Unit 7: Topic 8 - Continuing Evolution Flashcards
Evolution is continuous: True/False
True, populations are always evolving on a microevolutionary scale.
How do species genomically change over time?
As mutations arise and persist in populations, genetic variation continuously increases. As a result, significant phenotypic and genomic changes in species can occur. This can be seen by the ability of organisms, due to their genetic diversity, to adapt over many years to rapidly changing environmental conditions from human activity. Genomic change is also evident in the fossil record.
How does the fossil record help us understand evolution?
The fossil record provides evidence of change over time. Although our fossil record is incomplete, it gives a good understanding of past species and the evolutionary changes they underwent. Uncovered fossils can be dated to help us understand the timeline of such evolutionary changes.
Why and how do pathogens and other organisms evolve resistance to antibiotics, pesticides, herbicides, and chemotherapy drugs?
Colonies of bacteria and other microscopic organisms tend to have high population sizes, which increases the chances of having mutations and thus leads to greater genetic variation. When exposed to chemicals such as antibiotics or pesticides, only the organisms with traits that will let them survive in the presence of the chemical will remain. The remaining resistant organisms will reproduce, leading to a new population with the inherited resistance. An example includes bacteria cells causing golden staph and gonorrhea that have adapted to gain resistance against penicillin.
Why and how do pathogens create new emergent diseases?
Pathogens create new diseases because they are constantly evolving, often at a very fast rate. Bacteria populations are very large, which increases genetic variation, which then increases the chance for bacteria to get a new trait that leads to a new strain of a disease. Like bacteria cells, virus cells also have high replication rates and, as a result, an increased chance of mutation and greater genetic variation. Viruses can adapt fast and create new strains of pathogens due to their high genetic variation. One infamous pathogenic virus is Covid-19, in which a virus cell was able to adapt to target the human species. New strains of Covid-19 provide evidence of the adaptability and evolutionary change the virus has undergone.
