The Cycads, a Mostly Tropical Phylum of Gymnosperms, Evolved About

question 75

Multiple Choice

The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the age of the dinosaurs. Though their sperm are flagellated, their ovules are pollinated by beetles. These beetles get nutrition from the pollen and shelter from the microsporophylls. Upon visiting megasporophylls, the beetles transfer pollen to the exposed ovules. In cycads, pollen cones and seed cones are borne on different plants. Cycads synthesise neurotoxins, especially in the seeds, that are effective against most animals, including humans.
-If the beetles survive by consuming cycad pollen, then whether the beetles should be considered mutualists with, or parasites of, the cycads depends upon the ________.

• A) extent to which their overall activities affect cycad reproduction
• B) extent to which the beetles are affected by the neurotoxins
• C) extent to which the beetles damage the cycad flowers
• D) distance the beetles must travel between cycad microsporophylls and cycad megasporophylls

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Definitions:

Radiopaque

Describes substances that do not allow X-rays or similar radiation to pass through, appearing white or light on radiographic images, thus helping in the diagnosis of various conditions.

Internal Body Organs

Organs located within the main cavities of the body, such as the heart, liver, and kidneys, essential for various bodily functions.

Radiologist

A medical doctor specializing in the diagnosis and treatment of disease and injury by interpreting medical imaging techniques.

Nuclide

An atomic species characterized by the specific constitution of its nucleus, including the number of protons and neutrons.