9. Determining Relatedness over time

Which of the following is an example of a vestigial structure?

• Structures or traits of organisms that result from sharing a common ancestor

• Structures or traits that are inherited but have lost most of all of their ancestral function in a given species

• Structures or traits that have a common function based on shared ancestry

• Structures or traits that have a common function influenced by similar selection pressures

Which of the following is an example of a homologous structure?

• Limbs of mammals with similar anatomical arrangement but different functions

• Wings of distantly related birds and insects with similar function but different anatomical arrangement

• Fins of various aquatic wildlife with structures that enable efficient swimming but independently evolved from each other

• Reduced pelvis in whales and the human appendix, different anatomical structures and both non-functional

Vestigial structures in a specific organism would have likely to have been functional

• in an unrelated species living in a similar environment to the organism.

• in a closely related species to the organism.

• during the developmental stage of the organism.

• in an ancestral species of the organism.

It is reasonable to conclude that hedgehogs do not occur naturally in Australia because

• hedgehogs are only capable of surviving in the climates of Asia, Africa, Europe and New Zealand but not Australia, and vice versa for echidnas.

• hedgehogs were once present in Australia; however, as time passed, they became extinct.

• different ancestral species occupied different continents, and so over time they evolved into their own species distinct to their regions.

• hedgehogs migrated from Australia to other continents.

Deer, moose, zebras and horses have been found to be closely related, the major difference being that deer and moose have antlers while zebras and horses lack them. All four species possess similar bone structures in their forelimbs. These forelimbs are best described as

• embryonic structures.

• analogous structures.

• vestigial structures.

• homologous structures.

In some cases, mitochondrial DNA may be used to track lineage instead of nuclear DNA. This is because

• mitochondrial DNA can be passed on without being altered by recombination events that usually occur in nuclear DNA during meiosis.

• mitochondrial DNA is inherited from a paternal lineage, making it easier to recover from male specimens.

• nuclear DNA can differ between different groups of modern humans over time, making it harder to trace than mitochondrial DNA.

• nuclear DNA is less stable than mitochondrial DNA given they consist of different building blocks.

Through comparative genomics, scientists can

• identify the function of specific genes.

• make inferences about the evolutionary history of these species.

• explain genetic variation within a species.

• identify any chromosomal changes in the karyotype of a species.

Which piece of evidence is most useful for the construction of phylogenetic trees?

• Molecular evidence

• Structural evidence

• Stratigraphic evidence

• Embryological evidence

Pharyngeal arches and tails can be seen in the embryos of many organisms, providing evidence of

• embryos being subspecies rather than separate species.

• a shared common ancestor.

• vestigial structures between different species.

• analogous structures between different species.

The banding patterns of chromosomes and the genome from two different species show a high degree of similarity. This suggests that

• the two species shared a recent common ancestor.

• the amino acid sequences from the two species would also be very similar.

• not much time has passed since the two species diverged.

• All of the above.