Question

Among lions, tigers and domestic cats, all three have the same number of 38 chromosomes, yet they have different appearances. How do you account for such differences?

Answer 1

A chromosome is a long piece of DNA that has genes on it. Plants and animals have thousands or tens of thousands of genes spread around their chromosomes.
Each gene is a part of DNA that has instructions for a particular protein. These thousands or tens of thousands of proteins are all working together to create a working plant or animal.

Complete Answer:
- The word "phenotype" refers to an organism's measurable physical properties; these include the appearance, development, and behaviour of the organism. The phenotype of an organism is determined by its genotype, which is the set of genes borne by the organism, as well as by environmental effects on these genes.
- Organisms of similar genotypes, such as identical twins, inevitably express non-identical phenotypes due to the impact of environmental factors, since each organism experiences specific environmental influences as it grows. Height, wing length, and hair colour are examples of phenotypes. Phenotypes also have measurable traits, such as levels of hormones or blood cells, that can be measured in the laboratory.
- Not only are the characteristics of a species, such as physical appearance, body functions and behaviour, the product of chromosome number, but these depend on each organism's genotype. That means that lion, tiger and domestic cat can very much have the same number of 38 chromosomes in the set of genes present in the species, their characteristics (like different appearances) are the product of the genes located on the chromosomes.

Note: Genotype, an organism's genetic constitution. From embryonic development through adulthood, the genotype determines an individual's genetic ability and limitations. Among sexually reproducing species, the genotype of an individual comprises the whole complex of genes inherited from both parents.