The First Vertebrate Walks on Land
Tetrapods were animals with four legs and fingers and toes at the end of them. Considered transitional forms, that is, an semiaquatic animal that was adapted to living in the water, but also became able to live on land, a transitional form between fish with fins and gills and animals with limbs and lungs.
In this video, Jenny Clark, palaeontologist, examines when the first vertebrate walked on land.
The beak has been adapted to assist the bird in its way of feeding. Have a look at the following link and notice how different beaks are, in shape and size.
And to see how birds feed, you can have a look on the next series of videos, The insatiable appetite. Really interesting!
Marsupials are mammals whose babies are not fully developed when born. They complete their development inside the marsupium, as you can see in the next video:
Finally, if you want to review this unit in Spanish, here you have an usefull link where you will also find many activities.