Difference between animals and plants

Before approaching the positioning of trees in the world, I remind here some theories accepted in classification :
The first difference to be conceptualised is between the animal world and the plant world (in Latin: vegetabilis, from vegere, to "grow ").
At first glance, what differentiates is the absence of sensitivity and of mobility of vegetables, but plants and animals have the faculty to feed, to grow and to reproduce.

The animal moves to feed or to avoid his predators (the man also moves for his pleasure …)
The vegetable is fixed : on full earth, on a rock or a wall introducing crevices (some species as the tree of heaven or the fig content themselves with small areas to establish themselves), on a tree (the ivy clings) or on the surface of the water (waterlily) or even in the bottom of the sea (Posidonias and seaweeds).
All that is fixed is not plant. The first animals appeared on earth (more exactly in seas), 600 millions years ago, lived in the water: sponges, Gorgon's heads, anemones, corals (family Cnidaira - of ancient Greek meaning "nettle").
But how do they make to feed ? They have a wide surface generally in contact with the water and covered with urticantes cells; when tiny animals touch this surface, they are paralysed and captured (that is why, you should not touch them at the risk of having inflammations of the skin, more painful than injections of nettles). Anemones have the appearance of vegetables, because they are endowed with hairs, fine which keep decomposing material.
The mobility of vegetables is reduced to some slow indiscernible movements, for example the sunflower which follows the sun during the day.

2/growth :
It is a common faculty to the animals and to vegetables.

3/life and death
It is a common faculty to the animals and to vegetables.
But the life can be very long for vegetables (10.000 years).

4/The food :
The animal has a mouth to catch the food and the anus to reject what it does not digest. Digestion is first a physical dissociation of food then a chemical assimilation process (The gastric sap collaborates on digestion in the stomach).
Even Molluscs have a complete digestive tract resulting in an anus. An exception at the animals: Sponges feed by filtering the water.
Sponges do not have organ, the circulation of the water, capture of food and digestion are made by a cell type, Choanocytes.

Exception : The process of digestion is not reserved for the animals. Carnivorous plants capture other organisms, most often invertebrate animals, and digest them chemically (by acids and enzymes).
Mushrooms are also capable of digesting the organic equipment.

The vegetable feeds by absorption and assimilation of inorganic substances which it scoops out from the soil (or in the water for the aquatic plants), or even in air (plants Epiphyteses suspended in trees).
It is the role of roots (to make simple) to absorb the water and the contained substances. Trees plant their roots deeply to search the water in depth, up to the ground water sometimes.
That is why, when it is very dry, it is necessary to water the young trees still without deep roots. Species fitted to climatic conditions and do not support to be transplanted except their usual environment.
Plants produce some oxygen. Photosynthesis dissociates the water molecule, the oxygen is rejected in the atmosphere and the hydrogen is stocked in form of glucose. With the glucose, vegetables fabricate the starch and with the starch, the cellulose.
The mechanism of suckering of the oxygen was initiated 2 thousand million years ago by the blue seaweeds.

The animal is sensitive to its environment. To move in the space and to spot its prey or danger to which it is exposed, it is endowed with view (not the mussel) and with tactile sensitivity.
Some vegetables are also sensitive to contact and retract when they are touched.

6/reproduction :
The animal baby resembles the adult at his birth.
Exemple : fish or sea stars :
At the time of reproduction, males and females reject their sexual product in the seawater where eggs form giving birth to larvas which are going to swim before regaining to the bottom and taking the shape of the adults.
The vegetable does not lay and does not fertilise babies ressembling to it. The seed contains the information which is going to give birth to the plant.
The classification of vegetables is based on criteria of reproduction mainly.
Within the vegetable :


 continuation: the plant classification

  Rubric Knowledge

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