Genetics and Evolution Flashcards

Which RNA molecule carries the genetic information encoded in DNA out of the nucleus to the ribosomes for protein synthesis?

Answer: mRNA (messenger RNA)

Messenger RNA (mRNA) is transcribed from the DNA template in the nucleus and carries the codon sequence to ribosomes in the cytoplasm where it is translated into a protein.

A frameshift mutation is caused by:

Answer: Insertion or deletion of nucleotides that are not in multiples of three

Inserting or deleting nucleotides in a number not divisible by three shifts the reading frame of all downstream codons, drastically altering the amino acid sequence of the resulting protein.

Allopatric speciation occurs when:

Answer: A population is physically separated by a geographic barrier and the isolated groups diverge over time

Allopatric speciation occurs when a geographic barrier (e.g., mountain range, river) isolates a population into separate groups that then diverge genetically until reproductive isolation is complete.

Which of the following is NOT considered a mechanism of evolution accepted by modern evolutionary theory?

Answer: Inheritance of acquired characteristics (Lamarckism)

Lamarckian inheritance — the idea that traits acquired during an organism's lifetime are passed to offspring — has been disproven; modern evolution relies on heritable genetic variation acted upon by selection, drift, and gene flow.

Gene flow in evolutionary biology refers to:

Answer: The transfer of alleles from one population to another through migration of individuals

Gene flow is the movement of alleles between populations as individuals migrate and reproduce in a new population, which can introduce new genetic variation or homogenize allele frequencies between populations.

When unrelated species independently evolve similar traits due to similar environmental pressures, this process is called:

Answer: Convergent evolution

Convergent evolution occurs when distantly related species independently evolve similar adaptations (analogous structures) in response to comparable environmental challenges.

In the context of evolutionary biology, an organism's 'fitness' is best defined as:

Answer: Its reproductive success relative to other individuals in the population

Evolutionary fitness specifically measures an organism's ability to survive and reproduce in its environment, thereby passing its alleles to the next generation — not physical prowess per se.