A boa constrictor is a snake that is in the boidae family. They are usually found in rainforests due to the humidity and temperature. The time it was first evolved is unknown.
The boa constrictor has close relatives in the boidae family, such as the emerald tree boa and the green anacconda. These organisms are bonded through their nucleotides which are genetic building blocks.
Many snakes in the boidae have similar intertnal structures, such as their skeletal systems. These are called homologous structures, which are organs or bones that occur in more than one organism. This proves common ancestry between different species.
Boa constrictors, among other snake species, have vestigial structures. Since many snakes evolved from lizards, boa constrictors have tiny leg and hip bones. These bones are present in snakes they are present in snakes ancestry.
Fossils have been found of a large snake with small legs that lived in ancient rainforests. There have been fossils found of different species similar to the ancestors and current snakes. These are called transitional fossils, which show the evolution and loss of limbs the snakes would have.