Issues of genetics and DNA are constantly cropping up in the news from food production and health, to legal cases and ethics. We hear about DNA in movies like Jurassic Park and X-men, we learn bits and pieces about it from TV shows like Dexter and and CSI, but what exactly is DNA, and how does it work?
The next instalment describes the move from water to land. The fish that did so may have been forced to because of drought, or chose to in search of food. Either way, they eventually evolved into amphibians. Such creatures needed two things: limbs for mobility and lungs to breathe. The coelacanth is shown as a fish with bony fins that could have developed into legs, and the lungfish is able to absorb gaseous oxygen. However, evidence of an animal that possessed both is presented in the 450 million-year-old fossilised remains of a fish called a eusthenopteron. Three groups of amphibians are explored.
Describes the inhospitable habitats of snow and ice. Mount Rainier in America is an example of such a place: there is no vegetation, therefore no herbivores and thus no carnivores. However, beneath its frosty surface, algae grow and some insects, such as ladybirds visit the slopes. Africa’s mountains are permanently snow-covered, and beneath peaks such as Kilimanjaro and Mount Kenya, there are communities of plants and animals.