C22L3 Quiz
• How do land ecosystems change
over time?
• How do aquatic ecosystems
change over time?
 Ecological
succession is the process of
one ecological community gradually
changing into another.
 The
final stage of ecological
succession in a land ecosystem is a
climax community – a stable
community that no longer goes
through major ecological changes.
 In
a tropical forest biome, a mature
tropical forest is a climax community.
 Climax communities are usually stable
for hundreds of years.
 Ecological
succession in new areas of
land with little or no soil, such as a
lava flow or sand dune, is primary
succession.
 The first species that colonize new or
undisturbed land are pioneer species.
In areas where existing ecosystems have
been disturbed or destroyed, secondary
succession can occur.
 Freshwater
ecosystems change over
time in a natural, predictable process
called aquatic succession.
 In aquatic succession the buildup of
decomposed remains accumulate over
time as soil.
 Eventually the water disappears and
the area becomes land.
Eutrophication is the process of a body
of water becoming nutrient-rich.
 Eutrophication
is a natural process, but
humans contribute to it by introducing
fertilizer, waste, and other nutrient-rich
pollution to a body of water.
 High nutrient levels support large
populations of algae and other
microscopic organisms that end up using
most of the dissolved oxygen in the
water, leaving less available for fish and
other organisms.