What caused fish and other organisms to want to, and successfully move onto land billions of years ago?

Question

How were aquatic organisms suddenly able to live on land? It's not like i can just say,"Oh, i want to live underwater," and then jump in the water and i'm suddenly able to breath underwater. How did they adapt, and how long did it take them to adapt?

Answer 1

Well, the water starts to dry up and only the fish that could withstand the air and sun survived. There are some fish around today that have, lobed type fins for crawling. When the dry season comes, they crawl off to another, hopefully deeper, water hole. They survive to reproduce and pass their new talent on to their offspring.

These changes occur slowly over thousands of generations. How long does it take? Depends upon how long a generation is. Some fish do not reach maturity for a few years. It would take thousands of years for evolution to occur. However, if you are talking about something like a bacteria which reproduces on an hourly basis, you can observe evolution over a few short decades. (This is how we got antibiotic-resistant strains.)

Also, organisms don't evolve because they "want to". They evolve because the environment changes and if they happen to be lucky enough to have a trait which helps them survive, then they survive to reproduce and pass on that trait. It's all luck.

Answer 2

Successive mutations that allowed breathing air and leg like structures would have given a huge advantage to amphibious creatures. They would have little to no competition for resources like food and shelter on land and so would flourish, spreading the genes for amphibious-ness to many!

Answer 3

Lower water levels, salinity, search for food, bad neighborhood,who knows for sure

Answer 4

People p????ing in the water!

Answer 5

They heard there was a McDonald's.