book1 unit5 after-class reading 2 : Ready for Danger

Have you ever thought about how different animals are from each other? For example, think of a jellyfish and an elephant. Apart from the differences in size, the jellyfish does not have a skeleton. It lives in water and its shape can change.


Why are animals so different? Because if they are to survive as a species, they must be able to change slowly to live in their surroundings. So animals living in different places have to develop different ways of fitting in with their surroundings.


Over thousands of years, climate changes, and so does vegetation. Animals have to change as well, or die out. Today we find the fossils of many types of animals which did not change in the right way, and so died out millions of years ago. One of these was the dinosaur. Dinosaurs were very large animals, some of them 50 feet long and 20 feet high. Think of the size of an elephant, and you will see how very big dinosaurs were.


What does an animal need if the species is to survive? Several things. It must certainly be able to get enough food. It must be able to go on living without being killed off. And it must produce enough young ones.


Some fish produce huge numbers of young ones. They may lay a million eggs in a year, but very few of these will ever become adult fish. Even so, because of the vast numbers of eggs laid, it does not matter that the young fish get attacked by so many enemies.


But some animals do not produce so many young, and so more of them have to survive. One of the ways that some animals have adopted to keep themselves safe is protective coloring. The angelfish has stripes which make it very hard to see among reeds.


The tiger also has stripes to make it hard to see in the jungle, but this is to help it in hunting. The tiger is fierce and powerful, but there are other things which help animals to find food and defend themselves. Some snakes, for instance, are extremely poisonous and can kill an animal much bigger than themselves. The giraffe has such a long neck that it can reach food that many other animals are unable to reach.


When it comes to defense, some creatures can actually change their colors to blend with their surroundings. One of these is the chameleon.


Another way of dealing with enemies is either to have a very good protection or to be able to escape quickly. Many animals can run extremely fast, like the deer.


There is another useful trick that some animals use. They can grow new parts of themselves. The starfish, for example, is not very good at escaping or defending itself, but it can grow another "foot" if it loses one. Sometimes a lizard, if it is in danger, will drop its tail and run away while its enemy is still looking at the twisting tail. Of course, not all species of animals that are alive today have adapted themselves equally well to their surroundings. Several species may become extinct if we do not do something about them.


Within the last 300 years, which is a very short time as far as nature is concerned, the Dodo has become extinct. You can see what a Dodo looked like from the picture.


In our own times, we find several species in danger. Sometimes this is because of human beings. In part of Australasia, people are very fond of eating turtles' eggs. As soon as the mother turtle has laid the eggs, someone digs them up. As a result, not nearly enough eggs are left to hatch out, and the number of turtles is going down.


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Australasia


adapt
adopt
angel
angelfish
apart
blend
chameleon
climate
creature
deer
dinosaur
dodo
extinct
fierce
fossil
giraffe
hatch
instance
jellyfish
jungle
lizard
poisonous
protection
protective
reed
skeleton
species
starfish
stripe
surroundings
turtle
twist
vegetation


apart from
as far as...is concerned
die out
dig something up
fit in with
for instance
go down
in danger
kill off