Explore & Learn

Page number 54 and 55.

In species is the most basic unit of classification, as well as a taxonomy rank. The next taxonomic rank on the hierarchy of biological classification is a genus. On earth, there are currently 8.7 million species living today, however,that number is just a fraction of all organism that have ever lived.

The concept of specie dates back to the time of Aristoles. He used the term ‘’génos’’,

Which ment ‘’a king’’ [eg;fish], and’’eidos’’, which means ‘’a specific form’’ [eg; tuna, sardine etc]. These terms were eventually transplanted into Latin as ‘’genus’’ and ‘’species’’, though they do not correspond to the terms under the Linnaean taxonomy.

Define the term species = Species is defined as a group of organisms that consist of similar individuals capable of interbreeding or exchanging genes among themselves.

 A species includes all of the organisms that may interbreed and produce viable offspring that is also capable of reproducing the same kind. Species are based on their ability to interbreeding,not on physical similarities.

Page number 50 and 51.

Energy resources are natural sources or systems that can be used to generate power for various human activities, such as electricity production, heating, and transportation. They can be classified into two main categories

1. Renewable Energy Resources – These sources replenish naturally and are generally sustainable. Examples include

• Solar energy (from the sun)

• Wind energy (from wind turbines)

• Hydropower (from moving water)

• Geothermal energy (from heat inside the Earth)

• Biomass energy (from organic materials like wood, crops, or waste)

2. Non-Renewable Energy Resources – These sources are finite and take millions of years to form. Examples include

• Fossil fuels (coal, oil, and natural gas)

• Nuclear energy (from uranium and other radioactive materials)

Each type of energy resource has its own benefits and drawbacks in terms of availability, environmental impact, and efficiency.

Page number 48 and 49.

DEFINITION: Conservation = save

Conservation means protecting and preserving natural resources and the environment for current and future use, encompassing actions like reducing waste, promoting sustainable practices, and safeguarding biodiversity.

1. Definition:

   Conservation is the act of protecting, maintaining, and preserving something, typically natural resources like forests, water, wildlife, and cultural heritage. 

   
   

2. Focus:

   It involves using resources carefully and responsibly to ensure their availability for future generations.

3. Examples:

   
   

   • Environmental Conservation: Protecting ecosystems, reducing pollution, and promoting sustainable resource management. 

   • Wildlife Conservation: Protecting endangered species and their habitats. 

   • Cultural Heritage Conservation: Preserving historical sites, artifacts, and traditions. 

   • Resource Conservation: Reducing consumption of energy, water, and other resources. 

     
     

4. Importance:

   Conservation is crucial for maintaining ecological balance, ensuring the long-term health of the planet, and providing resources for future generations. 

   
   

5. Community-based conservation:

   Efforts to protect biodiversity in which the local community participates as much as possible.

   
   

6. Conservation of energy:

   a principle in physics that states that energy can neither be created nor destroyed and that the total energy of a system by itself remains constant. 

Page number 46&47

Ozone Layer Definition

What is Ozone Layer Depletion?

Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere. This happens when the chlorine and bromine atoms in the atmosphere come in contact with ozone and destroy the ozone molecules. One chlorine can destroy 100,000 molecules of ozone. It is destroyed more quickly than it is created.

Some compounds release chlorine and bromine on exposure to high ultraviolet light, which then contributes to ozone layer depletion. Such compounds are known as Ozone Depleting Substances (ODS).

The ozone-depleting substances that contain chlorine include chlorofluorocarbon, carbon tetrachloride, hydrochlorofluorocarbons, and methyl chloroform. Whereas, the ozone-depleting substances that contain bromine are halons, methyl bromide, and hydro bromofluorocarbons.

Chlorofluorocarbons are the most abundant ozone-depleting substance. It is only when the chlorine atom reacts with some other molecule, it does not react with ozone.

Montreal Protocol was proposed in 1987 to stop the use, production and import of ozone-depleting substances and minimise their concentration in the atmosphere to protect the ozone layer of the earth.

What is an Ozone Layer?

The ozone layer is mainly found in the lower portion of the earth’s atmosphere. It has the potential to absorb around 97-99% of the harmful ultraviolet radiations coming from the sun that can damage life on earth. If the ozone layer was absent, millions of people would develop skin diseases and may have weakened immune systems.

However, scientists have discovered a hole in the ozone layer over Antarctica. This has focussed their concern on various environmental issues and steps to control them. The main reasons for the ozone hole are chlorofluorocarbons, carbon tetrachloride, methyl bromide and hydrochlorofluorocarbons.

Let us have a detailed look at the various causes and effects of ozone layer depletion.

Page number 44&45.

Pollution is one of the greatest threats to our planet, affecting everything from the air we breathe to the food we eat. Air pollution, caused by vehicle emissions, factories, and deforestation, not only accelerates climate change but also increases respiratory illnesses like asthma. Water pollution turns once-pristine rivers and oceans into toxic wastelands, endangering marine life and contaminating drinking water. Soil pollution, often overlooked, reduces the quality of crops and seeps harmful chemicals into our food chain. Even noise pollution, from traffic and industries, disrupts sleep and mental well-being. The fight against pollution isnt just about laws-its about daily choices. Reducing waste, using cleaner energy, and holding industries accountable can make a real difference. Our planets future depends on what we do today.

Here are some additional points about pollution:

1. Plastic Pollution— Millions of tons of plastic waste end up in oceans and landfills each year, harming wildlife and taking centuries to decompose.

2. Light Pollution— Excessive artificial lighting disrupts ecosystems, affects human sleep cycles, and obscures natural wonders like the night sky.

3. Thermal Pollution— Factories and power plants release hot water into rivers and lakes, disrupting aquatic life by altering temperature balances.

4. Radioactive Pollution—Nuclear waste and radiation leaks pose long-term environmental and health risks, contaminating land and water sources.

5. Chemical Pollution—Pesticides, industrial chemicals, and household cleaning agents seep into the environment, poisoning water, soil, and air.

6. E-Waste Pollution—The improper disposal of electronic waste (like phones and computers) releases toxic substances, polluting land and water.

7. Deforestation and Habitat Destruction—Clearing forests for agriculture and urbanization increases carbon dioxide levels and destroys wildlife habitats.

To combat pollution, individuals can adopt sustainable habits like reducing plastic use, conserving energy, recycling properly, and supporting eco-friendly policies. Governments and industries must also implement stricter regulations and invest in green technologies to protect the environment for future generations.