These worksheets will help students understand all the intricacies of ecological succession. This is more complex concept to grasp, but when presented with direct examples, as these worksheets do, it is not an insurmountable topic by any means. Students will learn how they are predictable and have a cyclic nature. We will look at the work of several scientists that help us better understand how nature interacts and affects one another. We also look at how humans have had a hand in accelerating these nature process or turning them completely upside down.
The term primary succession describes the colonization of new land or bare rock for the first time. Weathering and other natural forces break down the surface of the rock enough for some very rugged plants to be able to grow.
Scientists now know that even stable (formerly called climax) communities continually undergo various kind of cyclic succession.
Over time, weathering and other natural forces break down the surface of the rock until eventually some very hardy plants with minimal soil requirements are able to grow there.
What happens to the surface of an area once the life cycle of pioneer species begins to occur?
The exact way that any particular area becomes repopulated with organisms depends on the conditions that existed before the catastrophic event.
Plants that don't have any woody stem above the ground are called: ____________.
Cicadas remain underground for between thirteen and seventeen years at a time before emerging all at once, and their appearance can dramatically change an ecosystem.
The idea that an ecosystem moves through a fixed and predictable development pattern that ends with a climax community was proposed by the botanist Frederic Clements in the 1890s.
The ecologists that followed him built upon this idea and began to think of an ecological system as a single "superorganism" that could be compared to a single, complex organism.
The main land biomes are tropical rainforest, grasslands, desert, temperate deciduous forest, taiga (also called coniferous or boreal forest), and tundra.
When describing and measuring ecological communities, ecologists use two important terms. What are they?
Foundation species often modify an environment in a way that allows it to support other organisms in the community.
A keystone species is a species that has a much larger effect on community structure than the other species in the community due to its abundance.
In the context of ecology, productivity means how quickly biomass (the total mass of organisms in a given area) is generated in an ecosystem.
An ecological community that has been disturbed can only recover to its undisturbed state when the disturbance is no longer taking place.
The forms of life in a climax community reflect the type of climate that exists there, and organisms that die are replaced by organisms of the same kind.
Some regions are always vulnerable to some disastrous event like a wildfire. Succession after a catastrophic event that happens rapidly to reestablish shrub dominance is called a catastrophic climax.
As these changes take place, the animal life changes too. It continues to change as the composition of vegetation turns over.
There are species of plants and animals that rely on recurring disturbances of climax communities and the resulting shrublands and juvenile forests in order to survive.
What Is Ecological Succession?
Our world's current landscape appears far from where it started. This may be credited to ecological succession, a foundational concept in ecology.
Ecological succession is the steady change undergone by a biological community over time. Such changes are reflected in the types of species present, their abundances, and their arrangement.
If we were to take a look at all the living things that interact and do not in a given physical area, we would have an ecological community. Over time and throughout history these living things and even the surrounding physical environment that they inhabit have been known to undergo a series of changes. The process by which that occurs is called ecological succession. Ecological succession is most often brought upon a region by natural disasters such as wildfires or huge storms, but changes in weather or living things can also slowly progress this process into a region. The is a natural development as to how living things make these changes starts with small livings things slowly inhabiting an area.
Types of Ecological Succession
In ecological succession, species in a community consecutively replace one another, depending on which of them thrive better in the current environment.
For instance, a specific area may initially be teeming with grasses and low shrubs. However, changes in the soil and the addition of nutrients may shape the site to allow for taller plants and larger shrubs. Over the years, trees may even grow. This is an example of species succeeding each other.
There are two types of ecological succession: primary and secondary. The main difference between the two lies in the conditions that started the chain of succession.
Primary succession occurs in lifeless areas or places that had not been inhabited by any life form before the start of ecological succession.
Examples of primary succession are:
- Lava flows. Plants and other species may survive on lava that has dried up.
- Melting glaciers. Glaciers that melt or retreat reveal land beneath the ice. This land may serve as a new home for organisms.
- Sand dunes. The Dune Succession Trail in the Indiana Dunes is a classic example of ecological succession. Pioneers of the theory observed that the farther the dunes are from the water, the more complex and stable the species that thrive in it.
What Is a Pioneer Species?
When discussing primary succession, it is crucial to recognize the pioneer species' role in making the area more stable and inhabitable.
A pioneer species is the first community of organisms that reside in an area. These species start from scratch. Typical examples are plants and lichen, a result of algal and fungi symbiosis. These organisms break down the earth and help make it more livable.
Although they were the first to be in the area, the pioneer species doesn’t need to stay there forever. As with succession, they are likely to be replaced by species that could thrive better in the land they had shaped.
Unlike primary succession, life doesn't start from scratch with secondary succession. Secondary succession is when there has been a stable community in the area before, but it underwent some disturbance.
In primary succession, pioneer species build the soil and nutrient profile by themselves. However, in secondary succession, the soil profile is preserved and may be used by the next community.
A classic example of secondary succession is a prairie, meadow, forest, or any area that experienced a wildfire. During a fire, most life – plants and animals – die. It is a disturbance that disrupts the stable community in the area. Thereafter, a new community will emerge and start the secondary succession.
Changes in Ecological Succession
Ecological succession describes the changes undergone by communities of life in an area. These changes may be reflected in three aspects:
- Species composition.
- Abundances and hierarchy of species.
- Arrangement of species and vegetation.
An example I previously provided illustrates these changes. A land filled with grasses and low shrubs undergoes ecological succession when towering trees replace those species, thus, modifying the species composition.
What Is the Climax Community?
Another essential concept in ecological succession is the climax community. It is even regarded as the endpoint of succession.
The climax community is a stable community or one that is at equilibrium. At this point, the organisms that live in the area are already well-adapted to the environment and each other. They are unlikely to be succeeded by another community unless there is a disturbance.
Although ecological succession remains to be studied and revised based on discoveries, it is still relevant and essential.
Wildfires rage now and then, and many glaciers are starting to melt. Our world's landscape is constantly changing, and by understanding why that happens, we can easily adapt to such change.