QUESTION: How various taxons like species,kingdom,etc are arranged for an organism?
ANSWER: Organisms firstly are sorted out by Kingdom...Plant, Animal or Protist.
So, for a horse,
KINGDOM = Animalia (as opposed to being a plant or a protist.)
PHYLUM = Chordate (it has a spinal chord, unlike, say a starfish.)
(usually a sub-Phylum is listed as Vertebrata....in which it is again further refined. Vertebrates all have a backbone, a head, heart is below the head and neck, and all have well developed sense organs
CLASS = Mammalia. (It shares the traits of hair, warmbloodedness, and nursing it young with all other mammals.
ORDER = Perissodactyla Odd toed animals with hoofs.... usually one to or three. Along with horses in this order are tapirs, and rhinos.
FAMILY = Equidae. In this are zebras, wild asses, donkeys, and mules.
GENUS = Equus. All modern horse like animals
SPECIES = Caballus. The true horse.
SubSpecies, would be all the various breeds of horse. All can interbreed, and produce live, fertile young. Attempting to cross a horse with a zebra might not always produce live, and fertile young. Several have tried.... the animal is called a Zorse. You might wish to google one to see what they look like.
Lots of interesting things to read.
Helpful? If you need more, feel free to write.
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QUESTION: How long evolution take place?
Since the very first time RNA split and came apart, and then reattached to other pieces of RNA....reproduction.
And this needed to have happened only once. It did. Once molecules discovered the trick of splitting, and then reforming with a different half, life was off and running. And from that moment on, plants, animals and protists were "born" and every generation provided new and different arrangements of RNA. If the odds of this simple first act were billions and billions to one, that would make it at utter certainty, that life would begin.... there were billions and billions of atoms and molecules, and it had billions and billions of years to start. With that many atoms and molecules, and that many years, certainty was inevitable.
Think of it as our 26 letters in our alphabet. Put "a" and "n" together, and you get either "an" or "na". Add another letter and you get "and" "dan" or "adn" or "nad", and so on. With just 26 letters, every single book written using this alphabet has emerged. And there are literally billions and billions of books.
It is the same with RNA, and then the more complicated molecule, DNA.
From the moment RNA did that first split, evolution has been going on. And it goes on today, tomorrow, and will go on thru mutations until life can no longer exist on this planet.
And when will that be?
When our sun begins to die, first becoming a red giant, as it envelops first Mercury, Venus and Earth, and Mars.....some 5 billion years from now. It would be too hot for life as we know it to exist on earth.
For a long discussion, you might try Google: "When did evolution start" or "Beginning of evolution on Planet Earth"