Orders , General characteristics of Eutheria and Modern technologies in classification of living organisms
All living Eutherians are placental mammals , The Eutherian fetus is fed during gestation by the placenta , Eutherians are distinguished from noneutherians by various phenotypic traits of the feet , the ankles , the jaws and teeth , All extant eutherians lack epipubic bones .
It is the taxonomical name for the main group of living mammals , It contains the placental mammals , of which humans are one species, It was introduced by Thomas Henry Huxley in 1880 , Members of Eutheria are now found on all continents and in all oceans .
Order : Edentata
Some are without teeth , while others lost their front teeth only , They have strong , curved claws , such as armadillo and sloth .
Order : Insectivora
They feed on insects and their front teeth extend outwards like pincers for capturing the prey , such as Hedgehog .
Order : Carnivora
They have large pointed canines , The premolars are sharp , while the molars are broad and grinding , They have strong , sharp curved claws , Such as lion , tiger , wolf , fox , dog , cat and seal .
Order : Perissodactyla
They are herbivore animals , They are odd-toes ( 1-3 ) , each toe has a horny hoof , Their teeth are big-sized and adapted to grind food , such as horse , donkey , zebra and rhinoceros .
Order : Artiodactyla
These animals are herbivores , They are even-toed , Each toe is coated with a horny hoof , Such as sheep , Goats , Giraffe , Deer and Camels .
Order : Cetacea
They are huge aquatic animals live in seas and oceans , the fore limbs are modified into paddle-like structures for swimming and the hind limbs are disappeared .
They breathe atmospheric air by lungs , Sexes are separate , The females give birth and suckle their youngs , Tail fin is horizontal , Such as whale and Dolphin .
Order : Rodentia
They have a pair of incisors in both upper and lower jaws , The incisors are sharp and chisel-shaped , The tail is long and ears are small , such as Rat , Gerbo , Mouse and squirrel .
Order : Lagomorpha
They have two pairs of incisors in upper jaw and one pair in the lower jaw , The tail is short and ears are long , Such as Rabbit .
Order : Chiroptera
Their fore limbs are modified into wings , where the fingers from the second to the fifth are elongated and the skin extends from the body to in between these fingers , They become active during the night , Such as Bat .
Order : Proboscida
They have a long muscular proboscis , The two upper incisors grow to form what is known as the two elephant canines , Such as Elephants .
Order : Primates
They are the most higher mammals , They have two pairs of pentadactyl limbs and the thumb finger lies away from the rest of fingers , The brain is large-sized and nervous system is highly developed in the higher forms , Such as Monkey , Lemur , Gorilla , Chimpanzee and Man .
Modern technologies in classification of living organisms
For classification of living organisms , First scientists depend upon the morphological comparisons to determine the similarities and differences between living organisms .
Scientists turned to classify living organisms ( hundreds years ago ) on the basis of determining the degree of relevance and relatedness ( evolutionary relationships ) among them through .
The researches in the field of comparative anatomy for determining the anatomical similarities , Similarities in natural structures as Skeletal structures , Glands and Embryonic development .
Nowadays , through the development of microscopic screening techniques by invention of electron microscope and the development of biochemical analysis techniques , new foundation for determining the degrees of relevance and relatedness among living organisms appeared , such as :
The scientific researches on the nucleic acid DNA existing in the nucleus through DNA sequencing technique in which the arrangement and sequence of nucleotides of DNA double helix are identified , Scientists found that the greater the sequence in the order of nucleotides in DNA strand , The organisms were more relevant and related .
Frontiers in biology
Recently , researchers used the extract of sponges and cnidarians ( especially jellyfishes ) in the biochemical and pharmaceutical industries , where :
Some possible medical uses for the paralyzing toxins that some jellyfish use to capture the preys were investigated , Investigating promising new antibiotics and anticancer compounds in some sponge species .
Although this type of biotechnology is still recent but it is very exciting where researches will probably result in the development of new medicines .