Plants and animals interact with each other in the environment. They also interact with the environment itself. The plants and animals depend on each other.
Animals and humans depend on plants. Animals need food, protection and shelter. In human terms, food, clothing and shelter.
Some people use plants and plant material as decoration to make themselves attractive.
Animals and humans depend on other animals. In the food chain, some animals eath other animals and use them for food. Humans also use animals as sources of food and clothing.
Plants benefit from animals.
Relationships between animals and plants are complicated. The food chain begins with the Sun shining on plants. The plants use sunlight for energy to make food. The plants are at the base of the food chain.
The plants are eaten by various types of animals. A particular type of plant may be eaten by more than one type of animal. In addition, a particular type of animal may be eaten by different types of animals. Some food chains share components. A given plant or animal may be found in more than one food chain. These interconnected food chains form a food web.
Examples of food chains and food webs
A food chain always derives its energy initially from the Sun. Writing a food chain this way would be as follows.
Sun ---> corn plant ---> cow ---> human
Students at the K-4 level are expected to remember about the Sun as the source of energy and write it at the beginning of each food chain. Scientists remember that all energy comes from the Sun so they generally begin each food chain with a green plant.
The following set of food chains might be expected in a coastal area of New Jersey near the shore where there are marine creatures, predators and humans.
algae ---> mollusk ---> human
algae ---> mollusk ---> bird
algae ---> sandworm ---> fish ---> bird
algae ---> sandworm ---> fish ---> human
microflora ---> sandworm ---> fish ---> bird
microflora ---> sandworm ---> fish ---> human
microflora ---> arthropods ---> bird
microflora ---> arthropods ---> fish ---> bird
microflors ---> arthropods ---> fish ---> human
It can be seen that these individual food chains share components (fish, bird, human) and they also share common pathways (sandworm ---> fish or algae ---> mollusk). They can be put together to form a food web as shown in the figure below.
In this figure, the algae and microflora are at the producer level and the mollusk, sandworm and arthropod are at the primary consumer level. The other consumers may be at different levels depending upon the nature of each of the food chains in which they participate.
Interactions in the community
A community consists of all of the plants and animals in a given area. All these plants and animals depend on each other. The plants in the community provide food. They use sunlight to produce food for themselves and the community. Only plants can produce food. Consult Pyramid of Energy in Ecology for additional information.
The food pyramid relationship
When the food supply changes, the sizes of the populations of organisms depending on that food supply change. For example, if there is plenty of water and abundant rainfall there will be good growth of plants. The populations of animals depending on these plants will increase. On the other hand, if there is a drought, there will be a smaller supply of plants. The animals depending on these plants will decrease in population as a result of the decrease in the plant population.
Properties of the ecosystem
Thee are some components of the ecosystem that are important to animals.
Some animals will migrate from one place to another in order to meet their needs. A permanent change in the ecosystem could cause an organism to become an endangered species.
Human needs and the environment
The environment is impacted by humans. When human needs impact the environment, the result can be beneficial or detrimental. Humans use parts of other organisms for food and clothing. Some animals are used as pets for humans for enjoyment or protection. Animals can be used for asistance when compensating for disabilities and to perform work or provide recreation.
Humans can control and alter the environment. Farming by humans increases the amount of food by encouraging plants to grow by cultivation. Humans can also control the environment to compensate for disabilities. Humans can permanently damage the environment. The resources and minerals that are removed from the ground are not renewable.
1. At the outset students discuss the different habitats or ecosystems in the area of the school and in New Jersey. Among others, we have the forest habitat in northwest New Jersey, the Pine Barrens, the shore, and urban environments and habitats including parks.
2. Students work in groups or individually. They select a plant or an animal that is common in the community and study it. They write about it in their Science Journals. Some examples:
3. Students combine their individual studies to determine the relationships between the different plants and animals they have studied.
1. Students make presentations to the class about the plants and animals they studied. In their Science Jorunals, all students write about the plants and animals in the environment.
2. Students develop food chains based on the relationships they have discovered between the plants and animals. Example:
Sun ---> oak tree (acorn) ---> squirrel
3. Students make posters about their food chains using pictures as illustrations.
4. Once the individual food chains are completed, they are studied by the class to see if there are any common organisms and pathways. The food chains are then combined into a food web. They draw the food web in their Science Journals.
1. Students investigate other ecosystems and habitats that they have not studied or that are not found in New Jersey. They make diagrams in their Science Journals to illustrate the food chains and make them into food webs.
2. Students investigate the marine environment and the food chains that are present in the ocean. They learn that the ocean will be called upon to provide more and more food in the future, a field known as aquaculture.
3. Students investigate nutrient cycles in the environment. They learn about the role of the bacteria and fungi of decay in the process of recycling organic nutrients in the ecosystem.