HSC Biology Notes – All Modules

Summary:

The HSC BIOLOGY NOTES – ALL MODULES notes are organized by “Inquiry Question” headings and syllabus dot points, including both hand-drawn diagrams and well-written notes. The notes cover all syllabus dot points efficiently and effectively, making them a perfect source of knowledge for revision, trials, HSC prep, or general studying. These notes have helped the author place second in their school for their internal exams and can help students prepare for all parts of the syllabus, including skills questions.

Excerpt:

Reproduction
Inquiry question: How does reproduction ensure the continuity of a species?

• Explain the mechanisms of reproduction that ensure the continuity of a species by analysing sexual and asexual methods of reproduction in a variety of organisms, including but not limited to
  • Reproduction: the production of offspring by a sexual or asexual process to pass on genes to the next generation.
  • Reproduction is a fundamental evolutionary process ensuring the continuity of life. Reproductive success is determined by an organism’s ability to produce fertile offspring that survive to reproductive maturity, in this way, replacing the parent.
    • Asexual
      ○ Involves only one parent and gives rise to offspring that are genetically identical to the parent and to each other
      ○ No fertilisation, unlike sexual
      ○ Better for increasing the size of a population, growing in number exponentially
      ○ Very rapid, an advantage for many organisms such as bacteria, outcompete slow organisms
      ○ Rely on mutations for variations in DNA → Similar vulnerabilities
    • Sexual
      ○ Usually involves two parents who produce offspring that have a mix of the parent’s genes and therefore differ from each other
      ○ Involves fertilisation
      ○ Introduces genetic variation → genetic diversity
      ○ Random variations are better suited to the changing environment and conditions
      ■ Gives organisms or even populations a better chance of survival
      ○ Smaller number of offspring, but less susceptible to disease
      ○ But the greater expenditure of time and energy → courtship, mating, danger, gamete prod.
      ○ Some organisms are bisexual and self-fertilise → counts as sexual reproduction