logo

Study resource

Genetics and ecosystems official content study guide

Study Genetics and ecosystems official content with curriculum-aligned Study Guide resources, practice links, and exam-focused support.

At a glance

study guide

Resource type

Topic

Genetics and ecosystems official content

AqaA LevelBiologyGenetics, populations, evolution and ecosystems

Study guide overview

  • Genetics and Ecosystems Study Guide

    A structured guide to help you study genetics and ecosystems, including key terms, principles, and practical applications.

    Study Guide for Genetics and Ecosystems

    Genetics

    Key Terms

    • Genotype: The genetic constitution of an individual.
    • Phenotype: The physical expression of the genotype.
    • Dominant: An allele that expresses its trait even in the presence of a recessive allele.
    • Recessive: An allele that only expresses its trait when homozygous.
    • Codominant: Both alleles in a heterozygote are fully expressed.
    • Homozygous: Having two identical alleles for a trait.
    • Heterozygous: Having two different alleles for a trait.

    Genetic Crosses

    • Monohybrid Cross: A genetic cross focusing on a single trait.
    • Dihybrid Cross: A genetic cross focusing on two traits simultaneously.
    • Sex-Linkage: Inheritance patterns associated with genes located on sex chromosomes.
    • Multiple Alleles: More than two alleles exist for a gene within a population.
    • Epistasis: Interaction between genes where one gene masks the effect of another.

    Population Genetics

    • Hardy-Weinberg Principle: A model that describes how allele frequencies remain constant in a population under certain conditions.
    • Chi-Squared Test: A statistical method to determine if observed data fits expected data.

    Ecosystems

    Key Concepts

    • Population: A group of individuals of the same species in a given area.
    • Community: Different populations living together in a defined area.
    • Ecosystem: A community of living organisms and their physical environment interacting as a system.
    • Niche: The role and position a species has in its environment.

    Ecological Dynamics

    • Abiotic Factors: Non-living chemical and physical parts of the environment.
    • Biotic Factors: Living components that affect the population size.
    • Succession: The process of change in the species structure of an ecological community over time.

    Conservation

    • Conservation Methods: Strategies to protect biodiversity and manage ecosystems sustainably.

Ready to practise?

Choose your next step

Use the study guide for understanding, then switch into an active revision mode.