Chapter 15 – Life on the Earth
- What is the biosphere?
The biosphere is the global sum of all ecosystems where life exists. It includes land, water, and the atmosphere and supports interactions among organisms and their environment. - What are ecosystems?
An ecosystem is a functional unit where living organisms interact with each other and their non-living environment in a balanced way. Examples: forests, lakes, grasslands. - What are biotic and abiotic components?
Biotic components are living parts like plants and animals. Abiotic components are non-living factors like sunlight, air, water, soil, and temperature that influence ecosystems. - What is ecology?
Ecology is the scientific study of relationships between organisms and their environment. It helps understand biodiversity, ecosystems, and environmental conservation. - What are producers in an ecosystem?
Producers are green plants that make their own food using sunlight (photosynthesis). They form the base of the food chain and supply energy to all organisms. - Who are consumers?
Consumers are organisms that depend on other living beings for food. They include herbivores, carnivores, omnivores, and decomposers. - What are decomposers?
Decomposers like fungi and bacteria break down dead organisms and recycle nutrients back into the environment, maintaining ecosystem balance. - What is a food chain?
A food chain is a linear sequence showing how energy flows from producers to consumers and decomposers. Example: grass → deer → tiger. - What is a food web?
A food web is a complex network of interconnected food chains in an ecosystem, showing multiple feeding relationships among organisms. - What is a trophic level?
A trophic level represents each step in a food chain, from producers (1st) to primary consumers (2nd), secondary consumers (3rd), and so on. - What is energy flow in an ecosystem?
Energy flows in one direction—from the Sun to producers to consumers. Only 10% of energy transfers from one trophic level to the next. - What are biogeochemical cycles?
These are natural pathways that recycle nutrients through biological, geological, and chemical processes. Examples: carbon, nitrogen, and water cycles. - What is the carbon cycle?
Carbon moves through the atmosphere, biosphere, and hydrosphere via photosynthesis, respiration, decomposition, and combustion. It regulates climate and supports life. - What is the nitrogen cycle?
Nitrogen circulates through fixation, nitrification, assimilation, ammonification, and denitrification. It’s vital for DNA, proteins, and plant growth. - What is biodiversity?
Biodiversity refers to the variety of life on Earth—plants, animals, microorganisms, and ecosystems. It’s crucial for ecological stability and human survival. - Why is biodiversity important?
It supports ecosystem services, provides food, medicine, and raw materials, and helps ecosystems recover from disturbances like climate change and pollution. - What are biomes?
Biomes are large ecological areas with distinct climate, soil, and life forms. Examples: tundra, desert, tropical rainforest, grassland, and temperate forests. - What is a tropical rainforest biome?
Located near the equator, tropical rainforests have high rainfall and biodiversity. Example: Amazon rainforest, home to half of the world’s species. - What is a desert biome?
Deserts are arid areas with low rainfall, extreme temperatures, and sparse vegetation. Adapted organisms include camels, cactus, and snakes. - What is a tundra biome?
Found in polar regions, tundra has permafrost soil, low biodiversity, and cold-resistant plants like mosses and lichens. - What is deforestation?
The clearing of forests for agriculture, logging, or development. It leads to habitat loss, soil erosion, and contributes to climate change. - What is desertification?
The degradation of land in dry areas due to overgrazing, deforestation, and poor land use, turning productive land into desert. - What is conservation?
Conservation involves protecting, managing, and restoring natural ecosystems and biodiversity to ensure sustainability for future generations. - What is sustainable development?
Development that meets present needs without compromising future generations’ ability to meet theirs. It balances economic, environmental, and social goals. - What are endangered species?
Species at risk of extinction due to habitat loss, pollution, hunting, or climate change. Examples: tiger, rhino, and snow leopard. - What are national parks and sanctuaries?
Protected areas set aside to conserve wildlife and biodiversity. National parks prohibit human activity; sanctuaries allow limited use. - What is an ecological footprint?
A measure of human demand on natural resources, showing how much land and water is required to sustain a person or population. - What are invasive species?
Non-native species that disrupt native ecosystems by outcompeting local species, reducing biodiversity. Example: water hyacinth in Indian lakes. - What is global warming’s impact on life?
It alters habitats, disrupts food chains, increases extinction risk, causes extreme weather, and affects ecosystems globally, threatening human and animal life. - Why is environmental education important?
It promotes awareness, encourages sustainable practices, and empowers people to protect and restore ecosystems, ensuring a healthier planet for future generations.