Genetic Variation and Evolution Review

Ministry of Education and Purpose of Text

  • The Year 13 Biology textbook is owned by the Ministry of Education, Heritage, and Arts of Fiji.
  • It is permitted for reproduction for classroom purposes with proper acknowledgment.
  • Aimed to enrich students' understanding of the Year 13 Biology syllabus and encourage exploration beyond its confines.

Structure of the Textbook

  • Organized into three main strands:
    1. Structure and Life Processes
    2. Living Together
    3. Biodiversity, Change, and Sustainability
  • Each strand includes key concepts and self-test questions to solidify understanding.

Strand 1: Structure and Life Processes

Genetics
  • Field focused on genes, heredity, and variation.
  • Genes are made up of DNA (Deoxyribo Nucleic Acid).
  • Chargaff's Rules:
    • A = T and C = G, ensuring a 1:1 base pairing ratio.
  • DNA can replicate through a semi-conservative process involving:
    • Enzymes: DNA helicase, polymerase, ligase.
Variation
  • Difference in characteristics resulting from genetic or environmental factors.
  • Types of Variation:
    1. Continuous: Smooth gradations (e.g., human height).
    2. Discontinuous: Distinct forms (e.g., blood types).
Natural Selection
  • Theory explaining how advantageous traits become prevalent within populations.
  • Factors influencing it include overproduction, competition, and survival of the fittest.

Strand 2: Living Together

Ecological Relationships
  • Interaction between organisms and their environment (abiotic and biotic components).
  • Niche: Role of a species and how it meets its needs.
  • Communities and populations reflect interdependence and competition among species.
Biological Timing
  • Daily (circadian), seasonal (circannual), and lunar (circadian) rhythms dictate behaviors such as migration, reproduction, and dormancy.

Strand 3: Biodiversity, Change, and Sustainability

Importance of Biodiversity
  • Biological diversity encompasses the variety of life and its interdependence in maintaining ecological stability.
Environmental Issues
  • Human activities lead to habitat destruction and pollution, threatening biodiversity.
  • Increase in greenhouse gases results in climate change affecting all organisms.
Carbon Cycle
  • The exchange of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
  • Carbon sinks, such as forests and oceans, store carbon, while driving factors include deforestation and fossil fuel combustion.
Environmental Impact Assessment
  • Process of evaluating the potential environmental effects of proposed projects.
  • Key to sustainable development and biodiversity conservation.