This phylogenetic tree depicts the evolutionary relationships of eight major vertebrate classes.  Tiktaalik is an intermediate fossil that represents an early ancestor of all tetrapods. Specifically, Tiktaalik is known for its wrist, a key feature of the tetrapod limb that made it possible for which major evolutionary transition in animals? [answer1] If you were to add Tiktaalik to this phylogeny, where would the Tiktaalik branch extend from? [answer2]

CHOOSE THE BEST ANSWER Use the table below to transcribe and translate the following DNA sequence and identify the final polypeptide strand. DNA: 3′ – TTGCGACCAGGGAACCGA – 5′

A study on blood sharing among vampire bats has shown that a hungry bat is more likely to receive a blood meal from another unrelated individual if the hungry bat has fed that same individual in the recent past. This observation supports the hypothesis that sharing of blood meals could have evolved by way of…

In the figure below, fossil elephant skulls are shown along with their age. Based solely on these fossils, what hypothesis would Darwin have proposed for the evolution of elephant tusks?  

Based on the biological definition of sex, what is the single character that distinguishes males from females?

Blue-headed wrasse fish are born as biological “females”, but change into biological “males” when they grow to a certain size. This switch is the result of fitness differences between “males” and “females” at different stages of development. Large individuals are better able to defend nesting sites from competitors, so fitness is higher in “males” that are larger. Which of the following graphs illustrates the relationship between size and fitness in the two sexes of blue-headed wrasse?

Artist Eduardo Kac includes “bio art” among his specialties.  In 2000, he unveiled “Alba,” an albino rabbit with some unusual features. Alba’s cells produce GFP, a green fluorescent protein. When Alba is illuminated with blue light, she fluoresces a bright lime green color (image below). The GFP-producing gene is naturally found in a species of jellyfish.  Kac collaborated with a group of French geneticists to insert the GFP jellyfish gene into a rabbit embryo using transformation. Born in France, this unique work of living art went home with Kac, his wife, and his daughter to live with them as a family pet in their Chicago home. Given this information, what of the following statements about Alba is correct?

Origin of life experiments by Miller, Urey, and others (Miller-Urey Experiments) involved circulating a mixture of simple gases (a simulated reducing atmosphere) past an energy source such as a spark in an enclosed glass apparatus. Results of these experiments showed that

A young male bird lives in an area where all the suitable nesting sites are hard to find because they are claimed by more experienced, older males. Of the options listed below, what is the young bird’s best choice, in terms of increasing his inclusive fitness?

CHOOSE THE BEST ANSWER A mother and her two daughters each develop breast cancer at approximately the same age in their lives. Based on genetic analysis, it is determined that mutations in the BRCA1,  tumor suppressor gene, is responsible for all three instances of cancer. Their specific mutations are presented below (bold base pair). Mother: ATCGGTCCADaughter A: ATCGGTCCADaughter B: ATCGCACCA Given these data, what is the most likely origin of each daughters’ cancer? Daughter A’s cancer is [answer1] Daughter B’s cancer is [answer2]