Ecology is the study of our living environment and how we relate to them. This implies that we are as important as our environment is important to us. This is seen in our immediate environment like our habitats, trees, forests, water bodies, etc.

Population is the number of individuals of the same species interacting in a habitat at a particular time.

1. It is the process by which series of life forms (plants and animals) inhabit or colonize a habitat at different times until a stable community is formed, or
2. It’s a series of gradual structural change in plants and animals composition, variety, diversity, and increase in numbers. Succession is usually a slow process which may take up to 1,000 years.
1.This occurs in newly formed natural habitats such as sea shores, sand dunes, or in artificial habitats like cultivated forests and grasslands.
2. Occurs partly because plants tends to inhabit bare lands. When plants establish in the habitats, animals also colonize the habitats since they depend on plants for food.
3. First colonizers are green plants which grow rapidly and are soon replaced by woody herbaceous plants.
4. Succession is an orderly directional and predictable process which results in community development.
5. The SERE is a whole sequence of temporary community which replaces one another in a given habitat. These temporal communities are called SERE STAGES OR PIONEER COMMUNITIES while the final stable community is called the CLIMAX.
6. A sere of a succession is likely to begin when any human activity disturbs the natural equilibrium between the biotic and the abiotic environment.

1. Species of organisms usually replace one another in the sere since populations make conditions suitable for others.
2. There is acceleration of the replacement process since some species that make conditions favorable for others , in turn create unfavorable conditions for themselves.
3. There are changes in the structure of species and the community activities due to changes in physical environment with time.
4. It brings about an equilibrium since bare or abandoned habitats are colonized by a variety of organisms similar to those in the neighboring habitats.
5. The establishment of the climax community is the final outcome of succession.

This is the process by which a vegetation or a community develops from newly formed natural habitat.
At the estuary, the particles of soil and silt deposited by the river gradually build up banks of bare mud which is saturated with salt.
The first set of plants to colonize this salty and muddy habitat are the red mangroves. They have silt roots which fix them firmly into the mud and seedlings which germinate on the parent plants where it will not suffocate for lack of air before landing on the mud. The first set of animals to colonize the red mangrove swamp or the mud are crabs, slug, snail and worms.
As soon as the banks are raised with accumulation of plant and animal remains, white mangrove trees succeed the red mangrove. The white mangroves which have breathing roots form an open forest with some succulent herbs growing around their roots. The animals that colonize the white mangroves are squirrels, rats, snakes, monkeys, etc.
With further accumulation of plant and animals remains, a more normal soil is developed and white mangroves give place to a more open association of a semi mangrove species. This is a collection of different trees, shrubs, herbs, grasses, ferns, and epiphytes.
As humus continues to accumulate, a normal forest fauna and flora soon emerge to form a stable community which is the climax of the succession.

Secondary succession is the development of a community in a habitat from which another community had previously been removed. E.g. the colonization of an abandoned farm land by a new set of organisms.

The process of succession in an abandoned farmland are highlighted below:
In an abandoned farmland, nutrients are left over from the destroyed old farm. The initial organisms usually found in the farmland are insects’ eggs, larvae, worms and even seeds of plants and underground stems. After sometime, grasses germinate and begin to grow. Also the insects’ eggs and that of other animals hatch. Rats and other rodents begin to see enough vegetation to feed on. Also, snakes and other reptiles begin to appear. Shrubs develop to displace some herbs. There is increase in the number of species that appear. More trees begin to grow and birds, monkeys and bigger snakes which live in different areas of the farmland appear. The population of detritus feeders also increase and a climax vegetation is reached. The animal community will include herbivores, carnivores, and detritus feeders which form a complex food web.

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