Explanation:
1. Genotype vs. Phenotype:
o Think of it as instructions vs. outcome.
Genotype: The genetic instructions inherited from parents (like the DNA code). (e.g., GG for green seeds in pea plants)
Phenotype: The observable outcome based on genotype and environment (like the actual green color of the seeds).
2. Dominant vs. Recessive Alleles:
o Dominant Allele: Like a bossy gene, it masks the effect of its partner (even if just one copy is present). (e.g., Green seed color (G) in pea plants)
o Recessive Allele: Needs to be paired with another recessive allele to show its effect (like a shy gene, needs two copies to be seen). (e.g., Yellow seed color (g) in pea plants)
3. Punnett Squares:
o Imagine a grid predicting baby traits. It shows all possible combinations of genes parents can pass on to offspring, helping predict genotypes and phenotypes.
4. Genetic Variation Matters:
o Think of it as population insurance. Variation allows populations to:
Fight disease: Some individuals might have resistant genes, helping the population survive new threats.
Adapt to change: Traits suited to a new environment (e.g., temperature) can help populations survive and evolve.
5. Environment Can Talk to Genes:
o Genes aren't always in charge. The environment can influence gene expression, deciding if a gene is used and how much protein it makes.
Examples: Nutrients, temperature, and light can all influence which genes are active in an organism.