life cycles of organisms

All living organisms are composed of structural and functional units called cells. The body of a living organism may be composed of a single cell - as in unicellular organisms or many cells - as in multicellular organisms. The number of cells in the body of ..

Summary - Biologists estimate that there are about 30 million species of living organisms inhabiting this biosphere and only a million and half of it have been discovered and described so far. The species of plants and animals identified so far exhibit a great deal of variation in their f..

. Neo-Darwinism attempts to explain evolution in terms of genotypic variations, natural selection and isolation. The occurrence of organic evolution is established by the innumerable evidences that are available from the different branches of biology. The study of extinct organisms..

Many diseases and pests of plants / animals follow a particular rhythm because of specific response of causal organism to a set of environmental conditions. Hence, disease / pest is more likely to attack a plant/animal if the environmental situations are favourable. These are called 'pre..

Death is the final termination of the life activities. Every living organism has a life cycle involving its birth, growth and deat..

Death is the final termination of the life activities. Every living organism has a life cycle involving its birth, growth and death. The duration of life between the birth and death of an organism, represents its life spa..

. According to this theory, Each adult organism grows from a zygote. The zygote is a diploid cell having two sets of chromosomes - maternal and paternal. The zygote by mitotic divisions results in the formation of an adult and thus, all the vegetative or somatic cells of an organismh..

. According to this theory, Each adult organism grows from a zygote. The zygote is a diploid cell having two sets of chromosomes - maternal and paternal. The zygote by mitotic divisions results in the formation of an adult and thus, all the vegetative or somatic cells of an organismh..

. The male sex organs are called antheridia and female sex organs are called archegonia. Antheridia produce antherozoids and archegonia enclose the egg cell. Fertilisation requires water. The diploid zygote is retained in the archegonial venter where it develops into an embryo. ..

All parasitic have successfully adapted to live either on or inside their hosts. Some of their important adaptations ar..