Terrestrial ecosystems could not function without the foods and habitats provided by plants. Plants produce oxygen and remove carbon dioxide from the atmosphere, help form soils, and hold soils in place against erosion by wind and water. Plants also provide us with many important medicines and are the basis (directly or indirectly) of virtually all of our food.
learning outcomes
You should be able to:
Describe how seed plants have been used for medicinal purposes.
Summarize the ecological services angiosperms perform.
Summarize the main plants humans use for food.
Name three plants that are used in medicine for humans, and give an example of how each is used.
There are many possible answers, some of which are shown below.
| Product | Plant Source | Medical Application |
|---|---|---|
| Atropine | Belladonna | Dilate pupils for eye examination |
| Bromelain | Pineapple stem | Control tissue inflammation |
| Digitalin | Foxglove | Strengthen heart muscle contraction |
| Ephedrine | Ephedra | Ease nasal congestion |
| Menthol | Japanese mint | Relieve coughing |
| Morphine | Opium poppy | Relieve pain |
| Quinine | Cinchona bark | Treat malaria |
| Taxol | Pacific yew | Treat ovarian and breast cancers |
| Tubocurarine | Curare plant | Muscle relaxant (used in surgery) |
| Vincristine | Periwinkle | Treat leukemia and lymphoma |
A parcel of agricultural land that has been used to produce corn for decades no longer produces healthy crops. Tests indicate that the soil is depleted of nitrogen and organic matter. A farm extension agent recommends that the farmer grow soybeans and then rotate this crop with corn in future years. She also recommends that the farmer till the stubble from the crops after harvest into the soil. Why are these practices expected to help crop production?
Among the possible answers: Plants produce oxygen and remove carbon dioxide from the atmosphere, and they play important roles in forming soils and renewing soil fertility. Plant roots help hold soil in place, providing protection against erosion by wind and water. Plants also moderate the local climate in various ways, such as by increasing humidity, providing shade, and blocking wind.
What major group of plants provides (either directly or indirectly) the majority of calories consumed by humans? Explain your answer.
Grasses produce the grain crops (including rice, wheat, and corn) that account for a large percentage of the calories in human diets. Grasses are also the basis for feeding grazing animals, such as cattle, which provide humans with meat and dairy products.