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Concept explainers
Insect-Assisted Fertilization in Moss Moss sperm can swim, but plant ecologist Nils Cronberg suspected that they sometimes hitch a ride on crawling insects or mites (tiny animals related to spiders). To test this hypothesis he carried out an experiment. He placed patches of male and female moss gametophytes in dishes, either next to one another or with water-absorbing plaster between them. The plaster prevented sperm from swimming between plants. He then looked at how the presence or absence of insects affected the number of sporophytes formed. FIGURE 22.30 shows his results.
FIGURE 22-30 Sporophyte production in female moss patches with and without either crawling insects (springtails) or mites. No sporophytes formed in the animal-free dishes when moss patches were 2 or 4 centimeters apart.
1. Why is sporophyte formation a good way to determine if fertilization occurred?
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Chapter 22 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
- This entire structure using lifecycle terminology is called what? megastrobilus microstrobilus megasporophyll microsporophyll microsporangium megasporangium none of thesearrow_forwardHow much protein should Sarah add to her diet if she gets pregnant? Sarah's protein requirements during pregnancy would be higher. See Hint B2. During calculations, use numbers rounded to the first decimal place. In your answer, round the number of grams to the nearest whole number. _______ g ?arrow_forwardC MasteringHealth MasteringNu X session.healthandnutrition-mastering.pearson.com/myct/itemView?assignment ProblemID=17396422&attemptNo=1&offset=prevarrow_forwardMost people, even those who exercise regularly at low to average intensity (1 hour at the gym or a 2- to 3-mile walk several times per week), do not need an increased protein intake. What would be the protein needs of a man named Josh who exercises moderately and is the same age and size as Wayne? Josh is 5 ft, 8 in tall and weighs 183 lb. Round the number of grams to the nearest whole number. During calculations, use numbers rounded to the first decimal place. Because protein requirement is a range, please enter two numbers: lower and upper range values, respectively. Separate the lower and upper range values, in that order, by a comma. ___, ___ g ?arrow_forwardC MasteringHealth MasteringNu X session.healthandnutrition-mastering.pearson.com/myct/itemView?assignment ProblemID=17396422&attemptNo=1&offset=prevarrow_forwardIf left untreated, most HIV-infected individuals will develop AIDS. Current treatments are focused on highlyactive antiretroviral therapy (HAART). HAART usually consists of an orally delivered drug cocktail containingtwo different reverse transcriptase inhibitors and one other drug, such as a protease inhibitor. Question: Develop a pharmacokinetic model of HAART treatment. Consider all 3 drugs. Make sure to include adiagram that illustrates your thinking, state all assumptions, and define your variables. Whatparameters would you need to know to find the concentration of drug in the plasma? In the T cells?(You do not need to write out or solve any equations.)arrow_forwardnot use ai pleseaarrow_forward(A) 25 20 20 15 NPP (Mg C/ha/yr) 10 10 5 0 0 2,000 4,000 6,000 ECOLOGY 4e, Figure 20.11 (Part 1) 2017 Sinauer Associates, Inc. Average annual precipitation (mm) 8,000arrow_forwardexplain the cascade of events (starting with relaxing trade winds) that occurs during El Niño in the eastern Pacific (off the coasts of California/North America and Peru/South America) and which lead to food-chain collapse - start with changes in the physical/oceanographic conditions, andthen systematically describe the cascading effects at each level of the food chain -arrow_forward3) Which statement(s) about the Pacific Decadal Oscillation (PDO) is/are TRUE? CIRCLE ALL THAT APPLY. A. It is a major driver of salmon populations in the Pacific B. It affects sea surface temperatures in the eastern Pacific C. Its cycles typically do not last as long as those of ENSO D. Evidence that it has occurred over many centuries has been gathered from tree ring dataarrow_forward4.arrow_forward2arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_iosRecommended textbooks for you
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