Ecosystems and Food Webs
Every living thing on Earth exists within an ecosystem - think of it as nature's neighbourhood where all organisms interact with each other and their non-living surroundings like air, water, and soil. Within these ecosystems, biodiversity refers to all the different species that call that environment home.
Each organism has its own specific niche, which is basically its job or role in the community. A species consists of organisms that can breed together and produce fertile offspring, whilst a population includes all members of one species living in the same habitat (their home address).
Food chains and food webs show us who eats whom in nature. The arrows always point in the direction of energy flow - from the grass to the grasshopper to the bird to the fox. Here's the important bit: about 90% of energy is lost at each stage through heat, movement, and waste, meaning only 10% gets passed up to the next level.
Quick Tip: Remember that indicator species are like nature's pollution detectors - their presence or absence tells scientists about environmental health. Mutations can create new genetic variations that might help species adapt to changing ecosystems.