JEE Preparation- Ecology Ecosystems

Biomass production in different ecosystems (g/m2/yr)

• For terrestrial ecosystems, you can use the following equation: $$BP=NPP-R$$

Where,

• BP is the biomass production

• NPP is the net primary production

• R is the respiration

• For aquatic ecosystems, you can use the following equation: $$BP=NPP-(P+R)$$

Where,

• P is the grazing

Net primary production of different ecosystems (g/m2/yr)

• NPP can be estimated using the following equation:

$$NPP=GPP-R$$ Where,

• NPP is the net primary production
• GPP is the gross primary production
• R is the respiration

Secondary production of different ecosystems (g/m2/yr)

-Can be estimated using this formula: SP = NPP * Ecological Efficiency

Energy flow through different trophic levels (kcal/m2/yr)

• To calculate the energy flow through different trophic levels, you need to know the amount of energy that is transferred from one trophic level to the next. This can be done by multiplying the amount of energy available at a given trophic level by the ecological efficiency

Species diversity indices (Shannon Index, Simpson Index, etc.)

• For the Shannon Index (H): $$H = -\sum p_i \ln p_i$$

• For the Simpson Index (D) $$D = \sum p_i^2$$ Where:

• (p_i) is the proportion of individuals belonging to species i in the community

Ecosystem stability indices (Resilience, Resistance, etc.)

• Resilience (R): $$R = \frac{\Delta E_s}{\Delta E_d}$$ Where:

• (\Delta E_s) is the change in ecosystem state at time t+1 as a result of disturbance (d_t)

• ( \Delta E_d) is the magnitude of the disturbance (d_t)

• Resistance (Rd): $$Rd= 1- \frac{\Delta E}{\Delta d}$$ Where:

• (\Delta E) is the change in Ecosystem State (ES)

• (\Delta d) is the change in the magnitude of the disturbance (d_t)

Nutrient cycling rates (Nitrogen cycle, Carbon cycle, etc.)

• To calculate the nutrient cycling rates, you need to know the amount of nutrient that is inputted into the system, the amount of nutrient that is outputted from the system, and the amount of nutrient that is stored in the system.

Ecological efficiency (Percentage of net primary production that is consumed by the next trophic level)

• Ecological efficiency is the percentage of net primary production that is consumed by the next trophic level. It can be calculated by dividing the amount of energy consumed by the next trophic level by the amount of net primary production. $$EE= \frac{Secondary \space Production}{Net \space Primary \space Production}$$

Population growth models (Exponential growth, Logistic growth, etc.)

• Exponential growth model: $$P_t = P_0e^{rt}$$ Where:

• P_0 is the initial population size

• t is the time

• r is the intrinsic growth rate

• Logistic growth model: $$P_t = \frac{K}{1+be^{−rt}}$$

Where:

• K is the carrying capacity
• b is a constant that determines the shape of the curve
• r exponential growth rate
• t is the time