Hypothesis: “Hypothesis is the tentative explanation of the observations.” It is the logical consequence of observations. Hypothesis is tested by experiments.
Example: When plasmodium was found in the blood of several malarial patients, it was hypothesized that: “Plasmodium is the cause of malaria.”
|A series of hypotheses supported by the results of many tests is called a theory. It is less general than scientific laws.
Examples: Cell theory, germ theory of diseases.
|Scientific law is a uniform or constant fact of nature. It is, virtually, an irrefutable theory. It is more general than theories & affords answers to even more complex questions.
Examples: Hardy-Weinberg law, Mendel’s laws of inheritance.
Deductive Reasoning: “Deductive reasoning moves from ‘general to specific’. It involves drawing specific conclusion from some general principle/assumptions.” It is a way to formulate a hypothesis.Example: If we accept that ‘all birds have wings’ (premise#1) and that ‘sparrows are birds’ (premise#2), then we conclude that ‘sparrows have wings’.
Vaccination: “Vaccination is the inoculation of weakened or dead microorganism of a disease, or proteins or toxins from the organism, into a healthy person to develop immunity against that disease.” Literally, the word ‘vaccine’ has been derived from Latin word ‘vacca’ meaning ‘cow’. This was first of all used by Edward Jenner in 1795, who inoculated the healthy persons with cow pox lesion to prevent from small pox. Later, Pasteur used this technique against the diseases like anthrax, cholera, rabies.
Cloning: “Cloning is a technology for achieving eugenic aims. It is the production of genetically identical copies of an organism or a cell by asexual reproduction.”
Clone: “A cell or an individual and all its asexually produced offspring are called clone.” All members of a clone are genetically identical except when mutation occurs.
Method of Cloning: In cloning, the nucleus from a fertilized egg is removed and a nucleus from a cell of a fully developed individual is inserted in its place. The altered zygote is then implanted in a suitable womb where it completes its development. The new individual formed in this way, is a genetically identical clone of the individual whose nucleus was used.Examples: Generally, no normal animal reproduces naturally by cloning. Several insects and many plants do, in some circumstances, whereas few do so regularly.
Molecular Biology: “Molecular biology deals with the study of the structure of organisms, cells and their organelles at molecular level.”
Microbiology: “Microbiology is the branch of biology which deals with the study of microorganisms including Bacteria, Viruses, Protozoa and microscopic algae and fungi etc.”
Marine Biology: “Marine biology is the study of life in seas and oceans. This includes the study of the marine life and the physical and chemical characteristics of the sea, acting as factors for marine life.”Biotechnology: Biotechnology is the branch of biology which deals with the use of living organisms, systems or processes in manufacturing and service industries.
When we look at the biodiversity (the number and variety of species in a place), we find that there are nearly 2,500,000 species of organisms, currently known to science. More than half of these are insects (53.1%) and another 17.6 % are vascular plants. Animals other than insects are 19.9 % (species) and 9.4 % are fungi, algae, protozoa, and various prokaryotes. This list is far from being complete. Various careful estimates put the total number of species between 5 and 30 million. Out of these only 2.5 million species have been identified so far. The life today has come into existence through Phyletic lineages or evolving populations of the organisms living in the remote past. Evolutionary change often produces new species and then increases biodiversity.
If we had a complete record of the history of life on this planet, every lineage would extend back in time to the common origin of all early life. We lack that record because many soft bodied organisms of the past had not left their preserved record as fossils.
Living world of today is enormous in size. It has been reproducing and evolving since the time of its origin on this planet. Today almost all parts of the world abounds in living organisms. The distribution of organisms in space can be studied through biomes. A biome is a large regional community primarily determined by climate. It has been found that the major type of plant determines the other kind of plants and animals. These biomes have, therefore, been named after the type of major plants or major feature of the ecosystem. The major biomes of the world you will study in the chapter of ecology.
Since the time of origin of life on this planet, various organisms were evolved and dominated this planet during various periods of geological time chart. This has been found by the evidence obtained from the discovery and study of fossils which allows biologists to place organisms in a time sequence. As geological time passes and new layers of sediments are laid down, the older organisms should be in deeper layer, provided the sequence of the layers has not been disturbed. In addition, it is possible to date/age rocks by comparing the amounts of certain radioactive isotopes they contain. The older sediment layers have less of these specific radioactive isotopes than the younger layers. A comparison of the layers gives an indication of the relative age of the fossils found in the rocks. Therefore, the fossils found in the same layer must have been alive during the same geological period. You can have an idea about the temporal distribution of various forms of life both plants and animals in the various geological periods.
Examples are the number of rats in a field of rice, the number of students in your biology class, or human population in a city.
Population is a higher level of biological organization than organism (whole) because here a group of organisms of the same species is involved. This level of organization has its own attributes which come into being by living together of a group of organisms of the same species. Some of these attributes are gene frequency, gene low, age distribution, population density, population pressure etc. All these are new parameters which have appeared due to population of an organism.
Communities are dynamic collections of organisms, in which one population may increase and others may decrease due to fluctuation in abiotic factors. Some communities are complex and well interrelated, other communities may be simple. In a simple community, any change can have drastic and long lasting effects.
The organisms, interaction can take many shapes. It may be predation, parasitism, commensalism, mutualism and competition.
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