Q. Ecological Evidence of organisms to environment?

Ecology is concerned with organisms in relationships to their environment. These relationships may be classified as biotic, abiotic,  spatial and temporal. Ecological studies demonstrate that the character states of many morphological features are correlated with environmental factors such as light, moisture, and soil fertility. The distribution of taxa both plants and animals, the variation within taxa and adaptations of organisms provide much information about the systematic position of various plant and animal species. As ecologists we should examine ecotypic variation. Edaphic specialisation, pollination mechanisms, the effect of habitat on hybridisation, plant herbivore interactions, seed dispersal mechanisms and ecology of seedling establishment. In plants the ecological information has implications for classification below the level of genus. These features are important in adaptation of populations to their environment. You can perform transplant experiments and grow under control the plants in order to study and describe the life histories and evaluate many characters.

In animals every species has its nearest relatives in food preference, breeding season, tolerance to various physical factors etc. You should know that when two closely related species coexist in the same general habitat they avoid fatal competition by their species-specific niche characteristics. Though the larvae of Drosophila rnulleri and Drosophila aldrichi live simultaneously in the decaying pulp of the fruits of the cactus (Opuntia  lindheimerii) yet both have specialities in their preferences for certain yeasts and bacteria.