Diversity of life on Earth

Life on Earth began approximately 3.5 billion years ago (possibly earlier) and the mechanism by which it started is still unknown. Since the beginning of life, it has developed in different forms and can thrive and survive in a wide range of conditions.

More than 99% of all types or more than five million species that have ever lived on Earth are estimated to have become extinct and extant species have from 10 to 14 millions. It is also possible that life started elsewhere in the Universe immediately after the Big Bang, 13.8 billion years ago (from 10 to 17 million years old Universe). Humanity confirms life only on Earth but many think it is possible beyond our blue Planet.

The definition of life is a distinguishing feature of physical entities that have biological processes. Such as signaling and self-sustaining process of those who do not. That's because they lack such functions and are classified as non-living or such a function is stopped, ie, the death occurred. The smallest unit of life is called the organism.

They consist of one or more cells, undergo metabolism, maintain homeostasis, can grow, respond to stimuli, reproduction (sexual or non-sexual). The evolution can be adapted to its environment through the generations. 

There are different forms of life such as:

Animals are multicellular organisms. All animals must eat other organisms or their products for food and thus belong to the group of heterotrophs. The same process takes place with humans. Most people eat meat and it is composed of muscle fibers with a certain fat content, connective tissue and organs. It is rich in protein, fat, vitamins and other values.

Products from animals include milk produced by the mammary glands and processed dairy products such as cheese and butter. Birds and other animals lay eggs, which are eaten. Bees produce honey, obtained from the nectar of flowers.

All animals are mobile, which means that they can move independently and spontaneously. Their bodies become stronger over time as they develop and some later undergo metamorphosis. They can be male and female, as well as human. They move that could find nutrients, an individual of the opposite sex for reproduction and to get away from the enemy. Almost all animals have some form of sexual reproduction and some have the ability non-sexual reproduction.

They are divided into different types of which are vertebrates (birds, mammals, amphibians, reptiles and fish), shellfish (clams, oysters, octopus, squid and snails), arthropods (millipedes, insects, spiders, scorpions, crabs, lobsters and shrimps), worms (earthworms, leeches), sponges and jellyfish.

The predator is in fact the biological interactions in which it feeds their prey, which belongs to the same group of animals (heterotrophs). Predators may or may not have to kill their prey before eating. But the act is almost always results in death. Another type of food consumption is the consumption of dead organic food. Parasites are going to their prey and then kneel down their eggs for their offspring. So these are two types of feeding behavior. Selective pressures imposed on one another has led to an evolutionary arms race between prey and predator and so there was an anti predatory adjustment.

Most animals indirectly used the sun’s energy by eating the plants or animals that eat plants. Plants use light to convert inorganic molecules to proteins, carbohydrates, fats and other biomolecules containing reduced carbon in the form of carbon-hydrogen bonds. Water and carbon dioxide in photosynthesis converts solar energy into chemical energy. In the form of simple sugars like glucose with the separation of molecular oxygen.

These sugars are used as materials for the production and the growth of plants and other biomolecules. When animals eat plants or animals that eat plants, reduced carbon in the food becomes a source of energy for animals. This helps animals to grow and releases the stored energy from the sun and therefore give an animal the energy required for movement. Animals living in the vicinity of hot water or in a cold hole in the bottom of the ocean, which is rich in methane, sulfur, hydrogen and hydrocarbon-rich liquid, do not depend on solar energy, but chemosynthesis and bacteria make up the base of the food chain.

Fish is an important source of high quality protein, minerals, essential fatty acids and contains many vitamins (A, D, E and K), all of which are vital to the healthy functioning of the body. There are different types, such as white, blue fish and shellfish. White fish contains little fat, less than 1% and the blue fish from 10 to 25%.

Fish are cold-blooded animals from the group of vertebrates that live in water and breathe with the help of gills. They extracting dissolved oxygen from the water that goes into the blood and excrete carbon dioxide. Fish have developed sense of lateral line and they move with fins.

About half of all vertebrates are fishes. They are divided into “without jaw” and “jaw mouth”. They are divided into cartilaginous (chondrichthyes – in which among others include sharks and devil fish) and drupes (osteichthyes), which includes all other fish. The bony group is most abundant species.

They are divided on both marine and freshwater, although there are between forms. Today in the world there are about 28.000 species of fish. The fish are very widespread in most aquatic ecosystems on Earth. They have been found in lakes, high mountain streams and greatest ocean depths. Fish can be herbivores, carnivores and scavengers that feed on the remains of dead plants and animals and the parasites that feed by sucking blood. About 50 species of fish is poisonous, they emit poison through spines and there are eels, which can generate electricity (voltage of 500 volts).

Plants do not move and are called green plants. These include conifers and other gymnosperms, flowering plants, ferns, liverworts, mosses and green age. The plants do not fall under the red and brown algae. It is believed that there are about 300.000 species of plants, most of which around 260.000 to 290.000 plants seeds. Green plants provide most of the world of molecular oxygen. Plants that produce cereals, vegetables and fruits are staple foods of mankind.

Some plants in it’s great variety were used for medicine and as a garnish. Green plants have cell walls of cellulose and most of it’s energy derived from sunlight via photosynthesis by primary chloroplasts, derived from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophyll A and B, which gives them their green color. Some plants are parasitic and have lost their ability to produce normal amounts of chlorophyll and photosynthesis. Plants are also characterized by sexual reproduction, non-sexual reproduction. Also common and by modular and indeterminate growth and change of generations.

There are many species of plants, 2000 species used for human consumption. Many are rich in nutritional value. People are consuming most plants with seeds, nutrients contain fats such as omega. It is a healthy food with a high amount of unsaturated fat. Edible seeds are cereals, legumes and oilseeds. Some seeds can not be eaten. Such as large seeds in the apple and cherries, which contain cyanide or lemon in which it occurs choking.

Fungi are any member of the group of eukaryotic organisms that includes single-celled organisms. Such as yeast and mold, as well as multicellular fungi that produce fruit known as mushrooms. It is estimated that there are 1.5 to 5 million species of fungi. The only difference, which is placed in different fungi life forms that it’s cell walls contain chitin, unlike plants. Much like the animals, they are heterotrophic and food absorption of dissolved molecules and normally secrete digestive enzymes into their surroundings. Growth is their mobility, except spores that can travel through air or water. Fungi are the major decomposers in ecosystems.

Most imperceptible due to the small size and because they live on the ground. They may become visible while the fertile, either while fungi or mold. Fungi perform an important role in the decomposition of organic matter and have a fundamental role in the nutrient cycle and the exchange in the environment. They have long been used as a direct source of food in the form of mushrooms and truffles. Such as a leavening agent for bread and in fermentation of various food products such as wine, beer and soy sauce. The fungus used for the production of antibiotics. Various enzymes derived from fungi are used in industry and in detergents.

They are used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides that are toxic to animals, including humans. Several species contain psychotropic compounds and are consumed recreational or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings and become significant pathogens of humans and other animals. Crop losses due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies.

Algae are mostly water photosynthetic microorganisms (unicellular and multicellular) like a plant. Living plant organism without roots, flowers or leaves. Most algae are found in the oceans and the rest are freshwater algae. There are about 25,000 species of algae. Seaweed, kelp, water flowers and moss, are all forms of algae.

Some algae purify water and most of the algae through photosynthesis produce oxygen. Can be used as a food additive. From brown algae which are milled and dried products are flour (porridge) and used as a food additive for livestock. Can be used as a highly valuable fertilizer. That is because the high concentration of fiber retains moisture and the concentration of minerals that algae contain, enriches the soil. 

There are also many smaller organisms such as different forms of life:

Archaea are single-celled microorganisms. These microbes have no cell nucleus. Archaea and bacteria are usually similar in size and shape, although some archaea have a very strange shape. They live in harsh environments such as hot springs and salt lakes, the soil, oceans, wetlands, in the human colon, oral cavity and skin. It is particularly abundant in the oceans and in plankton may be one of the most abundant groups of organisms on the planet. Archaea is a major part of the Earth’s life and may play a role in both of the cycle, carbon and nitrogen.

Protist a large group of different eukaryotic organisms mainly unicellular plants and animals that do not make the tissue. They live in almost any environment that has liquid water. Many protists, such as algae, are photosynthetic and vital primary producers in ecosystems, especially in the ocean as part of the plankton.

Bacteria have a variety of forms, several micrometers in length. They are prokaryotic microorganisms that have emerged as the first forms of life on Earth and are present in most of it’s habitat. They inhabiting of soil, water, acid hot springs, deep parts of the Earth’s crust and radioactive waste. Bacteria are vital in recycling nutrients such as nitrogen fixation from the atmosphere and putrefaction. In the biological communities surrounding hydrothermal vents, bacteria provide the nutrients needed to sustain life. By converting the dissolved compounds such as hydrogen sulfide and methane, into energy.

The vast majority of bacteria are harmless in the body due to the immune system and some are helpful. Several species of bacteria are pathogenic and cause infectious diseases such as cholera, syphilis, leprosy and plague. The most common severe bacterial diseases are respiratory infections. For the treatment of bacterial infections humans used antibiotics.