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

Answer 1

T‑chart (factor → effect on genetic variation; brief reason)

Increase
- Increased food source — larger populations and relaxed resource stress can maintain more alleles and allow more mutations to persist.

Decrease
- Disasters — cause population bottlenecks and strong genetic drift that remove alleles.
- Toxins (generally) — strong directional selection and mortality typically produce selective sweeps and reduce diversity.

Both (depends on context)
- Predator–prey relationships — can maintain or generate variation via coevolution and frequency‑dependent selection, but severe predation can cause bottlenecks and loss of diversity.
- Competition — can drive disruptive selection and niche partitioning (increasing variation) or lead to exclusion and population declines (decreasing variation).
- New habitat — founder effects and small colonizing populations can reduce variation, while new ecological opportunities can drive adaptive radiation and increase variation.