Category: Biology
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Siberian Tiger: Description, Habitat, & Fun Facts
Continue ReadingSiberian Tiger Classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Panthera
Species: P. tigris
Siberian Tiger Description
A tiger subspecies, known as the Siberian tiger is native to far eastern Russia, China, and North Korea. Genetically, the Caspian tiger native to Central and Western Asia is extinct now and closest to Siberian Tiger.
The body of these tigers comprises notorious transverse strips all over the body with red-rust or rust-yellow colored coarse fur. In comparison with other tiger species, the ground coat of the Siberian tiger is often pale and changes between seasons and populations.
These tigers have strong legs and a long tail with relatively short and extended bodies. The length of the Siberian tiger is up to 60 inches and they weigh up to 675 lbs. historically, larger tigers were targeted by hunters, even females weighing at least 220 lbs with most remaining tigers falling short of this.
Generally, tigers are solitary animals. They are territorial animals and claim their large territories by scent-marking. They hunt any prey that falls within their territory and aggressively defends it. The large deers and boars, young of even larger animals are the prey of Siberian tigers.
On availability, they also eat rabbits and badgers. They track their prey and then camouflage to ambush it. The females give birth to two to six cubs at a time after a 3-month pregnancy. The male tigers are involved a little in the parental care of cubs.
The cubs are unable to hunt for 18 months and remain with their mother for at least two to three years and then find their territory. In some cases, the female offspring shares a part of their territory with their mother when they become adults.
Current and Historic Range of Siberian Tiger
The historical range of the Siberian tiger ranges from the Korean Peninsula, northern China, and Mongolia. In different regions, they are also known are “Amur tiger”, “Manchurian tiger”, “Korean tiger”, and “Ussurian tiger”.
Now the remaining population is found in a mountainous area in southwest Primorye Province of Russia and a part of Siberia, thus they get the name “Siberian Tiger”. Only about 350 tigers remained in wild in 2005 but currently, the population is stable since, even increasing to about 550 individuals in 2014 due to intensive conservation efforts.
Habitat loss and illegal poaching are the major threats to the viability of tigers. Now, Siberian tigers are listed as “endangered” by the IUCN.
Fun Facts About Siberian Tiger
Tigers are the most famous animals in the world. They are well known for their mysterious, elusive, dangerous, and beautiful characters. In the 20th century, 3 species from a total of 9 tiger subspecies went extinct, and even more, are endangered. So this proves that we are failing to conserve them despite the collective awareness.
i. The Great Traveler
According to various genetic studies, the Siberian tigers share common ancestors with Caspian tigers. They traveled from Eastern China via the Gansu-Silk Road corridor, colonized Central Asia, and ultimately reach Siberia.
The Siberian tigers are also known as great travelers and travel for large distances. They even travel up to 1000 km in search of prey or mates, but their range is now limited.
According to some records, the Siberian tigers travel up to 60 km per day. Thus, tiger conservation essentially requires the conservation of large areas or tracts of undisturbed wilderness.
ii. Rare Neighbors
Besides the tiger, another large feline also lives in this region. Generally, leopards live at a higher elevation than tigers but the Amur leopard’s habitat overlap with a Siberian tiger in the Changbai Mountains. The Amur leopards are one of the most evasive cats in the world. The IUCN listed these leopards as critically endangered.
iii. Not a Man-eater
The Siberian tigers look very dangerous and are often seen as a threat but opposite to this, they are very elusive and avoid humans to eat. In all cases, when they are reported becoming aggressive towards humans, it is mainly due to any injury or being ill.
Occasionally, an individual tiger does such behavior due to the dwindling population of prey species. However, there are some terrifying exceptions to this rule. John Vaillant, in this book “The Tiger”, described the story of a hunter named Vladimir Markov, a poacher in Far East Russia.
Before stealing a part of its kill, he shot and wounded a tiger. The injured tiger stalked the hunter and waited at the door for him to come home before it killed him and ate him. This rare case is an apparent act of vengeance in which the tiger waits up to two days for the hunter before killing him.
Although in India, some populations of tigers kill humans relatively regularly, this is thought to be an extraordinarily rare behavior of these tigers. The retaliation killings by people led by this, which further increase the threat to their populations.
Siberian Tiger Citations
Siberian Tiger: https://www.nationalgeographic.com/
ABOUT THE SIBERIAN TIGER https://www.rgo.ru/
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Mycology: Definition, History, & Career
Continue ReadingMycology Definition
The study of fungi is called mycology. In this branch, the relationships between fungi and other organisms and their unique biochemistry are studied. Fungi belong to a separate kingdom, most of them are eukaryotic organisms.
Earlier, it was assumed that fungi are an offshoot of the plant kingdom but with the help of DNA and biochemical analysis, it has been revealed that they belong to a separate lineage of eukaryotes. Their cell wall is the main distinguishing feature between fungi and plants.
The fungal cell wall is made of chitin and glucans. Fungi are significantly different from both plant and animal kingdoms thus mycology is considered a necessary branch of biology.
History of Mycology
Until the 1800s, fungi were assumed as a different kind of plant. Some fungal species such as Mushrooms (their reproductive bodies) are edible and also used for medicinal uses, for their hallucinogenic effects since antiquity.
Fungi were considered by many Greek philosophers and naturalists but all relate them with plants. After the invention of the microscope in the 1800s, the inner workings of fungi began to examine.
In 1836, M.J. Berkeley coined the term mycology, when fungi were recognized as their separate kingdom. However, the differences were recognized after the advent of modern biochemistry and DNA analysis. The fungal cell wall is made of chitin, instead of the cellulose cell wall found in plants.
Unlike most plants and animals, the fungal cell is multinucleated and contains special pores, which allows the cytoplasm and nucleus to flow freely between various chambers in the fungal chambers. After observation, it was revealed by scientists that most fungi spend their time as a mold or ooze.
The multicellular fungi obtain nutrition from decaying organic matter. According to scientists, fungi are also responsible for fermentation, and crop diseases. The field of mycology exploded with various discoveries.
In agricultural mycology, we focus on controlling and utilizing fungi in commercial crops. The adverse effects of fungi on other organisms were studied by toxicologists. The useful compounds of mushrooms are extracted by pharmaceutical companies. Like the field itself, the careers in this field are also diverse and complex.
Careers in Mycology
In the agricultural industry, mycology was first used and emerged as an important science and it remains until today. Various plant diseases which affect crops were studied by a phytopathologist.
For many crops, fungi are the major pests, which also show some beneficial effects by serving as a symbiont as allowing the plant to extract nutrients and water from the soil. The beneficial and harmful are distinguished with the help of mycology and it is also needed to treat crops and other infections caused by fungi.
Several fungi can kill targeted insects thus they are used as pesticides that are more natural than synthetic pesticides. After the origin of mycology in agriculture, it expanded well. After knowing the diversity of this kingdom, the roles of fungi were understood properly in society.
For instance, fungi were used in the production of cheese. The organism was classified and described in mycology, which leads to better and efficient production of cheese and other dairy products.
The other form of fungi is yeast, which is used in fermentation and the process of yeast fermentation is science itself. A person can get a bachelor’s degree in fermentation science and work in the brewing and distilling industries.
Yeast is also used in bread making and to maintain the cultures to produce enough yeast for the production, microbiologists are required.
Mycotoxicology is another specialized field of mycology in which the toxic effects of mushrooms were studied. Typically, to become a mycotoxicologist, a person needs a doctorate in biochemistry or organic chemistry or a medical doctorate with concentrations in mycology and toxins.
A variety of chemicals with toxic effects on all kinds of organisms were produced by fungi. Since the earliest hunter-gatherers, humans have eaten mushrooms, but some mushrooms are highly toxic while some species of mushrooms are beneficial and also used as medicine.
Many mycotoxicologists try to develop new drugs from these compounds and work for pharmaceutical companies. Still, more specializations are found in mycology and it is still evolving. With continuous, the kingdom is becoming more large and complex.
Researchers are focusing on special areas and interesting applications for certain fungi. For instance, radiotrophic fungi could alleviate radioactive wastes because it appears to grow in the presence of radioactivity, and fungi can convert complex organic substances into simpler molecules such as CO2.
Many of these applications have important commercial values and institutes need researchers to explore the aspects of mycology. Finally, the scientist studying the historical uses of fungi is called an ethnomycologist.
Mushroom is used in various cultures as food, medicines, hallucinogens, etc. these uses were studied by an ethnomycologist and then inform the front-line researchers about known effects of certain fungi.
Ethnomycologists also provide a critical function by sorting the helpful information which is already gathered by past cultures and societies. As these professions are pushing the boundaries of knowledge and filling the missing gap, the field of mycology is still expanding.
Mycology Citations
Mycologist: What do you do?
Welcome to Mycology Online
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Equilibrium Constant: Definition, Types, & Examples
Continue ReadingEquilibrium Constant Definition
A chemical reaction’s tendency to proceed to completion is described by an equilibrium constant, Keq, which is a variable. It means that all the reactants are converted to products. The point at which the conversion of reactants into products is equal to the conversion of products back into reactants is called equilibrium.
What is Equilibrium Constant?
When the reaction proceeds in the forward direction, from reactants to products it means a large equilibrium constant until almost all the reactants have been converted to products. When the chemical reaction favors the reactants and the reaction proceeds in the opposite direction, the Keq is less than one.
When the equilibrium constant is 1, it indicates that the reactants and products will be equal at the stage of equilibrium. The equilibrium constant is used by scientists to understand how quickly the equilibrium will be reached, and it will be in favour of reactants or products.
When the equation has reached equilibrium, the constant can be calculated using the ratio of products to reactants. The variable Keq is used to represent the equilibrium constant, and the equilibrium constant expression defines it.
Equilibrium Constant Equation for a Chemical Reaction
The concentration of products divided by the concentration of reactants describes the equilibrium constant expression when the reaction reaches equilibrium. This expression can be seen below-
Keq = [C]ceq [D]deq / [A]aeq [B]beq
In this reaction= aA +bB<=> cC +dD
The concentration of a reactant or product in the reaction is described by each term when the product C and D are produced by chemicals A and B. the number of moles of each chemical is indicated by the lowercase letters.
The brackets around a letter [A], indicate the concentration of each chemical, and the equilibrium constant determined by the concentration if each molecule is denoted by the subscript.
A famous scientist, J. Willard Gibbs studied the energy present in the reaction. He described that the equilibrium constant is directly related to the amount of free energy change that occurred during the reaction.
The free energy change is denoted by ∆G. Gibbs proved that standard free-energy change or ∆G0 occurs in every reaction. The initial concentrations of chemicals govern the total free energy change of each reaction.
Using the equilibrium constant of the equation, the following equation is used to calculate the standard free energy.
∆G0 = -RTIn (Keq)
According to this equation, the standard free energy change is another method to describe the driving forces of reaction, and which way they will proceed. However, we can know whether we will have more reactants or products at the end of a reaction by the equilibrium constant but it does not hint about the time taken to complete the reaction.
This is called the rate constant and it is denoted by a lowercase k. A variety of other equations related to the speed of the reaction are also related to the rate constant. A number of biological reactions need the equilibrium constant, as seen in the examples below.
Equilibrium Constant Examples
i. Ionization of water
Life on earth is based on water. The main reason behind this is, it is a good solvent and it can form hydrogen bonds with other non-water molecules and itself. Due to this ability, water can dissolve and diffuse solutes and also carry an electrical current.
A hydrogen bond is formed by water or H2O, in which the hydrogen is pulled away from the oxygen, and the hydrogen molecule forms hydrogen ion (H+) and hydroxide ion (OH–) by dissociation. In solution, individual hydrogen protons exist freely and immediately form bonds with the water molecules.
Due to this, hydronium ion, or H3O+ is formed. The equilibrium constant for this reaction is-
Keq= [H+]eq [OH–]eq / [H2O]eq
The electrical conductivity of water is used to measure the equilibrium constant of this reaction, which is determined by the concentration of (H3O+). An electrical signal is passed by the hydronium ion in the form of the transfer of electrons. The signal is measured by sensitive electrical equipment.
Thus, using sensitive electrical equipment, the equilibrium constant of water is measured to be 1.8 x 10-16, which means that the water has much probability of being the reactant H2O instead of becoming the hydronium ion.
ii. Cells, free energy, and the equilibrium constant
The measurement of the equilibrium is done when a reaction is at equilibrium but it does not mean that all reactions are allowed to proceed to equilibrium. Many reactions are constantly resupplied in the cell by various chemicals due to which, the reactions of the cells are kept far from equilibrium.
However, the tendency of these reactants to form products is described by the equilibrium constant. Some reactions are exergonic, which means that when they happen, they release energy and they have high equilibrium constant that describes their tendency to become products.
It is also said that these reactions have a positive change in free energy, which means that they give off energy to reactions around them. Endergonic reactions are other important reactions that requires energy for completion.
A low equilibrium constant of these reactions describes their tendency to remain as reactants. These reactions are coupled in cells and allow the endergonic reactions to takes place.
Many cellular reactions convert ATP to ADP by using the high equilibrium constant of ATP to drive endergonic reactions. The examples include the formation of fatty acids and protein
Equilibrium Constant Citations
The equilibrium constant K
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Notochord: Definition, Types, & Function
Continue ReadingNotochord Definition
An elastic rod, found in all chordate organisms, is known as the notochord. It provides rigid support to the organism. The notochord is replaced by the vertebral column in chordates, called the vertebrates. It is formed by a cartilaginous substance between vertebrae. Lancelets are one of the simplest chordates, which also contain notochord.
What is Notochord?
In anatomy, the notochord is a flexible rod formed of a material similar to cartilage. If a species has a notochord at any stage of its life cycle, it is, by definition, a chordate. The notochord lies along the anteroposterior axis (front to back), is usually closer to the dorsal than the ventral surface of the embryo, and is composed of cells derived from the mesoderm.
The length of the notochord is extended to the length of the organism, and it allows the muscles to attach. Thus, the lancelet can swim in fast bursts. The notochord is developed at some point in all chordate organisms, like lancelets, however, some organisms may lose it later in life.
For instance, some marine organisms like tunicates, live in the bottom of the ocean and filter feed. The adult form of a tunicate does not require a notochord, but in the larval stage, it helps in swimming to potential settling sites, thus they lose notochord at the adult stage.
Other species do not grow a vertebral column and retain the notochord throughout life. These animals are called invertebrate chordates. Lancelets, tunicates, and some large fish such as the sturgeon and coelacanth are included in this group.
The length of the notochord can be around 3-4 feet in these organisms and will be really thick about half an inch. This huge notochord is used as a spine in notochord by these fish. However, how it protects the spinal cord and what it is made of are different in them. In invertebrates, the spinal cord is surrounded by the bony vertebrae and protects it on all sides.
This protection is not found in animals, which have only a notochord, and in these organisms, the spinal cord sits between the notochord and the skin. The spinal cord and notochord are protected by armored plates and thick skin in animals like sturgeon and coelacanth.
Invertebrates, the notochord is converted into cushioning intervertebral discs that provide protection to the vertebrae from smashing together. By the time a human is around 4 years old. However, the spine with other materials entirely replaces the original notochord.
Notochord Structure
There are several structural molecules such as glycoproteins, form the notochord, which resembles cartilage in many ways. Under a microscope, the cross-section of the notochord appears as a series of concentric rings.
The rings surrounded by each other are layers of the notochord and are made of various molecules, which provide strength and elasticity to the notochord. The glycoproteins and other structural molecules extend from cells and are spaced apart in the notochord.
A large vacuole is found in each cell that can pressurize. The cells push against each other and the surrounding structural materials by pressurization. The notochord becomes extra rigid due to this, which helps the organisms in swimming quickly.
Notochord Function
The notochord becomes a very important and useful structure to attach muscles to due to its strength. To flex properly, muscles need places for attachment. In small invertebrates, the muscles attach down the length of the notochord, due to this they can use muscles all over to swim.
It provides enough support for most of the muscles of the body of some large fishes, which rely on notochord. The cells of the notochord create turgor pressure that makes it extra rigid. While many organisms get enough support from this. In vertebrates, this body plan is taken one step further with the spine.
The spine is made of bone, which increases its rigidity and also protects the spinal cord by fully encompassing it. It is also recorded that during normal vertebrate embryogenesis, the notochord serves important signaling functions.
The proteins secreted by the notochord stimulate the formation of organ systems. This process is known as organogenesis, which starts when the embryo is a hollow ball of cells known as the gastrula. Gastrula has three layers, and the notochord arises from the middle layer, known as mesoderm.
The process of organogenesis is further started with the secretion of several chemical signals from the notochord. Eventually, the spine is created with the formation of bones, and the notochord gets sandwiched between these vertebrae. The vertebrae also protect the notochord from the bones rubbing and smashing together.
Notochord Citations
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Germ Cells: Definition, Types, & Function
Continue ReadingGerm Cell Definition
The unipotent stem cells that can divide and produce gametes are called germ cells. The gametes of haploid sex cells are produced by a germ cell, which undergoes meiotic cell division and produces genetically unique gametes. These gametes fuse during fertilization and form diploid zygotes. The germ cells produce eggs in females and sperms in male organisms.
What is Germ Cell?
Gametes are formed by the germ cells in all sexually reproducing organisms. Invertebrates are the precursors of male sperm cells and female egg cells. The germline is collectively called to all the germ cells in an organism.
In the early stages of embryonic development, the germline separated from the somatic cell line. Both the cell lines have very different functions. All the body structures are made up of somatic cells, whereas the gametes are made of germ cells and help in the transmission of genetic information to offspring.
The main difference between germ cells and sperm cell is, the germ cells divide by meiosis whereas somatic cells divide by mitotic division. The term unipotent means they can only become one other type of cells such as germ cells such as an egg or a sperm.
The gametes fuse and form a diploid zygote during fertilization, which is a totipotent cell. The totipotent cell can give rise to all other types of body cells.
Function of Germ Cell
Germ cells can give rise to gametes. Thus, a person can pass the genetic information to their offspring by germ cells and they are the original cells of all sexually reproducing organisms. Natural selection and evolution occur due to the inheritance of DNA and maximal genetic variation among gametes are ensured by the fact that germ cells divide by meiosis.
Development of Germ Cell
In humans, the stem cells known as primordial germ cells (PGCs) give rise to the germ cells. They originate in the epiblast region of the embryo. After migration of PGCs into the developing gonads, they divide by meiosis and give rise to either sperm or egg cells.
The gametes produced by meiosis are non-identical, haploid cells, which contain a single set of chromosomes. The zygote is formed by the fusion of haploid egg and sperm during fertilization, which contains DNA from both parents. The germline preserves the genetic information in the offspring which further passes on over generations of reproduction.
Germ Cell and Meiotic Division
Meiotic division only takes place in the germ cells of the body. Meiosis produces four, haploid, non-identical gametes, while mitosis produces two, diploid, genetically identical daughter cells.
Originally, germ cells are diploid cells and become haploid after meiotic division to form gametes. The gametes should be haploid to ensure that the offspring get the correct number of chromosomes are fertilization. Thus, the germ cell undergoes meiotic division to halve the number of chromosomes.
The gametes produced by meiosis are genetically unique, which ensures the genetic diversity within the species.
Stages of Meiosis in Germ Cell
There are two stages in meiosis: meiosis I, and meiosis II. During the interphase stage of the cell cycle, the DNA replicates to make its copy. During a complete round of meiosis, the germ cell divides twice and produces four haploid gametes.
i. Meiosis I
Prophase I: The DNA has already replicated, when the cell enters prophase I. At this stage, each chromosome consists of two sister chromatids that are identical and connected by a centromere.
The formation of the meiotic spindle takes place during prophase I and after the condensation of chromosomes, homologous pairs are formed. The process of crossing over occurs between the homologous chromosome pairs, in which a few genetic material exchanges. This ensures that the sister chromatids are not genetically identical.
Metaphase I: During metaphase, the homologous pairs line up in the middle of the cell and the chromosomes attach to spindle fibers.
Anaphase I: The chromosomes are pulled by the meiotic spindle fibers and drag one chromosome from each pair to opposite poles of the cells. The sister chromatids are still attached.
Telophase I and Cytokinesis: The chromosomes reach the end of the cell and the cytoplasm of the cell splits by the process of cytokinesis. It creates two non-identical daughter cells. In meiosis I, the haploid cells are produced with half of the number of chromosomes as the original germ cell.
i. Meiosis II
Prophase II: In meiosis II, the daughter cells produced by meiosis I undergo further division. During prophase II, the condensation of chromosomes takes place, and meiotic spindle forms.
Metaphase II: The chromosome is lined up along the middle of the cell and then each sister chromatid attaches to the spindle fibers.
Anaphase II: The sister chromatids are pulled by the spindle fibers towards the opposite poles of the cell and one from each chromosome move to opposite ends of the cell.
Telophase II and Cytokinesis: During telophase, the chromosomes reach the ends of the cell, and then the cytoplasm of the divided by cytokinesis. The two cells, which undergo meiosis II, produce four non-identical haploid cells.
In male organisms, four sperm cells are produced by meiosis or the process called spermatogenesis, while in females, the germ cell produces a single egg cell and four polar bodies, which cannot be fertilized. The process is known as oogenesis in females.
Location of Germ Cell
In an organism, the germ cells are found in the gonads. They are found in the testes of male vertebrates and female vertebrates, they are located in the ovaries.
Germ Cell Citations
Germ Cells Are Forever. MINIREVIEW| VOLUME 132, ISSUE 4, P559-562, FEBRUARY 22, 2008.
Germ line is the sex cells
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Chukar: Description, Habitat, & Fun Facts
Continue ReadingChukar Classification
Kingdom– Animalia
Phylum– Chordata
Class– Aves
Order– Galliformes
Family– Phasianida
Genus– Alectoris
Species– Alectoris chukar
Chukar Description
The chukar (Alectoris chukar) belongs to the family Phasianidae. It is an upland gaming bird. At first, chukar was considered a species of partridge as rock partridge, Philpy’s partridge, and Przevalski’s partridge.
They are mainly distributed to Asia but are now also found in parts of North America and New Zealand.
Chukar consists round body with small wings and feathers with black and white marks. The body appears light brown to grey that may change between populations. A solid black band forms a necklace-shaped ring and represents the face of the chukar and the breast have a white section.
A red outline covers their black eyes, which also matches their red beak. The legs are also red with clawed toes. A spur is present in the legs of males, which is absent in females. Females are also shorter than males.
The choker can be found throughout Asia including the western Himalayas to Nepal and also occur in northern Africa on the Sinai Peninsula. They prefer their habitats in rocky, grassy, and open hillsides in scrublands.
They usually reside in higher altitudes but in some areas, they are also found in low altitude areas. It is a common game bird of hunters for this they are now introduced to New Zealand, Hawaii, and mainland North America and to other parts of the world. They are non-migratory birds.
Chukar Predators and Threats
Chukar usually lives in small groups of around 10 birds. They prefer grassy lands and low-lying mountains for their habitats. The predatory organisms especially mammals feed on the chukar. For example, they are hunted by coyotes and bobcats in North America.
They can be easily targeted thus sometimes hunted by owls, hawks, eagles, and other larger birds. Chukars can fly but their body shape, short wings make it difficult and keep them on the ground. They prefer to run when disturbed.
The distribution of these birds around the world is also done for hunting and they have long been hunted by humans also. People use various unique techniques such as they force the bird to fly longer than its ability and tire it, at last chukar allow them to catch them.
But unlike many other species, chukar is not facing any habitat loss due to human development. However, the weather patterns affecting the populations especially during their breeding season.
Global climate change also has some impacts on local weather patterns. Seasonal events are also affecting by climate change that increases extreme weather events such as storms. These events have also an impact on chukar populations.
The food of chukar is primarily made of seeds but they are omnivores thus also eat insects. In arid parts, to avoid scarcity of water, they also eat succulents.
Chukar Nesting and Reproduction
They pair up with their mates in the breeding season. Males perform various display activities such as pecking at food to impress the female and female joins male if impressed. Males then catch females with their dropped wings, ruffled feathers, and low heads.
During this time, males or cocks often become aggressive to find a mate that often results in conflicts. After pair up, males remain monogamous and only mate with a particular female for at least during that breeding season.
The copulation is followed by nest formation, which is done by female chukar. She use grass and other soft materials and made a small depression in the ground to make a nest.
The female lays 7-14 eggs at a time, which are incubated for 3-4 weeks before hatching. Chicks form a convoy with other females until the next breeding season.
Fun Facts About Chukar!
i. Spelled just like it sounds
Chur sings a noisy song chuck-chuck-chukar-chukar therefore it gets its name chukar. They make this sound, especially in the mornings and evenings. A ‘rally’ call is one of their calls they used to bring the group together to protect them from a predator or any other threat such as storms. They also named Keklik and chukker in some parts of the world.
ii. The Evolution of Flight
Young chicks of chukar cannot fly until they learn a technique called “wing-assisted incline running”. The technique is considered as a model to explain the evolution of flight in avians. The technique is also present in many other bird species.
In wing-assisted incline running, the bird moves upslope while flapping their wing that helps them move up slopes easier than without the aid of their wings. This technique is seen in young birds of many species before learning to fly.
iii. Not like the others
In the past, chukar species were considered members of partridge species such as rock partridge (Alectoris graeca). But the phenotype of chukar partridge is different from the rock partridge, it has a browner back and more yellowish throat section than the rock partridge.
The red-legged partridge has a similar appearance as chukar. The Barbary partridge (Alectoris Barbara) consists reddish-brown collar and a grey throat and face that can be easily distinguished by the black collar of the chukar.
The chukar species are also distinguished based on their ranges. For example, the area of the Middle East and Asia is occupied by chukar which is replaced by the red-legged partridge species in southeastern Europe.
The chukar and partridge species also interbreed on getting the opportunity and also show various physical similarities but eventually, they are separated as different species.
They may share a common ancestor and undergo speciation due to their geographical divisions. The hybridization of captive stocks of these species is a threat to wild populations thus it is banned in many parts of the world.
Chukar Citations
Sperm characteristics of Chukar partridge (Alectoris chukar) breeders as affected by the addition of calcitriol to the semen extender. Poult Sci . 2019 Aug 1;98(8):3292-3297.
Parasitosis of the chukar partridge, Alectoris chukar in North Iraq. Turkiye Parazitol Derg . 2012;36(4):240-6.
Effect of sex ratio, storage time and temperature on hatching rate, fertility and embryonic mortality in Chukar partridge (Alectoris chukar). Anim Reprod Sci . 2019 Apr;203:68-74.
Phylogeography of chukar partridge (Alectoris chukar) in China based on mtDNA control region. Mitochondrial DNA A DNA Mapp Seq Anal . 2017 Jul;28(4):473-481.
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Swan: Description, Habitat, & Fun Facts
Continue ReadingSwan Classification
Kingdom: Animalia
Phylum: Chordata
Order: Anseriformes
Family: Anatidae
Subfamily: Anserinae
Genus: Cygnus
Species: 6 species
Swan Description
The swan is a genus of the family Anatidae consisting of 6 species. They are distributed in the temperate regions of the world including North Americ, Eurasia, Australia, and Southern America. They belong to the waterfowl family with ducks and geese.
Of all 6 species, four have purely white plumage that is found in the Northern Hemisphere, and the other two species found in the Southern Hemisphere including black swans and the black-necked swans.
Swans feed mainly on the leaves and stems of submerged vegetation of water bodies, thus they are pure vegetarians. They usually dip their head or upending their whole body to feed in the water.
They also eat the roots and tubers and obtain them by digging into the substrate. However, at the juvenile stage, the swans are not vegetarian and feed on insects and crustaceans to increase their protein intake, but they adopt herbivory in their maturity.
Swan Reproduction
The shallow ponds, undisturbed lakes, slow rivers, wetlands, are preferred breeding habitats for swans. Due to their large size and weight, they require large water bodies or open lands for taking off.
They make their nests on mounds of aquatic vegetation close to the water’s edge. The nest is normally made by both parents that are used for several years after repair. Swans are monogamous, and both take care of eggs. Typically 3-8 eggs are laid by female swans, the number can increase up to 12 eggs in some species.
The trumpeter swan is the largest swan, which lays the largest egg among all flying birds. The egg weighs up to 11.3 ounces and has 2.9 inches in width, 4.5 inches in length.
In some species, both the parents incubate the eggs for 3-45 days, whereas in some other species females incubate, and the male guards the nest. Most of the species of swan show territorial behavior only during the breeding season and protect their nests from predators, and other animals.
However, some species are territorial year-round. After hatching the eggs, the cygnets become able to swim after few days. However, they complete long distances on their parents’ backs.
The swans show parental care for their young for 3-5 months in most species. However, the cygnets can feed on their own after few weeks. The black swan shows much longer parental care and cares for around 9 months.
The juveniles of tundra swans develop faster as compared to other swan species and are thought to fledge after 40-45 days.
Fun Facts About Swan!
Besides their beautiful appearance, swans also exhibit several interesting adaptations.
Migration Swan
Swans use separate summer and winter ranges thus called partially migratory species. The long-distance movement of organisms on a seasonal basis is known as migration. Bids, mammals, reptiles, amphibians, fish, insects, and crustaceans all involve migratory movements.
The migration is affected by several factors such as local climate, mating requirements, season, food availability, etc. individuals migrate to complete their needs. For example, humpback whales migrate in winter to the warm waters of the pacific to give birth in the warm waters.
Swan including whooper swan and tundra swan are fully migratory species. They breed at northern latitudes during summer and then migrate towards southern latitudes.
The mute swans have the resident populations that exist in Western Europe, they are the only partially migratory swan species.
The black swan shows erratic migratory patterns thus it is called nomadic. They mainly migrates based on rainfall and climatic conditions.
Brittle Bones
The largest flying birds in the world include swans. The trumpeter swan, found in North America is considered the heaviest extant bird. To fly successfully, they need all the possible help including their weaker bone structure.
The bones are distinguishable by bones of other animals, which are honey-comb-like structures. The bones of swans are more vulnerable to breakages.
The weaker bones are an example of a trade-off. In this phenomenon, a beneficial change of one trait is connected to a harmful change in another trait.
For example, the body size, bone density, and flying ability of a bird cannot be optimized simultaneously due to the laws of physics. This problem is overcome by different species in different ways such as hummingbirds reduce their size, and swans evolve weak bones.
Mutual Courtship
Swans are monogamous and before reaching sexual maturity, they form pair bonds. For example, the trumpeter swan forms pairs from as early as 20 months old but it reaches sexual maturity at the age of 4-7 years.
Like other socially monogamous bird species, swans also follow courtship rituals before mating that strengthen their pair bonds. The courtship rituals in swans may vary.
It includes the formation of heart shape with both of their necks of male and female. They also use vocals during these rituals and black swans use specific feathers in their courtship ritual. The vocals also vary among species.
For example, a honking sound is produced by trumpeter swan with head bobbing, and soft sounds are produced by tundra swans and whooper swans after mating.
Swan Citations
- Treating the Proximal Interphalangeal Joint in Swan Neck and Boutonniere Deformities. Hand Clin . 2018 May;34(2):167-176.
- Volar transfer of the lateral band with transverse retinacular ligament is effective for the correction of swan-neck deformity caused by volar plate injury of the PIP joint. Mod Rheumatol Case Rep . 2020 Jan;4(1):152-155.
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Secretary Bird: Description, Habitat, & Fun Facts
Continue ReadingSecretary Bird Classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Sagittariidae
Genus: Sagittarius
Species: Sagittarius serpentarius
Secretary Bird Description
It is a type of terrestrial bird, which has native distribution among grasslands and savannahs of sub-Saharan Africa. The species belong to the family Sagittariidae, which consists of only living species.
They have long legs that look like cranes and the body and head resemble eagles. Their long legs extend their height to 4.9 feet.
They are found in grasslands where the length of the grass is less than 1.8 feet and avoid areas with long grasses of more than 3.3 feet.
There are two species of terrestrial birds of prey including secretory birds and caracaras. Caracaras are found in the regions of Central and South America. Their long legs help them to lift their body above the vegetation to spot the prey easily to hunt them.
They are terrestrial birds that mean they hunt on foot. They mainly feed on smaller mammals, amphibians, reptiles, birds, and insects. Sometimes they also act as scavengers and feed on dead organisms.
They hunt and police their territories and spend most of their time in these activities. These birds tend to hunt in proximity to their breeding partners or also in small family groups.
During the hottest part of the day, they take a break and rest in the shade of the tree but otherwise they hunt throughout the day. They cover long distances of more than 20 miles per day to hunt their prey.
Secretary Bird Reproduction
Secretory birds mate only with a single partner that means they are monogamous. They also make their territories that are much larger up to 19 square miles in size. They usually breed throughout the year however it is common in the late dry season.
A nuptial display is performed by both males and females which is done by making a loud croaking sound and soaring high above the ground.
They defend their territories by chasing each other with their wings up and back. They make their nest together and place it at the thorny acacia tree.
It takes around six months to build their nest with the help of twigs, leaves, grasses, animal fur, and dung. The nest is placed between 8-40 feet over the ground and has up to 8 feet width. The same nest of often used for several years.
The eggs are pale blue-green or white. Female lay 1-3 eggs at 2-3 days intervals. Most of the time, females are on the nest but eggs are incubated by both parents. After 45 days, the eggs hatch, and the chicks rely on their parents for food for at least 40 days.
After 75-80 days chick leaves the nest. Depends upon the food availability, secretory birds often raise more than one chick at a time.
Fun Facts About Secretary Bird!
The extremely long legs of secretory birds provide them a strange look but they adapted them for its terrestrial niche. There are many other interesting concepts about secretory birds.
Secretary Bird: a Terrestrial Birds
Instead of flying, they prefer running and spend most of their time moving around on foot. However, they are also able to fly but it requires a lot of energy. Therefore they fly without flapping their wings with the help of thermal columns to save their energy.
They prefer moving on the ground due to the difficulties in flying and prefer flying only if necessary such as they fly to perform courtship rituals and to reach their nests.
Besides secretory birds, the kiwis, ostriches, and penguins also adapted themselves to the terrestrial lifestyle. These all species have not any related taxonomic group that clears that they lose their flying ability because of numerous occasions throughout history.
Unique hunting technique They usually hunt their prey by using many unique techniques. For example, they stomp on vegetation to flush out animals inside the tall grass and then chase down their prey.
They use their feet or bill to strike their prey and can use a force up to 5 times their own body weight. It shows that they have adapted very well to this hunting style. Due to their short toes, the secretory birds have limited grasping ability.
Therefore they cannot carry their prey away in their feet as other birds of prey usually do and eat it immediately. Sometimes they tear it apart using their feet but usually, they eat their prey whole.
Secretary Bird: The Archer of Snakes
The secretory birds have a great ability to kill even dangerous venomous snakes with their stomping techniques, therefore they get the name Sagittarius serpentarious which means ‘archer of snakes’.
They can kill snakes including cobras and adders by their strong kick and also prevent themselves from the bite of their prey by other features.
For example, they have tough scales on the lower legs that protect them from bites, and their long wings distract their prey because the hollow feathers do not get affected by snake bites.
Secretary Bird Citations
- The fast and forceful kicking strike of the secretary bird. Curr Biol . 2016 Jan 25;26(2):R58-R59.
- Tracheal Resection in a Secretary Bird ( Sagittarius serpentarius) with Granulomatous, Foreign-body Induced Tracheitis. J Avian Med Surg . 2017 Dec;31(4):308-313.
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Cuckoo: Description, Habitat, & Facts
Continue ReadingCuckoo Classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Cuculiformes
Family: Cuculidae
Genus: Cuculus, 25 others
Cuckoo Description
Medium-sized bird, cuckoo belongs to family Cuculidae. The family includes more than 24 genera of slender birds including roadrunner, European cuckoo.
They are distributed throughout the world. Some species of cuckoo such as roadrunner spend much of their time in the ground and while most of the members are tree-dwelling.
Cuckoo Appearance
The bronze cuckoo is the smallest member of this family, which weighs only 0.03 lbs and has a length of about 6 inches whereas the channel-billed cuckoo, which is the largest species weighs up to 1.4lbs and have 25 in length.
The European cuckoo is a common and well-known species, which is 32 cm in length. The body of the common cuckoo appears greyish in color whereas some females and juveniles also show a red-rust or rufous color morph.
The tail of the cuckoo makes about 40 percent of its overall length and the belly feathers also present on their frontside that are barred black and white. Common cuckoo molts twice per year.
The members of the cuckoo family display a variety of traits and behaviors but still, they have some common traits.
For example, their feet are the significant distinguishing feature, which includes four toes among which two inner toes point forward while two outer toes point backward.
The condition is called ‘zygodactyl’. The members of the family Cuculidae consist of species having two general body forms named arboreal and terrestrial species.
The arboreal species including the common cuckoo have a slender body with shorter feet and are tree-dwellers. The terrestrial species have different body forms with larger feet and have rounder and heavier bodies.
The example includes roadrunner that spends their time on the ground and prefers running instead of flying. Due to their heavier body flying is not a viable option for terrestrial cuckoos.
Cuckoo Distribution
Cuckoo belongs to a large family and is distributed all over the world on every continent besides Antarctica. The brood parasite cuckoos from sub-family cuculinae are one of the most broadly distributed sub-family, which occur across Asia, Europe, Australia, and Oceania.
The different species have different habitat preferences such as arboreal species are primarily tree-dwellers and terrestrial species prefer to live on the ground. They select their habitat based on food availability and safety to form a nest and breeding.
Some species prefer arid deserts or less vegetated areas to live in, e.g. the greater roadrunner. Most of the species tend to remain in their tropical paradise but some species prefer seasonal migration while some others migrate within their range.
The example includes the long-tailed koel, which breeds in New Zealand but in winters it migrates to grounds of Polynesia, Melanesia, and Micronesia. Most cuckoo species feed on insects mainly on caterpillars.
Cuckoo Nesting and Reproduction
The breeding habits also vary among species of the cuckoo family. Most species including roadrunners are monogamous. They build their nests in trees while the terrestrial species from a nest on the ground.
The common cuckoo finds a perch to settle on during the breeding season. The cuckoo drops its wings at its side by raising its long tail. Some of the species resort to brood parasitism while the majority of species raise their young ones on their own.
The parasitic birds lay just one egg in the host species’ nest whereas non-parasitic birds lay up to 6 eggs in their own nest. The distribution of these species is worldwide.
Some species are threatened from habitat destruction or human development but most of the species are not threatened. The IUCN Red List for threatened species listed them as “Least concerned” species.
Fun Facts About Cuckoo!
Human culture has interacted with Cuckoos for millions of years, from ancient Greece to the Europe of Shakespeare to India and Japan.
Cuckoo is a Parasite Bird
The category of brood parasites includes common cuckoo and other members of the subfamily Cuculinae. The young ones of these species are reared by other species. When the owner of a nest is out for hunting or defending its territory, the female cuckoo lays her egg in its nest.
The males also do the bidding for females in some cuckoo species by luring the host species away from its nest. The other bird incubates the egg of the cuckoo and also feeds the cuckoo chick after its birth.
The cuckoo chick often pushes other eggs and chicks from the nest and takes over. Warblers are also one of the host adults that are much smaller than the large cuckoo chick.
In some cases, the young of these brood parasite species have cryptic plumage (feathers) at a young age and the plumage resembles similar to the host species. Some cuckoo eggs will also mimic the eggs of the host species.
Cuckoo: a Communal Bird
The cuckoo is a monogamous organism. However, several species of cuckoo show brood parasitism. This interesting behavior is only seen in the members of the cuckoo family.
However, besides brood parasitism, one another behavior is also seen in some species. The anis cuckoo and the guira cuckoo and some other species also lay their eggs in communal nests.
The large nest was built by all the members of the group and then used by all to rear their young. But the system has also some problems like many communal situations.
The females have competition between them to remove other eggs from the nest to lay their own.
Cuckoo: an Advanced Repertoire
The diverse calls and songs of cuckoo are well-known. They are secretive and deceptive birds and communicate via their variety of songs. They also announce their dominion and attract their mates with songs.
Interestingly, over vast geographical ranges, the songs remain highly consistent. But instead of learning from their parents, they may be innate to a species due to their communal raising.
Cuckoo Citations
- Parasitic cuckoo catfish exploit parental responses to stray offspring. Philos Trans R Soc Lond B Biol Sci . 2019 Apr 1;374(1769):20180412.
- A melanocytic cuckoo. JAAD Case Rep . 2018 Apr 6;4(4):384-385.
- A cuckoo in the nest. New Sci . 2020 Apr 11;246(3277):32.
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Embalming: Definition, Types, & Examples
Continue ReadingEmbalming Definition
Embalming is an ancestral practice that employs chemicals to inhabit the decomposition of human remains to preserve them for social rites or educational purposes. It has 3 goals and preserves the entire physical body. These goals include:
Sanitization: The body is thoroughly cleaned by utilizing disinfectant and anti-microbial solutions. This helps to reduce any unwanted foul odors and delay the process of decomposition.
Preservation: The circulatory fluids like the blood and lymph are emptied from the body to preserve it and then it is pumped with embalming fluids. These chemical fluids decrease the rate of decomposition and preserve it in the recent condition.
Presentation: This involves preparing the body and making it more visually pleasing and presentable for social events like a funeral. The body is staged by massaging of limbs to decrease effects of rigor mortis, hair is styled, the body is shaved, facial expressions are set, they are dressed, and make-up is applied to give a lifelike appearance.
Embalming Process
This has been practiced since ancient times and has been a part of religious and cultural rites. The techniques and tools for this practice have evolved and may differ regionally. This process begins by positioning the body in a supine position with the head slightly elevated. The various material or tools employed in this practice are given below:
Step 1: Verification of Death: It is assessed first whether the person is dead. To verify this rigor mortis, clouded eyes, general unresponsiveness, and absence of pulse are some features that are checked. The identification of a deceased person is ascertained by foot and hand tags.
Step 2: Wash and Massage the Body: The body is stripped and the personal effects are removed, then employing an antimicrobial detergent the body is sanitized. Orifices like the mouth are carefully rinsed. Massaging of limbs removes their stiffness.
Step 3: Setting the Features: A specialized eye cap is utilized to pose the eyes by the embalmer. Then the lips are closed shut by using an adhesive, wiring, or suturing. Any visible strands of hair are removed by shaving.
Step 4: Injection of Embalming Fluid: Various chemicals are injected to temporarily preserve the state of the body. These chemicals are injected into the peritoneal cavity and vessels of the body via different methods.
Step 5: Application of Cosmetics: The embalmer applies cosmetics and moisturizer to give the skin a more lively appearance and to hide any discoloration. They can refer to a recent photograph provided by the family members.
Lack of circulation can result in discoloration of the face, which can be corrected by using make-up that adds depth and color to the skin. Hair is often styled and perfumed oils and gels are often applied to mask the odor. Then the body is dressed in formal clothes.
Embalming Fluid
Arterial embalming: Under this process, the embalming fluid is injected via a centrifugal pump into the carotid artery which displaces blood and causes it to drain through the right jugular vein.
Following these, the vessels are properly massaged to prevent the formation of clots and to uniformly distribute the fluid. A single-injection may be enough or in some cases to ensure even distribution they are injected at multiple sites.
Normally a body can hold up to 2 liters of embalming fluid. A specialized machine pumps this chemical into the blood while monitoring the pressure of vessels. Lastly, a hypodermic needle is used to fill any location that is left.
Cavity Embalming: In this, an incision is made above the navel and the abdominal cavity is performed. Then a trocar is inserted into this cavity through the incision and the contents of organs are aspirated.
Employing a concentrated embalming fluid the peritoneal cavity is filled. After which it is sutured or employing a trocar button the peritoneal cavity is shut.
Surface Embalming: In this method, the embalming fluid is applied to the skin surface that helps to deter the damage caused during the autopsy, or any cancerous disease or as a result of organ donation.
How to Become an Embalmer?
An embalmer would require education in areas of human physiology and anatomy, chemistry, mortuary practice, and embalming methods and theory. They are certified after a practical examination and are often affiliated with a professional embalming society.
In certain regions, embalming may be performed by the doctors themselves and no embalmers are required. Morticians may also practice embalming.
Embalming Citations
- Thiel embalming method for cadaver preservation: a review of new training model for urologic skills training. Urology . 2015 Mar;85(3):499-504.
- The antimicrobial capacity of embalming solutions: a comparative study. J Appl Microbiol . 2019 Mar;126(3):764-770.
- Is thiel embalming worth the risk? Am J Surg . 2021 Aug;222(2):459.
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