Question

directions: read each description, determine which type of genetic drift it is, and write be for bottleneck effect, gd for genetic drift, or fe for founder effect in the space provided. 1. when christopher columbus came to the americas, he randomly chose 3 chickens from spain to bring along. these 3 chickens were the only chickens to breed in the americas for hundreds of years. 2. in 2013, typhoon haiyan is estimated to have killed over 5,000 water buffalo in the philippines. water buffalo are used in the philippines to plow crops. many of the water buffalo that perished were concentrated near farms. these animals are more muscular than buffalo allowed to roam free. 3. during a hike a man accidentally steps on a population of beetles that were in the path. a majority of the beetles that died had a rare mutation made them red in color. the population size was not greatly affected. 4. a forest fire, accidentally set off by humans celebrating a gender reveal party, randomly kills ten tall hemlock trees. the left - over population of hemlocks is still large in population, but short in height. 5. the afrikaner population of dutch settlers in south africa is descended from a few colonists. today, the afrikaner population has an unusually high frequency of the gene for huntingtons disease. 6. drought causes a local lake to shrink drastically. the fish population eventually returns to its original numbers. 7. the gene pool is calculated for a small population of snakes over several generations. these snakes vary in length. the last generation has a different allele frequency due to random chance. 8. the galapagos islands were colonized thousands of years ago by a small population of finches. each island selected for different adaptations among the birds. however, all of the finches shared many characteristics. 9. the northern elephant seal population was reduced by over hunting to 20 individuals in the 1890s. although the population had rebounded to over 30,000 individuals by 1974, the genetic diversity is still low with in the current population. 10. the american bison was hunted to near extinction and even today as the population has recovered, the result is a population of bison with little genetic variation. 11. a small population of lizards moves to a new region that isnt inhabited by any reptiles. the population quickly grows in size, but the genetic diversity stays low. 12. a population of monkeys is separated by a river. both populations of monkeys live in the same type of environment, have the same predators, and food sources. one of the populations randomly evolves into a new species. 13. green eyes are a recessive gene. the last green - eyed person in a small - town dies, leaving only brown - eyed and blue - eyed people. with the green eye gene gone, people only have brown or blue eyes in the town, with brown being more dominant. 14. in a population of mallards with red and orange bills, only offspring with orange bills are born by chance. the very last red - billed mallard dies, leaving only orange - billed mallard populations behind. 15. an original population of flowers has both blue and yellow flowers. a mudslide kills a large portion of blue flowers on a hill leaving only yellow flowers.

Explanation:

1. FE - A small group (3 chickens) starts a new population in a new area, which is characteristic of the founder effect.
2. BE - A natural - disaster (typhoon) significantly reduces the population size of water buffalo, indicating the bottleneck effect.
3. GD - Random event (a man stepping on beetles) changes allele frequencies without a major population - size reduction, typical of general genetic drift.
4. GD - A random event (forest fire) affects allele frequencies in the Hemlock tree population without causing extreme population reduction, representing genetic drift.
5. FE - The Afrikaner population is descended from a few colonists, leading to a unique genetic makeup due to the founder effect.
6. BE - Drought causes a drastic reduction in the fish population (bottleneck), and then it recovers.
7. GD - Random chance changes allele frequencies in a small snake population over generations, which is genetic drift.
8. FE - A small population of finches colonizes the Galapagos islands, showing the founder effect.
9. BE - Over - hunting reduced the northern elephant seal population to a very small number (bottleneck), and although it rebounded, genetic diversity is low.
10. BE - Hunting the American Bison to near - extinction is a bottleneck event, resulting in low genetic variation.
11. FE - A small lizard population moves to a new area and starts a new population with low genetic diversity, which is the founder effect.
12. GD - Random evolution in one of the monkey populations separated by a river is an example of genetic drift.
13. GD - The loss of the green - eye gene due to the death of the last green - eyed person in a small town is a random event of genetic drift.
14. GD - Chance events leading to the disappearance of the red - billed trait in mallards is genetic drift.
15. GD - A mudslide randomly killing a large portion of blue flowers is a genetic - drift event.

Answer:

1. FE
2. BE
3. GD
4. GD
5. FE
6. BE
7. GD
8. FE
9. BE
10. BE
11. FE
12. GD
13. GD
14. GD
15. GD