CHOOSE THE BEST ANSWERS In a population of cows, a single gene controls hair type. The curly hair allele (H) shows incomplete dominance with the straight hair allele (h). The hair of heterozygous individuals (Hh) is wavy. Another gene controls coat color. The red (R) and white (r) alleles are co-dominant. The coloring of heterozygous individuals (Rr) is called roan . After breeding a wavy, roan bull with several wavy, roan females, you observed the following phenotypic ratio in the offspring: 8 curly, red : 16 wavy, roan :  7 straight, white Part 1: Based on this observed ratio,  are the two genes linked?  Part 2:  If they are linked, how are the two genes’ alleles linked?   

Which of the following mechanisms would result in lower genetic diversity within a population?

Originally from South America, potatoes became a common food source in Europe during the late 1700s and early 1800s. During the 1840s, however, the European potato crop collapsed due to the rapid spread of potato blight (a fungal pathogen). The loss of this important food source resulted in mass migration and starvation. Most infamously, the potato blight contributed to the Great Famine in Ireland (though other socio-political factors were also to blame). Before the blight, potatoes were typically propagated clonally, by cutting up the tuber (the part you eat) into pieces and using these pieces to grow new, identical plants. Given what you know about the evolution of sex, why did the clonal propagation of the potato make the crop especially susceptible to a devastating pathogen outbreak?

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′

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

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…

Which statement is true about sexual selection?

Originally from South America, potatoes became a common food source in Europe during the late 1700s and early 1800s. During the 1840s, however, the European potato crop collapsed due to the rapid spread of potato blight (a fungal pathogen). The loss of this important food source resulted in mass migration and starvation. Most infamously, the potato blight contributed to the Great Famine in Ireland (though other socio-political factors were also to blame). Before the blight, potatoes were typically propagated clonally, by cutting up the tuber (the part you eat) into pieces and using these pieces to grow new, identical plants. Given what you know about the evolution of sex, why did the clonal propagation of the potato make the crop especially susceptible to a devastating pathogen outbreak?

Müller’s ratchet is a cost of asexual reproduction and can explain the evolution of sexual reproduction because…

Some dinosaurs had small, fluffy feathers called “downy” feathers (similar to down feathers in a pillow), but lacked the type of feathers necessary for flight. These dinosaurs are believed to be the ancestors of modern birds, which have several types of feathers that allow them to fly.  How can we explain the evolution of an “intermediate” trait such as downy feather, if they were functionally useless for flight?