Define the term encystation with one example.

Encystation is the process takes place in unicellular organisms during unfavourable condition. It is a type of response to abiotic factor called suspend in which the organisms develop different mechanisms to escape the harsh environment. In encystation, the unicellular organisms secrete a three layered hard covering or cyst around their cell membrane. When favourable seasons occur, these germinate to form new organisms. Example: Amoeba .

Describe briefly the biological effects of light on animal reproduction.

Light is an abiotic factor that has effects on every group of organisms, from animals to plants to microorganisms. Aspects such as growth, the colouration of plumage or body, migration, reproduction and diapause are affected by light in various insects, birds, fishes, reptiles and mammals. Effect of light on animal reproduction: In many animals (mostly birds), light is necessary for the activation of gonads and in initiating annual breeding activities. The gonads of birds are found to become active with increased illumination during summer and to regress during winter. In poultry, the production of eggs all through the year is regulated through photoperiod alteration. Light is applied to horse husbandry to restart and prolong the reproduction period.

Name two types of competition found amongst organisms. Which one of these is more intense and why?

In nature, living organisms such as animals, plants, and microbes, cannot live in isolation and, therefore, interact in various ways to form a biological community. Competition can be defined as a process in which the fitness of one species (measured in terms of its r, the intrinsic rate of increase) is significantly lower in the presence of another species. The two basic types of competition among the organisms are: Inter-specific competition Intra-specific competition Inter-specific competition is defined as the competition among the members of different species for limited natural resources. These species have a smaller contested resource overlap. Intra-specific competition: In such a type of competition, members of the same species compete for limited resources. Larger, dominant grizzly bears compete, and the winner occupies the best fishing spots on a river during the salmon spawning season.