What is Ecology?

Previously, you learnt that all biological molecules are composed of carbons. Every living being is just a collection of carbon atoms. We take in carbon (in food) for us to grow and satisfy our energy demand. When we die, our body decomposes and the carbon is a food source for other living organisms.

Carbon is like a currency in the ecosystem. Nobody holds on to it forever and it’ll continue circulating among different individuals in a carbon cycle.

Definitions

There are many terms you have to know in ecology. To start off, here are some of them:

Levels of Organisation

An ecosystem is a complex system of interaction between biotic and abiotic components in a certain location. Examples include forests, ponds, grasslands, deserts, etc.

Based on the definitions mentioned earlier, here is an example of the different levels of organisation in an ecosystem.

What are they?

Biotic components are biological influences on organisms. Such influences arise due to interactions between organisms, mainly for food and shelter.

Types of Components

Organisms of different species interact with one another differently. Here are just some of the ways in which organisms interact and are related to each other.

Types of Components

Abiotic components are the non-living parts of the environment that interact with organisms. Here are some examples:

Introduction

Energy enters ecosystems in the form of sunlight, which is captured by plants and converted to chemical energy during photosynthesis. This energy is then transferred to other organisms when the plants are consumed.

The transfer of energy in the form of food is shown by a food chain.

The Different Roles

All the organisms in an ecosystem play one of these 3 roles: producer, consumer & decomposer.

Producers produce their own food from simpler inorganic substances. An example would be plants undergoing photosynthesis.
Consumers obtain energy and organic materials by feeding on other organisms. There are different levels of consumers depending on where they are in the food chain.
Decomposers obtain energy from the breakdown of dead organisms, animal waste and plant litter.

The diagram below shows how these different roles are linked together in a food chain.

Different Levels of Consumers

Consumers range from primary to tertiary, even quarternary. What defines all these different levels of consumers?

The Food Web

You have seen how different organisms are linked via a food chain. The organisms each have their trophic level, which describes their position in the food chain.

Food chain is a sequence of organisms in a community where energy is transferred in the form of food. Many food chains can be interconnected to form a much more complex food web.

Sustaining a Food Chain

The bulk of the energy at the start is eventually lost to the atmosphere as heat. This means that a food chain can rarely have more than 5 trophic levels, which describe the position of the organism in the food chain. Why?

What are they?

The relationship between trophic levels can be represented by ecological pyramids. The producer is at the bottom and each consumer is stacked above it. Different ecological pyramids represent different information and have different shapes.

This is an overview of the two ecological pyramids.

Pyramid of Energy

The pyramid of energy shows the total energy content of each trophic level over a certain duration. The pyramid always has a pyramidal shape.

Energy is always lost in the trophic level (respiration, heat) and during transfer between the levels (uneaten parts, undigested material). Hence, the total energy of each trophic level is always lesser than the previous level. This results in a constant pyramidal shape.

Importance

The balance of the ecosystem and the relationships between organisms are very difficult to maintain. The recent spike in destructive activities against the environment are resulting in damage to the ecosystem.

For example, water and air pollution are on the rise. Chemical wastes discharged into rivers & oceans harm the organisms there whereas air pollution erodes the ozone layer and endangers all living things.

Such things can be avoided if the chemical wastes are removed prior to discharge or if pollution prevention policies are implemented to reduce environmental pollution.

Destructive Activities

Other than pollution, humans have engaged in other destructive activities.

Introduction

Carbon, oxygen and nitrogen are essential elements. They are constantly being passed from organism to organism. When you eat, you are taking over these atoms. When you die and decompose, these atoms are returned to the environment in the form of fertilizer or food.

Nutrient cycles ensure these useful elements are always available to support new life.

Carbon Cycle

Carbon is a vital element as all living things are constructed from carbon compounds. Yet only 0.04% of our air comprises of carbon. The carbon cycle ensures that carbon is always available on Earth and that the concentration of carbon in the air is constant.

This balance is maintained by the following processes, of which only photosynthesis removes carbon from the atmosphere.

Nitrogen Cycle

Nitrogen is another essential element as it is heavily involved in protein and DNA synthesis. The nitrogen cycle ensures that it is always available on Earth and that its concentration in the air is constant at 78%.

This balance is maintained by the following processes, of which only denitrification returns nitrogen to the atmosphere.

Summing Up

Our Earth and the ecosystem have been under constant attack by our destructive activities ever since the Industrial Revolution. Our rapid development has become unsustainable. Recent spikes in massive deforestation and pollution are worsening the problem.

We have learnt that organisms interact with one another in an ecosystem via a variety of relationships. Rather than continuing our parasitic role when interacting with our Earth, we each need to play our part and reduce the damage we have been doing to our home.