eminent Arab zoologist of the Muslim world.
He used to slaughter animals for studying the internal organs of their bodies.
He also opened the abdomen of pregnant animals to find out the number of embryos and the location of each one of them in the body.
His Encyclopedic work in seven big volumes Kitab al-Haywan (Book of Animals) is the most famous work on zoology, in which he has described in detail, the kinds of animals, their behavioral characteristics, and their diseases and treatment.
In two kingdom classification system, all the organisms were classified into two groups;
i- Plant kingdom
ii- Animal kingdom
All the organisms possess cell wall were placed in plant kingdom and all the organisms do not possess cell wall were placed in animal kingdom.
Ernst Hackle in 1866, introduced a new Kingdom named Protista to accommodate the organisms exhibiting characteristics either common to both plants and animals or unique to their own such as Euglena, Bacteria were also placed under this kingdom.
According to this system of classification, organisms are classified into three kingdoms:
i- Kingdom Plantae
ii- Kingdom Animalia
iii- Kingdom Protista
In 1930s, electron microscopy revealed, two distinct patterns among single-celled organisms:
In 1937, Édouard Chatton clarified the concept of "Procariotique" and "Eucariotique" to describe the cellular characteristics of organisms.
After the clear concept for kingdom Protista, Copeland (1959) came forward with a four kingdom system to classify the living beings. He designed a new kingdom named as Monera to place all the lower protists which include prokaryotic unicellular organisms and remaining single celled eukaryotic organisms were included in Protista.
According to this system of classification, organisms are classified into four kingdoms:
i- Kingdom Plantae
ii- Kingdom Animalia
iii- Kingdom Protista
iv- Kingdom Monera
Robert Whittaker in 1969 classified the organisms into Five kingdoms which clearly categorized fungi into a separate kingdom. This system of classification was based on;
Cellular structure and body organization; unicellular Prokaryote, Unicellular and multicellular eukaryotes.
Mode of nutrition; autotrophs (plants), Ingestive heterotrophs (animals) and absorptive heterotrophs (fungi).
