1. need to make room for the young, ecosystems are not unlimited
2. we accumulate parasites and diseases as we live. Dying kills them off, too
3. much slower evolution, implying losing ground compared with quickly evolving competitors
1. need to make room for the young, ecosystems are not unlimited
2. we accumulate parasites and diseases as we live. Dying kills them off, too
3. much slower evolution, implying losing ground compared with quickly evolving competitors