Organisms and Populations Test - 3

A positive effect on population density is caused by immigration and natality. Both help in increasing the population.

Female wasp uses fig fruits for oviposition (egg laying). It also uses the developing fruits within the larvae for nourishing its larvae.

The relationship between cattle and egret shows commensalism interaction. Similarly, orchids show commensal interaction with mango branch. Orchids get support of the mango plant, while mango plant does not get any benefit. Similarly, egrets always forge where cattle are grazing and eat insects flushed out by cattle from the vegetation. However, cattle achieve no benefit from egrets.

Balanus dominatus of rocky sea coasts of Scotland excluded the smaller Barnacle Chathamalus from the intertidal area. This relation is competitive release (restriction of a species to a small geographical area because of presence of a competitively superior species).

According to Allen's rule, animals living in cold climate have shorter ears and limbs to prevent heat loss.

Female anopheles mosquito needs the host's blood for making eggs. Its eggs require iron, which it derives from the blood.

A population pyramid gives a clear picture of how a country transitions from high fertility to low fertility rate. The broad base of the pyramid means the majority of population lies between ages 0–14, which signifies that the fertility rate of the country is high.

Statement 1 is false as aquatic organisms are influenced by the pH of water. Different organisms can tolerate different salt concentrations.
Statement 2 is true as geographical distribution is dependent upon level of thermal tolerance of different species. Some animals can tolerate high temperatures whereas optimum temperature for others is different.
Statement 3 is false as sunlight plays a significant role in the life of animals that are dependent on plants for food. Animals use diurnal and seasonal variations in light intensity and duration as hints for foraging, reproductive and migratory activities.

A biome is a community of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biological communities that have formed in response to a shared physical climate.

Kangaroo rat in North American desert has the capability to meet all its water requirements through internal oxidation of fats. This enables the kangaroo rat to survive for months without water.