Have you ever stepped into your garden and noticed the incredible display of nature, from ladybirds crawling on leaves to worms burrowing in the soil to bees buzzing around flowers? Or have you been to the beach and seen the variety of marine organisms that are washed ashore, like crabs, barnacles, or seaweed? If yes, then you have witnessed ecology in action!
- First, we'll discuss the definition of ecology and what it seeks to explain.
- Then, we'll have a look at the different components of an ecosystem.
- Finally, we will tackle ecological concepts you might encounter: ecological niche, population ecology, and ecological succession.
- As a bonus, we will also touch on the concept of human ecology, a concept that was inspired by the biological concept of ecology and is popularly used in the social sciences.
Ecology Definition
Ecology is the branch of biology that helps us to understand everything from the surrounding organisms to the environment that they live in.
It helps us understand how these organisms interact with each other and the surrounding environment.
People who study, and research, ecology are called ecologists. Ecologists seek to explain:
Interaction between living organisms
How organisms interact with their habitats
Energy transfer between organisms
The distribution of living organisms in the world
Ecology System
A system in ecology means a specific community of biological and physical factors that interact with each other. These components are called biotic and abiotic factors, respectively. Ecological relationships depend on the dynamics between abiotic and biotic factors.
Biotic factors are living things within an ecosystem. They also include organisms that were once living. Examples of biotic factors include animals, fungi, plants, bacteria, and more.
Abiotic factors are non-living factors in the environment. This includes weather conditions, such as temperature, humidity, wind speed, and light intensity, among many other factors.
A major part of ecology is to understand how and why living organisms live in the places they do or why their populations increase or decrease. Biotic factors and abiotic factors influence these patterns.
To understand what biotic and abiotic factors are, let’s take the example of woodlice.
Woodlice prefer damp environments, such as moist soils. This is why you may find them crawling in the soil in your garden. Soil moisture is an example of an abiotic factor, a non-living component of the environment that affects how living organisms are distributed (spread).
In terms of feeding, woodlice feed on organic matter like plants. This is why woodlice are found in gardens. Plants are biotic factors, a living component of the environment that affects how living organisms are distributed.
Ecological Niche
Ecological niche describes the role that an organism plays within a community. This includes all biotic and abiotic factors that influence this organism.
When talking about the ecological niche of an organism, we have to consider factors such as:
The abiotic factors that an organism can tolerate, such as weather conditions, humidity, and more.
The resources that these organisms require. This could include water required by the organism, and food.
How this organism interacts with other organisms. This includes whether it competes with other organisms for resources, whether it acts as a pest or whether it is involved in a predator-prey or mutualistic relationship.
Competition can be interspecific or intraspecific. Interspecific competition refers to a situation where organisms have to compete with organisms of another species for resources. Intraspecific competition refers to a situation where organisms have to compete with organisms from their own species for resources.
There are many types of relationships behind organisms that we have to consider when thinking about an ecological niche. +/- relationships involve relationships where one organism benefits, whilst the other suffers. We call such relationships parasitic.
Examples of this would be predator/prey interactions or competition.
Another type of relationship is a +/+ relationship, which is a relationship where both organisms benefit. Such relationships are called mutualistic.
An example of this is the relationship between the spider crab and algae. Spider crabs live in shallow areas of the ocean floor, while greenish-brown algae live on the crabs' backs, camouflaging the crabs from predators by allowing them to blend into the ocean floor. By helping the crabs, the algae get a place to live.
The third type of relationship, +/O is where one organism benefits from one organism while neither benefitting nor harming the organism. Such relationships are called commensal relationships.
An example of this may be between barnacles and whales. Barnacles attach themselves to whales and use them as protection from predators.
Did you know that the difference between a parasite and a predator is the length of time in which they cause damage?
- A parasite tends to have a longer effect on the host, draining resources and causing damage over time.
- A predator, however, hunts and kills prey in a shorter period of time.
Both of these interactions are +/- relationships.Population Ecology
Ecologists study ecology at six levels, increasing from small to large (see figure on levels of ecology). These are listed in the table below:
Table 1. Showing ecological hierarchy and the importance of each ecological level
Ecological Hierarchy | Definition | Ecological Importance |
Individual | An individual is any organic, living system that functions as an individual entity. | Ecologists studying ecology at the organism level are mainly interested in how living organisms are adapted to live in their environment or habitat. |
Population | A population is a group of living organisms of the same species that live together in the same area. | |
Community | A biological community involves populations of different species living in the same area. | Ecologists study communities to find out why and how different populations interact with each other. |
Ecosystem | An ecosystem includes all the living organisms in a biological community and their interactions with the environment. | Ecologists study ecosystems to find out how energy and nutrients are transferred amongst organisms in an ecosystem, as well as how different factors can affect the stability of ecosystems. |
Biome | A biome is a life zone with communities of organisms with a particular adaptation to that area. | Ecologists study biomes to determine what kind of life inhabits a particular biome, like grasslands, deserts, lakes, etc. Abiotic conditions like water, air availability, and soil type help understand what kind of life exists in a biome. |
Biosphere | The biosphere is the sum of all living organisms and ecosystems on Earth. | Ecologists study ecology at the biosphere level to explore migration (long-distance movement) patterns in animals, interactions between different ecosystems, as well as how global warming may affect different ecosystems. |
Ecological Succession
Ecological succession is the process by which biotic and abiotic factors change over time in an ecosystem. There are two main types of ecological succession:
Primary succession
Secondary succession
Primary Succession
In primary succession, a newly formed rock is colonized by living organisms for the first time. The first species that colonize the region is called the pioneer species. These species are specially adapted to living in very hostile environments with little soil depth, water availability, or other resources.
An example of primary succession is the succession that occurs after a volcanic eruption.
Secondary Succession
In secondary succession, an area that was previously already colonized is recolonized. An example of when secondary succession occurs is after a wildfire. Secondary succession happens much faster than primary succession, as the area used to be colonized before the new species appeared.
As succession progresses, the following trends happen:
The following trends happen up until a climax community is reached.
The climax community is the point where both biotic and abiotic factors can coexist in a stable environment.
There are two types of climax communities, a climatic climax, and a biotic climax.
Human Ecology
So far, we have talked about important ecological concepts in Biology, but ecology is a concept that is not exclusive to this subject. Scientists from other disciplines have also taken inspiration from how biologists study the interactions between organisms and their environment. An example of this is human ecology.
Human ecology is a concept used in the social sciences. It looks at how the quality of natural resources and the existence of other humans influence the collective behaviour of humans, giving rise to different social systems and structures.
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Ecology - Key takeaways
Ecology refers to how living organisms interact with each other and their physical environment.
A biotic factor is a living component of the environment that affects how living organisms are distributed.
An abiotic factor is a non-living component of the environment that affects how living organisms are distributed.
Ecologists study ecology mainly at six levels: individual, population, community, ecosystem, biome, and biosphere.
Succession is the process by which biotic and abiotic factors change over time. There are two types of ecological succession: primary and secondary succession.
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