Question

1. let’s apply our understanding! llamas have sexual reproduction. some types of llamas have 74 chromosomes. that is how many chromosomes are in their somatic (body) cells. how many chromosomes would be found in their gametes? explain how you would know.
2. since llamas have sexual reproduction, the offspring have the potential to be genetically diverse. how can genetic diversity be an advantage when compared to asexual reproduction?

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Explanation:

Question 20 (about lizards' chromosomes in somatic and germ cells)

Step1: Recall sexual reproduction and meiosis

In sexual reproduction, somatic cells are diploid (2n), and germ cells (gametes) are produced via meiosis, which halves the chromosome number (n).

Step2: Calculate germ cell chromosomes

Given somatic cells have 74 chromosomes (2n = 74), gametes (germ cells) will have \( n=\frac{74}{2}=37 \) chromosomes. This is because meiosis reduces the diploid number to haploid for gamete formation, ensuring fertilization restores the diploid number in offspring.

1. Sexual reproduction mechanisms: Involves meiosis (crossing - over, independent assortment) and fertilization (random fusion of gametes). These create new allele combinations.
2. Asexual reproduction: Offspring are clones (genetically identical to parent), so no new genetic combinations.
3. Advantage of genetic diversity:

• Environmental change: Diverse offspring have a higher chance of having traits suitable for new environments (e.g., new predators, climate change). Asexual offspring, being identical, all face the same risk if the environment turns hostile.
• Disease resistance: Diverse gene pools mean some individuals may have alleles that confer resistance to new diseases, while asexual populations (with uniform genetics) are more likely to be wiped out by a single disease.
• Evolutionary potential: Genetic diversity provides more raw material for natural selection, allowing populations to adapt and evolve over time, which is limited in asexual reproduction.

Answer:

Somatic cells: 74 chromosomes (diploid, 2n). Gametes: 37 chromosomes (haploid, n). Reason: Meiosis halves the diploid (2n) chromosome number to form haploid (n) gametes for sexual reproduction, so \( \frac{74}{2} = 37 \).

Question 21 (genetic diversity advantage in sexual vs asexual reproduction)