Unit 5 Notes
Scientists think Earth has experienced five major extinctions, based on info gathered from the fossil record. These five major extinctions are depicted in the graph below: Which of the following inferences can be drawn from the graph?
Extinctions can be a natural phenomenon that is unrelated to human activity.
A researcher is studying environmental conditions that cause the expression of genes that ultimately affects the phenotype. The following schematic diagram depicts the researcher's findings regarding the expression of gene Z. In his research, the scientist determined that the active repressor expression was determined by environmental pH levels. In his investigation, he obtained the following data. Predict what will happen when the organism is exposed to a mildly basic pH of 8.5.
Gene Z will be expressed
Which of the following is NOT a major scientific theory that helps explain how ecosystems on earth have changed due to large-scale events?
The vast majority of extinctions are caused by human impact.
A scientist is studying two previously undocumented organisms to determine how environmental conditions affect phenotype expression. In one study, the scientist determines how temperature affects the growth rate of these two organisms. The graph below depicts the data gathered by the scientist. Based on the data collected by the scientist, which of the following is the most appropriate conclusion?
both organisms appear to have the ability for proteins to interact with the environment
A scientist is studying a certain predator-prey interaction between two species of fish in an isolated pond ecosystem. In the predator fish population, she notices that faster fish catch more prey than slower fish, with no noticeable drawbacks to the increased speed. Which type of selection will this scenario most likely produce in the predator fish for speed?
directional selection
Researchers determine an organism from Africa has a normal distribution for body size. The organism is introduced and released into the U.S. as an exotic species. After 20 years, scientists have recorded how the organism has fit into the U.S. ecosystem. Data shows that predators have selected against the average body size of the exotic species. Predict the most likely type of natural selection that occurred on the exotic species over the 20 year period because of the change in genotype.
disruptive distribution
A scientists observing a specific species over a long period of time notices an increase in the frequency of extreme phenotypes and a decrease in the frequency of intermediate phenotypes. What is the best explanation for this observation?
disruptive selection is creating a shift in phenotypes due to environmental conditions
Which of the following human activities will have the greatest effects on both local & global ecosystems?
elevated atmospheric levels of CO2 due to the burning of carbon reactants
Which of the following evolutionary mechanisms occurs when a small group of individuals experience a deviation from the expected inheritance pattern due to random events in mating?
genetic drift
Which factor had the greatest influence on the near extinction of the Illinois greater prairie chicken?
lack of fertility within the population due to low genetic diversity
Mr Johnson has an entire breeding stock of heterozygous black Labs. He wants to breed his animals in a location that takes advantage of this environmental change on the new coat colors produced. If Mr Johnson moves to Alaska, what color of labrador retriever can he expect to produce the most of in his first generation of offspring?
roan
Which of the following best explains why an "exotic" species introduced into a new ecosystem often outcompetes the native species and forms a viable niche for itself?
the exotic species has few predators to slow its reproduction in the new environment
What negative consequence can occur when non native species are introduced into an ecosystem?
the introduced species preys on native species
