Question

interaction of plants and animals

Answer 1

Pre-Visit Activity Have students observe and record the behavior of animals (insects, spiders, birds, amphibians, mammals, etc.) in their yards and see how they interact with the plants there. Is there any evidence of animals eating plants or of animals helping plants? Students can create a chart of their own observations and propose relationships between the plants and animals studied. Background Information All organisms interact with individuals of other species. They may feed on them, or try to avoid being eaten by them. They may compete with other species for a common resource, or cooperate with them for a common good. In this class we will examine the types of inter-species interactions that can occur between plants and animals. These interactions generally fall under a few categories. Predation occurs when one organism eats another. Herbivores eat plants. Carnivores eat animals. There are even carnivorous plants. Carnivorous plants consume insects because the soil in which they grow is very poor in nutrients and the plants need more nitrogen. These plants still obtain their energy from the sun through photosynthesis. Parasitism is similar to predation in that one species benefits at the expense of the other. The differences are that the host is not usually killed in the process and the parasite is usually smaller than the host. The parasite can be internal to the body of the host, such as roundworms or external, such as ticks and leeches. We often call plant sucking insects, like aphids, plant parasites. Commensalism describes a situation in which one individual benefits and the other is neither hurt nor helped by the interaction. For example, epiphytes on the trunks of rain forest trees are helped by the trees which give them a surface on which to grow. The trees do not seem to be affected by the epiphytes, unless the weight of the epiphytes gets so heavy that the tree branches break! Materials Needed For each student: Student Data Sheet: “Plant and Animal Interactions” pencil clipboard For each adult: Leader Sheet: “Plant and Animal Interactions” Maps: “Plant and Animal Interations” Plant and Animal Interactions 164 Background Information continued Mutualism occurs when organisms of both species benefit from their association. The relationship between pollinators and plants is a great example of mutualism. In this case, plants get their pollen carried from flower to flower and the animal pollinator (bee, butterfly, beetle, hummingbird, etc.) gets food (usually nectar or pollen). Seed dispersal is also often accomplished through a mutualistic relationship between the plant and its animal disperser. Many animals eat the sweet fruit that surrounds the seeds. The seeds are then deposited in a new location some distance away from the parent plant, often in fecal material which adds a little fertilizer as well! These types of interactions occur between species in every ecosystem. In this exercise, you will search for and see many specific examples of the interspecific interactions outlined above while walking through the Perennial Garden, Gladney Rose Garden, and the Climatron. Post-Visit Activity Have students look for these relationships in their own backyard or nearby park. Challenge them to find one example each for herbivory (predation), pollination (mutualism) and seed dispersal (mutualism). The inferences that students make observing organisms in their back yard are hypotheses. For example, a beetle on a flower might be hypothesized to benefit the plant as a pollinator . Alternatively, it may harm the plant as a herbivore. How can you test each hypothesis? Divide students into small groups to pick a particular biome to study (desert, savannah, tundra, etc.). Challenge them to find examples in these other environments, of the complex relationships studied in this lesson. Emphasize that organisms engage in complex relationships everywhere and part of the challenge we face is to help preserve the delicate balance of our natural world. Key Terms Predation Mutualism Commensalism Pollination Parasitism Missouri State Standards 5-8 SC VII.C.2 VII.E.I VIII.A.4 VIII.B.I A PLACE TO LEARN 165 Missouri Botanical Garden Leader Sheet Pla