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He used those principles to study the primordial elements of the nature of which the bodies of animals are composed and the intrinsic conditions that make bodies become what they are. First they start from the combination of the fundamental elements of nature (earth, water, air and fire) forming tissues and these organs.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
The following outline is provided as an overview of and topical guide to zoology: . Zoology – study of animals.Zoology, or "animal biology", is the branch of biology that relates to the animal kingdom, including the identification, structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems.
Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million in total. Animals range in size from 8.5 millionths of a metre to 33.6 metres (110 ft) long and have complex interactions with each other and their environments, forming intricate food webs.
Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, and desmosomes. [26] With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues. [27] These include muscles, which enable locomotion, and nerve tissues, which transmit signals and coordinate the body.
The dead bodies of vertebrate animals and insects are sometimes called carcasses. The human body has a head, neck, torso, two arms, two legs and the genitals of the groin, which differ between males and females. The branch of biology dealing with the study of the bodies and their specific structural features is called morphology. [2]
Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of superficial anatomy . Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology , and also in the study of cells .
There are 107 classes of animals in 33 phyla in this list. However, different sources give different numbers of classes and phyla. For example, Protura, Diplura, and Collembola are often considered to be the three orders in the class Entognatha. This list should by no means be considered complete and authoritative and should be used carefully.