Author Archives: I am hassan

Leptosporangium vs Eusporangium

Leptosporangium vs Eusporangium – In the first step in leptosporangium, the epidermal cells of leaf or sporangiophore some sperm cells behave as superficial initial cells. Superficial initial cell divides periclinally due to which to form two celled body structures. Secondly, the outer cell as sporangial initial cell and inner cell that does not take part in further division as stalk ...

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Sporangium and Different Spore Types

Sporangium Sporangium has been derived from modern Latin word “spora” means spores and classical Greek word “angeion” which means vessel. So, sac like structure, which develops spores as tetrad after meiosis of spore mother cell. Spore: Reproductive unit of a plant body which upon germination to form a new plant body. Types of Sporangium (Depending upon Organization with Position, Shape, ...

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Female Cone Lecture

Female Cone Female cone has whorl of loosely arranged megasporophylls. In cycas, whereas in pinus there is in compact arrangement of megasporophylls, behave ovuliferous scale. So, in pinus female cone behave as inflorescence due to aggregation of female flower (ovuliferous scale). Each megasporophyll quite large in size, bearing 1-5 pairs of big ovules of cycas whereas, in pinus there are ...

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Virus Lecture Notes

Virus The term virus was coined by Pasture. For the discovery of viruses’ first-time work was performed by a scientist Iwanowsky, who was discovered TMV (tobacco mosaic virus). it was later crystallized by a scientist Stanley. Now another scientist Beijuinuk called ‘viruses as “Contagium Vivum Fluidum”. What that mean? Living infectious fluid. As today we know viruses are passed in ...

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Quantitative Characters of Plant Community

Attributes of Community Quantitative characters of plant community – A collection of organisms interacting directly or indirectly is a community. Within the community some species carry out similar functions or exploit the same resources. These groups are called guilds. For example, birds feeding mostly on insects make up an insect-feeding guild. A community may be autotrophic when it includes photosynthetic ...

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Reproductive Strategies

Reproduction and Reproductive Strategies in Plants Reproductive Strategies – Reproduction is the major drive of all living things. The role of the reproductive drive is to transmit genetic characteristics from one generation to another. The ability of organism to leave behind reproducing offspring is it fitness. Achieving fitness involves among other things, fecundity and survivorship, physiological adaptations, modes of reproduction, ...

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What is a Seed Bank and Why is it Important

Seed Bank Seed bank – Dispersal can occur through time. Plant seeds can lie dormant for many years. When a seed does not germinate after a period of dormancy, many of the plants which were alive when the seed was produced may have died. Plants can disperse in time if the seeds join the dormant seed bank. The store of seed, ...

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Population Dynamics

Population Dynamics – Population dynamics are always changing. They fluctuate considerably depending on the season. There are four ways in which changes take place in the numbers of individuals in populations. These changes make the population dynamics. Populations gain individuals when young are born in the area (Birth, B) or new members join the group from other populations (immigration, I). Immigration ...

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Properties of Population Ecology

Properties of Population Properties of population ecology Populations have many unique features. They have an ago structure, density, and distribution in time and space. They exhibit a birth rate, a death rate (mortality), and a growth rate. They respond in their own ways to competition, to predation, and to other pressures. Individuals make up a population affect one another in various ...

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The Study of Interaction Between Organisms and their Environment

Organisms and Their Environment

Organisms and their Environment Organisms and their Environment – All organisms live in a varying physical environment of temperature, moisture, light and nutrients. These factors differ from location to location like in latitude, region and locality. In addition, at any location, the physical environment varies with time to time, yearly seasonally and daily. One important example of environmental variation is ...

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