Download Ecological Succession

2/27/2013
OH Grade 6-8, Science
Standard
 Life
Environmental
Changes and
Extinction Pt. 2
Mr. Gluckin’s Science class
2/27/13
Study Island Lesson 3h
OH Grade 6-8, Science
Standard
 Life
Sciences D
how extinction of a species occurs
when the environment changes and its
adaptive characteristics are insufficient to
allow survival (as seen in evidence of the
fossil record).
 Covered by topics:
 Adaptation & Natural Selection
 Ecosystems: Energy Transfer & Population
Dynamics
 Environmental Changes & Extinction
 Explain
Sciences C
how energy entering the ecosystems as
sunlight supports the life of organisms through
photosynthesis and the transfer of energy through
the interactions of organisms and the environment.
 Covered by topics:
 Ecosystems: Energy Transfer & Population Dynamics
 Environmental Changes & Extinction
 Organism Interactions
 Explain
Learning Goals:
I
will know what ecological succession is
and the effects on the environment
 I will be able to explain evolution and
extinction and adaptations and how
these help populations to survive and
thrive
Before we begin …
Ecological Succession
 Get
a piece of paper and something to
write with.
 Put up a
when you have done this,
please!
 Ecological
succession is the process
by which an ecosystem undergoes
a series of changes as communities
of organisms change their
environment and new communities
of organisms move into the
ecosystem.
1
2/27/2013
Ecological Succession
2
Types: Primary and Secondary
 If
A drastic ecological disturbance, such as a
forest fire, could cause ecological succession, as
new species move in where old species once
were.
succession begins in a new, unoccupied
habitat where there is no soil present, it is
called primary succession
 Primary succession can occur after severe
landslides or volcanic eruptions
 Development of an ecosystem in an area
where life did not exist before
Primary Succession Stages
Primary Succession Stages
 During
 As
succession, producers typically
enter the developing ecosystem before
consumers.
 Succession begins when the first
organisms, usually lichens or mosses,
colonize a bare rock. Acids from the
lichens and mosses weather the rock.
 Eroded sediments combine with bacteria
and dead lichens and mosses to form a
thin layer of soil.
soil forms, more and more plants are
able to grow in the area.
 Grasses usually grow in this thin layer of soil
first, followed by shrubs and, eventually,
trees. This attracts insects and other
animal species.
 Over time, the soil layer thickens and the
biodiversity of the community increases.
Primary Succession Stages



After many years, a stable ecosystem
develops. Often, this is a forest ecosystem.
Depending on the ecosystem’s abiotic
factors, however, a stable ecosystem may be
a mature desert community, a coral reef, or
any other kind of ecosystem on Earth.
The final stage of ecological succession is
called the climax community and the species
in this community are in relative equilibrium.
2
2/27/2013
A brand new island!
Google Earth
http://www.vulkaner.no/n/surtsey/esurtplant.html
http://www.surtsey.is/index_eng.htm
Kasatochi Volcano: Eruption
and Recolonization Google Earth
 Aug.
6, 2008
 Oct.
23, 2008
http://alaska.usgs.gov/science/kasatochi/field_work/field_work.php
http://geology.com/usgs/kasatochi-volcano/
Succession Takes Time!
Ecological Succession
 If
there is a disturbance in an area but soil
is still present after the disturbance, this
change in species structure is known as
secondary succession.
Evolution
Adaptation vs. Extinction
 Adaptations
are what organisms use to cope with
and survive environmental pressures.
 Populations that have diverse trait variations have a
better chance of adapting to changes in their
environment.
 These populations that can adapt will survive,
reproduce, and pass on their strong genes. Those
that cannot will eventually die-off, and become
extinct.
 This process is also known as natural selection, or
“survival of the fittest.”
 As
natural selection takes place, a
species will gradually change from
generation to generation; this
process is also known as evolution.
 Again, these adaptations usually
take place in response to an
environmental factor.
3
2/27/2013
Evolution
Example
 If
birds migrate to an area where it is easier
to catch food with a longer beak, those with
shorter beaks are less likely to survive.
 Those with the longer beaks will continue to
prosper and pass along their "long beak
genes." The shorter-beaked birds might
eventually die-off completely.
 The birds of that area have now evolved to
having longer beaks.
Two types of evidence
for evolution
fossils are found, scientists
examine the bones and try to determine as
much as they can about the past animal in
order to compare it to present day animals. This
allows them to determine what modern
animals might have evolved from the fossilized
creature.
 Anatomical and Physiological Similarities—We
can tell that two types of fish are related based
on their anatomy and physiology. We can see
whether they have similar shapes of fins, or
whether they have similar eating habits.
Evidence of
Evolution
 When
talking about evolution, biologists often
refer to one species of organisms being
related to another species.
 This is similar to the way you are related to
your family because there is a genetic
connection, but it is also different in some very
important ways.
 Evolutionary relationships are relationships
between species, not individuals. They are
also very distant relationships compared to a
family.
FILE TRANSFER – Today’s Slides
1.
 Fossils—When
3.
2.
Questions?
(If you don’t have a questions,
you are free to go!)
 Raise
your hand and use the mic
when I call on you
OR
 Write
it in the chat and hit enter when I
call on you
 Thanks for coming today 
 Do a pathway in Math and Reading
everyday!
4