Biology

Biology (from Greek βιολογία - βίος, bios, "life"; -λογία, -logia, study of) is the science of studying living organisms. Prior to the nineteenth century, biology came under the general study of all natural objects called natural history. The term biology was first coined by Jean-Baptiste de Lamarck.[citation needed] It is now a standard subject of instruction at schools and universities around the world, and over a million papers are published annually in a wide array of biology and medicine journals. Biology examines the structure, function, growth, origin, evolution, distribution and classification of all living things. Five unifying principles form the foundation of modern biology: cell theory, evolution, gene theory, energy, and homeostasis
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Traditionally, the specialized disciplines of biology are grouped by the type of organism being studied: botany, the study of plants; zoology, the study of animals; and microbiology, the study of microorganisms. These fields are further divided based on the scale at which organisms are studied and the methods used to study them: biochemistry examines the fundamental chemistry of life, molecular biology studies the complex interactions of systems of biological molecules, cellular biology examines the basic building block of all life, the cell; physiology examines the physical and chemical functions of the tissues and organ systems of an organism; and ecology examines how various organisms interrelate with their environment.

Tentacles

Tentacles can refer to the elongated flexible organs that are present in some animals, especially invertebrates, and sometimes to the hairs of the leaves of some insectivorous plants. Usually, they are used for feeding, feeling and grasping. Anatomically, they work like other muscular hydrostats.

Tentacles in marine animals

The phylum mollusca includes many species with muscular hydrostats in the form of tentacles and arms (octopuses do not have tentacles: they have arms). Tentacles are longer than arms and usually have suckers at their tips only. Squid and cuttlefish have eight arms like octopuses, and also two tentacles, which is one good way to distinguish squid from octopuses.

The tentacles of the Giant Squid and Colossal Squid are particularly formidable, having powerful suckers and deadly teeth at the ends of the tentacle. The teeth of the Giant Squid are small, "bottle-cap" shaped circular saws, while the tentacles of the Colossal Squid wield two long rows of thick, sharp, finger-length screws of protruding bone.

Cnidarians, which include among others the jellyfishes, are another phylum with many tentaculated specimens. Cnidarians often have huge numbers of cnidocytes on their tentacles. Cnidocytes are cells containing a coiled thread-like structure called nematocyst, which can be fired at potential prey.

Many species of the jellyfishlike ctenophores have two tentacles, while some have none. Their tentacles have adhesive structures called colloblasts or lasso cells. These cells burst open when prey comes in contact with the tentacle; sticky threads released from each of the colloblasts will then capture the food.

Bryozoa (Moss animals) are tiny creatures with a ring of tentacles surrounding the mouth.

Tentacles in amphibians

Some wormlike amphibians have tentacles. The caecilians have two tentacles at their heads, which are probably used for the olfactory sense.

Tentacles in mammals

The star-nosed mole, Condylura cristata, possesses nasal tentacles which are mobile and extremely sensitive, helping the animal to find its way about the burrow and detect prey.
Tentacles in plants


In carnivorous plants, tentacles refer to the stalked glands of the upper surface of the leaves. On a sundew plant, they are hairlike projections with a drop of nectar-like glue which attract insects. When an insect is captured, the tentacles bend inward and the leaf rolls together as shown in the picture. The tentacles then secrete digestive enzymes to dissolve and engulf the insect.

Superficial anatomy

Superficial anatomy (also called surface anatomy) is a descriptive science dealing with anatomical features that can be studied by sight, without dissecting an organism. In particular, in the case of human superficial anatomy, these are the form and proportions of the human body and the surface landmarks which correspond to deeper structures hidden from view, both in static pose and in motion. It is also called "visual anatomy".

In addition, the science of superficial anatomy includes the theories and systems of body proportions and related artistic canons.

Studying of superficial anatomy is the basis for depiction of human body in classic art.

Some pseudo-sciences such as physiognomy, phrenology and palmistry rely on superficial anatomy. (The relation is one-sided, like that of astrology to astronomy.)

This is a list of superficial anatomical features. That is to say, externally visible parts of the body in humans and animals.

Sorted roughly from cranial to caudal. Homologues share a bullet point and are separated by commas. Subcomponents are nested. Alternative names or category members in parentheses. Class in which component occurs in italic.

* Tentacle
*Head

Antler

Crest

Hood

Horn

Mane

Eyes

Ear

Snout

• Nose, TrunNostril

• Whiskers

• Beak Aves only, Mouth

• Lip not in Aves

• Philtrum

• Jaw not in Aves

• Gums not in Aves

• Teeth not in Aves, Tusk

• Tongue

*Throat

Adam's apple

Vocal sac Ranidae

* Spine (extends dorsally)

Tail

* Arm Mammalia, Amphibia, ..., Fin Fish, Wing Aves

Elbow

Wrist

Hand

+ Fingers (Thumb: Primate)

# Hoof, Claw, Nails

# Webbing

* Chest (roughly Thorax)

Gills

Breast Mammalia

* Abdomen (roughly Stomach)

Pouch Marsupialia

Genitals

+ In females

# Vulva

+ In males

# Penis

# Scrotum

* Leg

Thigh

Knee

+ Kneecap

Shin

Calf

Ankle

Foot

+ Toe

# Hoof

* Skin

Feather Aves, Scale Reptilia, Hair Mammalia

Shell

Meaning: Anatomy

Anatomy (from the Greek ἀνατομία anatomia, from ἀνατέμνειν ana: separate, apart from, and temnein, to cut up, cut open) is a branch of biology that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy (zootomy) and plant anatomy (phytotomy). In some of its facets anatomy is closely related to embryology, comparative anatomy and comparative embryology, through common roots in evolution.

Anatomy is subdivided into gross anatomy (or macroscopic anatomy) and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by unaided vision. Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organisation of tissues), and cytology (the study of cells).

The history of anatomy has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. Methods have also advanced dramatically, advancing from examination of animals through dissection of cadavers (dead human bodies) to technologically complex techniques developed in the 20th century.

Anatomy should not be confused with anatomical pathology (also called morbid anatomy or histopathology), which is the study of the gross and microscopic appearances of diseased organs.