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Created: Wednesday 11, March 2015
Groups of animals
Scientific term for "animals" are as follows: multicellular living organism belonging to kingdom animalia and are characterized by voluntary movement
Living things are broadly grouped and classified into different categories but we will focus on the major ones which includes:
- Invertebrates - these are animals that do not have back bones and are belived to locomote by crawling and creeping, they are assumed to be the first animals to evolve from a single micro organic cell. Examples include worms, echinoderms, arthropods, sponges, cnidarians, molluscs and flatworms.
- Fishes - cold-blooded aquatic vertebrates usually having scales and breathing through gills and are believed to be the first animals to have evolved from invertebrates. The earliest ever discovered fish was named ostracoderms it was jawless. Since then rapid growth have took place to now current known bonny fishes which include cartilaginous, hagfishes and lampreys.
- Amphibians - cold-blooded vertebrate typically living on land but breeding in water; aquatic larvae undergo metamorphosis into adult form. They were the first animals to change living in water to living on land, they include toads, frogs, salamanders, newts and caecilians.
- Reptiles are cold-blooded vertebrate of the class Reptilia including tortoises, turtles, snakes, lizards, alligators, crocodiles, and extinct forms. They diverged from amphibians during the carboniferous period, this ancient reptiles included Petrolacosaurus, Archaeothyris, Hylonomus, and Paleothyris,
- Mammals. They are warm-blooded vertebrate having the skin more or less covered with hair; young are born alive except for the small subclass of monotremes and nourished with milk. They include elephants rodents primates rabbits and all carnivores.
- Birds. Warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings which makes it possible for them to fly and they include flamingos, perching birds, game birds, pigeons and doves, hummingbirds, owls, pelicans, and penguins
Advantages of animals
- Keeps earth fauna and flora in balance
- As for humans pets convey psichological benefits
- Facilitates to organ transplantation.
- Makes it possible to create identical copies of the very best individuals in a population, such as the highest milk producing cow, or the largest hog
Disadvantages of animals
- Animals may develop some forms of sickness which may be damaging to one’s health.
- Quite expensive to keep and maintain especially home based animals I.e. pets.
- It takes much time to keep this animals in comfort