Natural selection and genetic modification study guide

Genetic engineering is a scientific process that involves altering the genetic make-up of an organism. This modification is typically done to introduce desirable characteristics that the organism might not naturally possess or to enhance existing traits. The process commonly involves isolating specific genes from one organism, then inserting these genes into the DNA of another organism. For example, a gene for pest resistance from a bacterium can be inserted into a crop plant, making the plant resistant to certain pests. This technology has wide-ranging applications in medicine, agriculture, and industry, leading to the development of genetically modified organisms (GMOs). While offering significant benefits, genetic engineering also raises ethical considerations and concerns about potential long-term impacts on ecosystems and human health.

The original five kingdoms classification grouped organisms by how they looked and how they lived. Later, scientists used genetic analysis, especially sequencing of DNA and ribosomal RNA (rRNA), to compare organisms at the molecular level. This revealed that what was once thought to be one group of prokaryotes (Monera) actually contained two fundamentally different genetic lineages: Bacteria and Archaea. These groups are as genetically distinct from each other as either is from Eukarya (all organisms with nuclei). This molecular evidence led scientists to propose the three domains system—Bacteria, Archaea, and Eukarya—which reflects true evolutionary relationships based on genetic differences rather than just physical characteristics.