Nature Merit Badge

 

1. Name three ways in which plants are important to animals.

 

Oxygen:

          As a waste product of photosynthesis, oxygen became the second most abundant gas in the earth’s atmosphere. This alone is a testament to how important plants are to our planet. Without oxygen, no respiration could take place and complex life forms would not be able to develop. Photosynthetic algae in the oceans release much of the oxygen in our atmosphere and another large source are tropical rain forests. Fluctuations in the amount of oxygen in earth’s atmosphere over time have been measured in glacier ice and from oxygen isotopes. Present levels in oxygen have been fairly stable for the past 550 million years.

 

Energy:

          Plants are autotrophs, meaning they produce their food from inorganic sources and some source of energy. They use the sun’s energy to create food to use for growth. This means that virtually all other organisms on the planet get their energy from plants. This could be through a direct means (eating the plant) or by indirect means (by eating the organism that ate the plant). Animals are heterotrophs, since they cannot make their own food and rely on other living things for their energy. Because of this, plants are said to be in the first trophic level of a food pyramid. All other organisms that feed on plants, or herbivores, are on the second trophic level, and those who eat the herbivore, or carnivores, are on the third trophic level. The amount of energy however, is reduced as one ascends the trophic pyramid. Essentially, plants help all other life survive by converting sunlight into usable energy for all to use.

          Humans also use plants for mechanical energy for life in modern society. Coal, oil, and natural gas are all fossil fuels, which are dead plants from millions of years ago. These fuels are burned to create electricity and to move our vehicles. When we burn these fuels, we are releasing stored energy in those plants from many years ago.

 

Shelter:

          Vascular plants can be harvested, hollowed, or used outright as homes for many different animals. Beavers and humans chop down trees to build homes. Some animals drill or bore holes into trees to make a nest or raise their young. Birds may use other plants to construct nests high up in trees. There are some animals in the tropical rain forests that spend their entire lives up in the canopy layer of the forest.

          Humans also make thousands of products from many different plants. Furniture, medicines, spices, and a host of other modern conveniences all come from wood products or derived from their fruits or seeds. Many of these products make modern life possible.

 

2. Name three ways in which animals are important to plants.

 

Carbon Dioxide (CO₂):

          A waste product of respiration becomes an essential ingredient to photosynthesis. Along with water, some nutrients, and sunlight, plants can manufacture their own food and store it to use later. Although CO₂ levels have fluctuated throughout earth’s history, the recent increases in atmospheric levels can be viewed two ways. First, since humans are a part of the natural environment, their additional inputs of Carbon are indeed a natural event. On the other hand, the human combustion of fossil fuels has disrupted the natural release of carbon back into the atmosphere and therefore causing harm. This increase in CO₂ could also be viewed as good for plants since they have more usable Carbon to manufacture food. This view is also unsound since Carbon is only one ingredient for photosynthesis and plants can only use so much. The increase does however affect plants in a different way. An increased level of CO₂ does cause rain water to become more acidic. Rain is naturally acidic due to the fact that water and carbon dioxide will combine to form Carbonic Acid (H₂CO₃). Even a slight decrease in a rain’s pH (used to measure how acidic a substance is) can cause harm to plants that do not respond well to changes in the soil pH. Other documented drastic acid rain plant/tree kills have happened in the Adirondacks of New York due to air pollution. (This happened because of sulfur emissions from coal-fired power plants)

 

Nutrients:

          When an animal dies, it immediately begins to decompose. This process releases important micronutrients into the surrounding soil that plants need to grow. Nitrogen (N), Phosphorus (P), Potassium (K) also called ‘potash’, and Calcium (Ca) all can be extracted from a rotting animal. Plants absorb these nutrients through their roots and use them to manufacture essential molecules for growth and survival. Plants can also store these nutrients in their roots for use later when the soil becomes depleted. In the Artic Tundra, a dead decomposing Musk Ox or Polar Bear can cause a small garden to bloom during the short summers. The abundance of nutrients, liquid water, and long hours of sunlight help plants quickly grow. Humans help certain types of plants growth by adding nutrients directly to the soil. Fertilizers add N-K-P to the soil and help crops, gardens, and flowers grow.

 

Reproduction:

          Animals are mobile and plants are not. In order for some plants to reproduce, animals are needed to pollinate or move seeds to be germinated. Certain flowers attract insects to carry pollen to another flower to allow for further pollination and fertilization. Seeds also attach to the fur of mammals or they could pass through the digestive tracts of some birds. This allows plants to radiate out to new habitats and expand the gene pool. There are certain types of plants in the world who are only pollinated by one type of insect. Without this relationship, both organisms would die since the insect could not eat and the flower could not reproduce.

          Humans can spread plants across previously large gaps in habitats. The introduction of non-native species to new habitats has occurred over the last 500 years. The new exotic specie has no natural predator in the new habitat and because of this, it can overtake its new habitat. This can crowd out native species of plants and upset the existing habitat’s plants and animals. When this happens, the non-native species is considered an invasive plant. You can prevent this by planting only native species in your garden instead of non-native ones. Also, control any invasive species so that a wide variety of wildlife can enjoy your garden.

 

3. Explain the term “food chain.” Give an example of a four-step land food chain and a four-step water (aquatic) food chain.

 

A food chain illustrates the movement of energy and nutrients from one feeding group of organisms to another in a series that begins with plants and ends with carnivores and decomposers. This is a simple model and does not properly illustrate what happens in nature. A food web however, which is many food chains fused together, will paint a better picture as to how energy flows in nature.

 

Land food chains:

 

Seeds → Mouse → Snake → Hawk

Shrub → Rabbit → Fox → Fungi

Leaves → Caterpillar → Small Bird → Falcon

Grass → Grasshopper → Shrew → Great Horned Owl

 

Aquatic food chains:

 

Algae → Minnow → Trout → Human

Aquatic Plant → Insect Larvae → Frog → Great Blue Heron

Plankton → Fresh Water Clam → River Otter → Fungi

Plankton → Shrimp → Small Fish → Sharks

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