JEE Main

Shortcut Methods and Tricks:

• Simpson’s index: This index takes into account the dominance of species in a community. A higher Simpson’s index indicates lower species dominance, meaning there are more evenly distributed species.
• Shannon diversity index: This index considers both species richness and evenness. A higher Shannon diversity index indicates higher species diversity.
• Species richness: This measure is the total number of species present in a given area and it is directly related to the habitat size and diversity.
• Population density: It is usually expressed as the number of organisms per unit area (per square kilometer or square meter).
• Abundance: It refers to the actual number of individuals of a species in an ecological community.
• Extinction rate: It is usually measured as the number of species that go extinct per million species per year.
• Endemism: It can be calculated by dividing the number of endemic species by the total number of species in a given region.

Common Numerical Values:

• Simpson’s index: Moderate diversity (0.5-0.8), High diversity (0.8-1)
• Shannon diversity index: Low diversity (1-3), Moderate diversity (3-4), High diversity (4-5)
• Species richness: Low diversity (10-100), Moderate diversity (100-1000), High diversity (1000-10000)
• Population density: Low density (1-10), Moderate density (10-100), High density (100-1000)
• Abundance: Low abundance (1-10), Moderate abundance (10-100), High abundance (100-1000)
• Extinction rate: Natural background extinction rate (0.1-1 species per million species per year), Elevated extinction rate (1-10 species per million species per year)
• Endemism: Low endemism (1-10%), Moderate endemism (10-20%), High endemism (20-30%)

CBSE Board

Shortcut Methods and Tricks:

• Simpson’s index: Similar to JEE Main, a higher index indicates lower species dominance.
• Shannon diversity index: Also similar to JEE Main, where higher diversity index means higher species diversity.
• Species richness: It is affected by factors such as habitat size, environmental conditions, and the rate of speciation and extinction.
• Population density: It is influenced by factors such as resource availability, predation, and competition.
• Abundance: It is influenced by factors such as birth rate, death rate, immigration, and emigration.
• Extinction rate: It is influenced by factors such as habitat loss, pollution, climate change, and overexploitation.

Common Numerical Values:

• Simpson’s index: Moderate diversity (0.5-0.8), High diversity (0.8-1)
• Shannon diversity index: Low diversity (1-3), Moderate diversity (3-4), High diversity (4-5)
• Species richness: Low diversity (10-100), Moderate diversity (100-1000), High diversity (1000-10000)
• Population density: Low density (1-10), Moderate density (10-100), High density (100-1000)
• Abundance: Low abundance (1-10), Moderate abundance (10-100), High abundance (100-1000)
• Extinction rate: Natural background extinction rate (0.1-1 species per million species per year), Elevated extinction rate (1-10 species per million species per year)