In a species of fish, two neighboring populations occupy slightly different habitats; the first mainly lives in shallow waters with low predation, the second lives in deeper waters with increased predation. Males in the first population develop a long anal fin as secondary sexual trait in population, but males in the second population do not have long fins. When researchers artificially attached long anal fins to males from the second population, they found that female fish much preferred males with the longer fins. They also found that gene flow between these populations exist, and that long anal fins make it harder to swim fast. Why aren't long fins more frequent in this population? Natural selection is counteracting sexual selection O There isn't enough genetic variation for long tails to develop These populations are in the process of speciating, and eventually females will develop a preference for short tails. O Drift is causing long tails to disappear from the population

Icefishes live in the Southern Ocean, which encircles Antarctica. Icefishes have evolved to produce antifreeze proteins which prevent ice crystals from forming in their blood, when ocean temperatures drop below the freezing point of fresh water.  The antifreeze proteins, which are produced in different amounts (high, medium and low) in different fishes, help them live in the cold waters.   What are the different variations of the antifreeze protein present in the population of icefish?           2. Out of the variations which one is the favorable trait in the environment of the icefish?       3. Which icefishes will natural selection select for?       4. How will the icefish population in very cold waters, change over time?           5. Describe the adaptation in icefish (in terms of allele frequency and reproductive fitness)

The gender of an American alligator is determined by the temperature at which the egg incubates. A temperature of 34°C and higher produces male offspring, while a temperature closer to 30°C produces female offspring. Which statement best explains gender determination in American alligator offspring? O The gender of the offspring is determined to keep an even number of males and females in the American alligator population. O The gender of the offspring is determined to ensure a large number of mature females in the American alligator population. O The gender of the offspring is determined as a result of environmental and not genetic factors. O The gender of the offspring is determined as a result of genetic and not environmental factors. hp -> esc & 司

Name some traits for which you think humans exhibit nonrandom mating. Is mating for these traits likely to be positive or negative assortative mating? Name some traits for which you think people mate randomly. How could you test whether mating for these traits is random?

Results of a study on local adaptation of color patterns in snakes show the frequency of different color patterns of water snakes of Lake Erie (Nerodia sipedon) found on the mainland shores and scattered islands within the lake. Type A snakes are unbanded, Type D is strongly banded, and Types B and C are intermediates. Given that natural selection favors unbanded snakes on the islands, how can you account for the presence/perpetuation of banded snakes on the islands? 100 Percentage 80 N=63 60 40 20 0 ABCD Ontario mainland N=64 A B C D Peninsular mainland N=16 ABCD Kelleys Island N= 214 A B C D Bass complex islands N=188 L ABCD Middle and Pelee islands O Natural selection favors unbanded snakes on the mainland. O Snakes on the islands represent a case of the so-called founder effect. O Natural selection favors banded snakes on the mainland, which occasionally migrate to the islands. O Mutation rates converting unbanded alleles to a banded form operate at high frequencies on islands.

Imagine there's a population of Cichlid fish living in a lake in East Africa. Some of the fish have a genetic predisposition to feed from the deeper parts of the lake and also enjoy breeding down there, while the other fish have a genetic predisposition to feed near the surface and enjoy breeding up there. Eventually, individuals from the upper parts of the lake stop breeding with individuals from the bottom because their hybrid offspring have poor fitness (and can't competitively feed at the top or bottom of the lake). These two sub-populations will likely experience and possibly evolve into two species. Genetic Drift Post-zygotic Isolation Directional Selection O Disruptive Selection

Scientists have also noticed unusual coloration among certain condor populations. Andean condors are typically black in color.  However, a few unique white feathered individuals have occasionally been noted. These white feathered individuals are not well-camouflaged, and are easily spotted by larger predators.  Recently, scientists noted that a black feathered condor had mated with a white-feathered condor, and their three chicks all appeared to have gray feathers. Closer examination of these condor chicks revealed that the chicks actually possessed a mixture of black feathers and white feathers, giving them a gray appearance from a distance. Please NAME and EXPLAIN the genetic phenomenon described here.

If predators reduce prey abundance to very low levels, how might variable predator environments affect the evolution of flexible mating strategies?