Organisms and Populations Test - 9

The zone of earth occupied by living organism is called biosphere. It includes, lands, water and air where living organisms survive.

Xylem vessels are responsible of water transportation in plants. Hydrophytes grows in plants therefore there is no requirement of special water transporting tissues in hydrophytes.

Success of an organism in nature can be determined by measuring population size and biomass of the organism. An organism having large number of species is more successful than those with lesser numbers.

Temperature is an environmental factor that influence the type and number of species in a given habitat. Temperature may change the enzyme kinetics, physiology and geographical distribution of species. Photoperiod is the duration of light that fall on plant and not affected by temperature.

At higher altitudes concentration of oxygen decreases in air due to decreae in air pressure. Our body compensate the deficiency of oxygen at higher altitude by reducing affinity of hemoglobin (Hb) for oxygen binding.

The parasite obtaintheirfood from host body. Gut parasite like round worm and tap worm absorbed digested food from our body. They do not require alimentary canal as they absorb digested food.

The unit of evolution and ecology is population. Evolution occurs due to change in genome of individual that affects the whole population. Ecology is the study of population along with their variation in ecosystem.

Culture medium provide all the nutrients required for the growth of bacteria. To avoid the death or decline of bacterial cells in medium, culture medium must be changed periodically.

Negative acceleration phase is caused due to increase in environmental resistance. An environment have limited amount of resources after reaching climax phase negative acceleration occurs.

In deep lakes differenet zones are formed according to availabilityof light, food and temperature. These zones are called littoral, limnetic and profundal zone. It is a kind of community stratification or separation.