Answer these questions if ! (biology) 100 only answer if u know the ! 1. what indicates that evolution is taking place in a population? use the word alleles in your "answer". 2. what are three sources of genetic variation? 3. how does the range of phenotypes for single-gene traits differ from the range for polygenic traits?

1 - The change in gene pool (change in alleles) which means that the individuals are changing and devolping new characteristics along with new species.

2 - Sex, mutation and gene flow are the three sources of genetic variation.

3 - Single-gene traits can only have 2 different phenotypes while polygenic traits can have many phenotypes.

Hope it helped,

BioTeacher101

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.