Evolution, the process by which species change over time, is supported by multiple lines of evidence. One of the strongest pieces of evidence for evolution comes from the fossil record. Fossils provide a chronological history of life on Earth, showing how organisms have changed over millions of years. Another piece of evidence comes from comparative anatomy, where scientists study the similarities and differences in the structures of different organisms. Homologous structures, like the forelimbs of humans, bats, and whales, suggest a common ancestry, while analogous structures (such as wings in bats and birds) indicate adaptation to similar environments.
Which of the following is NOT considered evidence for evolution?
Answer: D) The fossilization of soft-bodied organisms
The forelimbs of humans, whales, and bats are examples of:
Answer: A) Homologous structures
The wings of birds and bats are examples of:
Answer: B) Analogous structures
The presence of similar DNA sequences in different species suggests:
Answer: C) Common ancestry
Charles Darwin's theory of natural selection is one of the key principles in the study of evolution. According to Darwin, organisms produce more offspring than can survive, and within a population, there is variation. Those individuals with traits that are advantageous for survival in a given environment are more likely to survive and reproduce. Over time, these advantageous traits become more common in the population. This process is called natural selection. One famous example of natural selection is the case of the peppered moth in England, where darker-colored moths became more common during the industrial revolution due to the pollution of the environment.
Which of the following is a principle of Darwin’s theory of natural selection?
Answer: B) There is variation within populations
The process where organisms with advantageous traits survive and reproduce more successfully is known as:
Answer: C) Natural selection
The dark-colored peppered moths became more common during the Industrial Revolution because:
Answer: B) They were better camouflaged against pollution
According to Darwin, the main factor that determines whether an organism survives and reproduces is:
Answer: B) The ability to compete for resources
Speciation is the process by which one species splits into two or more distinct species. There are two main types of speciation: allopatric and sympatric. Allopatric speciation occurs when populations are geographically isolated, leading to genetic divergence over time. Sympatric speciation occurs without geographic isolation, often due to reproductive barriers such as changes in mating behavior or chromosomal mutations. An example of allopatric speciation is the formation of new species of Darwin's finches on the Galápagos Islands.
Allopatric speciation occurs due to:
Answer: B) Geographic isolation
Sympatric speciation occurs:
Answer: C) Without geographic barriers
Which of the following is an example of allopatric speciation?
Answer: B) Formation of new species of Darwin's finches on different islands in the Galápagos archipelago
In sympatric speciation, reproductive isolation occurs due to:
Answer: B) Genetic mutations or behavioral changes
Genetic drift refers to random changes in allele frequencies in a population, particularly in small populations. One example of genetic drift is the bottleneck effect, where a large portion of a population is wiped out by a disaster, and the surviving individuals may not represent the original gene pool. The founder effect is another type of genetic drift, where a small group of individuals establishes a new population, and the gene pool may be limited to the genetic variation present in that small group.
The bottleneck effect occurs when:
Answer: B) A disaster dramatically reduces the size of a population
Genetic drift has a larger effect in:
Answer: B) Small populations
The founder effect is a form of genetic drift that occurs when:
Answer: B) A new population is established by a small number of individuals
Which of the following is an example of the bottleneck effect?
Answer: B) A population of cheetahs experiencing reduced genetic variation due to a past near-extinction event
Molecular evolution refers to changes in the genetic material (DNA or RNA) of populations over time. This can occur through mutations, natural selection, and genetic drift. A major part of molecular evolution involves comparing the genetic material of different species. The more closely related two species are, the more similar their DNA sequences will be. The concept of molecular clock is used to estimate the time of divergence between two species based on the rate of genetic mutations.
The concept of the molecular clock is used to estimate:
Answer: B) The time of divergence between two species
Molecular evolution involves:
Answer: B) Changes in DNA and RNA sequences over time
If two species have a high degree of similarity in their DNA sequences, it suggests:
Answer: B) They have diverged recently from a common ancestor
Which of the following is a result of molecular evolution?
Answer: D) All of the above