Question

complete the t-chart by categorizing each environmental factor as something that would most likely increase or decrease genetic variation. some answers will fit in both columns depending on the situation. predator-prey relationships competition toxins new habitat disasters increased food source increase decrease both increase variation decrease variation

Explanation:

Predator - prey relationships:

• Explanation: If prey has traits (like camouflage) that help avoid predators, those traits are selected for, increasing variation. But if predators target a specific phenotype, that phenotype decreases, so in some cases it can decrease variation. So it can be "Both".

Competition:

• Explanation: Competition can drive natural selection. If organisms with certain traits (e.g., better foraging) succeed, those traits spread (increase variation in favorable traits), but if a dominant phenotype outcompetes others, it can decrease variation. So "Both".

Toxins:

• Explanation: Toxins can act as a selective pressure. Organisms with resistance genes will survive and reproduce, increasing variation in resistant traits. But if toxins kill many organisms, reducing population size (bottleneck effect), genetic variation decreases. So "Both".

New habitat:

• Explanation: A new habitat has new selection pressures. Organisms with traits suitable for the new habitat will thrive, leading to an increase in variation of adaptive traits. There's no strong reason for it to decrease variation in general, but if only a few colonize (founder effect), variation could decrease. However, the primary effect is often an increase as new niches are filled. So "Increase" (or "Both" depending on context, but "Increase" is more likely as new habitat allows for new adaptations).

Disasters:

• Explanation: Disasters like floods or fires can cause a bottleneck effect (only a few survive), which decreases genetic variation. But if the disaster selects for certain traits (e.g., heat - resistant organisms in a fire - prone area), those traits increase, so "Both" (but "Decrease" is more common due to bottleneck).

Increased food source:

• Explanation: More food means less competition for resources. Organisms can reproduce more, and with more individuals, there's more chance for mutations and genetic diversity to be maintained or increased. So "Increase".

Answer:

• Predator - prey relationships: Both
• Competition: Both
• Toxins: Both
• New habitat: Increase (or Both)
• Disasters: Both (or Decrease)
• Increased food source: Increase