What Is Ecology? Understanding the Relationship Between Organisms and Their Environment
Ecology is the study of how living organisms interact with each other and their environment. Learn the basics of ecology, its importance, and how it helps us understand and protect the natural world.
Ecology is the branch of biology that studies how living organisms interact with each other and with their physical environment. It explores the relationships between plants, animals, microorganisms, and their surroundings—including air, water, soil, and climate. These interactions determine the distribution, abundance, and health of organisms within ecosystems.
Ecologists examine everything from individual organisms to entire ecosystems, focusing on how energy flows and how nutrients cycle through the environment. The study of ecology helps us understand the balance of nature, the impact of human activity on ecosystems, and how to protect biodiversity and natural resources. It plays a crucial role in addressing environmental challenges such as deforestation, pollution, climate change, and conservation efforts.
By studying ecology, we gain insights into how life on Earth is interconnected and why protecting habitats and maintaining ecological balance is vital for the survival of all speciesincluding humans.
Definitions of terms used in ecology.
1. Environment: This refers to everything in the surrounding of an organism that influences its life. The environment of a tadpole for example is everything in the water where it lives.
2. Biosphere: This is the part of the earth and its atmosphere that is occupied by living things or where life exists. It’s the largest habitat.
3. Habitat: This is a place where an organism lives. In the habitat, the organism obtains water, shelter and it is able to reproduce there. The habitat of a tapeworm is the mammalian intestines.
4. Population: This is the total group of organisms of the same species living in a particular place at a given time.
5. Ecological niche: This refers to a particular place an organism occupies within a habitat and the role it plays there.
6. Community: This is a collection of populations living and interacting with non-living components. It is therefore the total of all organisms in an area.
7. Ecosystem: This is a unit of the environment consisting of both living (biotic) and nonliving (abiotic) components interacting to form a self-sustaining unit. E.g. living things may include fish, cockroaches, and nonliving things may include lake, pond, forest, etc.
COMPONENTS OF AN ECOSYSTEM
The ecosystem is made up of two components;
1. The abiotic component (non-living component)
2. The biotic component (living component)
THE ABIOTIC COMPONENT OF THE ECOSYSTEM.
This is the non-living component of the ecosystem. Living organisms interact with the non-living components in their community to form a self-sustaining unit called an ecosystem.
The abiotic components in the ecosystem include the soil factors (edaphic factors).
Edaphic factors:
These are physical and chemical factors in soil and atmosphere that influence the life and activities of living organisms. These factors affect different organisms differently. Such factors include.
1) Light intensity. Light intensity affects the process of photosynthesis in plants, visibility in some animals and causes responses such as phototropism.
2) Temperature. This affects the activity of enzymes in the body of organisms and therefore determines the overall activity of an organism. Temperature also affects germination of seeds.
3) Water. This is a very important edaphic factor. Water is a component of the bodies of living organisms. It is a raw material for photosynthesis, it aids dispersal of seeds, it is an agent of pollination, it is a habitat for some organisms, it is a condition for germination, etc.
4) Humidity. This is the amount of water vapour in the atmosphere. Humidity affects the rate of transpiration in plants; it also affects the rate at which water is lost from the bodies of animals through evaporation.
5) PH. This is the alkalinity or acidity of soil. PH affects the dissolution of mineral elements in water; it affects growth of plants and microbes in an area, etc.
6) Nutrients. Presence or absence of a particular nutrient in soil determines the organisms, which can grow in that soil. Nutrients are required for proper growth of all organisms in the ecosystem.
7) Oxygen concentration. Most of the organisms are aerobic, i.e. they require oxygen for their respiration. Oxygen is abundant in air (21% by volume) however in water the concentration of oxygen varies due to factors that affect its dissolution in water and over exploitation by organisms. This affects the growth of organisms in water. In such a case anaerobic organisms can thrive and aerobic ones die.
BIOTIC COMPONENTS
This is made up of living organisms in the ecosystem. They are categorized into the following.
i) Producers. These are green plants and some bacteria that are able to manufacture their own food by use of light, chlorophyll, Carbon dioxide and water in the process called photosynthesis and chemosynthesis. They are nutritionally referred to as autotrophs.
ii) Consumers. These are organisms, which are not capable of manufacturing their own food. The consumers get their food by feeding on other organisms.
iii)The decomposers. These are organisms that feed on dead decaying organic matter. They are commonly called saprophytes. The major examples are bacteria and fungi. Decomposers are important because they bring about decay of plant and animal tissues. This enables the recycling of materials in the soil. They also reduce the amount if wastes and litter in the environment.
LEVELS OF CONSUMERS
Consumers are classified into feeding levels called trophic levels. The classification is based on the type of food they feed on.
The feeding levels/trophic levels of consumers include:
ü Primary consumer
ü Secondary consumer
ü Tertiary consumer
The primary consumers: These are organisms that feed directly on plants (producers). They are called herbivores. Examples are cattle, grasshoppers, goats, sheep, etc.
The secondary consumers: These are organisms that obtain their food by feeding on primary consumers. They are also referred to as carnivorous organisms since they feed on flesh. Examples include cats and reptiles.
The tertiary consumers: These are organisms that obtain their food by feeding on the flesh of secondary consumers. These are usually big carnivorous animals like lions, crocodiles, vultures and tigers
BIOTIC INTERACTIONS
Each category of feeding is known as a trophic level. Feeding methods are useful in showing the relationship that exists in a community by means of food chains and food webs.
TYPES OF FOOD RELATIONSHIPS
FOOD CHAIN
This is a feeding relationship between organisms showing which organism feeds on what. It is always expressed in a linear fashion beginning with primary producers and ending with tertiary consumers.
Organisms at the beginning of a food chain are usually numerous while organisms at the end of the food chain are often large and few in number.
The food chain shows the passage of energy from producers to consumers. Energy from the sun is fixed by producers (plants). The herbivores eat the plants and obtain this energy. The carnivores feed on herbivores and obtain this energy. At successive levels some energy is lost. At the end of the food chain energy reduces.
Example 1:
Grass
Arrows are used to show the movement of energy from one organism to another. Energy moves from the producers to tertiary consumers through the food chain.
There are usually few links in the chain because as the links increase energy reduces and organisms feeding at the terminal end of the chain gain little energy.
Chemicals on the other hand accumulate in tissues and increase in succeeding levels in the food chain.
Elimination of one level from the food chain disrupts the food chain. For example in the above food chain, when the grasshoppers are eliminated from the ecosystem, the following occur.
1) The grass grows and increases in number because the grasshopper that used to feed on it has been removed.
2) The doves lack food because they feed on grasshoppers, which have been removed. This causes their numbers to drop.
3) The cats also reduce in number because as the doves die due to lack of food, the cats lack food and start to reduce because they feed on doves.
Example 2
Draw a food chain for the following organisms;
a)Vegetation, beetle, owl, fox.
b) Cow, man, lion and grass.
c) Nile perch, algae, water flea and tilapia.
