Unit 8 Review Board Quizlet

Bison in Yellowstone National Park have a food-limited carrying capacity that determines how their population grows. If the population grows too large, some bison will either starve or migrate to search for more food. The park is able to support a maximum population of 4,500 bison. Park conservation officials must watch the population and prevent the bison from overpopulating, since they would migrate to nearby farms, causing agricultural damage and creating hazards to drivers. The bison begin to migrate when the population reaches 4,000 because of competition for food. If the current population size of bison is 3,652 and the maximum growth rate of the population is 0.28, calculate the population size after one year and determine whether the park will need to take measures to control the population. Responses

The population will be 3,845 after a year. The bison will not pose a problem until the following year, and no conservation action will need to take place.

The marine iguana, Amblyrhynchus cristatus, is endemic to the Galápagos Islands and is especially vulnerable to El Niño events. These iguanas feed on red and green algae. During an El Niño climate event, surface waters and their currents in the central and eastern Pacific Ocean become significantly warmer than usual. Also during El Niño years, land masses experience increased rainfall. A researcher suggests that El Niño conditions cause a significant decrease in the size of the Galápagos marine iguana population. Which of the following would best support this alternative hypothesis?

Warm surface water contains fewer nutrients needed by red and green algae than cooler surface waters does.

What are some techniques for estimating population density?

1. Sample plot method.2. Mark recapture method.

What is a survivorship curve?

A graph that allows population ecologists to estimate how many members of an original study group are still alive at different time intervals.

What is the sample plot method for estimating population density?

Count the number of organisms of the study species in a plot of a known size.

What is the difference between density dependent and density independent limiting factors?

Density dependent factors are a result of the population itself limiting growth (eg. build up of waste from the population or overgrazing can limit the growth.Density independent factors are from an outside influence such as fires, droughts, temperature etc.

With what type of organisms is the sample plot method appropriate?

In a sessile population (stationary organisms) eg. plants

In a study of energy flow, the following data were collected: Each human requires 55 grams of protein per day. An acre of soybeans produces 200,000 grams of protein per year. A cow grazing on one acre of land produces 19,000 grams of protein per year. Based on these data, an acre of land would support: 10 humans per year on a diet of soy, or 0.9 human per year on a diet of beef. Which of the following statements best explains these relationships in terms of energy transfer?

Only 10% of the energy on each level of the trophic pyramid is available for use by the next level. The rest is lost as heat or used for growth and repair.

What is the formula for density in the sample plot method?

Population Density = Number of individuals in a population sample plots/total area of all sample plots.

Meerkats live together in groups to help raise and protect their offspring. Meerkat pups are most vulnerable when they are away from their burrow foraging for food. Adult meerkats exhibit sentinel behavior, standing upright and making alarm calls to warn other members in the group that predators are nearby. In a study of meerkat behaviors, scientists observed meerkat foraging groups and recorded the presence or absence of pups along with the frequency of adult sentinel behavior. The scientists determined that sentinel behavior increased when pups were present in the foraging group. What correctly identifies the dependent and independent variables in the described study? Responses

The presence of pups is the independent variable, and the frequency of sentinel behavior is the dependent variable.

What are the three types of survivorship curves?

Type 1 - Curve in which there are few offspring born and there is good parental care so that most of the individuals live to an old age. (eg elephants, humans, large mammals)Type II - The organisms die at an equal rate at all ages. There is some parental care (eg. rodents and birds)Type III - Many offspring are produced because many do not survive in the first few days. If they do survive they have few predators (eg mussels, grasses, oysters etc.)

What is the mark recapture method for estimating population density?

Use two trapping events. First, the study area is determined and a trap is set. All animals caught in the trap are marked and released. Later, the traps are set again and the proportion of parked to unmarked animals captured in the second trapping gives an estimate of the number of individuals in a population.