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Mechanism of evolution:
Darwin said that variations cause evolution. Variation are small & directional.
Lamarck’s theory about evolution: A French naturalist Lamarck had said that evolution of life forms had occurred by use and disuse of organs. He gave th
Brief account of Evolution:
1) About 2000 million years ago (mya) the first cellular forms of life appeared on earth. Some of these cells had the a
Adaptive radiation: This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas o
Chemical properties of Alkanes
Alkanes are quite inert substances with highly stable nature. Their inactiveness has been explained as:
(
Human genome project:
The total cost of the project was 9 billion US dollars and this project was a 13-year project by the U.S. D
Duration of earth’s history:
It is divided into five geological life spans called eras:
Similarities between Mitochondria and Chloroplasts:
Mitochondria and Chloroplasts may h
Scientists and their theories about the origin of life:
*Theory of special creation: According to it life has been originated from
Evolution of animals:
1) Sea weeds and few plants existed probably around 320 mya. Jawless fish probably evolved around 350 mya.500 mya, invertebra
Evolution of Man:
Hardy-Weinberg principle: This principle says that allele frequencies in a population are stable and is constant from generation to generation. The gene pool
Reproduction: Reproduction is the biological process in which an individual gives rise to an offspring similar to itself.
Purpose of Reproduction:
DNA Fingerprinting
Dr. Alec Jeffreys developed the technique of DNA fingerprintin
Significance of cell cycles:
Mitosis and meiosis both involve cells division to make new cells. This makes them both vital processes for the existe
Nitrous Acid Test,Separation of primary , secondary and tertiary amines by Hoffmann's method: Amines
Test of 10, 20 and 30 amines. (nitrous acid test)
The three classes of amines react differently with nitrous acid.
Nitrous acid is a source of electrophilic nitrosonium ion (O = N+), which reacts with amines. Ni
Evidences of evolution:
(1) Paleontological evidences ⟶ Paleontology is the study of past life based on f
Evolution of plants:
1) Plants invaded land before animals.
2) Bryophytes originated earlier than the vascular plants like pteridophyte
SEXUAL REPRODUCTION involves formation of male and female gamates, either by the same individual or different individuals of opposite sex.These gametes
Important points regarding human history and origin:
(1) Closest primate of Human is Gorilla
(2) Human evolution started in Africa
Asexual Reproduction- Where offspring is produced by single parent with or without formation and fusion of gametes. e.g. Amoeba, Plan aria etc.
Her
Formation of galaxies & solar system:
(1) The origin of universe occurred by Big-Bang theory, 20 million years ago.
(2) Our universe
Red Data book:-
IUCN maintain the document of threatened species called Red Book data.
Basic utility of Red list
Test Details
A proton and an particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 µsec to make 5 revolutions, then the periodic time for the particle would be
Test Details
In a satellite if the time of revolution is T, then kinetic energy is proportional to
Test Details
A 10 kg satellite completes one revolution around the earth at a height of 100 km in 108 minutes. The work done by the gravitational force of earth will be
Test Details
The time of revolution of an electron around a nucleus of charge Ze in nth Bohr orbit is directly proportional to
Test Details
An earth satellite S has an orbit radius which is 4 times that of a communication satellite C. The period of revolution of S is
Test Details
A proton and an ∝-particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 µ sec to make 5 revolutions, then the periodic time for the ∝-particle would be [MP
Test Details
A proton and an α−particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25μ
Test Details
The displacement of the point of the wheel initially in contact with the ground, when the wheel roles forward half a revolution will be (radius of the wheel is R)
Test Details
Age of fossils in the past was generally determined by radio-carbon method and other methods involving radioactive elements found in the rocks. More precise methods, which were used recently and led to the revision of the evolutionary periods for different groups of organisms, include
Test Details
A proton and an ∝-particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 µ sec to make 5 revolutions, then the periodic time for the ∝-particle would be
Test Details
A 10 kg satellite completes one revolution around the earth at a height of 100 km in 108 minutes. The work done by the gravitational force of earth will be
Test Details
In Bohr model of hydrogen atom, the ratio of periods of revolution of an electron in n = 2 and n = 1 orbits is
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