What are the characteristics of animals

Animal characteristics:

1, species system: invertebrates are a diverse species system, in addition to the absence of vertebrae, they have little other **** with the same characteristics, there is just a little bit of each other have other relatives. All invertebrates have different forms and lifestyles.

2, life cycle: the life cycle of different kinds of invertebrates there are differences. Most invertebrates are oviparous, some go through a variety of larval forms, such as butterflies, moths and other insects; others hatch as adults.

3, locomotor habits: most invertebrates have a distinct anterior and posterior end, and the sensory organs are clustered close to the mouth. This structure helps them to detect new situations when they are moving forward and to take quick action to make their movement faster and more agile.

4, link body: many invertebrates have can be divided into a number of separate links of the body, this body structure is conducive to their random change of shape, in a complex way to carry out the movement. For example, centipedes have a pair of legs on most of their segments, which are unusually flexible when they move.

Reproduction and Development:

Almost all animals engage in some type of sexual reproduction. Mature individuals are diploid or polyploid. They have a number of specialized germ cells that undergo meiosis to produce smaller swimmable sperm or larger immobile eggs. The sperm and egg combine to form a fertilized egg, which develops into a new individual.

The fertilized egg initially develops into a small ball, called an embryo, where it reorganizes and differentiates. In the sponge, the embryonic larva swims to a new location and develops into a new sponge.

In most other taxa, on the other hand, the embryo undergoes a more complex reorganization. The embryo begins by internalizing to form a protocoelom with a digestive cavity and two distinct embryonic layers - an ectoderm and an endoderm. In most cases, there is a mesoderm in between. These layers then differentiate into various tissues and organs.