Question

match the traits with examples of how they influence the phenotype of an organism.
fish will only grow colorful tails if no predators are present during development.
a gene influences both the height of a tree and the number of branches that it produces.
chickens will produce a \walnut comb\ on their head only if they possess at least one dominant allele in each of two different genes.

Explanation:

• Pleiotropy: When a single gene affects multiple phenotypic traits. In the example, one gene influences both the height of a tree and the number of its branches, which is a classic case of pleiotropy.
• Epistasis: It occurs when the expression of one gene is affected by the expression of one or more independently - inherited genes. For chickens to have a "walnut comb", the presence of at least one dominant allele in each of two different genes is required. This shows that the interaction of two genes (epistasis) determines the comb phenotype.
• Environmental effects: The phenotype of an organism can be influenced by environmental factors. Here, the presence or absence of predators (an environmental factor) during the development of fish determines if they will grow colorful tails.

Answer:

• "Fish will only grow colorful tails if no predators are present during development" → Environmental effects.
• "A gene influences both the height of a tree and the number of branches that it produces" → Pleiotropy.
• "Chickens will produce a 'walnut comb' on their head only if they possess at least one dominant allele in each of two different genes" → Epistasis.