Question

In laboratory experiments, two species of the protist Paramecium(species 1 and 2) were grown alone and in the presence of the other species. The following graphs show the growth of species 1 and 2, both alone and when in mixed culture with the other species.

Which of the following conclusions can be drawn from the graphs?
A. Competitive exclusion occurred in these experiments
B. Both species are affected by interspecific competition but species 1 is affected less
C. Both species are affected by interspecific competition but species 2 is affected less
D. Both species are affected equally by interspecific competition

Answer 1

Paramecium is a unicellular entity with the appearance of a shoe heel. Its scale ranges from 50 to 300um, depending on the animal. It is mainly present in freshwater habitats. It is a well-known genus of ciliate protozoa and a single-celled eukaryote belonging to the kingdom Protista.

Complete answer:
A mixed culture involves more than one kind of organism growing in a sterile medium, such as agar, in the study of microorganisms. The mixed culture can include several species of viruses, bacteria, and parasites that may or may not coexist and share available resources. Different species in a mixed culture may be sorted by age, weight, and other considerations, or they can be separated by species and placed in separate mediums to establish pure communities of just one species.

Technicians may add different substances to the medium to determine what causes each culture to develop or die, such as determining which antibiotic is effective for bacteria isolated from a particular host. Alternatively, you will watch as the mixed-species fight over available resources, or how one species overwhelms and eradicates the opposing species. When species 1 was kept with species 2, the number of individuals decreased dramatically, while when species 2 was kept with species 1, the number of individuals did not change significantly. As a result, interspecific competition affects all groups, but species 2 is less affected.

Hence the correct option will be C (Both species are affected by interspecific competition but species 2 is affected less).

Additional information:
Van Leeuwenhoek's 1684 experiments on mixed cultures were the first to investigate microorganisms. In 1718, Micheli, when dealing with fungi, published on the germination of mold spores on cut surfaces of melons and quinces. Brefeld obtained pure cultures of fungi in 1875, and Koch obtained pure cultures of pathogenic bacteria in 1878. Both Brefeld's and Koch's experiments sought to classify pathogenic microorganisms. They needed to determine which organism was to blame for a certain disease. Thus, Koch's fame stems in part from his discovery of the origin of tuberculosis.

Note: It is impossible to do scientific research on mixed cultures. Studying fermentation becomes more complex where more than one microorganism is involved. Since one component is eliminated, most biochemical experiments are performed as single-culture fermentations.
- In patent and regulatory processes, defining the substance and the microorganisms used are more active.
- Fermentation contamination is more difficult to detect and monitor.