IB Marine Science Standard Level (SL) Practice Exam 2026 - Free Marine Science Practice Questions and Study Guide

Ecology examines how living things interact with each other and their surroundings—how energy flows through ecosystems, how organisms affect their environment, and how these interactions shape populations and communities. This includes interactions among organisms (like predation, competition, and symbiosis) and between organisms and abiotic factors (such as light, temperature, water, and nutrients). The other fields describe different topics: evolution of species focuses on how populations change over time due to genetic variation and natural selection; the distribution of fossils deals with where ancient organisms lived in the past; genetics of populations studies how gene frequencies change under evolutionary forces. Because ecology centers on relationships and environmental context, it is defined as the study of the interactions of organisms with their environment.