Question

Population size keeps changing depending on different factor/s such as

• A. Food availability
• B. Predation pressure
• C. Adverse weather
• D. All of the above

Answer 1

The Correct Option is D

The size of a population (the number of individuals of a species in a given area) is dynamic and fluctuates over time. These changes are influenced by various environmental factors that affect birth rates, death rates, immigration, and emigration.

Let's consider the factors listed: 

• Food availability: The amount of available food resources directly impacts the carrying capacity of the environment.
  • Abundant food can lead to higher birth rates (better nutrition for reproduction) and lower death rates (less starvation), potentially increasing population size.
  • Scarcity of food can lead to lower birth rates, higher death rates, and potentially increased emigration, causing a decrease in population size.
• Predation pressure: The presence and activity of predators affect the mortality rate of the prey population.
  • High predation pressure increases the death rate, leading to a decrease in population size.
  • Low predation pressure allows for higher survival rates, potentially allowing the population to grow (if other factors are favorable).
• Adverse weather: Environmental conditions like extreme temperatures, droughts, floods, storms, etc., can significantly impact populations.
  • Severe weather events can directly cause mortality (increasing death rates) and reduce reproductive success (decreasing birth rates), leading to a decline in population size.
  • Favorable weather conditions can support population growth.

Since population size keeps changing depending on food availability, predation pressure, and adverse weather conditions (among other factors like disease and competition), all the listed factors contribute to fluctuations in population size.

Therefore, the correct answer is All of the above.

Answer 2

The population size of a species is influenced by several factors, including:

• Food availability: When food is abundant, populations tend to grow. A lack of food can lead to a decrease in population size due to starvation or lower reproduction rates.
• Predation pressure: High predation can reduce the population size by increasing mortality rates. Conversely, in the absence of predators, populations may increase.
• Adverse weather: Extreme weather conditions (such as droughts, floods, or cold temperatures) can negatively impact survival and reproduction, thus reducing population size.

Since all these factors influence population size, the correct answer is (D) : All of the above.