Saif Ali

Aquatic ecosystems are those that have water as their primary habitat. Aquatic ecosystem is classified on the basis of salt content in water. Many different kinds of aquatic communities like biomes show similarities wherever in the world they occur. Such communities are being referred to as biomes for convenience. These may be called aquatic ecosystems.

Aquatic ecosystem examples are:

• Fresh water ecosystem
• Streams and Rivers
• Ponds and Lakes
• Marine water ecosystem
• Open Seas
• Hydrothermal Vents
• Sea Shores
• Estuaries ecosystem

Fresh water ecosystem

There are two main types of freshwater ecosystem: streams and rivers, ponds and lakes.

Streams and Rivers

The streams and rivers are running and hence ever changing, inland fresh waters. Because it has a huge surface area to absorb oxygen from the air, moving water in streams and rivers is usually well oxygenated.It maintains its oxygen content unless it is polluted by sewage or industrial wastes.

Physical factors and Organisms:

• It has a lower mineral concentration and more light penetration than sea water. The perennial rivers originate from springs or melting glaciers.

• They are narrow and have cool, swift-flowing water in the upper reaches. In the middle reaches, they become wider, volume of water also increases but its flow become slower.

• With more sunlight available, the temperature of the water rises, and sediments are deposited on the riverbed. In the lower reaches, flow of water slows down further, water is usually muddy and light is reduced at the riverbed.

• Filamentous algae grow on the rocks. Insect larvae and fishes, such as trouts are common.

• In slow water, grow plankton, attached algae, aquatic mosses and grasses, submerged seed plants and reeds as producers. The consumers include flatworms , leeches, water insects, crayfish, mussels, snails, fishes, crocodiles, otters, musk-rat and mink. Many birds and mammals get their food from the water.

Ponds and Lakes

The ponds and lakes are stagnant inland waters. Ponds are small, but very common. Every village has a pond, natural or man-made. The pond receive water from rain and surface runoff.

Physical factors and Organisms:

• The ponds vary greatly in size. Small ponds are often seasonal. Large ones are perennial, at least in their central region. Though not flowing, pond water slowly circulated by winds.

• Ponds have a great deal of vegetation, both floating on the surface and rooted at the bottom. This supports a plenty of animal life like Phytoplankton, zooplankton, rotifers, minute crustaceans, Nekton like Wolfia, pistia, azolla.

• Macrophytes such as Ceratophyllum and Utricularia float just below the surface. The bottom dwelling animals inlcude Hydra, prawns, crabs, mussels and snail.

Lakes are often large and deep, upto 100 metres. They have permanent water. The lakes develop in three ways:

• As natural or man-made depressions filled with water,

• As a result of glaciation, and

• As a cutoff acute bend of a winding river. The lake formed by the last method is called ox-bow or cut-off lake.

The physical factors of lakes depend on the source of water, location, altitude , latitude and surrounding biome. In lake’s open surface waters, occur floating plants, which need sunlight and animals that need oxygen, such as fishes and small arthropods. The deep waters of the large lakes are still and have less oxygen, poor light and low temperature. The rooted vegetation is absent there and the animal life is represented by a few annelids, clams and midge larvae.

Marine water ecosystem

The marine water has a high concentration of salt and mineral ions, about 3.5%.Sodium and chloride are the most abundant ions, followed by sulphur, magnesium, and calcium. Water salinity varies somewhat at different depths and near the surface. It is at its lowest around river mouths and poles.

Physical factors:

• Temperature of the surface water varies at different latitudes. At the equator, temperatures are around 28°C, while near the poles, temperatures are below zero.It is minor in deep waters. Water is ice cold at great depths.

• Hot and cold currents keep the ocean water in continuous circulation.Light varies at different depths of the ocean.

Regarding availability of light for photosynthesis, the ocean is divided into 3 vertical zones:

1. Photic or Euphotic Zone : It is the upper 200 metres well lighted region.
2. Aphotic Zone: It is the dim light region from 200 to 2000 metres.
3. Abyssal Zone: It is the permanently dark region below 2000 metres.

Nature of sea floor varies in different regions. It is described in individual biomes. Pressure increases in the ocean with depth, approximately at the rate of one ton to a square inch for every 1800 metres.

The ocean is divided into 3 major ecosystems : open seas, hydrothermal vents, sea shores or coastal regions.

Open Seas

Physical factors:

The open seas are so very vast that their physical conditions vary greatly in different regions.The depth, pressure, temperature, and oxygen concentration of water are all characteristics that show fluctuations.The open sea has all the three light zones: photic, aphotic and abyssal. Sea water is in continuous circulation due to currents. Sea floor is soft, but highly uneven.

Organisms :

The organisms of the open seas are classified ecologically into three categories: plankton, nektons and benthos.

Plankton:

They are microscopic organisms that float and drift in surface waters as a result of waves, currents, and wind.They have very weak or no locomotory organs. The common phytoplankton are diatoms and the common zooplankton are protozoans, tiny crustaceans, larvae and eggs. The plankton is confined to the photic region only.

Nektons:

These are the actively swimming animals. They have well-developed locomotory organs. They occur in surface as well as deep waters. They include jellyfishes, cuttlefishes, sharks, bonyfishes, turtles, snakes, seals, whales, etc. Both photic and aphotic zones are occur in nektons.

Benthos:

These are animals that live on the bottom and crawl over, burrow through, or are linked to it. Crabs, starfish, brittle stars, and sea urchins lurk beneath the surface. Clams, and sea cucumbers dig into the spongy ground. Attached are sponges, corals, sea pens, and tunicates.

Hydrothermal Vents

The hydrothermal vents are hot water springs in the deep ocean. The vents, where temperature is suitable for life, have rich fauna comprising coelenterates, clams and crabs. The majority of these creatures are unknown to science. 

How these animals live in total darkness at a depth of several thousand metres in the complete absence of green plants is an interesting matter. The water from the hydrothermal vents contains a variety of dissolved minerals and a high concentration of hydrogen sulphide. Mixing of this water with oxygen rich ocean water oxidizes H₂S, producing energy. This energy is used by bacteria in their metabolism.

Sea Shores (Coastal Regions)

Every day-night cycle, the tide alternates between exposing and covering the intertidal zone. The tidal action causes a great mechanical disturbance and brings about drastic changes of temperature, light, moisture and salinity. There is abundance of light, oxygen, carbon dioxide and minerals and this makes the intertidal region one of the most favourable habitats of the world, Inspite of the above difficulties. The substratum may be rocky, sandy or muddy.

Physical factors and Organisms:

• The intertidal region teems with life. Mudflats occur where water moves slowly enough to deposit a sediment of small particles. Algae cover the particles and provide food for a variety of burrowing insects, crustaceans and clams.

• Minute protists and crustaceans living between sand grains feed on plankton stranded when the tide is out, or on algae attached to the sand grains. Many kinds of shore birds feed on the invertebrates.

• Very few vertebrates live in the intertidal zone. However, a number of birds visit at low tide to scavenge or prey on invertebrates.

• The Subtidal zone is seaward to the intertidal zone, and varies in depths from about 50 to some 200metres. There is no air exposure. Water is well oxygenated. Light is abundant. Mineral nutrients are readily available, washed from land by rivers.

• Plankton include minute algae and protozoans. Nekton comprise variety of fish. Benthos have large seaweeds, sponges, crustaceans, sea-urchins, sea-cucumbers, brittle stars, and molluscs.

Estuaries Ecosystem

The region where rivers enter the oceans are known as estuaries. It is the example of Aquatic ecosystem example

Physical conditions and Organisms

• Estuary waters are very fertile. Minerals, oxygen, carbon dioxide, and light are available in plenty. Water is less saline than in the sea as it mixes with fresh water from the rivers.

• Tide action brings about rapid circulation of nutrients and helps in removal of waste products.

• Estuary waters often have more life than the adjacent sea or the fresh water up the river.

• Plankton include microscopic as well as large forms. These include diatoms, algae, protozoans, small crustaceans, etc.

• A large number of species of bony fishes form the nekton fauna. Benthonic life comprises algae, fixed plants, clams, snails, prawns, crabs, oysters , skates and rays.

Define Coral Reefs.

Coral reef occur in clear, shallow, warm water where temperature rarely falls below 20⁰C and there is enough light for photosynthesis. Reefs are made up of calcareous material secreted by the coral polyps and lime-secreting algae. Most of the coral reef is submerged, although its top may be exposed at low tide. A reef being rocky, provides anchorage for algae and sessile animals. Variety of swimming invertebrates and fishes find shelter in the reef cervices. Coral reef is the highly productive part of the coastal region. It is one of the example of Aquatic ecosystem example.

Summary

To wrap up our post, we conclude that Aquatic ecosystem is vast and there are also many different kinds of aquatic communities. Mainly, aquatic ecosystem is divided into three categories- Fresh water, Marine and Estuaries ecosystem. All the aquatic system have different life and physical factors.

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In this post you will find desert biome examples and detailed explanations about their physical conditions and life.

Biomes are the world’s terrestrial biotic communities, each containing a distinct array of plant and animal life. Desert biomes are found in rain shadow zones,  where dry air from the equator falls from the high sky and warms as it is compressed towards the land.

Desert biome examples are discussed below:

• Sahara desert
• Gobi desert
• Arabian desert
• Thar desert
• Antarctic desert
• Atacama desert
• Kalahari desert
• Ladakh desert
• Mojave desert

Characteristic of Desert Biome

Physical conditions:

• The weather is a mix of hot, cold, and dry. Because there is little water vapour in the air, it is a poor insulator.

• Because the ground radiates heat swiftly, the temperature rises throughout the day and drops dramatically at night.

• Rainwater swiftly penetrates into deeper layers of the ground or evaporates when annual rainfall is less than 20- 25cm. The soil type is either sandy or rocky.

Life:

• The desert biome has less life than most other terrestrial biomes. Only species with adaptations to resist temperature extremes and arid conditions may survive in this environment.

• The vegetation is xerophytic and sparse. Individual plants are often spread widely, with enormous distances between them.

• Succulents, such as cacti and euphorbias, which store water in their tissues, hardy grasses, and prickly shrubs and trees with long spreading roots, such as Acacia, Prosopis, Tamarix, and date palm, are among the distinctive plants.

• Annual flowers and grasses bloom during the wet season and have a short life cycle. Ephemerals are what they’re called.

• The animals are primarily small and nocturnal, burrowing into the cooler earth to avoid the heat of the day, when they would lose water rapidly.

• Arthropods, reptiles, birds, and mammals are among the animals. Scorpions, spiders, centipedes, and insects are all examples of arthropods.

• Horned lizards, Gila monsters, collard lizards, coral snakes, and rattle snakes are among the reptiles.

• The roadrunner, cactus woodpecker, burrowing owl, raven, Gambel’s quail dove, turkey, vulture, swifts, and swallows are among the local birds.

• Camels, white-tailed deer, mountain sheep, jack rabbit, various rodents, grey fox, jackal, cat, skunk, and badger are among the mammals. A few toad species are also prevalent.

Thar Desert

The Great Indian Desert, often known as the Thar Desert, is located in India. Rajasthan’s territory to the west of the Aravalli Hills is stony and sandy. It runs from Gujarat’s Rann of Kachchh across Rajasthan and into Haryana’s borders.

A heavy layer of loose sand blankets the Thar desert. Sand dunes are little sand hills that can be seen in some areas. Strong gusts blowing here may carry a lot of sand with them. They have the ability to alter the sand dunes. In the Thar Desert, there are extremely few streams. 

They are usually dry. The most important river is the Luni. Oasis can be found in some areas. The ground surrounding an oasis is rich in nutrients. Crops are grown in this area. Throughout the year, the thar desert is hot and dry. Rainfall is scarce or non-existent. Because of the hot and dry climate, the vegetation is largely scattered plants and spiny shrubs.

The eastern half of the desert is home to the khejri, kikar, and babul trees. Camels, blackbucks, chinkaras, and big Indian bustards can all be found in this area.

Sahara Desert

It is the largest desert on the planet. It covers around 8.54 million square kilometres. Eleven countries are bordered by the Sahara desert. Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Sudan, Tunisia, and Western Sahara are the countries involved. 

Despite its difficult climate, it is home to a diverse population. There are nomadic tribes who raise goats, sheep, camels, and horses as livestock. They get milk and hides from these animals, which they use to produce leather belts, slippers, and blankets. People cultivate date palms as well as rice, wheat, and barley.

Cactus, date palms, and acacia trees make up the vegetation. Camel, hyenas, jackals, foxes, scorpions, and a wide variety of snakes and reptiles are among the most common animals found there.

Atacama Desert

It is situated west of the Andes Mountains. It is considered as the “absolute desert”. There are regions where no rain has ever been reported in recorded weather history. The Andes mountain range, as well as wind patterns from both the Atlantic and Pacific Oceans, obscure this location, preventing water from being deposited there.

Even though it is one of the driest deserts, it serves a role even without life. Saltpetre is an combustible similar to powder that has been used for decades in the mining of silver, tin, and copper in the Andes region. Because of the dry circumstances, saltpetre is actually extracted from this desert.

Gobi Desert

It is Asia’s second largest desert, as well as the world’s largest non-polar cold desert.

China and Mongolia are also home to this desert. Summers are scorching hot, while winters are bitterly cold. This desert is traversed by the Yellow River. 

Kalahari Desert

This desert is located on the African continent and encompasses Botswana, Namibia, and South Africa. Kalahari is a word that means “great thirst.” The Okavango River circles the desert. It is known for diamond mining and hunting by the San people.

Antarctic desert

Antarctica is the world’s largest desert, covering twice the area of the Sahara desert.

The atmosphere is relatively dry, and clouds are uncommon. It has an average annual precipitation of 150 mm, which is less than 250 mm, which qualifies it as a desert.

Ladakh Desert

It’s a frigid desert. It is located between the Karakoram and Zanskar ranges. The Indus River runs through Ladakh. 

Ladakh is home to a number of glaciers. E.g. Gangri glacier. A very cold temperature has been discovered. It is located in a rain shadow location, with annual rainfall as low as 10cm. The area is subjected to bitter cold winds and scorching heat.

Mojave desert

It is North America’s driest desert. The Mojave Desert covers 47,877 square miles in southern California and southern Nevada, with small sections in Utah and Arizona.

The wide plains of this desert contain some of the harshest and deadliest environments in all of America. Death Valley National Park, as its name suggests, is an arid area in the Mojave Desert where temperatures regularly exceed 120 degrees Fahrenheit. The Mojave Desert is home to about 700 animal species and over 2000 plant types.

Joshua tree is one of the most fascinating plant species found in the Mojave Desert. The desert tortoise is one of the animals that live in this area that is steadily becoming endangered.

Arabian desert

In Western Asia, the Arabian Desert is a large desert region. It runs from Yemen to the Persian . It encompasses the majority of the Arabian Peninsula. It is the world’s fifth largest desert and the largest in Asia. 

Although there are a few indigenous plants in the Arabian desert ecoregion, there is limited biodiversity. Hunting, habitat damage, cattle overgrazing, off-road driving, and human encroachment on their habitat have all contributed to the extinction of many species, including the striped hyena, jackal, and honey badger. Other species, such as the Arabian sand gazelle, have been added to protect them for the desert.

Frequently Asked Questions

Define Desert.

The amount of precipitation (rain, snow, mist, and fog) in an area defines a desert. A desert is a location with relatively little precipitation. Deserts come in a variety of shapes and sizes, including subtropical, coastal, and polar deserts. They all share a desolate, windswept landscape that makes it difficult for plants and animals to establish themselves on land.

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In this post you will find the insectivorous plant example and their detailed explanations.

Insectivorous plants are those that trap and consume animals or protozoans, such as insects and other arthropods. Photosynthesis is still used by insectivorous plants to generate some energy.

Some Insectivorous plant examples are discussed below:

• Venus flytrap
• Pitcher plant
• Drosera
• Common butterwort
• Drosophyllum  
• Pinguicula
• Utricularia
• Genlisea
• Byblis

Venus flytrap

The Venus flytrap  (Dioanaea muscipula) is a carnivorous flowering plant.  The plant consist of two leaf like hinged lobes which act as a trap for the insects. Hair like projections are present which are called Trichomes. These trichomes induce the lobes to immediate closing when prey comes in touch with it.

• This type of movement is known as Thigmonasty.The lobes will only shut if the trichomes present on it is being touch by the prey for many times. This action will prevent the plant to lose its energy when there is no insect.

• The hinge has tiny bristles at the edge, so that once the prey is trapped, it cannot escapes out.

• This insectivore plant eats all kinds of insects and arthropods to gain nutrition but also derives nutrition from soil. It can kill all flying insects, spiders, grasshopper, ants etc.

• This plant can digest any creature within 3-5 days and can survive for months without eating.

Pitcher plant

Pitcher plants (Sarracenia) are carnivores having jug-shaped morphology with modified leaves which act a lid of the jug. Leaves close the open hollow part of the plant and act as pitfall trap. Main body is filled with fluids which digest the prey once get trapped. Plant use the nectar to attract the insects, once the insect enter the deep chamber get drowned and digested.

• Members of the Nepenthaceae and Sarraceniaceae groups are referred to as “pitcher plants.”

• The edge of the hollow part which is called peristome becomes wet, it secretes nectar and produces anthocyanin colors by which insect get into the trap.

• Pitcher plants may also have waxy scales and projecting aldehyde crystals that insects can’t climb out of. The small fluid bodies are embedded within the pitcher plant called Phytotelmata  that  submerge the insect, causing its body to disintegrate over time.

• Enhanced viscoelasticity is linked to higher insect retention, which can aid in the capture of flying insects like flies, while increased fluid acidity reduces insect dying time, which can help in the capture of crawling insects like ants.

Drosera

Drosera, they are also known as sundews. It is one of the largest genera of carnivorous plants. These Droseraceae members use stalked mucilaginous glands on their leaf surfaces to attract, capture, and consume insects. The insects are utilised to compensate the plants’ lack of mineral nourishment in the soil. Every continent except Antarctica is home to a variety of species that differ significantly in size and form.

D. capensis has strap-like leaves that can grow to be 3.5 cm long and 0.5 cm broad. The brightly colored tentacles of all sundews release a sticky mucilage that captures arthropods. The plant blooms in the summer (December and January in its native South Africa) with up to 50 pale violet, 2 cm wide flowers carried on up to 35 cm tall racemose inflorescences. When the blooms close, they can self-pollinate and generate a large number of minute, spindle-shaped seeds, which are released from capsules that form when the flowers die. This plant grows well on full sunlight and nutrient depleted environment having damp and lime restricted soil. 

Common butterwort

Common butterwort is a plant that feeds on insects. Its bright yellow-green leaves release a sticky fluid that attracts insects; once caught, the leaves gently curl around and consume their victim. 

Example of common butterwort is Pinguicula vulgaris which carnivore perennial. It is 3-16 cm long and having a funnel shaped purple flower which is 15mm longer. White flower can also be seen but its rare.

This butterwort can be found in bogs and swamps, as well as low and subalpine elevations.

It has glands on its leaves that secrete a sticky substance that captures plants on the leaves, as well as digestive enzymes that function to digest insects externally. Because they typically thrive in acidic, low-nutrient soil, such as bogs, this allows the plant to reach a supply of nitrogen.

Drosophyllum

The genus Drosophyllum has only one species, Drosophyllum lusitanicum (Dewy Pines). When grown outside, these fascinating plants produce a unique honey scent to attract prey and are always covered with the black carcasses of unfortunate insects. They have beautiful yellow flowers.

The plant has a characteristic sweet scent that attracts the insects it feeds on. Insects gets stuck to the mucilage released by the stalked glands on the leaves when they strike on them. The more the insects resist, the more entrapped they become, eventually dying to suffocation or fatigue. Enzymes are secreted by the plant which digests the prey or insect and releases the nutrients which is then absorbed by the plant. These nutrients are used by the plant to replace the nutrient-deficient soil in which it thrives.

Pinguicula

Pinguicula, or butterworts, are carnivorous flowering plants belongs  to the  family of Lentibulariaceae . To supplement the low mineral nutrition they get from the environment, they use sticky, glandular leaves to attract, capture, and digest insects.

Tropical butterworts either create compact winter rosettes of fleshy leaves. They are usually found in areas where water is scarce throughout the year, as overly wet soil can lead to rotting. They’re found in regions where, due to acidic soil conditions, nitrogenous supplies are known to be scarce, rare, or absent.

Butterwort leaf blades are smooth, stiff, and juicy, and are usually bright green or pinkish in color. The leaves size ranges from 2-30cm in accordance with species.  The shape of the leaf varies per species, but it is commonly obovate, spatulate, or linear. The leaves can also be yellow in appearance, with a velvety texture and greasy consistency.

Utricularia

They are called bladderworts and belongs to the genus of carnivorous plants. Different species of Utricularia are found on different continents  of terrestrial, fresh water and damp soil areas but cannot found on Antarctica region.Utricularia are carnivorous and use bladder-like traps to catch small organisms. 

Terrestrial species have tiny traps that feed on microscopic food like protozoa and rotifers that swim in water-soaked soil. Utricularia gibba is a small to medium-sized aquatic plant that can be  free-floating in the water column, or attached to the substrate in shallow water but it will flower more if supported by a substrate beneath shallow water.

Genlisea

Genlisea  are often called corkscrew plants. They are little herbs that grow from a short rhizome and have two leaf types: photosynthetic foliage leaves and highly adapted subterranean leaves that capture insects. 

The plants attract, trap, and digest little micro-fauna, especially protozoans, using highly modified subterranean leaves. Although the plants lack roots, the subterranean traps fulfil many of the same tasks as roots, such as anchoring and water and nutrient absorption.

Byblis

Byblis is a tiny genus of carnivorous plants known as the rainbow plants because of its colourful mucilage-covered leaves in intense sunlight. It possesses sticky hairs that attract insects by tricking them into thinking the glandular secretions are nectar drops. 

Byblis, on the other hand, differs from the sundew in that its hairs do not wrap around the trapped prey. Byblis aquatica has main axis of stem which is not further branched and fine fibrous root like structure are attached to the main axis.The core stem can grow to be 45 cm long. The entire length of the leaf is coated with stalked mucilaginous glands. These not only attract and capture insect prey, but they also allow the plant to “hold fast” on nearby objects for support. Flowers emerge singly at the terminal of 1.5–3 cm stalks that look similar to leaves.

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In this post you will find algae examples, their characteristics and detailed facts.

Algae are non-vascular photosynthetic aquatics that produce auxiliary spores for asexual reproduction and non-jacketed sex parts for sexual reproduction.

Algae examples:

• Chlamydomonas
• Volvox
• Ulothrix
• Spirogyra
• Chara
• Fucus
• Laminaria

Chlamydomonas

Chlamydomonas is a common resident in ammonium-rich fresh and marine environments. Water bloom is caused by excessive growth of the alga . Only a few species can grow in the snow, they are  called  Cryophytes, such as C.nivalis and C.yellowstonensis, are among them.

Chlamydomonas is a minute green alga with a length of 10-30μm. A mucilage coating surrounds the algae. Glycoproteins and non-cellulosic polysaccharides make up the cell wall. Dictyosomes, mitochondria, endoplasmic reticulum, and ribosomes are examples of cytoplasmic structures. In the cytoplasm, there is usually a single big basin-shaped chloroplast. It has one or more pyrenoids for starch storage and a number of photosynthetic lamellae with 2-20 thylakoids per lamella.

Volvox

It’s also known as rolling alga or rolling ball. Volvox is a green colonial alga that can be found in fresh water ponds, pools, and lakes. Because it has a constant number of cells, the colony is also known as coenobium.

All of the cells are organized in a ring around the outside of a tougher mucilage membrane. Watery mucilage covers the colony’s center. Biflagellate cells have 2-6 contractile vacuoles, a single nucleus, a single chloroplast with a stigma, and one or more pyrenoids.

Individual cells coordinate their flagellar motions to help the colony swim in water. Gonidia, or reproductive cells, are larger than the other somatic cells. Daughter colonies are formed during asexual reproduction. Oospores are produced during  sexual reproduction (Oogamous).

Ulothrix

Algae (green algae) Ulothrix thrives in aerated fresh water such as rain puddles, lakes, tanks, springs, and slow-moving streams. It has a 30cm long unbranched filament. An elongated non-green cell termed a holdfast or rhizoid attaches the filament to the substratum.

In the surrounding cytoplasm, each cell possesses a central vacuole and a single collar-like parietal chloroplast. The nucleus and other organelles can also be found in this cytoplasm. For starch storage, chloroplast contains one or more pyrenoids.

Spirogyra

It’s a silky green alga that floats freely in stagnant fresh water like ponds and ditches. It is a 1 metre long unbranched filament. The filament is made up of a single file of elongated cylindrical green cells stacked one on top of the other. A mucilage sheath surrounds the entire filament. 

A huge central vacuole is crossed by cytoplasmic threads in each cell. These strands hold the nucleus in place at the center. In S.sahnii and S.rectispora, the peripheral cytoplasm contains 1-16 chloroplast, respectively. Spiral-coiled ribbons make up chloroplast. A row of tiny nodules, similar to pyrenoids, can be found on each chloroplast.

Over them, pyrenoids store starch. Vegetative reproduction is accomplished through fragmentation. Asexual reproduction is extremely uncommon. The scalariform and lateral kinds of conjugation are used in sexual reproduction.

Few species, such as S.adnata and S.jogensis, are found affixed to solid substrate.

Chara

It’s a green alga that grows on the bottoms of shallow ponds, pools, and lakes. Because of its jointed look, the alga is also known as aquatic horsetail. The axis and rhizoids make up the plant’s body. 

The upright jointed section of the axis called the stem. Branchlets are whorled at the joints or nodes. Each branchlet has four to fifteen segments. Secondary laterals emerge from the nodes of branchlets. Small cells are found in nodes, while long cells are found in internodes. Rhizoids are multicellular filaments with oblique septa that are not green. They penetrate the substratum and aid in the fixing process.

Fragmentation, tubers, bulbils, amylum stars, and secondary protonemata are all used to multiply Chara vegetatively.

Sexual reproduction is oogamous. Antheridium or globule is the male sex organ. The oogonium or nucule is the female sex organ.

Fucus

It’s  a brown marine alga. There are over 100 species of fucus globally, however none are found in India. The plant body is well branched, with fronds, a small stipe, and a holdfast that aids in attachment to the substratum. 

Some species, such as F.vesiculosus, have air bladders. The fertile receptacle is located at the end of the branch, and the frond surface has a number of pores known as cryptostomata or cryptoblast. Again, there are two types of reproduction: vegetative and sexual. Vegetative reproduction is accomplished through fragmentation or adventitious branches, while sexual reproduction is accomplished through external fertilization. In nature, F.spiralis is monoecious, whereas F.vesiculosus is dioecious.

Laminaria

It is a 2m long marine brown alga. The body is separated into three sections: lamina, stipe, and holdfast. Lamina can be solitary or multi-segmented (L.saccharina and L.digitate) respectively. 

Vegetative, sexual, and asexual reproduction are all possible. The emergence of stolon from the holdfast allows for vegetative reproduction. Sexual reproduction is fully external, antherozoids and eggs are discharged outside the body, and asexual reproduction is done by producing zoospores.

Characteristics of algae:

• Algae can be found in both saltwater and freshwater environments. Damp soil, wet rocks, tree trunks, and other moist terrestrial habitats are also home to several species. It’s possible that they’re epiphytes or epizoics.

• Algae of the kingdom Plantae are multicellular in nature. However, due to their ultrastructure and reproductive similarities, a number of unicellular (Chlamydomonas) and colonial (Volvox) algae are listed among them.

• A thallus is the plant’s main body. Filament is the most basic form. There is a holdfast for attachment. Kelp algae resemble palms, ferns, and other plants on the outside. They have a lamina-like leaf and a stipe-like stalk.

• Size ranges from microscopic(Chlorella) to macroscopic (Macrocystis).

• The mucilage covers the entire body. Mucilage shields algae from desiccation, epiphytic development, harmful compounds, and water degradation.

• Algae, unlike land plants, do not require water to be carried.

• Algal photosynthetic plastids come in a variety of forms and colours. Pyrenoids are found in several of them. Pyrenoids are involved in the storage of starch in green algae. Others are completely bare. Green algae’s plastids are named chloroplast, while others are called chromatophores.

• Agranal plastids are those that lack grana. 1-20 thylakoids make up its photosynthetic lamellae.

• All contain chlorophyll a, carotenes, and xanthophylls. Fucoxanthin and chlorophyll c in brown algae are examples of extra photosynthetic pigments found in each algal group.

• Every algal community has its own specific reserve food. Red algae produce floridean starch, while brown algae produce laminarin.

• Fragmentation, tubers, stolons, adventitious branches, and other means of vegetative reproduction are used.

• Asexual reproduction is carried out by zoospores, aplanospores, hypnospores, akinetes, autospores, tetraspores, and other accessory spores. Among these, zoospores are flagellate spores formed under favourable conditions. Each zoospore comes to rest after swimming for a while and germinates to generate a new plant.

• Isogamy, anisogamy, oogamy, spermatization, and other methods of sexual reproduction are used.

• All aquatic ecosystems rely heavily on algae for production. They generate energy rich organic compounds are the basis of food cycles for all aquatic animals.

• Algae fixes over half of the total world CO2 through photosynthesis. They aerate the aqueous medium by releasing oxygen.

• Proteins, vitamins, and minerals abound in chlorella and spirulina. They are utilized as a food supplement and are a rich source of single cell protein.

• Medicinal qualities are found in Codium, chlorella, Laminaria, and Durvillaea.

• To provide oxygen to decomposer organisms, aerobic algae are cultured in sewage oxidation tanks.

• Several algae species grow on the hulls of ships, causing fouling.

• Algae are used to extract bromine, iodine, and potash.

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In this post, you will find the obligate parasites examples their characteristics and  detailed facts.

The Obligate parasites are those parasites that depends on their host to complete their life cycle. They are also called holoparasites.

The Obligate parasites examples are:

• Rickettsia
• Chlamydia
• Mycoplasma
• Lice
• Virion
• Prions
• Trypanosoma
• Leishmania
• Plasmodium
• Pneumocystis

Rickettsia

They are very tiny, non-spore-forming gram-negative bacteria. They are pleomorphic, usually found as small Cocco-bacilli. They are spread by various arthropods like lice, ticks, and fleas. These are obligate intracellular parasites, and they live inside the bacterial cell or animal cells. They cannot survive outside the host body, just like virions.

Example: Rickettsia rickettsii causes Mountain spotted fever

Chlamydia

These are the tiny obligate intracellular parasite. Species of chlamydia cause various problems in humans, and arthropods do not transmit them.

Example: Chlamydia trachomatis causes severe eye illness and is also a causative agent of STD. Chlamydia pneumoniae causes lung contagion.

Mycoplasma

It is an extracellular obligate parasite that has developed the ability to attach to the host cells. Mycoplasma can damage host cells by producing hydrogen peroxide and superoxide radicals, which activate the immune response. 

They can directly enter the tissues and replicate within the host’s cell. Species like Mycoplasma genitalium is one of the emerging cause of STDs.

Example: Myoplasma pneumoniae causes chronic lung ailment or asthma in patients.

Lice

They are obligate parasites that live externally on warm-blooded animals’ surface, in their hair or feathers.

Removing them from the host can make them die. They can survive their entire life on a single host by planting their eggs called nits in the feather or hairs of the host. Eggs hatch and transform into nymph where they molt three times to become fully mature.

Example: The human specie is Pediculus humanus.

Virion

All virions are an intracellular obligate parasites. They require host metabolic machinery to replicate their DNA or RNA to make viral proteins.

Virion contains the protein coat called a capsid, which helps the virion protect its genes outside the cell and serves as a carrier to switch into another host because it can bind to the receptors of the host cell. An example of obligate parasites is Retrovirion which opts for host machinery to make their virion particles.

Prions

They are protein particles without having any nucleic acid. They are also intracellular obligate parasites and cause various abnormalities in animals and humans.  They are so small and can escape the host’s defense mechanism.

Actual mechanism for the activity of prions is still unknown, but some theories suggests, they select protein similar to themselves from the membrane of brain cells and line up around the brain cells to make conformational changes and convert the brain cells into prions.

It causes brain disorder in sheep, cow and humans. Scrapie in sheep, Kuru in Humans

Trypanosoma

It causes African sleeping sickness. It is polymorphic and digenetic in nature. It is elongated, flat and colorless with length of 15-30μm. It is transmitted by vector -Tsetse fly (Glossina palpalis). 

Bite of Tsetse fly releases the parasite in human blood, it gets the nourishment from plasma, multiplies by binary fission and then passes into pancreas and liver and cause damage to the organs.

Examples of obligate parasites : Trypanosoma gambiense and Trypanosoma rhodesiense.

Leishmania

It is dimorphic and digenetic in nature. The parasite is oval, small, non-flagellate in humans having 2-4μm in length called leishmania (amastigote). It is intracellular parasite mostly prevalent in India (U.P, Bihar and Bengal), Nepal, china. This parasite has a blood sucking vector called Sandfly (Phlebotomus). After introducing into the human body it passes into macrophages and then attacks white blood cells causing the breakdown of immune system. The skin, legs and abdomen become dark, hence the name is given Kala azar.

Obligate parasites examples of Leishmania are :

• Leishmania donovani causes Kala azar (Black fever).
• Leishmania tropica causes oriental sore or Delhi sore.
• Leishmania brasiliensis causes expundia.

Plasmodium

It is malarial parasite. It is digenetic, female anopheles mosquito is primary host while humans are secondary host. Sporozoite of plasmodium is mainly responsible for causing malaria. Once sporozoites are released by female anopheles saliva into human blood, sporozoites molts 2-3 times to develop the stage called merozoites that contains brown pigment granules called haemozoin which brings out the symptoms of malaria.

There are about sixty species found, out of which only four species occur in humans: Plasmodium malariae, P.vivax, P.ovale, P.falciparum.

Pneumocystis

It is a yeast-like fungus who shares biological characteristic with protozoa. Pneumocystis jirovecii is responsible for causing PJP (Pneumocystis jirovecii pneumonia) in immuno-compromised persons. 

This pneumonia is parasitic type of pneumonia which occurs when CD4 count is less than 200 cells/ml. The symptoms are cough with scanty sputum, fever and breathlessness. This fungus is ubiquitous and air-borne, once entered into lungs, macrophages are activated to remove pneumocystis, we can find them in alveolar air spaces, as the pathogenicity increases, macrophages, T and B cell dysfunctions.

Characteristics of Obligate parasites.

• They exploit their one of the hosts if the life cycle is direct or indirect. The direct life cycle involves the exploitation of a single host, e.g Ancylostoma species, while the indirect life cycle exploits more than one host, e.g. malaria plasmodium.

• If the life cycle is indirect or complex, then the intermediate host is affected for short duration. The primary or final host are more likely to exploit.

• They are temporary or permanent. The permanent obligate parasites are can live upto as long as they can by producing number of generations while temporary parasites like mites are limited to single stage development and adult stage is non-parasitic.

• They live on their host as ectoparasites (Lice) and endoparasites (Chlamydia).

• Obligate parasites have evolved the host mechanism to suppress the apoptosis to make their survival.

• Obligate parasites can only survive in the presence of their host.

Frequently Asked Questions

Q1.What is black water fever?

–It is a malarial fever caused by the Plasmodium falciparum

Q2. What is the infective stage of the parasite Entamoeba histolytica?

–Tetranucleate cyst.

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In this post, you will find the examples of endoparasites, their classification and detailed characteristics.

Endoparasites are parasites that stay inside the host’s body living as intracellular or intercellular and derive nutrition from the host. They are permanent parasites.

Examples of Endoparasites are :

• Fasciola
• Taenia
• Echinococcus
• Ascaris
• Ancylostoma
• Enterobius
• Trichinella
• Trichuris
• Dracunculus
• Wuchereria

Fasciola

It is a leaf-like structure having 2-5cm in length. It is soft and pinkish-brown with a black lining in color. The body contain different parts for attachment, ingestion and egestion. 

The mouth takes part in ingestion as well as egestion. The Acetabulum is present for attachment of the body to the host. Genital pore is present between two suckers. The body contains the cuticle with tiny spines. These endoparasites are digenetic in nature means having two host. Excretory organ is flame cells which excrete ammonia and fatty acids.

Examples of endoparasites : Fasciola hepatica. Fasciola gigantica

Taenia

It has elongated tape or ribbon-like appearance having 2-12m in length which varies among different species. Body is divided into neck, head and strobila. Body color is creamy yellow or greyish. Strobila constitutes the main body. 

It contains 800-1000 of segments which are called proglottides. Only neck portion is unsegmented which helps in producing new proglottides and this phenomenon is called strobilisation. It is also digentic in nature, man is primary host while pig is secondary host in T.solium

Examples of endoparasites : Taenia solium and T.saginata

Echinococcus

It is 3-6mm in length. Body is divided into scolex, neck and strobila. Scolex contain four suckers, neck is short and strobila have only three proglottides. Adult worm generally reside in small intestine i.e., duodenum and jejunum of dogs while larval stage is found in humans. It completes its life cycle by using two hosts: Dog and Fox is definitive host while sheep is intermediate and man is accidental intermediate host. 

Intermediate host ingests the eggs of echinococcus, hexacynth embryos are released that penetrate the intestinal wall and reached the liver, further developed into hydatid cyst, some embryos passed from liver and get caught in pulmonary capillaries. After this, if carcasses of sheep are ingested by dog, it will grow in intestine and develops into adult worm and further eggs are released into feces and cycle continues.

Examples of endoparasites : Echinococcus granulosus

Ascaris

It is elongated and cylindrical in morphology with variation in size as sexes are separate. The male is short and narrow having 15-30cm in length while female is broader and longer having 20-40cm in length. 

Color is pinkish to white with pointed ends and four streaks – one dorsal, one ventral and two lateral. It is monogenetic in nature means having only one host. Common intestinal endoparasite generally found in the small intestine of human beings. It is more common in children.

Posterior  end is curved in male. Cloaca is present in male at posterior end having two penial spicules. Gonophore and a separate anus is present in female.

Example: Ascaris lumbricoides

Ancylostoma

It is commonly called hookwarm endoparasite found in human small intestine. Its appearance is small and cylindrical having size of 8-13mm long. Sexes are separate, female is quite long in comparison to male.

The anterior portion has a buccal capsule that contains a mouth with two chitinous cutting plates. These cutting plates posses teeth which helps the organism to tear the intestinal mucosa. They basically sucks 0.8ml of blood per day which results in a condition called anemia.

Example: Ancylostoma duodenale

Enterobius

It is also called pinwarm, seatwarm or threadwarm. It is small and round in appearance having size of 3-13mm and monogenetic in nature, males are comparatively shorter than females. This parasite generally inhabits the colon and other parts of the large intestine in children and women.

The anterior portion of mouth has a pair of cuticular expansion called cephalic alae. The posterior end is curved in males having a penial spicule and pair of cuticular expansion called caudal alae. It causes enterobiasis or oxyuriasis.

Example: Enterobius vermicularis

Wuchereria

It is cylindrical and thread like in appearance having size of 4-8cm. They were commonly known as filarial worm. As the sexes are separate, males are shorter than females. Digenetic in nature, primary host are humans and secondary host is female mosquito of Culex.

Cycle starts when male and female bug copulate in lymphatic gland. It gives birth to juveniles called microfilariae. These microfilariae pass on to blood vessels of skin during night. Female culex picks up the microfilariae from the skin where juveniles grow and become mature to affect the new human host.

Their growth in human host causes blockage of lymph vessels and causes a condition called lymphodema. The tissue around the blocked lymph grows and become harder. As a result that area becomes enlarged and huge, it is also called elephantiasis. Common organs which are affected : breast, leg and foot.

Examples of endoparasites: Wuchereria bancrofti

Trichuris

It is also called whip bug generally inhabits the large intestine of humans. Males are shorter having length of 30-40mm while females are quite longer with size 40-50mm. Anterior end in males is very thin while posterior end is coiled. Monogenetic in nature i.e.,man is the only host. 

Embryonated eggs (which have larva inside them) are ingested by human, these embryonated eggs are reached to small intestine where they hatches. Adult male and female are formed in the cecum and  inhabits the large intestine once they hatched.

The fertilisation occurs and forms unembryonated eggs which further passes to the stools once they are completely divide to form embryonated eggs which is again ingested by humans through contaminated food or water.

Example: Trichuris trichuiria

Trichinella

It belongs to the class Nematoda, commonly called trichina bug. Found in Europe, USA, Africa except India. They generally resides in duodenal and jejunal mucosa i.e., small intestine. Males are shorter than females. Larva of adult worms are encysted in straited muscles of deltoid, diaphragm and biceps.

Life span of these organisms is very short, males dies after fertilisation while female dies after releasing larvae. Monogenetic in nature but require another host to complete the cycle. Humans ingest pork flesh, digestive enzymes release the larval form in stomach.

Differentiated into male and female worms, produces larva into small intestine, larva moves to straited muscle and become encysted as man is the last host, while if it encysted in rat, it can transfer to the another host like pork or other rat to complete their cycle.

Example: Trichinella spiralis

Dracunculus

It is also called Guinea bug. Digenetic in nature i.e., definitive host is man while intermediate host is copepods or cyclops. One can affected by this organism by drinking contaminated water having cyclops with L3 larvae. 

Larvae are released in the body when copepods dies. They penetrate the stomach and intestinal wall of the host wher they and reproduce to form new L1 larvae.

Fertilized female bug moves to the skin and causes blister to release larvae. These L1 larvae are released into water body by affected host. Copepods consume the L1 larvae where they molt and forms type L3 larvae and continue the cycle.

Example: Dracunculus medinensis

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In this article you will find the brown algae examples and their detailed facts.

Brown algae of class Phaeophyceae are multicellular eukaryotic algae rich in phycocolloid and fucoxanthin which posses chlorophyll c, 3-thylakoid lamellae and food reserve unit called laminarin.

List of Brown algae examples

• Ectocarpus
• Alaria
• Dictyota
• Nereocystis
• Padina
• Laminaria
• Sargassum
• Fucus
• Durvillaea
• Pelvetia
• Ascophyllum
• Sphacelaria

Ectocarpus

It is filamentous algae and can grow upto 30cm. There are mostly marine but some are also fresh water. It shows cosmopolitan distribution like colder areas or polar regions. Species of ectocarpus are mostly littoral and supralittoral. Most of the species are lithophytic but some are epiphytic (E.coniferous & E.breviarticularis grow on other brown algae thallus) and some are endophytes ( E.dermonematics which grow inside the other algae).

Alaria

It is a large brown seaweed algae of class phaeophyceae and are mainly eaten as food in many countries like china, korea and japan. They can grow upto 2m in length. Example : Alaria esculenta is an example of edible seaweed.

Dictyota

It is a salt water algae. The thallus is unique and has mat like appearance. They are widely spread in warm seas of tropic, most of the time they are attached with rocks of the basal holdfast. Thallus is plant body which is a strap like structure which can grow between 10-20cm in length and are repeatedly branched and each of branch is further divided into two branch(dictyota) and keep dividing. Every tip of the branch have an apical cell and these cells decides the growth of the thallus.

Nereocystis

They are commonly called bull kelps mainly found on the beach of Pacific coast. They are easy to identify having large spherical bulb at the end and long stalk. They die once in a year especially in winters.

Padina

Padina has flattened, erect, fan-shaped thallus and rolled apical margin. It has the capacity to incorporate calcium into their thallus. Its common name are Mermaid’s fan seaweed, Peacock’s tail, turkey feather algae and white scroll alga. Another feature is they are slow growing and complex in nature. Pedina has 27 species found globally.Examples: Pedina pavonica (Peacock’s tail), P.gymnospora, P.adanson etc. Habitat is obviously marine and coastal region.

Laminaria

It is marine brown alga having length of 2m. Body is divided into lamina, stipe and holdfast. Lamina can be single (L.saccharina) or having many segments(L.digitate). Reproduction can be done by vegetative, sexual and asexual means. Vegetative reproduction can be done by arising stolon from holdfast. Asexual reproduction is done by developing zoospores and sexual reproduction is completely external antherozoids and eggs are released outside the body.

Sargassum

They are mainly found in the atlantic ocean having a region called “Sargasso sea”. They are branched, sporophytic, body is differentiated into main axis and holdfast. Main axis differentiated into many primary laterals and these laterals bears leaves. Surface of leaves has many pores called ostioles. Growth is done by using apical cells. Reproduction  is done by two modes: Vegetative and Sexual. Vegetative is usually takes place by fragmentation while sexual reproduction is external. They contain flask-shaped cavity called conceptacles where sex organs are produced.

Fucus

It is also marine brown alga. There are about 100 species found worldwide but there is no species of the fucus found in India. Plant body is well branched, divided into frond, short stipe and holdfast which helps them to attach to the substratum. Air bladders are found in some species like F.vesiculosus. The terminal part of branch has fertile receptacle and frond surface contain number of pores called cryptostomata or cryptoblast.Again reproduction occurs by two modes: Vegetative and sexual. Vegetative occurs by fragmentation or by adventitious branches and sexual reproduction is done by external fertilization. F.spiralis is monoecious while F.vesiculosus is dioecious in nature

Durvillaea

Durvillaea antartica is one of the massive brown algae found at different coast of Australia. Many species D.poha and D.antartica shows buoyancy due to honey-comb like structure in their fronds. They have been using as tool, clothing and a food source in many regions of south pacific.

Pelvetia

They are very common brown algae generally found at the littoral  regions of Europe. They grows upto 15cm in dense tufts having receptacle at terminal branch. Mucus layer is present to prevent desiccation when there is no tide. Example: Pelvetia canaliculata.

Ascophyllum

Ascophyllum nodosum is one of the large algae found that generally grows in the north altantic ocean. It has long and tough fronds having egg shaped air bladder at regular intervals. This algae is harvested for many purposes like fertilizers, alginates and seaweed meal for animals and for human consumption also. It has many benefits as it provides heat tolerance so that animals can work harder and longer  in hot weather without getting overheated.

Sphacelaria

They have big apical cell at terminal branch which play major role in mitosis and helps in increasing the length of the plant as well as of the branches. The girth of the pluriseriate filament is accomplished through parenchymatous development. They have plurilocular and unilocular sporangium that form the asexual reproductive cycle. Vegetative reproduction is done by using propagules.

Frequently Asked Questions

Q1. Define thallus.

Thallus is a somatic plant body like structure which do not have true stem, leaves and roots.

Q2. What is food reserve of phaeophyta?

Laminarin and Mannitol

Q3. What are fronds?

Leaves like structures are called fronds.

Q4. Define fucoxanthin.

Brown algae develops their colour due to presence of abundant brown colour pigment xanthophyll called fucoxanthin.

Q5. What is Phycocolloids?

Brown algae have two types of nonsulphurated phycocolloids: algin and fucoidin. This will protect the algae from dessication during winters and low tides.

Q6. Give algin uses.

It is a phycocolloid obtained from various species of Phaeophyta like fucus, laminaria etc. They are used as emulsifiers and thickeners and gelating agents in number of products like tooth paste, shaving creams, cosmetics, paints and shampoo.

Q7. What are Phaeoplast?

Plastids of brown algae are called phaeoplasts. Each photosynthetic plastid is connected to endoplasmic reticulum and form the complex called CER (chromatophore endoplasmic reticulum).

Q8. What is the minimum and maximum size of the brown algae?

It varies from 1mm to 60m. The larger forms of brown algae are called giant kelps. Example : Ectocarpus filifer has small size of around 1mm and while largest size is about 60m of Macrocystis pyrifera. Laminaria is a small kelp of size 2-3m.

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In this post you will find the thermophilic bacteria examples, their importance and detailed facts.

Thermophiles or thermophilic bacteria are those who have affinity towards the high temperature. In simple words high temperature loving bacteria are called thermophiles. Their optimum temperature for growth is lies between 50⁰C to as high as 121⁰C.

Thermophilic bacteria examples are:

• Thermus aquaticus
• Deinococcus radiodurans
• Thermus thermophilus
• Thermotoga maritima
• Geobacillus stereothermophilus
• Rhodothermus marinus
• Thermococcus atlanticus
• Geoglobus ahangari
• Sulfolobus acidocaldarius

Thermus aquaticus

Classification

• Domain: Bacteria
• Phylum: Deinococcota
• Class:  Deinococci
• Family:  Thermaceae
• Genus:  Thermus
• Species:T.aquaticus
• Binomial name: Thermus aquaticus

Thermus aquaticus is a pretty common bacterium that can live in a lot of different environments, both natural and human-made.Thermus aquaticus can copy its DNA at high temperatures using its enzymes. Using Thermus aquaticus PCR becomes faster.

It is one of the extremophile that inhabits environments with very challenging conditions, places like deep sea vents.

Thermus aquaticus is used in polymerase chain reaction. Previously, the process is quite intensive so for each round of DNA copying in the old process of PCR, new enzymes are added.

Enzymes are proteins and heating them up usually breaks them down. . Until one researcher suggested trying out a DNA polymerase enzyme (Taq DNA polymerase) isolated from a bacteria that thrives in hot springs.

Example : Thermus aquaticus was first isolated from thermal springs in Yellowstone National Park (USA)

Deinococcus radiodurans

Classification

• Domain: Bacteria
• Phylum: Deinococcota
• Class: Deinococci
• Order: Deinococcales
• Family: Deinococcaceae
• Genus: Deinococcus
• Species: D.radiodurans
• Binomial name: Deinococcus radiodurans

As its name suggests it is one of the most potential extremophile who can tolerate extreme radiations. It also helps in the bioremediation of heavy metals especially those having radioactive property. Study shows that strain of D.radiodurans have the ability to form biofilms the remediation of uranium.  

Thermus thermophilus

Classification

• Domain: Bacteria
• Phylum: Deinococcota
• Class: Deinococci
• Order: Thermales  
• Family: Thermaceae
• Genus: Thermus
• Species: T.thermophilus
• Binomial name: Thermus thermophilus

It is aerobic and gram-negative bacterium having two strains (HB8 and HB27) whose complete genome sequence is available and used a model organism for systems biology. Strains of T.thermophilus are known to produce high amount of carotenoids. This property of biosynthesis of carotenoids may be due to presence of plasmids. This bacterium was first isolated in Japan from natural thermal environment.

Thermotoga maritima

Classification

• Domain: Bacteria
• Phylum: Thermotogota
• Class:Thermotogae
• Order: Thermotogales  
• Family: Thermotogaceae
• Genus: Thermotoga
• Species: T.maritima
• Binomial name: Thermotoga maritima

It is an hyperthermophilic eubacterium isolated from heated marine environment. An anaerobic bacterium which is known to contain an encapsulin. Encapsulins are protein based bacterial nanocompartments found in bacteria and archaea which quite look like virion icosahedral particle. These encapsulins contain cargo enzymes (FLP-ferritin like protein) in their shell. These encapsulins facilitate isolation and catalysis of toxic substance in the cell.

• DNA is unstable at high temperature.Horizontal gene transfer (HGT) is one such mechanism of bacteria which provides the adaptation and thermotolerant abilities. An example is reverse gyrase enzyme which is transferred from archaea to bacteria. Reverse gyrase helps in supercoiling which result in lowering the melting temperature of DNA. So bacteria will start to grow slowly at higher temperature. Transfer of these genes from one bacteria to another through HGT will help in acquiring the same traits and become thermophiles.

• In most of the cases, it is seen that microorganism having high G+C content shows higher thermostability but it is not applicable to every microorganism.

• The arrangement of genes into operons are also seen as an important part of adaptation to temperature and environmental stress. Bacteria can respond to environment stress by regulating their operon system.

• Expression of gene in bacteria make different products like Heat Shock Protein (HSP)  which responds by protecting against cell damage with extreme heat.

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This article discuss the eubacteria examples, their classification and detailed facts.

Domain Bacteria contains a single kingdom of eubacteria having some members of monera except archaebacteria. Eubacteria are modern in comparison to archaebacteria. All Eubacteria are prokaryotes. They are also called true bacteria.

Biological Classification of Eubacteria

1. Bacteria
2. Mycoplasma
3. Cyanobacteria
4. Actinomycetes

Some Eubacteria examples are:

• Bacillus spp
• Clostridium spp
• Pseudomonas spp
• Escherichia coli
• Rhizobium
• Staphylococcus aureus
• Treponema dendicola
• Mycoplasma pneumoniae  
• Mycoplasma hominis 
• Mycoplasma salivarium
• Mycoplasma orale  
• Mycoplasma bovigenitalum 
• Oscillatoria
• Anabaena
• Nostoc  
• Aulosira
• Spirulina
• Streptomyces
• Corynebacterium
• Mycobacterium
• Actinomadura

Bacteria

Morphologically, they are not very complex, the tiny bacteria have complex biochemical, cytological and genetical characteristics. Their small size favours many charcteristics like fast cell division, resistant to environmental factors and ease to get nutrition or food from the surroundings.

They are found everywhere and well adapted to all type of habitats where organic matter is present. They inhabits our body starting from oral cavity to the end of alimentary canal. Dominantly, they lives in soil, water and air. Some are beneficial to humans and live in a mutualistic relationship while most of them are pathogenic in nature.

Some live as mutualist with plants or commensals in alimentary canal of animals. Some bacteria may remain viable when cold upto minus 197⁰C  while some live upto 100⁰C.

Bacteria are unicellular prokaryotic microorganism having simple internal structure. They lacks all membrane bound organelles like mitochondria, golgi apparatus, lysosome, endoplasmic reticulum, chloroplast and true vacuole. They do not have nucleus but having structure without true membrane called nucleoid.

Structure of typical bacterial cell

The outermost layer in bacteria is mucilage sheath. The next layer is cell wall and inner layer is living cell membrane.

Components of a bacterial cell

Cell envelope– contains layer of mucilage (glycocalyx) +cell wall+ plasma membrane

Cytoplasm – matrix in the cell

Nucleoid– genetic material of the cell

Plasmid – circular extrachromosomal genetic material

Flagella – thread like structure used for the motility

Pilli and Fimbriae – outgrowth present on outermost layer used for exchanging genetic material between two bacterium.

Glycocalyx– if it is a loose covering in bacteria, it is called slime layer. If thick and tough then it is called capsule. Protective in function such as helps bacteria to reduce dehydration.

Cell wall – It is rigid and solid in nature, protects the cells from bursting in hypotonic solution. Madeup of peptidoglycan. Peptidoglycan is made up of two sugar derivatives NAG (N-acetyl glucosamine) and NAM (N-acetyl muramic acid).

Plasma membrane– It is selectively permeable and metabolically active. It takes part in cell wall synthesis and respiration. The gap between plasma membrane and cell wall is periplasmic space.

Mesosomes – it is formed due to inwards folding of plasma membrane.

Ribosomes –  Small membraneless ribonucleoprotein having 70S dimension where S reperesents Svedberg. Generally are of two types : Free or scattered in cytoplasm and fixed or attached to plasma membrane. Ribosomes generally occurs in groups called polysomes.

Chromatophores – This special organelle is found in photoautotrophic bacteria which uses sunlight to produce their food. In Blue-green algae it is called chlorosomes. Chlorosomes contain photosynthetic pigments ( Bacteriochlorophyll, Bacteriophaeophytin and Carotenoid).

Nucleoid –  True nucleus is absent, they have a single molecule of DNA having covalently joint ends. Genetic material is naked and without bounded by  histone protein as they lacks membrane therefore it is also called prochromosome. Nucleoid is bound to plasma membrane directly or indirectly with the help of mesosome.

Plasmid-  Extrachromosomal circular segments of DNA present in the cytoplasm of bacterial cell. Some plasmids which are transferable provides extra benefit to the bacteria. However they are not essential for their survival but gives strength to the bacteria to combat environmental stress.