MCAT Biology › Speciation and Phylogenetics
A scientist studies three populations of frog (populations A, B, and C) that live in the same rainforest. He notices some interesting similarities between the three groups. What would be the best evidence that A and B have a more recent common ancestor than A and C or B and C?
Which of the following is not necessary for designation as a chordate?
I. A notochord
II. Vertebrae
III. A post-anal tail
IV. Gill arches
V. A dorsal, tubular nervous system
Passage:
A population of 1200 flamingos exists on an island in the tropics. The flamingos had previously been studied for many years due to their fascinating foraging habits. Many flamingos within this population hunt their prey out in the open, without any attempts to disguise themselves, which some feel predisposes them to being seen by their prey and evaded, or even attacked, sooner than flamingos who more stealthily hunt their prey. Still, so many of these flamingos continue to live viably and reproduce highly successfully, so it has puzzled scientists for years that this is an "evolutionarily successful" strategy. Of the 1200 flamingos initially present, 800 had pink feathers and 400 had white feathers. A tragic hurricane then struck the island, killing all but 10 of the flamingos. 8 of these 10 had white feathers. Years later, scientists again studied the flamings on the island and found a population of 600 flamingos. Of the 600 flamingos, 560 had white feathers and 40 had pink feathers.
A white-feathered flamingo mates with a pink-feathered flamingo, and produces a pink-feathered flamingo offspring. Two students debate as to whether or not this offspring is the same species as its parents, since its feather color differs from that of one of its parents. Which of the following examples best represents the evolutionary definition of a species?
Which of the following statements about chordates is true?
Which of the following is false of the phylum chordata?
A certain class of protein is found to exist in several different species. The amino acid sequence of this protein is compared between a large number of species. The greatest number of amino acid differences will be found between species of different __________.