Etymology

The word science comes through the Old French, and is derived from the Latin word scientia for knowledge, which in turn comes from scio, "I know". The Proto-Indo-European (PIE) root that yields scio is *skei-, and it means "cut, separate, or discern". Other words from the same root include Sanskrit chyati, "he cuts off", Greek schizo, "I split" (hence English schism, schizophrenia), Latin scindo, "I split" (hence English rescind).[7] From the Middle Ages to the Enlightenment, science or scientia meant any systematic recorded knowledge.[8] Science therefore had the same sort of very broad meaning that philosophy had at that time. In other languages, including French, Spanish, Portuguese, and Italian, the word corresponding to science also carries this meaning.
From classical times until the advent of the modern era, "philosophy" was roughly divided into natural philosophy and moral philosophy. In the 1800s, the term natural philosophy gradually gave way to the term natural science. Natural science was gradually specialized to its current domain, which typically includes the physical sciences and biological sciences. The social sciences, inheriting portions of the realm of moral philosophy, are currently also included under the auspices of science to the extent that these disciplines use empirical methods. As currently understood, moral philosophy still retains the study of ethics, regarded as a branch of philosophy.
Today, the primary meaning of "science" is generally limited to empirical science involving use of the scientific method.[9] Examples of the broader use include political science and computer science, which are named according to an older and more general use of the word "science".

Excretory system

The excretory system is the system of an organism's body that performs the function of excretion, the bodily process of discharging wastes. It is responsible for the elimination of wastes produced by homeostasis. There are several parts of the body that are responsible for this process, such as the sweat glands, the liver, the lungs, and the kidney system. It removes wastes of the organism, balancing and regulating the chemical composition of its body fluids. The excretory system eliminates excretory products from the body, collects water and filters body fluids. Its parts include anything that aids in depleting wastes and unneeded substances. Without the excretory system, the build-up of harmful wastes could damage the body, resulting in destructive, dangerous, and even fatal consequences.

Population

In sociology and biology a population is the collection of people or individuals of a particular species. A population shares a particular characteristic of interest most often that of living in a given geographic area.
Human populations can be defined by many characteristics such as mortality, migration, family (marriage and divorce), public health, work and the labor force, and family planning. Various aspects of human behavior in populations are also studied in sociology, economics, and geography.

The rock cycle

All rock (except for meteorites!) that is on Earth today is made of the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled or swam over. While the stuff that rocks are made from stays the same, the rocks do not. Over millions of years, rocks are recycled into other rocks. Moving tectonic plates help to destroy and form many types of rocks.

Muscular system

The human body contains more than 650 individual muscles which are attached to the skeleton, which provides the pulling power for us to move around. The main job of the muscular system is to provide movement for the body. The muscular system consist of three different types of muscle tissues : skeletal, cardiac, smooth. Each of these different tissues has the ability to contract, which then allows body movements and functions. There are two types of muscles in the system and they are the involuntary muscles, and the voluntary muscles. The muscle in which we are allow to control by ourselves are called the voluntary muscles and the ones we can? control are the involuntary muscles. The heart, or the cardiac muscle, is an example of involuntary muscle.

SKELETAL MUSCLE:
The skeletal muscle makes up about 40 % of an adults body weight. It has stripe-like markings, or striations. The skeletal muscles is composed of long muscle fibers. Each of these muscles fiber is a cell which contains several nuclei. The nervous system controls the contraction of the muscle. Many of the skeletal muscle contractions are automatic. However we still can control the action of the skeletal muscle. And it is because of this reason that the skeletal muscle is also called voluntary muscle.

Skeletal system

Skeletal systems are commonly divided into three types—external (an exoskeleton), internal (an endoskeleton), and fluid based (a hydrostatic skeleton), although hydrostatic skeletal systems may be classified separately from the other two, because they lack hardened support structures. An internal skeletal system consists of rigid or semi-rigid structures, within the body, moved by the muscular system. If the structures are mineralized or ossified, as they are in humans and other mammals, they are referred to as bones. Cartilage is another common component of skeletal systems, supporting and supplementing the skeleton. The human ear and nose are shaped by cartilage. Some organisms have a skeleton consisting entirely of cartilage and without any calcified bones at all, for example sharks. The bones or other rigid structures are connected by ligaments and connected to the muscular system via tendons.

Circulatory system

The circulatory system (or cardiovascular system) is an organ system that moves nutrients, gases, and wastes to and from cells, and helps stabilize body temperature and pH to maintain homeostasis. While humans, as well as other vertebrates have a closed circulatory system, some invertebrate groups have open circulatory system. The most primitive animal phyla lack circulatory systems.

Birds

Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals. Around 10,000 living and recently (after 1500) extinct species of birds compose the class Aves, making them the most diverse tetrapod vertebrates. They inhabit ecosystems across the globe, from Arctic terns to Antarctic penguins. Birds range in size from the tiny hummingbirds to the huge Ostrich. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic period, c 200 to 150 Ma (million years ago), and the earliest known bird is the Late Jurassic

Reptiles

Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane, and members of the class Sauropsida. Today they are represented by four surviving orders:
Crocodilia (crocodiles, gharials, caimans and alligators): 23 species
Sphenodontia (tuataras from New Zealand): 2 species
Squamata (lizards, snakes and amphisbaenids ("worm-lizards")): approximately 7,900 species

Mammals

Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex region in the brain. Most mammals also possess specialized teeth and utilize a placenta in the ontogeny. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals encompass approximately 5,400 species (including humans), distributed in about 1,200 genera, 153 families, and 29 orders,[1] though this varies by classification scheme.

Respiratory system

Among quadrupeds, the respiratory system generally includes tubes, such as the bronchi, used to carry air to the lungs, where gas exchange takes place. A diaphragm pulls air in and pushes it out. Respiratory systems of various types are found in a wide variety of organisms. Even trees have respiratory systems.

Nervous system

The nervous system is a highly specialized tissue network whose principal component are neurons. These cells are interconnected to each other in a complex arrange, and have the property of conducting, using electrochemical signals, a great variety of stimuli within the nervous tissue as well as from and towards most of the other tissues. Thus, neurons coordinate multiple functions in organisms.
The classification of the nervous system is mostly similar in humans as in other vertebrates.

Psyshology

Psychology (from Greek, Literally "to talk about the soul" (from psyche (soul) and logos)) is both an academic and applied discipline involving the scientific study of mental processes and behavior. Psychologists study such phenomena as perception, cognition, emotion, personality, behavior, and interpersonal relationships. Psychology also refers to the application of such knowledge to various spheres of human activity, including issues related to daily life—e.g. family, education, and work—and the treatment of mental health problems.

The Cell

Cell theory refers to the idea that cells are the basic unit of structure of all living things. Development of this theory during the 1800s was made possible by advances in microscopy. This theory is one of the fundamental foundations of biology. The theory says that new cells are formed from other existing cells and the cell is a fundamental unit of structure, physiology, and organization in all living organisms

Sponges

The sponges or poriferans (from Latin porus "pore" and ferre "to bear") are animals of the phylum Porifera. Porifera translates to "Pore-bearer". They are primitive, sessile, mostly marine, water dwelling, filter feeders that pump water through their bodies to filter out particles of food matter. Sponges represent the simplest of animals. With no true tissues (parazoa), they lack muscles, nerves, and internal organs. Their similarity to colonial choanoflagellates shows the probable evolutionary jump from unicellular to multicellular organisms. There are over 5,000 modern species of sponges known, and they can be found attached to surfaces anywhere from the intertidal zone to as deep as 8,500 m (29,000 feet) or further. Though the fossil record of sponges dates back to the Neoproterozoic Era, new species are still commonly discovered.

Amphibians

Amphibians (class Amphibia; from Greek αμφις "both" and βιος "life") are a taxon of animals that include all living tetrapods (four-legged vertebrates) that do not have amniotic eggs, are ectothermic (term for the animals whose body heat is regulated by the external environment; previously known as cold-blooded), and generally spend part of their time on land. Most amphibians do not have the adaptations to an entirely terrestrial existence found in most other modern tetrapods (amniotes). There are around 6,200 described, living species of amphibians. The study of amphibians and reptiles is known as herpetology. Amphibians are able to breathe through their skin.

Echinoderms

Echinoderms (Phylum Echinodermata, from the Greek for spiny skin) are a phylum of marine animals found at all ocean depths. The phylum appeared near the start of the Cambrian period, and contains about 7,000 living species, making it the second largest grouping of deuterostomes, after the chordates; they are the largest phylum without freshwater or terrestrial representatives.

Flatworms

The flatworms (Phylum Platyhelminthes from the Greek platy, meaning "flat" and helminth, meaning worm) are a phylum of relatively simple soft-bodied invertebrate animals. With about 25,000 known species[1] they are the largest phylum of acoelomates. Flatworms are found in marine, freshwater, and even damp terrestrial environments. A troublesome terrestrial example is the New Zealand flatworm, Arthurdendyus triangulatus, which rapidly colonized large areas of Ireland and Scotland since its unintentional introduction in the 1960s and has since destroyed most of the indigenous earthworms[2] . Most flatworms are free-living, but many are parasitic. There are four classes: Trematoda (flukes), Cestoda (tapeworms), Monogenea, and Turbellaria.

Ecosystem

Ecosystem is the interaction with the Biotic 'Living things' and Abiotic 'nonliving' and An ecosystem is a natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all the non-living physical factors of the environment.

Cnidarians

Cells specialized even more than sponges and tissues (groups of similar cells) began with the cnidarians family. Nerves and muscles first appear in these animals, although they had no brain. Their behavior is very simple, responding automatically to touch. Nerves can carry more information between cells than hormones can. Nerves are the main feature which makes animals different from plants. Cnidarians might have evolved into flatworms.
Cnidarians might have appeared 650 million years ago. They belong to the group of animals called Cnidaria or Coelenterata. This group includes corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans.

Arthropods

Animals with jointed legs and bodies covered by hard skin (exoskeleton) made of protein. They were the commonest animals then and have been ever since. This family of animals is called the arthropods ("arth-ro-pods"). They played a key role in the history of life.

Invertebrates

Invertebrates were living very long ago they were devided into lots of categories and they were

"Flat worms and Round worms-Mollusks which was discused it before-Arthropods which is next-Cnidarians-Echinoderms"

Flat and Round worms:reproduce Sexually.

Moluusks:Sexually.

Arthropods:Sexually and by the way Arthro means jointed and Pods means legs.

Cnidarians:They have a hollow body and reproduce sexually and asexually.

Mollusks

Most molluscs had a hard rock-like shell covering their soft bodies. Some, such as the whelk shown here, crawled along. Others, like bivalves, who have 2 shells surrounding them. Yet others lost their hard shell, like the octopus. To get enough energy to move, molluscs and most other animals have an organ called a gill. This absorbs oxygen from the water and gives out carbon dioxide.
Molluscs were one of the most successful of all animal groups.

Vertebrates

The third major type of animal was not closely related to the molluscs or arthropods. It is not clear which of the invertebrates was their ancestor, perhaps early flatworms. Although not so successful in terms of numbers they were far more successful in other ways. They first appeared around 500 million years ago, and are called the vertebrates, meaning "with backbone".
Bone was a key factor in the success of the vertebrates.

Fish

Fish without jaws were the first vertebrates. Just like the molluscs and arthropods, the early fish had a hard outer covering. This armor plating around their front ends was made of bone. Perhaps it was a defense against sea monsters. They first appeared around 500 million years ago, during the Ordovician period as small fish-like animals called ostracoderms.