Conservation and human impacts - Biology IGCSE Study Notes

Think of Conservation like being a responsible older sibling who makes sure everyone in the family (all the plants and animals, and even future humans) gets to enjoy the toys (natural resources) and the house (Earth) for a long, long time. It's about protecting and managing our natural world so it doesn't get used up or destroyed.

Human impacts are simply all the ways that people, like you and me, change the environment. Some changes are good, like planting trees. But many are not so good, like polluting rivers or cutting down too many forests. It's like when you play with your toys – if you're careful, they last. If you're rough, they break. Our planet is the 'toy' here, and we need to be careful.

We'll look at how our actions affect things like:

• Biodiversity (bio-die-ver-sih-tee): This is a fancy word for the huge variety of all living things on Earth – from tiny bugs to giant whales. Think of it as the amazing collection of different types of furniture and decorations in our 'house'.
• Ecosystems (ee-koh-sis-tems): These are like different 'rooms' in our house, where living things (like plants and animals) interact with each other and their non-living surroundings (like water, soil, and air). A forest is an ecosystem, and so is a pond.

Let's take the example of deforestation (dee-for-ess-TAY-shun), which means cutting down lots of trees, especially in big forests like the Amazon rainforest. Imagine the rainforest is a huge, bustling apartment building, and each tree is an apartment.

1. Humans cut down trees: People cut down these 'apartment buildings' to make space for farms (like growing crops or raising cattle) or to get wood to build things or make paper. It's like tearing down an apartment building to build a shopping mall.
2. Loss of homes: When the trees are gone, all the animals that lived in those trees (monkeys, birds, insects) lose their homes and their food. It's like all the people living in the apartment building suddenly have nowhere to live and nothing to eat.
3. Less oxygen, more carbon dioxide: Trees are super important because they breathe in carbon dioxide (a gas that can make the Earth too hot, like a blanket) and breathe out oxygen (the air we need to live!). When we cut down trees, there are fewer 'air purifiers' for the planet. It's like turning off all the air conditioning in our 'house' and letting the bad air build up.
4. Soil erosion: The roots of trees hold the soil together, like glue. When trees are removed, the soil can easily be washed away by rain, making it harder for new plants to grow. It's like removing the carpet from a floor – suddenly, the dirt underneath gets everywhere.

This simple act of cutting down trees has a huge ripple effect, impacting biodiversity, the air we breathe, and even the land itself.