Acknowledgements

Source: Natural History Museum

All other material within this course originated at The Open University.

Course image: Nishanth Jois [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] in Flickr made available under Creative Commons Attribution 2.0 Licence.

Don't miss out:

If reading this text has inspired you to learn more, you may be interested in joining the millions of people who discover our free learning resources and qualifications by visiting The Open University - www.open.edu/ openlearn/ free-courses