Download Ecological Succession

KEY
Ecological Succession
PreAP Biology Student Notes Sheet
During the discussion on ecological succession, supported by photos and diagrams in the
powerpoint, please make sure you note the following:
What is ecological succession? Process by which communities in a particular area
change over time
What is a climax community? It is a stable community that is not going to be replaced
over time due to simple ecological succession; a major natural disaster would have to
occur for it to be replaced (such as a hardwood forest)
Why do some species die out and/or are replaced by others? Because they are either no
longer fit for the environment due to the changes that have occurred (i.e. they can not
survive here anymore), or because they are out-competed by other species for the
resources available (they could survive without competition, but are not the best
competitor) – good place to introduce the idea of introduced species such as bamboo,
kudzu, rabbits in Australia, fire ants, etc
Primary succession occurs where there is no existing community (there’s not even soil).
Give some examples of events that can occur that would lead to primary succession.
Receding glaciers (such as Glacier Bay), volcanic eruptions (such as Krakatoa)
An organism that is first to live in a new community, such as a lichen, is an example of a
_____pioneer species________.
When soil is present a more rapid form of succession can occur called ______secondary
succession__________.
When a change occurs in a very limited area of a biome or ecosystem new communities
form. This is an example of _____gap succession______.
Does succession only occur in terrestrial areas? No
What is one cause of wetland ecological succession? Sedimentation
Eutrophication is the increase in nutrients (usually due to run-off of fertilizers or other
chemicals) that causes algal blooms. This leads to more photosynthesis, reduced oxygen, &
fish kills. It is considered a type of pollution. Do you think that a pond or lake that is
described as being eutrophic is a beautiful crystal clear blue body of water or a green,
murky body of water? Why? Eutrophic ponds or lakes are green & murky due to all of
the algae present. Oligotrophic lakes are crystal clear because they are devoid of
almost all nutrients and therefore life. (The tropical regions of the ocean are also
devoid of nutrients and therefore life, but – as far as I know – this term is not applied
there…)