Humankind has learned to live in many environments based on successful adaptation.
Interaction of humans with environment (surroundings) results in major changes both good and bad.
Bad changes often from making too big a change in environment. e.g. first settlers in Americas caused 50 million deaths by disease resulting in a fall of carbon dioxide due to expansion of rain forests resulting in a new geological epoch.
Ecosystem – community of organisms, other natural resources and their influence on each other. Plants and animals exist in ecosystem are those most adapted to that environment. Natural selection.
Use of natural resources causes imbalance in ecosystem. Ecosystems naturally change over time but if change occurs too quickly than it can be destroyed.
Can be small or large e.g. a garden pond or the Great Barrier Reef. Usually no boundaries between ecosystems, blend together as external factors change.