Hello Roflguy,

Brown-Sequard syndrome (BSS) is a rare neurological condition characterized by a lesion in the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side.

BSS may be caused by a spinal cord tumor, trauma (such as a puncture wound to the neck or back), ischemia (obstruction of a blood vessel), or infectious or inflammatory diseases such as tuberculosis, or multiple sclerosis.

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GOOD LUCK!

Hello Roflguy,

The development of the nervous system in humans, or neural development or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience to describe the cellular and molecular mechanisms by which complex nervous systems form, and develop during prenatal development, and continue to develop postnatally.

Neural development is one of the earliest systems to begin and the last to be completed after birth. This development generates the most complex structure within the embryo and the long time period of development means in utero insult during pregnancy may have consequences to development of the nervous system.

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GOOD LUCK!

Hello,

Pennate Fasciculli : The pennate fibre muscles resemble the feather, the fleshy fibres correspond to the bars of feather and the tendon to the shaft, as they are all inserted by tendon. Fascicles are attached in an oblique manner to the tendons.

They maybe

• UniPennate : Flexor pollicis longus, extensor digitorum longus
• Bipennate : Rectus femoris, flexor hallucis longus
• Multipennate : tibialis anterior, subscapularis and acromial fibres of deltoid

Hello Roflguy,

The inguinal region of the body, also known as the groin, is located on the lower portion of the anterior abdominal wall, with the thigh inferiorly, the pubic tubercle medially, and the anterior superior iliac spine (ASIS) superolaterally.

The contents of the inguinal canal -

In males-

IIt consist of the spermatic cord (with the genital branch of the genitofemoral nerve) and the ilioinguinal nerve.

In female -

T he contents include the round ligament, genital branch of the genitofemoral nerve, and the ilioinguinal nerve.

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GOOD LUCK!

Mutagens can be classified into two broad categories :

Physical Mutagens : Radiations are the most important physical mutagens. These are of two types.

• Ionizing Radiations :  These include X-rays, gamma-rays, alpha-rays and beta-rays. These cause breaks in chromosomes and cells show abnormal cell division.
• Non-Ionizing Radiations : These include UV rays. They have longer wavelengths but lower energy, and thus are insufficient to induce ionization. Thymine dimer formation is the major effect.

Chemical Mutagens : Large numbers of chemical mutagens exists. These are more harmful. Usually divided into two groups

• Mutagenic to both replicating and non replicating DNA - Nitrous Acid
• Mutagenic to Replicating DNA - Acridine Dyes, Base Analogues

Procedures, methods and information that are useful in identification and classification of organisms are called taxonomical aids .

Taxonomical Aids are of the following types. :

• Herbarium : It is a collection of dried, pressed and preserved plants. This is usually done on sheets for reference.Standard size is 41cm*29cm.The largest herbarium of the world is at Kew.
• Botanical Gardens : It is a collection of living plants maintained for reference.Largest botanical garden is in Moscow.
• Zoological Parks : Eenclosed areas where animals are kept in open enclosures instead of cages.Useful for exsitu conservation through acaptive breeding of endangered animals.
• Museums : A place used for storage,preservation and exhibition of objects of natural history,art and objects of natural antiquities.  Provides information about local flora and fauna but also other areas.
• Keys : Itis used in identification of organisms based upon similarities and dissimilarities.It is a dichotomic table of alternate characters known as couplet, each character of couplet is known as lead.Keys are unique for each category.

Hello Aspirant!

You may know that Commensalism (+0) is a type of ecological Host-Parasite interaction (between two organisms) where the parasite species derives nutrition, shelter, protection, locomotion etc. from the host species. And here, the parasite species is benefitted while the host species is neither benefitted nor harmed.

Some common examples of Commensalism are :-
1. Goby fishes live on the body surface of other marine animals. They change colour to blend in with the host, thus gaining protection against predators.
2. Burdock plants produce spiny seeds that cling to the fur of animals or human clothings. The plant relies on this method for dispersion of seeds during its reproductive season, while the animals are unaffected.
3.The small suckerfish (or Remora) is a member of the ray-finned fishes. The remora forms a commensal association with large marine organisms, like turtles, whales and sharks. Its specially-designed suckers attach to the fins of the host organism and thus it attains benefit of transportation and protection from predators. It also utilizes the leftover of sharks for feeding, without causing any harm to the host.
4.Barnacles are the organisms which are unable to move on their own as they lack well developed locomotory organs . So, during the larval stage, they stick to other organisms such as whales or they attach themselves to shells, ships, and rocks. They grow and develop on these surfaces without causing any negative affect to the host. Barnacles feed on plankton and other food materials during the movement of whales.They do not feed on blood or flesh. Therefore, they cause no harm to the whale. This way, they get benefit in transportation (or locomotion) and nutrition.
5. The emperor shrimp attaches itself to sea cucumbers where they get benefit in transportation and protection from predators without energy expenditure . The shrimp get off the host cucumber for feeding and then attaches to another host when it wants to move to a different place. As the emperor shrimp is small and light, it does not cause any harm to the sea cucumber.
6. Monarch butterflies derive certain toxins during their larval stage from milkweed hosts, which make them distasteful to predatory birds.These toxins are not poisonous to the butterfly larvae but its consumption is harmful for the vertebrates. Milkweeds are not carnivorous plants. They do not affect the growth and development of the butterfly larvae. So, in this way, the butterflies acquire protection against its predators without harming its host milkweed species.
7. Tree frogs get protection against its predators by cryptically hiding on the surface of the bark of trees. Due to similarity in colour of the frogs and tree trunk, its predator cannot differentiate and navigate the frog.

I hope you find this answer helpful.

Hello Aspirant,

Basically there are two dating methods

• Absolute Dating- used to determine a precise age of a rock or fossil through radiometric dating  methods. This uses radioactive minerals that occur in rocks and fossils almost like a geological clock. It’s often much easier to date volcanic rocks than the fossils themselves or the sedimentary rocks they are found in.
• Relative Dating- Most of the time this fossil dating technique  is used to determine the used age. Using relative dating the fossil is compared to something for which an age is already known.

I hope it helps

Thank you

Hello,

Coprolite is a fossilized feces . The are classified as trace fossils as they give evidence for animal's behavior . The are fossilized animal dung . They are the preserved remains of the contents of the intestine and excretion . They are rare as they tend to decay rapidly . They are most found among sea organisms . Coprolites of fishes and reptiles are most common .

Hope this helps you .

Hello Student,

Here are the names of all the theories and the scientists

Theories for Origin of Life

1. Big Bang Theory - Abbe Lemaitre

2. Nebular Theory - Kant and Laplace

Classical Theories

1. Theory of Special Creation - Father Suarez

2. Theory of Spontaneous creation/Abiogenesis -Aristotle and Pluto were great supporters of this theory.

3. Cosmozoic Theory/Theory of Panspermia - Richter

4. Theory of Biogenesis - Louis Pasteur

5. Theory of Catastrophism - Cuvier

6. Theory of Chemical Origin/Oparin Haldane Theory/Modern Theory -Oparin and Haldane(They proposed their theories seperately but now it is studied collectively)

Hope this helps