Organisms And Populations

Step 1: General effect of temperature.
Temperature plays a major role in determining the distribution of organisms and ecosystems.
Step 2: Analyzing statements.
(A) Correct — Temperature is indeed one of the most important environmental factors influencing organisms.
(B) Correct — Temperature decreases as we move from the equator to the poles.
(C) Incorrect — Actually, temperature decreases with increase in altitude/height, not increases.
(D) Correct — At the summit of a mountain, the temperature is low due to high altitude.
Step 3: Conclusion.
Thus, the incorrect statement is Temperature increases with increase in height.

Step 1: Understanding age pyramids.
An age pyramid represents the distribution of individuals in different age groups of a population.
Step 2: Case of decreasing order.
When the proportion is highest in the pre-reproductive phase, followed by reproductive, and lowest in post-reproductive, it indicates more young individuals, ensuring future population growth.
Step 3: Analyzing options.
(A) Expanding: Correct — More young individuals mean the population is expanding.
(B) Decreasing: Incorrect — Would show fewer young and more old.
(C) Stable: Incorrect — All three groups would be nearly equal in proportion.
(D) Unstable: Incorrect — Not the correct ecological term in this context.
Step 4: Conclusion.
Hence, the population pyramid in decreasing order of age groups indicates an expanding population.

Step 1: Concept of species co-existence.
Closely related species often compete for similar resources. However, they can coexist if they use resources differently.
Step 2: Case of warblers.
MacArthur studied warblers in spruce trees and found that five species coexisted because they utilized different parts of the same tree, thus minimizing competition.
Step 3: Conclusion.
This phenomenon is called resource partitioning, allowing species to coexist.

Step 1: Basic understanding.
Population growth depends on the balance between natality (birth rate), mortality (death rate), immigration (inflow), and emigration (outflow).
Step 2: Major factors.
1. Birth rate (Natality): Higher birth rate increases population.
2. Death rate (Mortality): Lower death rate increases population growth.
3. Migration: Immigration increases population, emigration decreases it.
4. Socio-economic factors: Education, healthcare, and awareness influence growth rate.
5. Government policies: Family planning, incentives, and awareness programs regulate growth.
Step 3: Conclusion.
Population growth is affected by demographic (birth \& death rate), social, and economic factors.

Step 1: General idea.
Parasites are organisms that live on or inside a host and derive nutrition at the host’s expense. To survive, they evolve specific adaptations.
Step 2: Morphological adaptations.
1. Loss of unnecessary organs (e.g., digestive system in tapeworm).
2. Presence of adhesive structures such as hooks and suckers.
3. Thick resistant cuticle to resist host enzymes.
Step 3: Physiological adaptations.
1. Secretion of anti-enzymes to neutralize host digestive juices.
2. Anaerobic respiration in intestinal parasites.
Step 4: Reproductive adaptations.
1. High reproductive capacity (e.g., tapeworm produces thousands of eggs).
2. Complex life cycles involving multiple hosts to ensure survival.
Step 5: Conclusion.
Parasites exhibit structural, physiological, and reproductive adaptations for survival inside host organisms.