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Food chains and Flow of Energy Video Lecture | Science for Grade 8

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FAQs on Food chains and Flow of Energy Video Lecture - Science for Grade 8

1. What is a food chain and how does it function in an ecosystem?
Ans. A food chain is a linear sequence that shows how energy and nutrients flow from one organism to another in an ecosystem. It starts with producers, like plants, that convert sunlight into energy through photosynthesis. This energy is then passed on to primary consumers (herbivores) that eat the plants, and subsequently to secondary consumers (carnivores) that eat the herbivores. Decomposers, like fungi and bacteria, break down dead organisms, returning essential nutrients to the soil.
2. What are the different levels of a food chain?
Ans. The different levels of a food chain are known as trophic levels. The first level consists of producers (autotrophs) that generate energy. The second level includes primary consumers (herbivores) that feed on producers. The third level is made up of secondary consumers (carnivores) that eat primary consumers. There can also be tertiary consumers that feed on secondary consumers. Finally, decomposers play a crucial role by breaking down dead matter and recycling nutrients back into the ecosystem.
3. How does energy flow through a food chain?
Ans. Energy flows through a food chain in a one-way direction, starting from the sun, which is captured by producers. When organisms at each trophic level consume others, only a fraction of the energy is passed on to the next level (approximately 10% due to the laws of thermodynamics). This means that energy diminishes as it moves up the chain, making higher trophic levels less energy-rich than lower ones.
4. Why are decomposers important in a food chain?
Ans. Decomposers are essential in a food chain because they break down dead organisms and organic waste, returning vital nutrients to the soil. This process enriches the ecosystem and supports plant growth, which is critical for the survival of all organisms in the food chain. Without decomposers, ecosystems would become overloaded with dead matter, and the recycling of nutrients would be disrupted.
5. What impact do human activities have on food chains?
Ans. Human activities such as pollution, habitat destruction, and overfishing can significantly disrupt food chains. Pollution can poison organisms, leading to declines in populations. Habitat destruction removes crucial habitats for various species, causing imbalances in the food chain. Overfishing can deplete fish populations, affecting those species that rely on them for food. These disruptions can lead to a loss of biodiversity and affect the overall health of ecosystems.
60 videos|141 docs|39 tests

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