#3 - About the history of fishes 关于鱼的历史

1.The first fish could not bite they were suckers!
About 500 million years ago, new animals appeared in the sea - the first fish. They had no jaws or teeth and probably sucked in worms and small pieces of food from the mud.
V Here is an illustration of the Hemicyclaspis!
Hemicyclaspis was an early Jawless fish. It had eyes on top of its head and probably lived on the seabed. This way it could keep a look out for predators above.

2.Some early fish wore suits of armor!
They had hard, curved plates of bone all over their bodies for protection. These fish were called placoderms and most were fierce hunters. Some had huge jaws with sharp sheets of bone for slicing up prey.

3.Spiny sharks had spines, but they were not really sharks.
These fish were similar in shape to today's sharks, but they lived in rivers and lakes, not the sea, about 430 million years ago. Climatius was a spiny shark that looked fierce, but it was only as big as your finger!
V The fins on the back of Climatius were supported by needle-sharp spines. These helped to protect it from attacks by squid or other fish. V

4.The first really big hunting fish was bigger than today's great white shark!
Dunkleosteus grew to almost 10 meters long and swam in the oceans 360 million years ago. It sliced up prey, such as other fish, using its massive teeth made of narrow blades of bone, each one as big as this book.
V This is a picture of a Dunkleosteus! V

5.Some early fish started to 'walk' out of water. Types of fish called lobefins appeared 390 million years ago. Their side fins each had a 'stump' at the base made of muscle. If the water in their pool dried up, lobefins could use their fins like stubby legs to waddle over land to another pool. Eusthenopteron was a lobefin fish about one meter long. Over millions of years, some lobefins evolved into four-legged animals called tetrapods.
V Eusthenopteron could clamber about on dry land when moving from one stretch of water to another. V

We finally have another DIY section for you guys that managed to reach the bottom of this post, and this will be a fish for you to watch swim away!

You will need, waxed card (like the kind used to make milk cartons), crayons, scissors, and a piece of soap.
Place the piece of waxed card face down. Fold the card up at the edges. Draw a fish on the card. Cut a small notch in the rear of the card and wedge the piece of soap in it. Put the "fish" in a bath of cold water and watch it swim away!

1。第一条鱼不能咬他们是吸盘！
大约5亿年前，新的动物出现在海上 - 第一条鱼。他们没有颚或牙齿，可能从泥里吸入蠕虫和小块食物。
** V **这是Hemicyclaspis的插图！
Hemicyclaspis是早期的Jawless鱼。它的头顶上有眼睛，可能住在海床上。这样，它可以留意上面的捕食者。

一些早期的鱼穿着盔甲！***
他们身上有坚硬的弯曲板骨，用于保护。这些鱼被称为placoderms，大多数是凶猛的猎人。有些人有巨大的颚骨与锋利的骨头切片猎物。

3。多刺的鲨鱼有刺，但他们不是真鲨鱼。
这些鱼的形状与今天的鲨鱼相似，但在约4.3亿年前，他们生活在河流湖泊，而不是海洋。 Climatius是一个多刺的鲨鱼，看起来很激烈，但它只有你的手指一样大！
** V ** Climatius背面的翅片由尖锐的脊椎支撑。这些有助于防止鱿鱼或其他鱼类的袭击。 ** V **

4。第一个真正大狩猎鱼比今天的大白鲨大！
Dunkleosteus长达近10米，在3.6亿年前的海洋中游荡。它使用其狭窄的骨头骨头的大块牙齿，像其他鱼一样切成猎物，每个都像这本书一样大。
** V **这是Dunkleosteus的图片！ ** V **

他们的侧鳍每个在由肌肉制成的基部都有一个“树桩”。如果他们的泳池里的水被干涸，lobefins可以使用它们的翅膀像粗短的腿在陆地上跨越到另一个游泳池。洋蓟鱼是约一米长的蛇翅鱼。数百万年来，一些蛇骨演变成四足动物，称为四足动物。
** V **从一段距离的水移动到另一个水域时，Eusthenopteron可能会在干旱的地方徘徊。 ** V **

我们终于有了另一个DIY部分为你们设法达到这个职位的底部，这将是一条鱼，让你看游泳！

你将需要打蜡卡（如用于制造牛奶纸箱的那种），蜡笔，剪刀和一块肥皂。
将打蜡的卡片面朝下放置。将卡片折叠在边缘。在卡上画一条鱼。在卡片的后部切下一个小凹槽，并将一块肥皂楔入其中。把“鱼”放在冷水浴中，看着游泳！