This page serves as a self-check for those who have completed the tasks on pages 54 and 55 and now want to see how I would have answered.
|This table shows my suggested solutions to the whale-related tasks.|
|1||Read the first few sections and find out how you can tell when a whale briefly emerges and then descends again that it is not a fish!|
There are also fin-shaped forelimbs, skin knots, humps and humps in fish, but fish do not have the blowhole on their head through which whales blow air before they breathe in again. You can see it from afar because tiny water droplets form in the warm and humid exhaled air as it cools, creating a kind of fog. We know it from ourselves when we run outside in winter and the same thing happens to the air we exhale.
The second characteristic described in the book that clearly distinguishes whales from fish is the horizontal caudal fin. In fish it is vertical.
|2||In Figure 54.2, find similarities and differences to the skeletons of other mammals in the skeleton of a humpback whale!|
|All the bones of the whale shown in the picture are also found in other mammals. We mammals share most of these bones in common because we are all related and because our common ancestor had these bones. The striking difference between whales and other mammals is that whales have no hind legs.|
|3||Think what the remains of the pelvic girdle and thighbones tell us about the early ancestors of the whales!|
|The fact that whales still have remains of the pelvic girdle and thighbones, although they obviously don't need them, tells us that they are descended from animals living on land that still had four legs.|
|4||Think about what the particular physique has to do with the habitat of the whales!|
|The habitat of the whales is the relatively cold sea or at least water, which is much denser than air. If you don't want to freeze to death in the sea, you have to have a thick layer of fat for insulation. If you have to swim fast in the water, you need a streamlined body. A swimming mammal needs fins instead of legs. In the book we see a pectoral and a caudal fin and a sleek shape of the whale, while the heat-insulating layer of fat is mentioned in the text.|
|5||Describe in your own words how baleen whales catch and devour their prey!|
|Baleen whales catch their prey by swallowing huge amounts of water and using a gigantic tongue to push this water out of the huge mouth through the long, horny whiskers. Countless small crabs and other small organisms belonging to the plankton get caught in the whiskers. As soon as the water has been largely squeezed out of the mouth, the tongue pushes the captured plankton into the throat and thus probably triggers the swallowing reflex.|
|6||Name the dimensions of a newborn blue whale baby!|
|A newborn blue whale baby is 6-7 meters long and already weighs around 2000 kilograms.|
|7||Think about why the humpback whales go on such incredibly long hikes!|
|The humpback whales find sufficient food in the plankton-rich seas of the Antarctic and Arctic (it was not you, but our book that "forgot" to mention the Arctic), in which it is too cold for the babies. This is why expectant whale mothers have to swim in tropical coastal waters to give birth to their babies and to nurse them until they are big and fat enough to survive in ice-cold water.|
|8||Take a look at the table on top of page 55 and think about the problems we humans would have if there were only so few survivors left!|
|If there were only 5,000 people left, many of whom were still too young or already too old, then the young people would hardly find life partners with whom they could fall in love and with whom they could have children. The fewer people or individuals of other species there are, the less they are different (genetic diversity). If their environment changes or new diseases appear, then such a species with only a few specimens can easily become extinct because not enough of them have adapted to the new situation. For us humans there would also be the problem that there weren't enough people left to practice all professions and learn all techniques from the masters who were still left. Our culture would largely collapse and we would have to return to a very simple life.|
Comments and criticism from professionals, learners and their parents are always welcome.