Genetics and biodiversity flashcards

Genetics and biodiversity explores how genetic variation arises and is maintained within and between species. Students must understand how mutations, meiosis, and sexual reproduction generate genetic diversity, and how this diversity is measured using indices such as the Simpson's index of diversity. The concept of a gene pool and allele frequencies within populations is central, as is how natural selection, genetic drift, and isolation can shift allele frequencies over time, potentially leading to speciation. Students should also appreciate how biodiversity operates at three levels: genetic, species, and ecosystem diversity. Conservation of genetic diversity is important for the long-term survival of species, and techniques such as DNA profiling and genome sequencing are used to assess genetic relationships between individuals and populations.

1. Card 1

   What is meant by genetic biodiversity within a species?

   Genetic biodiversity refers to the variety of alleles present within a species or population, reflecting the range of heritable differences among individuals.

2. Card 2

   What is a gene pool?

   A gene pool is the total collection of alleles present in all individuals of a breeding population at a given time.

3. Card 3

   How does meiosis contribute to genetic variation?

   Meiosis produces variation through independent assortment of homologous chromosomes and crossing over, generating gametes with unique combinations of alleles.

4. Card 4

   What is a mutation and why is it important for biodiversity?

   A mutation is a random change in DNA base sequence. It introduces new alleles into a population, providing the raw material for natural selection and evolution.

5. Card 5

   What does the Simpson's Index of Diversity measure?

   Simpson's Index of Diversity measures species diversity by accounting for both the number of species (richness) and the relative abundance of each species in a community.

6. Card 6

   What is the formula for Simpson's Index of Diversity (D)?

   D = 1 - (sum of n(n-1) / N(N-1)), where n is the number of individuals of each species and N is the total number of all individuals. A higher D means greater diversity.

7. Card 7

   What is genetic drift and when does it have the greatest effect?

   Genetic drift is random change in allele frequency due to chance. It has the greatest effect in small populations, where chance events can significantly alter the gene pool.

8. Card 8

   What is the founder effect?

   The founder effect occurs when a small group establishes a new population, carrying only a limited sample of the original gene pool, reducing genetic diversity.

9. Card 9

   How does geographic isolation contribute to speciation?

   Geographic isolation separates populations so gene flow stops. Different selection pressures and genetic drift cause allele frequencies to diverge, eventually producing reproductive isolation and new species.

10. Card 10

    What is the difference between allopatric and sympatric speciation?

    Allopatric speciation occurs due to geographic separation, while sympatric speciation occurs within the same location, often through polyploidy or behavioural isolation.

11. Card 11

    Why is maintaining genetic diversity important for conservation?

    High genetic diversity means a population has more alleles available to respond to environmental change or disease, reducing extinction risk and improving long-term survival.

12. Card 12

    How can DNA profiling be used to assess biodiversity?

    DNA profiling compares specific regions of DNA between individuals or populations, revealing genetic similarities and differences that indicate levels of genetic diversity and evolutionary relationships.

• Students often confuse species richness with species diversity, forgetting that a valid diversity index must also account for the relative abundance of each species, not just how many species are present.
• A common error is assuming that natural selection is the only mechanism that changes allele frequencies, overlooking genetic drift, the founder effect, and gene flow as equally important evolutionary forces.
• Many students incorrectly state that geographic isolation alone causes speciation, when in fact it is the subsequent reproductive isolation that prevents interbreeding and defines two populations as separate species.

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