This week we begin our final section for the year. It is a very interesting study, and worthy of being spread over a longer period of time (as we have done). (The Timeline of Significant Events at the start of the chapter is not required for 2022.)

The different stages in our History of Life have been explained and given over two pages of your Study Guide. They have also been described at length in your slides. Have a look at how the scientists have gone about analysing their evidence to draw up the geological time scale (shown in your Study Guide). See how it is structured, with the present being at the top, and the oldest being at the bottom. As you move upwards on that scale, so you are moving forward in time. We will use this time scale as a basis for all our subsequent discussions in this section.

Next week we start analysing this geological time scale by looking at the "explosion" of living things - how many different living things emerged - in the early Cambrian Era. And so these notes (that you have been given now) will be repeated next week.

All the answers for this full section have been included in these slides. As always, use them as your guide only after you have answered them properly.