Mechanism Of Evolution

Step 1: Definition of sympatric speciation Sympatric speciation refers to the process by which new species evolve from a single ancestral species while inhabiting the same geographic region. Unlike allopatric speciation, there is no physical separation between populations.

Step 2: Mechanism of sympatric speciation Sympatric speciation often occurs due to factors such as: Behavioral isolation Ecological isolation (e.g., habitat preferences within the same region) Polyploidy in plants Genetic divergence without physical barriers

Step 3: Elimination of incorrect options (A) Incorrect: Geographic isolation is a characteristic of allopatric speciation. (C) Incorrect: Migration to a new habitat implies geographic separation, which is not sympatric. (D) Incorrect: Gradual accumulation of changes is part of the speciation process but does not define sympatric speciation specifically.

In Drosophila, the normal wing phenotype is determined by the presence of at least one dominant allele. The recessive alleles , etc., cause abnormal wing development only when present in homozygous recessive combinations.

Step 1: Evaluate each genotype. : Both alleles are wild type, so the wings are normal.

Normal wings. : One dominant allele is sufficient for normal wings.

Normal wings. : One dominant allele is sufficient for normal wings.

Normal wings. : One dominant allele is sufficient for normal wings.

Normal wings. : One dominant allele is sufficient for normal wings.

Normal wings. Step 2: Count the genotypes. All five genotypes contain at least one dominant allele and hence represent normal wings. Thus, the correct answer is: