Today's post is the reading (article) and worksheet for Pod's Travels. This is another episode of Dinosaur Planet. It is based in Southern Europe . . . possibly Romania. At the time the continents had split up and North America was drifting away from Europe. The climate was much warmer and so much of what is now Europe was a series of islands. Much of what we now call Europe was flooded. In the process of the continents moving apart because of tectonic plate activity or movement there were many earthquakes. Some earthquakes under the ocean cause enormous tsunamis. A tsunami is a giant wave that can travel at 500 miles per hour or 804 kilometers per hour.
Pod, and his pack, are caught in one of these tsunamis. They are washed out to sea with only Pod and one of his sisters surviving. But his sister gets eaten by a Plesiosaur. Eventually Pod drifts into an island that has been separated from the mainland for some time. The island was separated many years before, but not millions of years before. Probably only about 100.000 years before. It may have separated because of the plate tectonic activity. The island is inhabited by the same species as found on the mainland of Europe, but the animals are all much smaller. These are called dwarf species.
Pod sees Sauropods on the island but they are not the huge animals that he is familiar with on the mainland. They are much smaller. He COULD have killed and eaten them but his instinct is to avoid this type of animals because on the mainland they could squash him like a bug. This changing of traits in animals that are separated by geography is called evolutionary drift. In other words, when animals evolve to be somewhat or slightly different or even very different due to geographical separation it is also evolutionary drift. The animals that live on the island and on the mainland are were once the exact same species. With the separation caused by the island breaking off from the mainland the species drifted. The ones on the island had less food available so they evolved to be smaller.
The way it works is that the original inhabitants of the island, when the island got broken off from the mainland... they were the same size as all the animals on the mainland. But since there was less food available on their new home, the island, they were under evolutionary pressure to need less resources. So animals that were born smaller had a better chance of survival. This is natural selection at work. The animals, over the years, that were born with genes that made them smaller had an advantage on the island with its limited resources.
In the video Pod becomes the leader of the pack. If he had descendants then they would be bigger than the mini-raptors, but the offspring would be bigger than their mother. But since the island's environment selects for smaller size, Pod's descendants would eventually all be smaller. They would evolve to be the size of the other mini-Pyroraptors. (Pod is a full size Pyroraptor.) But his descendants will eventually all be mini-raptors or mini-Pyroraptors.
This same kind of situation of Evolutionary Drift caused by Geographical Separation can be seen in Arizona in The Grand Canyon. Squirrels on one side of the canyon have a common ancestor on the other rim. But when the canyon was cut by the Colorado River the two species drifted apart. The Evolutionary Drift created two different species of squirrels.
So, here is the Reading or Article and the accompanying worksheet for Pod's Travels. You should be able to find the video on the internet.
NOTE: Right below is the two page Reading and the one page Worksheet.
Click on the button labeled: Science Readings & Worksheets to print these.
Pod's Travels Rdg Pg. 1
Pod's Travels Rdg. Pg. 2
Pod's Travels Wksheet
Click on the button labeled: Science Readings & Worksheets to print these.
Pod's Travels Rdg Pg. 1
Pod's Travels Rdg. Pg. 2
Pod's Travels Wksheet
NOTE: The following are some species of animals that are similar to some of the species of animals seen in the video. They are not the exact same species in most cases. They are coloring page drawings I have done in the last 3 or 4 years.
Troodon in the Forest
Patagotitan mayorum the biggest dinosaur
Igruanodon and Dermodactylus
T. rex with Pteranodon in front of a Volcano
Saltwater Crocodile by a River
(This is a modern species.)
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