The field of ecology includes many research areas and subdisciplines. Some of the major types or levels of ecology include ecosystem, community, population, organismal, microbial, and global.
Ecosystem Ecology
Ecosystem ecology concerns the interaction of all organisms and abiotic factors in an area. Instead of just looking at individual species or how two species interact, scientists study how organisms impact their physical environment and vice versa. For example, an ecosystem ecologist might learn how beaver dams affect water flow through a forest ecosystem and how that impacts the survival of aquatic species or the distribution of sediment. A coral reef ecologist might study how changes in water temperature impact coral survival.
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Community Ecology
A biological community is a group of different species populations that live close enough to interact. Community ecology looks at how those species interact with one another and with other environmental factors. Researchers study competition relationships that limit species abundance and also examine symbiotic relationships and predator-prey interactions.
Population Ecology
Population ecology is the study of organism populations in relation to the environment. A population is a group of organisms of the same species that live in the same area. The area can be small or large but generally has similar resources throughout. The organisms in that population are likely to breed and interact in other ways. Population ecologists study the density of the organisms, which is the number of individuals per unit area, and their dispersion, or how they space themselves out within their population boundaries.
Organismal/Behavioural Ecology
Organismal ecology examines how an organism's adaptations impact its distribution and survival. Studying a species's physical structures or morphology can help scientists understand its feeding behaviors, habitat usage, and social interactions. Beak shape, for example, gives ecologists and animal scientists knowledge of what foods a bird may eat in its local environment. Characteristics like horns tell them that aggression may be observed when defending territories or choosing mates. Behavioral ecology is a branch of organismal ecology that studies an organism's behavioral adaptations and how they impact species survival and evolution.
Microbial Ecology
Microbial ecology is the study of how microorganisms interact with animals, plants, the environment, and each other. Microbes are essential to the movement of nutrients through food webs, and they also affect oxygen levels in an environment. Microbes can have positive interactions with some organisms, aiding in processes like digestion and infection control. In other cases, microbes can cause diseases to spread through a population, potentially upsetting the balance of an entire ecosystem.
Global Ecology (Biosphere)
Global ecology involves the interactions of all living and nonliving things on the planet, considering the total of all ecosystems. It examines the effects of material and energy movement on organism distribution around the world. This field is also called biosphere ecology because it addresses every place that life exists on Earth. The three spheres of the biosphere are:
- Lithosphere- the terrestrial component
- Hydrosphere- all the Earth's water systems
- Atmosphere- the air layers surrounding the planet
Global ecologists study topics like the effects of ocean currents, air currents, climate, and geological processes on species survival and distribution.
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Ecology is the study of how organisms interact with each other and their environment. These interactions may occur at the organism level, among populations of a species, and in communities of different species. Ecologists may study interactions among the different trophic levels of a food web, or symbiotic relationships to understand how species interact. Broader ecological studies look at interactions among all the biotic and abiotic factors that make up an ecosystem and the impact of global environmental conditions on species survival. Other important terms and concepts in ecology include:
- Biodiversity- the number of different species in an ecosystem.
- Competition- an interaction that limits the survival and reproduction of two or more species by placing them in competition for limited resources.
- Biosphere- the regions of Earth that support living things.
Ecology has many applications in human society. Understanding interactions between biotic and abiotic factors can help people predict, reduce, and reverse the negative impacts of resource harvesting and economic development. These efforts make practices like energy harnessing, fishing, and hunting more sustainable for the benefit of future generations.
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Video Transcript
What Is Ecology?
The prefix 'eco' has become synonymous with environmentally-friendly living. This green fad, however, has more to do with conservation biology than with ecology, where the prefix is borrowed from.
All organisms, no matter their size, their species, or where they live, need to interact with other organisms in their 'neighborhood' and with their environment in order to survive. Ecology is the scientific study of the interactions between organisms and their environment. The term comes from the Greek 'study of house', or the study of the place we live in.
The scope of ecology is huge, and it encompasses all organisms living on Earth and their physical and chemical surroundings. For this reason, the field is usually divided into different levels of study including: organismal ecology, population ecology, community ecology and ecosystem ecology.
Organismal Ecology
To begin exploring these levels of ecology, picture an American alligator hanging out in the swamp in the Florida Everglades.
Organismal ecology looks at how individuals interact with their environment, which is made up of biotic (living) and abiotic (non-living) components. Consider the biotic and abiotic factors that affect alligators.
At the organismal level, ecology looks at how organisms are adapted to these living and non-living components of their surroundings. For example, because an alligator is cold-blooded, it needs to maximize daylight hours absorbing heat from the sun, so it hangs out on the swamp banks soaking up the rays. This is a behavioral adaptation.
Now, when hunting - especially during cooler or cloudy days - the alligator will move very slowly and is able to hold its breath underwater for almost an hour waiting for its prey. This is a physiological adaptation.
Alligators have developed eyes and a nose on the top of their heads so they can hide just below the surface while still being able to look out for prey and predators. This is a morphological adaptation.
So, with organismal ecology, individual species are linked to various adaptations - behavioral, physiological, or morphological. The adaptations of the alligator allow it to survive in its environment.
Population Ecology
A population is a group of individuals belonging to the same species and living in the same geographic area at a given time. They use the same natural resources and are affected by similar environmental factors. Population ecology examines the factors affecting population density and distribution. Population density is the number of individuals in a given area or volume. Population distribution is how spread out the individuals are in that area. Basically it is how populations change over time. For example, what would happen to the gator population in the swamp if the catfish population decreased due to disease, or if a new competing predator was introduced?
By looking at birth and death rates of specific populations, ecologists can determine the carrying capacity (maximum number of individuals) a habitat can sustain. This helps to determine whether a species will thrive in a particular area, if it is endangered, or if its numbers need to be controlled in order for other species to thrive and resources to be replenished. The human carrying capacity of the Earth is estimated at around 12 billion. In 2011, the population of the Earth was believed to have reached 7 billion and it continues to grow exponentially!
Community Ecology
A biological community is made up of two or more populations of different species inhabiting a particular geographic area. Community ecology looks at the interactions between the populations - for example, competition and predation. One way to represent these relationships is through a food web, which shows predators and prey in a biological community. Let's consider the alligator and the swamp food web as an example.
In this swamp community, the alligator is the top predator. It competes with the heron and the snapping turtle for food because they all share snacks (catfish and invertebrates). However, the alligator also preys on the heron and turtle. The duck, catfish, invertebrates and snake are all primary consumers. This is because they are herbivores and they eat the plants, which are producers in the food chains. The nematodes at the bottom of the food web serve as detritivores. Detritivores clean up (eat) dead matter at the bottom of the swamp.
Ecosystem Ecology
An ecosystem is made up of all the communities living in the same area plus the abiotic factors that affect them. Abiotic factors may include salinity and climate. Major ecosystems which are defined by similar geography, climate, and wildlife, are called biomes. Examples of biomes include deserts, forests, savannas, tropical seas and wetlands like this swamp.
Ecosystem ecology encompasses aspects of all the living organisms and non-living factors and their interactions. It looks at things like how nutrients are recycled in the ecosystem, water availability, and energy flow in food chains. An understanding of the living and non-living components that make up an ecosystem is particularly important in conservation biology and habitat restoration efforts. An example of said efforts is that of the alligator of the Florida Everglades and its ability to thrive due to the protection of its habitat.
Understanding ecological relationships is important for preserving the Earth's diverse habitats and the species that live there, including humans. Our survival depends on the oxygen produced by trees, marine algae, and the food provided by animals and plants. As long as the human population is using natural resources and depending on nature, ecology will help society understand how to maximize its resources without depleting them.
Lesson Summary
Ecologists study interactions between organisms and the living and non-living components that make up their environment. Therefore, ecology is the scientific study of the interactions between organisms and their environment. An organism's environment is made up of the living, or biotic, and non-living, or abiotic, components of its surroundings. Ecology is separated into various levels of study which include:
- Organismal ecology
- Population ecology
- Community ecology
- Ecosystem ecology
Organismal ecology looks at how organisms have adapted to the living and non-living components of their surroundings. Adaptations can be morphological, behavioral, or physiological.
Population ecology examines the factors affecting population density and distribution. Ecologists study the carrying capacity of habitats to determine how well a species may thrive.
Community ecology looks at the interactions between the populations. In this area of ecology, a food web is a way to visualize the predator/prey relationships.
Ecosystem ecology encompasses the interactions between the living organisms and non-living factors in a specific area. Ecosystem ecology provides important information to the field of conservation biology.
All organisms interact with other organisms that are near them, and the vast branch of science that this has become is ecology.
Key Terms
| Key Terms | Definitions |
|---|---|
| Ecology | the scientific study of the interactions between organisms and their environment |
| Organismal ecology | how individuals interact with their environment |
| Biotic | environment made up of living components |
| Abiotic | environment made up of non-living components |
| Population | a group of individuals belonging to the same species, living in the same geographic area |
| Population ecology | examines the factors affecting population density and distribution |
| Carrying capacity | maximum number of individuals a habitat can sustain |
| Community ecology | looks at the interactions between the populations |
| Food web | shows predators and prey in a biological community |
| Top predator | top consumer in a food web |
| Primary consumers | eats the producers |
| Detritivores | eats dead matter at the bottom of the environment |
| Ecosystem | made up of all the communities living in the same area as well as the abiotic factors that affect them |
| Ecosystem ecology | encompasses aspects of all the living organisms and non-living factors and their interactions |
Learning Outcomes
Finishing this lesson should give you the ability to do the following:
- Describe ecology
- Illustrate the various types of ecology
- Identify the abiotic and biotic participants in ecology
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