Evolution of biological complexity

Once upon a time, long long ago, there were tiny living things called cells. Some cells lived alone, while others joined together to form groups. These groups of cells discovered that if they worked together, they could do more things than when they were alone.

Over time, cells that worked together got better at it. Some cells started to specialize in certain jobs, like making food or moving the group around. These specialized cells helped the group survive better and do more things.

Then, some groups of cells started to join together to form bigger groups. These bigger groups had even more specialized cells and could do even more things that helped them survive. For example, some groups could move around faster or defend themselves better.

As time went on, some of these big groups of cells went through even more changes. They developed new ways of communicating and coordinating with each other. This made them even more efficient at doing things that helped them survive.

Eventually, some groups of cells turned into animals and plants. These animals and plants were incredibly complex with many specialized cells and systems inside them. For example, we humans have a whole bunch of specialized cells and systems in our bodies that work together to keep us alive and healthy.

So, in summary, cells started out simple but became more complex as they worked together and specialized. This led to the evolution of many different kinds of living things, including us!