Goals
- Understanding the basics of ecology, environmental factors and being able to define the concept of an ecological niche.
The levels of ecological study
Ecology studies the interactions between organisms and their living and non-living environments, as well as the factors that influence the abundance and distribution of organisms.
The levels of ecological study range from looking at individual organisms to studying the function of the entire global ecosystem or biosphere.
Levels of biological analysis
Population and organism community
- Often, ecological research focuses on all the individuals of a single species living in the same area, i.e. the population.
- Ecological research can also look at all the populations of different species that live in the area together, i.e. the organism community. This is justified because individuals of different species interact with each other.
Classifying environmental factors
The environmental factors that organisms use, such as food, water and light, are resources. These resources can be divided into living and non-living factors.
Living or biotic factors are related to other organisms in the community living in the same area. Biotic factors are individuals of the same or other species that influence the success of an organism. They can be food, predators, breeding partners, competing species, parasites or pathogens.
Crows (Corvus corone cornix) feeding in winter. The cold winter weather is bad for organisms, but biotic factors such as access to food and avoiding predators are even more important for survival.
Non-living or abiotic factors relate to the properties of land, air and water. Abiotic factors can be divided into chemical and physical factors. Chemical environmental factors include rock types, soil pH, salinity and nutrient concentration. Physical environmental factors include things such as the amount and quality of light, variations in temperature and precipitation, and wind.
Light makes life on Earth possible. Plants need light for photosynthesis.
One of the most important abiotic factors is sunlight. Plants need sunlight for photosynthesis, together with water and carbon dioxide. During photosynthesis, plants produce a sugar called glucose, which they use to grow and reproduce.
The amount and quality of light can vary from region to region and from season to season. In Finland, for example, the amount of sunlight is lower than at the equator, while in summer it is available almost 24 hours a day.
The sun's heat radiation or infrared radiation is an important environmental factor for life on Earth.
Other important abiotic factors for plants include nutrients (e.g. nitrogen, phosphorus and potassium), the carbon dioxide needed for photosynthesis, the appropriate soil acidity (pH), oxygen and salinity.
In a greenhouse, plant growth can be boosted by regulating things such as temperature, lighting, as well as moisture and nutrient levels.
Environmental factors
Living (biotic) factors | |
food | The quantity and quality of nutrition affect the success of an individual. |
herbivores | Herbivores have a big influence on the success of plant species. |
competitors | Individuals of the same or another species may compete with each other, for example for food. |
predators, parasites and pathogens | No species can reproduce indefinitely even if food is plentiful, because at some point predators, parasites or pathogens will start to take their toll on the population. |
Non-living (abiotic) factors | |
sunlight | The amount of light (i.e. its intensity and duration) is an important factor for the success of plants. |
water | All living organisms need water. |
nutrients | Plants need elements such as nitrogen and phosphorus in order to grow. |
soil pH, wind | Many factors connected to climate and soil have a particular impact on plants and, through them, on animals. |
Ecological niches
When you take into account the resources that the species needs, such as its nesting site and food, and other environmental factors that affect its success, such as predators, mates, diseases and temperature, they form a whole known as the species' ecological niche.
The ecological niche describes all the resources provided by nature that a species needs. The ecological niche expresses the species' interactions with the inanimate environment and other organisms through predation and competition.
The different structures of various species makes it easy to conclude that they have different ecological compartments.
There are different degrees of ecological niches. The basic ecological niche is the broadest and occurs in a situation where there is no competition. Competition reduces the basic niche to a realised niche. In a niche that is narrower than the specie's core niche, the population can no longer survive.
The relationship between two species (or their niches) can be described by looking at how much the two niches overlap. If two organisms share some of the same resources, they are in competition with each other for these resources. This leads to a shrinking of the ecological niches of the two organisms.
Species living in the African savanna have different ecological compartments.
Test your knowledge
1. Mark the biotic factors that can affect the life of an individual.
- bacteria
- the Sun
- water
- rocks
- plants
- birds
2. Mark the abiotic factors that can affect the life of an individual.
- bacteria
- the Sun
- water
- rocks
- plants
- birds
1. Arrange the following things from the smallest (top) to the largest (bottom.)
- molecule
- cell
- organ
- tissue
- atom
2. Arrange the following things from the smallest (top) to the largest (bottom.)
- organism
- population
- ecosystem
- community
- biome
- Atmospheric carbon dioxide is an important biotic factor for plants.
- Atmospheric carbon dioxide is an important abiotic factor for plants.
- Plants need atmospheric carbon dioxide for photosynthesis.
- Sunlight is a resource for plants.
- If a bird nests in a burrow, it is part of the bird's ecological niche.
- Potassium (K)
- Phosphorus (P)
- Carbon dioxide (CO2)
- Water (H20)
- Nitrogen (N)
- oxygen (O2)
- glucose (C6H12O6)
1. Ecology is the study of the relationship between the environment and
- organisms.
- water.
- soil.
2. A group of the same species living in a certain place make up
- a community.
- a population.
- an ecosystem.
3. An organism’s role in its habitat is its
- ecosystem.
- niche.
- environment.
4. The ecological niche of a heron can include
- its nesting tree
- weather
- frogs
- a nearby wetland
- polar ice
- eagles.
Summary
- The environmental factors used by an organism are called resources.
- Resources can be divided into biotic and abiotic factors. Abiotic factors can be divided into chemical and physical factors.
- The most important abiotic factors are water, nutrients, light, oxygen, heat, acidity and salinity.
- The ecological niche describes the resources provided by nature that a species needs to live and thrive.
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