Interdependence Among Living Things and the Environment
By the end of this chapter, you should be able to:
- Explain the interactions of the components of the ecosystem from the survey.
- Explain the patterns of relationships between organisms and different species living in the same habitat from the survey.
- Build a model to explain the energy transfer in a food web.
- Explain the relationship between producers, consumers and decomposers in the ecosystem.
- Explain the accumulation of toxins in organisms in food chains.
Levels of Organization in Ecology
Species, Population, community, ecosystem, biome and biosphere
Ecology is the branch of biology that studies the interactions between living organisms and their environment.
To study interdependence among organisms, we need to be familiar with the following terms: SPECIES, POPULATION, COMMUNITY, ECOSYSTEM, BIOME AND BIOSPHERE.
Species
Example: fish, deer, frog and other individual animals.
- Organisms with common characteristics.
- Can breed among themselves to produce a fertile offspring.
Population
Example: population of fish, population deer, population frogs.
- Is made up of a number of organisms of the same species.
- All the organisms of the species live and breed in a particular habitat.
Community
Example: All the fish, deer, frogs and all the organisms make up the pond community.
is made up of many populations living together in a particular habitat.
all fish, tadpoles, shrimps, water lilies, water weeds, frogs and snails make up the pond community.
*Habitat
Example: the pond. The fishes, deer and frogs are living in a pond.
- The habitat of an organism is the place where it lives.
- It is the place where the organism obtains its food, shelter and protection.
- It is also the place where the organism reproduces.
- A habitat has many kinds of organisms living in it.
*Niche
Example: A honeybee's niche includes collecting nectar from flowers (for food), pollinating plants (helping them reproduce), and living in a hive.
- A niche is the role or function of an organism in its environment — how it gets food, where it lives, and how it interacts with other organisms.
- It includes everything the organism needs to survive, stay healthy, and reproduce.
- No two species can occupy the exact same niche in the same habitat for long — they would compete until one outcompetes the other.
Ecosystem
An ecosystem refers to the community of organisms living in the same habitat, together with the non-living.
Example of an Ecosystem.
- Forest ecosystem
- Marine ecosystem
- Wetland ecosystem
- Grassland ecosystem
An ecosystem is made up of BIOTIC COMPONENTS (the living components) and ABIOTIC COMPONENTS (the non-living components).
All the organisms found in the pond (fish, snails, tadpoles, water lilies, water weeds and shrimps) and non-living components (rocks, sand, water, air and mineral) make up a pond ecosystem.
Biome
A biome is an area classified according to the species that live in that location
Example
- Tropical rainforest
- Temperate forest
- Boreal forest
- Desert
Biosphere
A biosphere is made up of the parts of Earth where life exists—sum of all ecosystems.
There are usually more than one habitat in an ecosystem. For example, in a school field, the tree is a habitat for birds and grass is a habitat for grasshoppers.
Interdependence of Organisms creates a Balanced Ecosystem
Examples of the interdependence among living organisms:
- Most plants make their own food by photosynthesis and so are reliant on interaction with non-living components such as sunlight, air and water. They also require nutrients from the soil.
- Animals cannot make their own food and so depend on other organisms for food and on plants for the supply of oxygen.
- Some organisms depends on other organisms for food, shelter and protection. Some depends on rocks and soil for shelter.
- Microorganisms such as bacteria help to decompose dead organisms. The decomposition releases minerals into the soil which in turn become nutrients for plants.
- Some insects such as bees and butterflies obtain food like pollen and nectar from flowers. In the process of obtaining food, these insects help in the pollination of flowers. Some plants rely on wind and water for pollination and seed dispersal.
Interdependence of Organisms creates a Balanced Ecosystem
A balanced ecosystem is one which does not appear to change very much over a period of time.
In order to maintain a balanced ecosystem, the following factors need to be maintained:
- The number of individuals in the different populations.
- The number of populations in the different communities.
- The composition of gases in the air and the quality of the air.
- The availability of water, soil and nutrients.
Practice Test
Q1. Define each of the following:
Species
Community
Ecosystem
Population
Biome
Biosphere
Niche
Habitat
Q2. Why is the wetland considered as an ecosystem?
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