örümcek bir havayandır (spider is an animal)
what is the use of dir ? and we used both bir and dir ?
thanks.

the -dir suffix has 2 uses i think.

1. meaning "is" when being formal. you may also see it on signs.

2. emphasing a fact that doesnt change
ie- your own example

im sure that other people could explain it more but im not a native speaker or a teacher.. (yet!! hehe)..
and iv always said that when i know enough turkish id love to help people the same way as theyve helped me

We use the -dir when we make a general statement. Facts about nature or science are general statements.

Kuşlar iki kanatlı hayvanlardır.
Birds are animals with two wings.

Sometimes in story telling we can use -dir as well.

O gün Ahmet erkenden evine gelmiştir. Çok yorgundur ve yatmak üzeredir. Tam bu sırada telefon çalar.

So, can anyone give me a few more examples of -Dir? Can you use it in past, present and future? Can someone give me some examples with English translation comparing it to -di and -miş?

The -dir suffix is used to make a statement. When you use -dir either you are telling a fact or you are telling something that you believe is the fact. We can add it to nouns and adjectives directly:

"İstanbul çok büyük bir şehirdir."
"Istanbul is a very big city."

"Türkiye'nin en büyük şehri İstanbul'dur."
"The biggest city in Turkia is Istanbul."

We can use it with verbs:

İstanbul daha da büyümektedir.
"Istanbul is growing even bigger"

Şu kız benim sevdiğimdir.
that girl is my love.