A biologist conducting a long-term field study noticed there were two types of mice in a valley, one type of mouse had webbed toes and one type of mouse lacked webbed toes. A dam was built in the valley turning the land into a wetland. As
the years passed, all mice living in the valley were found to have webbed toes. No mice were found with non-webbed toes.
Which statement best explains the observed change in the mouse population?

they dont have any evidence

ok yes, but what is the question? as soon as you ask the actual question i will answer it. : )

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.