Question

What characteristics are true for cline? ______________

• A. Continuous variation driven by single trait; however, trait may or may not be genetically controlled
• B. Many traits which are genetically controlled and population pattern is distinct
• C. Many characteristics following continuous variation and genetically controlled
• D. Single character with distinct population pattern and controlled by gene

Hint:

Cline = Gradual Change. It is like a "gradient" of genetic traits that matches the gradient of the environment.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the defining characteristics of a "cline," a concept in evolutionary biology and forest genetics.

Step 2: Detailed Explanation:

• Definition of Cline: A cline is a measurable, gradual, and continuous change in one or more phenotypic characters or allele frequencies within a species across its geographic distribution.

• Environmental Linkage: Clines are usually driven by a corresponding gradual change in environmental factors, such as temperature, altitude, or rainfall. For example, tree height might decrease gradually as you move up a mountain range.

• Genetic Basis: To be a true biological cline, the variation must be "genetically controlled" (it shouldn't just be a temporary response to the environment). This is confirmed when seeds from different points of the cline are grown together in a single "common garden" experiment.

• Multi-trait nature: Clines often involve "many characteristics" (e.g., leaf size, timing of flowering, and frost resistance) that vary together in a "continuous" pattern, rather than being sudden and distinct.

Step 3: Final Answer:
Clines are characterized by many traits following continuous and genetically controlled variation.