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Biology - Conservation

Grade 9IGCSE

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

🔑Concepts

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Biodiversity refers to the number of different species that live in a particular area. High biodiversity increases the stability of an ecosystem.

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Sustainable resources are resources that are produced as rapidly as they are removed from the environment so that they do not run out.

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Sustainable development is development providing for the needs of an increasing human population without harming the environment.

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Deforestation causes loss of habitat, which can lead to extinction. It also increases the concentration of CO2CO_{2} in the atmosphere because there are fewer trees to perform photosynthesis: 6CO2+6H2O→C6H12O6+6O26CO_{2} + 6H_{2}O \rightarrow C_{6}H_{12}O_{6} + 6O_{2}.

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Eutrophication occurs when excess fertilizers (containing nitrates and phosphates) leach into water bodies, causing algae blooms that block sunlight and deplete dissolved O2O_{2}.

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Captive breeding programs and seed banks are methods used to protect endangered species from extinction.

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Pollution from plastics can persist in the environment for hundreds of years, harming marine life through ingestion or entanglement.

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CITES (Convention on International Trade in Endangered Species) is an international agreement to ensure that international trade in specimens of wild animals and plants does not threaten their survival.

📐Formulae

Population Density=Total Number of IndividualsTotal Area Scan (units)2\text{Population Density} = \frac{\text{Total Number of Individuals}}{\text{Total Area Scan (units)}^2}

Percentage Increase/Decrease=New Value−Old ValueOld Value×100%\text{Percentage Increase/Decrease} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100\%

Efficiency of Energy Transfer=(Energy available after transferEnergy available before transfer)×100%\text{Efficiency of Energy Transfer} = \left( \frac{\text{Energy available after transfer}}{\text{Energy available before transfer}} \right) \times 100\%

💡Examples

Problem 1:

A forest area of 1200 km21200 \text{ km}^2 is being monitored. Scientists count 180180 tigers in this area. Calculate the population density of tigers in this forest.

Solution:

Density=1801200=0.15 tigers per km2\text{Density} = \frac{180}{1200} = 0.15 \text{ tigers per km}^2

Explanation:

Population density is calculated by dividing the total count of the species by the total area they occupy.

Problem 2:

In a study of energy flow in a food chain, the primary producer captures 10000 kJ10000 \text{ kJ} of energy. The primary consumer receives 1200 kJ1200 \text{ kJ}. Calculate the percentage efficiency of this energy transfer.

Solution:

Efficiency=(120010000)×100=12%\text{Efficiency} = \left( \frac{1200}{10000} \right) \times 100 = 12\%

Explanation:

Energy transfer efficiency is the ratio of energy passed to the next trophic level compared to the energy available at the current level, expressed as a percentage.

Problem 3:

The population of an endangered species of orchid was 400400 in 2010. By 2020, due to conservation efforts, the population rose to 550550. Calculate the percentage increase.

Solution:

550−400150\begin{array}{r} 550 \\ - 400 \\ \hline 150 \end{array} Percentage Increase=150400×100=37.5%\text{Percentage Increase} = \frac{150}{400} \times 100 = 37.5\%

Explanation:

First, find the absolute increase in population (550−400=150550 - 400 = 150). Then divide this increase by the original population and multiply by 100100 to get the percentage.

Conservation Grade 9 Notes & Examples | IGCSE Science