Lesson: Succession
Unit: Ecosystems
Purpose: to teach students the process of succession in nature
Age Level: 4th-6th grade
Time: 45 minutes
Materials: five overhead sheets, overhead markers(4 green, 4 brown,
4 red), 30 sheets of paper,
makers/crayons.
Participants: 30
Plan: (5 minutes) Discuss Succession
Ask students if they know what succession means. Write the definition
on the
board: A non-seasonal, directional and continuous pattern of colonization
and extinction on a site by species population. Tell them this is a
long and confusing definition and ask them to figure it out with you.
Take it apart by sections. For example, what do they think non-seasonal
is? It means it's not affected by seasons. And directional means it's
a process moving in one direction. Continuous pattern of colonization
and extinction, means it is a cycle of growth and death. Tell the students
there are two types of succession. One is primary succession, which
is when a species starts for the first time in a new habitat. An example
of this is after a volcanic eruption. New species start growing in the
volcanic ash, which is a different habitat than what it was before the
eruption. Tell them the other type of succession is secondary succession,
which happens after a disturbance to a habitat. Disturbances can be
forest fire, crop harvest, or tree falling. Tell the students we are
going to explore secondary succession a bit more.
(15 minutes) Re-growth of a forest
read the following story
'Jane and John and their parents loved to go for picnics in the woods
by their house. It was a forest of mainly beech and maple trees. But
one day there was a huge forest fire in the valley. Jane and John were
extremely saddened. Shortly there after the family moved away and Jane
and John thought they would never see the forest the way they remembered
it again.
One day, a few years later, their father suggested that they go back
and visit their forest. Jane and John were not very excited because
they remembered how sad looking the ash and burnt stumps had been, but
they went anyway. When they got to the forest they were overjoyed. There
were grasses and wildfires and even berry bushes. They spent the day
walking around and picking berries. John said that when he had children
he was going to bring to their valley to pick berries.
Well, Jane and John grew older and John moved far away from the valley.
Years later, Jane went back to the valley and found small trees and
shrubs had grown where the grasses were before. There were lots of sassafras
and sumac trees.
John had married and had kids, and remembered his promise to himself.
He took his children on a trip to the valley, but when they arrived
he could not find the berry bushes that he had remembered. Instead their
were early successional trees like dogwood and elm. Although they did
not pick any berries, they had a lovely day of walking through the woods.
Many years later, after Jane and John had both passed away, Jane's great-grand
daughter found a letter that Jane had written to John. Jane had described
the forest in the valley to John. Jane's great grand daughter decided
to find this forest that her great grandmother had talked so fondly
about. She found a forest of late successional trees. There were many
beech and maple trees.
Jane and John had never dreamed that their great grandchildren could
enjoy the forest just as they had when they were young. The forest had
rebuilt itself back up after the fire.'
discuss the story
Ask the students, What came first after the fire? Then what? They should
come up with first grasses, flowers and berry bushes; then shrubs and
small trees, like sassafras and sumac; then early successional trees,
like dogwood and elm; then late successional trees, like beech and maple.
Talk about how long it took the forest to grow back. Have them look
back at the definition of succession and see if this story fits. Ask
them what the disturbance was: the fire.
3) draw the succession
Split the class in to four groups. Ask the class to describe what the
forest looked like after the fire. Draw this on one of the overhead
sheets. Make sure to use the short side as the bottom. Then assign every
group a step of the succession. The four groups are: grasses, flowers,
berry bushes; shrubs and small trees; early successional trees; late
successional trees. Have each group draw what the forest looks like
during their period of the succession. So the early successional group
will draw dogwood and elm trees. [trouble shooting- only hand out brown,
green, and red markers so that the kids don't color in the sky or draw
the sun]. Tell the students that each person in the group can draw one
thing than they pass the marker to the next person. Tell them that everyone
needs a chance to contribute. When they are finished collect the markers.
Putting it together
Hold up the burnt forest and ask the students what comes next. Place
the next sheet on top of the old one. Continue this until you have all
of the sheets on top of each other, until you have the complete re-growth
of the forest.
(15 minutes) When a tree falls
Tell the students you are going to explore another example of secondary
succession. Tell them another disturbance that can cause succession
is a tree falling in a forest.
Brainstorm and discuss what would happen when a tree falls. Ask them
the first
thing that happens. The wood will start decomposing into soil. Termites
and worms help with this process. Then a seed may fall on the decomposing
wood. How might the seed get there? The wind may blow it there, or a
bird may put it there. Then the seed grows in to a seedling, using the
rich nutrients from the fallen tree. The dead tree becomes more and
more soil, and other grasses and mosses grow on it. The seedling grows
in to a tree.
Give them each a piece of paper. Have them fold it in half once, and
then
again, so that their paper is divided into quarters. Have them trace
the lines so they have four distinct boxes.
Instruct them to draw the succession of the tree falling on their paper.
In the
first box we see the tree down. In the second box we see the tree becoming
soil, mosses and grasses growing, and a seed on the old tree. In the
third box we see a seedling (small tree). And in the fourth box we see
a full grown tree, and the tree below it as become soil.
sharing
Have the students share their work with each other. Have them partner
up and
describe to their partner, using their pictures, what happens when a
tree falls.
Objectives:
Students will illustrate secondary section in groups and individually
Students will describe the process of secondary succession to a partner
Students will listen to a story and identify the different steps of
succession in that story
Outcomes:
Students will learn about the ecological process succession, and how
it occurs in nature
Students will gain appreciation for the environment by exploring it's
complex cycles
Students will gain communication skills by describing a process to a
partner
Students will gain analyzation skills, through analyzing a story and
breaking it apart into parts
Justification of importance of Outcomes:
Learning how a community changes over time and how materials are cycled
throughout an ecosystem satisfies the Michigan State Framework Standard
in Science III.5.LE.2
Students need to understand the environment they live in so that they
can appreciate it and live in a way that protects it.
Communication skills are life skills. Many occupations require people
to be able to explain and describe a process or product.
Many occupations also require students to be able to analyze.
