Concept explainers
SCIENTIFIC THINKING A recent experimental study looked at the combined effects of ocean acidification (see Module 2.15) and increased ocean temperatures, both aspects of climate change, on the growth of polyps, juvenile coral animals.
Researchers reported the average polyp biomass (in μg/polyp) after 42 days of growth under four treatments: a control with pH and temperature maintained close to normal reef conditions, a pH lowered by 0.2 units, a temperature raised by 1°C, and a combined lower pH and higher temperature. The results showed that polyp biomass was reduced somewhat in both the low-pH and high-temperature treatments, but the combined treatment resulted in a reduction in growth by almost a third—a statistically significant result. Experiments often look at the effects of changing one variable at a time, while keeping all other variables constant. Explain why this experiment considered two variables—both a higher temperature and a lower pH—at the same time.
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
CAMPBELL BIOLOGY:CONCEPTS... >CUSTOM<
- If you will think abstractly, Water cycle on earth uses what somewhat similar method to give back water on the ground? a. decantation b. centrifugation c. distillation d. sublimation *Choose only one answerarrow_forwardThese are natural sources of air pollution responsible for as much as two-thirds of the methane in the air. a. Volcanoes b. Bacterial metabolism of decaying organism c. Pollen and Spores d. Storms Which of the following BEST describes water? a. Water is composed of 2 atoms of Oxygen and 1 atom of Hydrogen. b. Water is odorless, clear and has a sour taste. c. Water is liquid at 0 degree Celsius. d. Water is the most abundant compound in the Earth's surface.arrow_forwardA well-written research question states the independent and dependent variables in the experiment. For example, a student investigated the effect of soil pH on the number of strawberries produced by a strawberry plant. Her research question was “How does the pH of soil affect the number of strawberries produced by a strawberry plant?arrow_forward
- Plants and algae need phosphates for growth. Many fish and other animals feed on aquatic plants and algae. Why, then, is an excess of phosphates in the water (eutrophication) harmful to the organisms in a lake?arrow_forwardHumans cannot survive long without water making this a vital ingredient of life. Why? Cite at least 3 scientific reasons.arrow_forwardwhy cant human live without water? explain in scientific explanationarrow_forward
- The following diagram illustrates a typical marine food web. Mercury, a toxic heavy metal, can accumulate in the fatty tissue of organisms. Which organism would you predict to have the highest level of mercury? Explain your answer.arrow_forwardWater circulation is complex.Arrange five distinctive steps of water that continually cycle around the planet.arrow_forwardAs water cools below 4°C, it expands and becomes less dense. Why is this beneficial to organisms living in a lake during a cold winter?arrow_forward
- A scientist conducted an element to determine how the amount of salt in a body of water affects the number of plants that can live in the water. Which is the independent variablearrow_forwardWhich of the following effects is produced by the high surface tension of water? Group of answer choices Organisms resist temperature changes, although they give off heat due to chemical reactions. Evaporation of sweat from the skin helps to keep people from overheating Lakes don't freeze solid in winter, despite low temperatures. A layer of strongly bonded water molecules occurs at the air-water interface Water flows upward from the roots to the leaves in plants.arrow_forwardA tree grows and increases its mass. Explain why this is not a violation of the law of conservation of matter.arrow_forward