In crossbill birds the beaks have a specialized shape to allow the crossbills to extract pine seeds out of cones. Crossbills in one forest feed on two different pine species. For one kind of cone a long thin beak is most efficient while in the other type of cone a short thick beak is most efficient. Birds with shapes in between these two shapes are not good at feeding on either type of cones. What evolutionary force is likely happening on beak shape? Group of answer choices A. disruptive (natural) selection B. intersexual selection C. intrasexual selection D. stabilizing (natural) selection E. directional (natural) selection

In crossbill birds the beaks have a specialized shape to allow the crossbills to extract pine seeds out of cones. Crossbills in one forest feed on two different pine species. For one kind of cone a long thin beak is most efficient while in the other type of cone a short thick beak is most efficient. Birds with shapes in between these two shapes are not good at feeding on either type of cones. What evolutionary force is likely happening on beak shape? Group of answer choices A. disruptive (natural) selection B. intersexual selection C. intrasexual selection D. stabilizing (natural) selection E. directional (natural) selection

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter21: Microevolution: Genetic Changes Within Populations

Section: Chapter Questions

Problem 1ITD: Peter and Rosemary Grant of Princeton University have studied the ecology and evolution of finches...

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During drought years on the Galapagos islands, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection? small birds gaining larger beaks by exercising their mouth parts small birds anticipating the long drought and eating more to gain weight and, consequently, growing larger beaks More small beaked birds dying than larger beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks. larger birds eating less so smaller birds can survive small birds mutating their beak genes with the result that later generation offspring have larger beaks
Thousands of years ago, the jaws and teeth of jaguars were more varied in size than they are today. During a period of climate change about 11,000 years ago, jaguars faced a shortage of food. There were fewer mammals to eat, so the jaguars had to eat shelled reptiles. The jaguars with the largest jaws and teeth could most easily eat the shelled reptiles. Which of the following statements best explains why large jaws and teeth are common characteristics in jaguars today? Jaguars with smallest jaws and teeth died out completely. Jaguars with the smallest jaws and teeth were not able to mate. Jaguars with the largest jaws and teeth survived and reproduced more successfully than the other jaguars. Jaguars with the largest jaws and teeth strengthened them by using them more frequently than the other jaguars.
According to Lamarck’s theory of evolution, organisms change during their lifetime to survive then pass these changes to their offspring. What supports the hypothesis of Lamarck? a. Webbed toes of ducks to quickly move through the water, retractile claws of carnivorous mammals to catch the prey, millipede producing awful smell for self-defense and evolution of short-necked to long-necked giraffe b. Evolution of short-necked to long-necked giraffe, webbed toes of ducks to quickly move through the water, disappearance of limbs in snakes and retractile claws of carnivorous mammals to catch the prey c. Rattlesnake producing venom against predators, jellyfish bioluminescence for intraspecific communication chameleons camouflage to hide from predators and millipede producing awful smell for self-defense d. Disappearance of limbs in snakes, chameleons camouflage to hide from predators, evolution of short-necked to long-necked giraffe and rattlesnake…
Peter and Rosemary Grant of Princeton University have studied the ecology and evolution of finches on the Galapagos Islands since the early 1970s. They have shown that finches with large bills (as measured by bill depth; see Figure) can eat both small seeds and large seeds, but finches with small bills can only eat small seeds. In 1977, a severe drought on the island of Daphne Major reduced seed production by plants. After the birds consumed whatever small seeds they found, only large seeds were still available. The resulting food shortage killed a majority of the medium ground finches (Geospizafortis) on Daphne Major; their population plummeted from 751 in 1976 to just 90 in 1978. The Grants research also documented a change in the distributions of bill depths in the birds from 1976 to 1978, as illustrated in the graphs to the right. In light of what you now know about the relationship between bill size and food size for these birds, interpret the change illustrated in the graph. What type of natural selection does this example illustrate? Source: P. R. Grant. 1986. Ecology and Evolution of Darwins Finches. Princeton University Press.
A species of Caribbean fish lives in groups of individuals in a burrow in the sand. When a predator swims by, one or more of the fish flick their fins to warn others to retreat to the safety of the burrow. Fish that flick their fins are more likely to be killed by predators than fish that do not. What is the most useful piece of information you would like to know in order to explain how fin-flicking can evolve, and why?
Of the following, which one is an example of an evolutionary explanation (as opposed to a functional explanation)?A. People evolved a fear of snakes because many snakes are dangerous.B. Humans have a (tiny) tailbone because our ancient monkey-like ancestors had a tail.C. People evolved an ability to recognize faces because that ability is essential for cooperative social behaviors.D. People evolved a tendency to form long-term male–female bonds because human infants benefit from the help of two parents during their long period of dependence.
What is Natural Selection? (Use the follow-up questions below to construct your answer) How did different environments 'select' for certain beaks? What will happen to the birds that are no longer well suited to eat the type of food the island provides?
This spectacular animal is a Lesser Bird of Paradise, Paradisea minor, from the highlands of Papua New Guinea. In the context of various evolutionary phenomena, why is this bird confined to New Guinea and two nearby islands? Why would you not expect to find it in the mountains of Borneo? This spectacular tail presumably attracts predators; why hasn't natural selection acted to reduce it or camouflage it?
Almost all birds starved during the dry season depicted here. What type of selection would have been present if only the intermediate-beaked birds had survived (instead of the small- and large-beaked birds)?
Data was collected concerning Galapagos bird beak size over time. There are 13 types of Galapagos finches, and they are also known as Darwin's Finches. These finches share the same habits and characteristics except for one; they all have different beaks. The differences in their beaks might be the most important aspect of their survival because beak size determines the type of seed able to be eaten. Only the birds with the largest of beaks are able to eat the toughest, biggest, and spine covered seeds. Based on the data given, choose the BEST conclusion. A) This data shows that over time the type of food available remained constant. Eliminate B) This data shows that the environment did not change over the course of time. C) This data shows a fluctuation in bird species over time most likely due to food availability. D) This data shows a fluctuation in bird species over time most likely due to the inheritance of acquired characteristics. Not Graded
Many lines of evidence, including biochemical evidence, show that living birds are direct descendants of dinosaurs. A number of dinosaur lineages had feathered dinosaurs, not just the lineage that includes living birds. Do you think that is it justified to believe that all feathered dinosaurs had behaviors known from living birds? Such behaviors of birds include colonial nesting, sexual displays by males using feathers, males moving to display their ornamental feathers to female mates. Give a brief reason for your answer.
Bipedalism has many selective advantages. However, there is one disadvantage to walking on two feet: giving birth to an offspring with a large head through a small pelvic opening, which is necessitated by an upright posture, is very difficult. This situation results in a high percentage of deaths (for mother and child) during birth compared to primates. How do you explain the selection of a trait that is both positive and negative?