下面的汉译英对吗？是否还有可以改进的地方？

有些物种已经灭绝了,因为它们不能适应越来越恶劣的环境.
Some species have become extinct because they could not adapt to the environment which has been getting worse and worse.
species就可以表示物种!
最好用现在完成进行时!原因我就不说了...
你的汉语也不太规范.

Some species were already extinct because they could not adapt to the deteriorating environment.

Some species of animals have extincted because they could not adapt to the environment which is getting worse and worse.

Had some animals' already to wipe out an entire race, because they could not adapt the more and more bad environment.

have extincted

Some species have become extinct because they couldn't adapt(themselves) to the environment which is getting worse and worse.