A newly formed and uninhabited area is colonized by pioneer species such as lichens
They begin to break down rock and form soil
Eventually grasses are able to grow
The shrubs pop up, then shade intolerant trees like pines, and finally shade tolerant trees like oaks
As plant live moves in, so do animals who feed upon those plants
Eventually animals further up the food chain move in as well
Anthropogenic disruptions include nuclear explosions or mountain top removal
This exposes bare rock and begins the succession cycle
Natural disruptions include volcanic eruptions and retreating glaciers
Secondary Succession
Starts with soil and some grasses but follows the same progression
Anthropogenic disruptions can be human-caused forest fires, logging, mining, fossil fuel extraction, clearing land for agriculture, and abandoning fields
Natural causes include forest fires often caused by lightning, and storm events
Community Structure
Keystone Species
These are species whose activities have a particularly significant role in determining community structure
Their role supports many other organisms in the community
Like how some predators help control prey populations, which in turn affects quantity of plants and animals in the food chain
Ecosystem Engineers
Organisms that create, change, or destroy a habitat
For example, beavers take down trees to make their dams
This allows for new growth and diverts water, changing and creating wetland habitat
Mutualists
Two species that interact for mutual benefit
Bees and hummingbirds pollinate flowers and consume nectar
Without these pollinators, plants would struggle to reproduce
Without the flowers, the pollinators would have no food source
Indicator Species
A plant or animal that, by its presence, abundance, scarcity, or chemical composition, demonstrates that some distinctive aspect of an ecosystem is present
They typically has a narrow ecological tolerance, like coral
Pioneer Species
The species who move into unoccupied habitat and adapt very quickly
They are able to outcompete established vegetation that survived the disturbance
They have a broad ecological tolerance
Being very adaptable, they can pass on beneficial genetic traits quickly