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Biology: Ecology and Sustainability - Conservation, Climate Mitigation, and Environmental Policy

Grade 8IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Biodiversity Conservation: The practice of protecting and preserving the wealth and variety of species, habitats, and ecosystems. This includes in-situ (in natural habitat) and ex-situ (outside natural habitat) conservation methods.

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Greenhouse Effect and Climate Change: Certain gases, such as CO2CO_{2}, CH4CH_{4}, and N2ON_{2}O, trap heat in the atmosphere. The enhanced greenhouse effect leads to global warming, which is expressed as an increase in the Earth's average surface temperature TT.

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Climate Mitigation: Strategies to reduce or prevent emission of greenhouse gases. This includes transitioning to renewable energy sources, enhancing carbon sinks through reforestation, and improving energy efficiency.

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The 10% Rule in Ecosystems: In a food chain, only approximately 10%10\% of the energy is transferred from one trophic level to the next. The remaining 90%90\% is lost as heat or used for metabolic processes.

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Carbon Footprint: The total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of CO2CO_{2}.

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Environmental Policy: International frameworks like the Paris Agreement aim to limit global temperature rise to well below 2∘C2^{\circ}C above pre-industrial levels.

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Sustainable Development: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs, often visualized through the 'Three Pillars': Social, Economic, and Environmental.

📐Formulae

6CO2+6H2O→light/chlorophyllC6H12O6+6O26CO_{2} + 6H_{2}O \xrightarrow{light/chlorophyll} C_{6}H_{12}O_{6} + 6O_{2}

Etransfer=EconsumerEproducer×100%E_{transfer} = \frac{E_{consumer}}{E_{producer}} \times 100\%

D=1−(∑n(n−1)N(N−1))D = 1 - \left( \frac{\sum n(n-1)}{N(N-1)} \right)

Net Carbon Flux=∑Carbon Sinks−∑Carbon Sources\text{Net Carbon Flux} = \sum \text{Carbon Sinks} - \sum \text{Carbon Sources}

💡Examples

Problem 1:

An ecosystem receives 50,000 kJ50,000\text{ kJ} of energy from the sun. If the producers capture 1%1\% of this solar energy and the primary consumers follow the 10%10\% rule, how much energy is available to the primary consumers?

Solution:

Eproducers=50,000×0.01=500 kJE_{producers} = 50,000 \times 0.01 = 500\text{ kJ} Eprimary_consumers=500×0.10=50 kJE_{primary\_consumers} = 500 \times 0.10 = 50\text{ kJ}

Explanation:

First, calculate the energy fixed by producers (1%1\% of solar input). Then, apply the trophic efficiency rule where only 10%10\% of that energy is passed to the next level.

Problem 2:

A city aims to reduce its annual CO2CO_{2} emissions from 8,000,0008,000,000 metric tons to 3,456,7893,456,789 metric tons through a new green policy. Calculate the total reduction required using vertical subtraction.

Solution:

8000000−34567894543211\begin{array}{r} 8000000 \\ -3456789 \\ \hline 4543211 \end{array}

Explanation:

To find the reduction needed, we subtract the target emission level from the current emission level. The city must reduce emissions by 4,543,2114,543,211 metric tons.

Problem 3:

In a small habitat, there are two species. Species A has n1=10n_1 = 10 individuals and Species B has n2=5n_2 = 5 individuals. Calculate the total number of individuals NN and the value of ∑n(n−1)\sum n(n-1).

Solution:

N=10+5=15N = 10 + 5 = 15 ∑n(n−1)=10(10−1)+5(5−1)=10(9)+5(4)=90+20=110\sum n(n-1) = 10(10-1) + 5(5-1) = 10(9) + 5(4) = 90 + 20 = 110

Explanation:

This calculation is the first step in determining Simpson's Diversity Index, where nn is the number of individuals per species and NN is the total population.