Free SAT Biology Genetics & Evolution Questions and Answers — Questions and Answers
Question 1: What is the primary mechanism of evolution?
- Mutations only
- Natural selection (Correct answer)
- Genetic drift
- Random mating
Correct answer: Natural selection
Natural selection is the primary mechanism driving evolution, as proposed by Charles Darwin. It describes the process where organisms better adapted to their environment tend to survive and produce more offspring. Over time, this leads to changes in the genetic makeup of populations, favoring advantageous traits and leading to the development of new species.
Question 2: Which structure carries genetic information?
- Ribosomes
- Mitochondria
- DNA (Correct answer)
- RNA
Correct answer: DNA
Deoxyribonucleic acid (DNA) is the molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. It contains the hereditary material that is passed from parents to offspring. DNA's double helix structure allows it to store vast amounts of information in a stable form.
Question 3: What term describes a change in DNA sequence?
- Transcription
- Mutation (Correct answer)
- Replication
- Translation
Correct answer: Mutation
A mutation is a permanent alteration in the DNA sequence that makes up a gene or chromosome. These changes can range from a single nucleotide substitution to large-scale chromosomal rearrangements. Mutations are the ultimate source of genetic variation, which is essential for evolution, though they can also be harmful.
Question 4: What is genetic drift?
- Natural selection
- Genetic drift (Correct answer)
- Artificial selection
- Speciation
Correct answer: Genetic drift
Genetic drift is a random change in the frequency of alleles (gene variants) in a population over generations. Unlike natural selection, which is driven by adaptation, genetic drift is purely by chance, especially significant in small populations. It can lead to the loss of some alleles and the fixation of others, regardless of their adaptive value.
Question 5: What is a phenotype?
- Genetic code
- DNA sequence
- Protein structure
- Observable traits (Correct answer)
Correct answer: Observable traits
A phenotype refers to the observable physical or biochemical characteristics of an organism, resulting from the interaction of its genotype with the environment. Examples include hair color, height, or the presence of a disease. While primarily determined by genes, environmental factors can also influence the final expression of the phenotype.
Question 6: What does a Punnett square illustrate?
- Chromosomal crossover
- Trait inheritance (Correct answer)
- Genetic mutation
- Gene sequencing
Correct answer: Trait inheritance
A Punnett square is a diagram used in genetics to predict the probability of offspring inheriting specific genotypes and phenotypes from their parents. It visually represents all possible combinations of alleles from two parents. This tool helps understand Mendelian inheritance patterns and the likelihood of traits being passed on.
Question 7: Which scientist is known for the theory of evolution by natural selection?
- Gregor Mendel
- Isaac Newton
- Charles Darwin (Correct answer)
- Albert Einstein
Correct answer: Charles Darwin
Charles Darwin is widely recognized for his groundbreaking work on the theory of evolution by natural selection, published in "On the Origin of Species." His theory proposed that species evolve over time through a process where individuals with advantageous traits are more likely to survive and reproduce. This concept revolutionized biology and our understanding of life's diversity.
Question 8: What is speciation?
- Mutation
- Extinction
- Speciation (Correct answer)
- Fertilization
Correct answer: Speciation
Speciation is the evolutionary process by which new and distinct species arise from an ancestral population. This typically occurs when populations become reproductively isolated, preventing gene flow between them, and then diverge genetically over time due to natural selection, genetic drift, or mutations. It is a fundamental process in the diversification of life on Earth.
Question 9: What is a genotype?
- An inherited behavior
- A visible trait
- The genetic makeup of an organism (Correct answer)
- A protein
Correct answer: The genetic makeup of an organism
A genotype refers to the complete set of genes or the specific genetic constitution of an individual organism. It represents the inherited genetic information that determines an organism's potential characteristics. The genotype, in conjunction with environmental factors, ultimately determines the phenotype.
Free SAT Biology Genetics & Evolution Questions and Answers
What is the primary mechanism of evolution?