True or false? All living organisms have the same number of chromosomes.
The Correct Answer and Explanation is:
False.
All living organisms do not have the same number of chromosomes. The number of chromosomes varies widely between species, and even within species, individuals can show variations in chromosome number due to genetic mutations or conditions like aneuploidy.
Chromosomes are structures made of DNA that carry genetic information. Each species has a characteristic number of chromosomes. For example, humans have 46 chromosomes (23 pairs), while dogs have 78 chromosomes (39 pairs). In contrast, certain species of ants may only have 2 chromosomes, and some plants, such as the fern Ophioglossum reticulatum, can have over 1000 chromosomes.
The number of chromosomes is linked to the complexity of an organism, but it’s not a direct correlation. For instance, while humans have 46 chromosomes, the fern Polyploidy species can have many more chromosomes, but that doesn’t necessarily imply that a fern is “more complex” than a human.
Some organisms can also have variations in chromosome number due to factors like polyploidy, where an organism ends up with more than two sets of chromosomes. This can occur naturally, as in some plants, or through artificial means, such as in agricultural crops to increase size and resistance to disease.
In humans and other animals, the typical number of chromosomes is consistent within a species, but this number can still be affected by genetic disorders. For example, Down syndrome, a condition in humans, is caused by the presence of an extra copy of chromosome 21, leading to a total of 47 chromosomes.
Thus, chromosome number is specific to each species and varies considerably across the biological world.
