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
A 2-column table has columns with labels Increase variation and decrease variation.

Answer 1

Increase variation | Decrease variation
---|---
Predator–prey relationships (can drive coevolution, frequency‑dependent selection and niche diversification) | Predator–prey relationships (strong predation can remove many genotypes → directional selection or bottleneck)
Competition (can cause character displacement and niche partitioning, creating new selective pressures) | Competition (competitive exclusion or strong selection can eliminate genotypes)
New habitat (new niches and selective pressures can promote adaptive radiation and diversification) | New habitat (founder effect when a few colonizers start the population → reduced variation)
Increased food source (larger population size → more mutations and higher standing variation) | Increased food source (if one genotype monopolizes the resource, a selective sweep can reduce variation)
Toxins (rarely: can favour new resistant alleles and novel adaptations over time) | Toxins (kill susceptible individuals → strong selection/bottleneck, usually reducing variation)
— | Disasters (population bottlenecks and mass mortality sharply reduce genetic variation)

(Items placed in both columns are context‑dependent; the short note after each explains the usual mechanism.)