BIO 2 GO!
Interactions of Organisms in an Ecosystem
3521 - Diversity
3522 - Succession
Interrelationships and Interdependencies among different organisms in
an ecosystem are affected by factors in the environment.
These relationships contribute to the stability of an ecosystem.
Objective: You should be able to
1. Explain the hierarchy of organisms interactions
2. Define biodiversity
3. Explain how diversity affects the ecosystem.
4. Explain and describe how succession happens.
5. Describe primary succession.
6. Describe secondary succession.
7. Use the following words in their correct context:
Biodiversity
Organism
Population
Community
Ecosystem
Biosphere
Succession
Primary succession
Secondary succession
Diversity
3521
Diversity is a good thing, in most cases. Biodiversity is the amount of
different species of organisms that occupy an area. The measure of the
amount of different types of organisms that can live in an area is a sign of
the biological complexity in that area. It is generally thought that an area
that contains a lot of different types of organisms is better off than an
area that does not show the same amount of diversity.
Interesting Scientific Fact: Biologists are monitoring the amphibian
population in areas of concern. It is thought that the number of amphibians
will show whether an area is healthy or unhealthy. The more amphibians
they are able to locate, the better the area.
REMEMBER THIS!!!
Biodiversity is the number of different types of organisms that can live
in an area. Biodiversity is usually a good thing.
It is helpful in understanding Biodiversity to also understand the
organization of organisms. Below is a helpful reminder of how organisms are
grouped.
Organism—Population— Community—Ecosystem—Biosphere
The organism stage refers to the smallest units. Organism refers to
the individual organisms. Population is a grouping of organisms. Finally, the
biosphere includes all organisms, populations, communities and ecosystems in
that area.
Similar organisms make up a population. Several populations of
different organisms make up a community. Several communities make up an
ecosystem. And several ecosystems make up the biosphere.
Biodiversity
Diversity is the variety of living organisms in a community. You may
have already heard the term biodiversity which is the measure of the
numbers of organisms living in an ecosystem. An ecosystem is healthy and
doing well if it has a lot of biodiversity. It means that there are a lot of
different types of organisms living there and that there is plenty of food.
That is good! Unhealthy ecosystems do not have a good biodiversity.
An example of an ecosystem with good biodiversity would be a forest
that has been untouched for hundreds of years. There are a lot of
different organisms there and there are lots of them. A forest that just
had a fire would not have good biodiversity because there are not many
plants or animals there anymore.
Interesting Scientific Fact: Airports do not like biodiversity. In fact, they
prefer an ecosystem that does not have ay flying organisms. Why? Because
flying organism, like birds, get in the way of the airplanes as they take-off
and land. Sometime larger birds, like geese, actually fly into the airplane
motors and create problems for the plane.
Question 1: Define biodiversity in your own words.
Student’s answers will vary
Question 2: Does the North Pole have more biodiversity or less biodiversity
then Maryland? Why do you think so?
Less- the environment is colder and there are more organisms in
Maryland.
Succession
3522
Succession
Ecosystems change over time. A shallow lake gradually fills in over time
and becomes a meadow. A forest burns and becomes a field. A beaver dams
a stream and creates a pond. These changes occur in a regular pattern and
are called succession. Succession is the change in an ecosystem from
simple to more complex. Remember a complex ecosystem is one that has
great biodiversity.
REMEMBER THIS!!!
Succession is a process where the ever-changing environment favors one
species over another. Certain species will replace another species
because they are more suited to the new environment.
After a forest fire, new sun-loving plants are often the first to begin the
secondary succession. As they grow and create shade, shade-loving plants,
such as maple trees, grow and create even more shade. The increased shade
creates a lack of sunlight for the sun-loving plants. Because of the shade,
the sun-loving plants fail to reproduce. The sun-loving plants are replaced in
the ecosystem by the shade-loving plants that reproduce successfully in the
shade.
There are two types of succession: primary and secondary.
1. Primary succession is when plants grow where they have never
grown before, such as on a new volcanic island.
2. Secondary succession is when plants grow in an area that had
plants growing before, such as a field or forest that was cleared.
A good definition of primary succession is when life begins to grow in
an area that previously did not support life. It is also defined as the type
of succession that occurs where no ecosystem existed before.
Primary succession can occur on rocks, cliffs, and sand dunes. Usually the
first species to begin primary succession is some type of algae or moss-both
are very hardy and simple plants. You normally see them as a green film
growing on the shady sides of trees and sometimes houses. Once these
pioneers get established, they can change the area so that more complex
organisms can live there.
Secondary succession is more common than primary succession.
Secondary succession occurs in ecosystems that have been disturbed or
disrupted.
A good example of secondary succession is when a fire destroys an area
and the plants and animals begin to reestablish themselves in the area that
was burned.
Question 3: What is the major difference between primary and secondary
succession?
Primary succession occurs where nothing has been before, secondary is
when organisms return to an area that was disturbed by a disaster.
Question 4: Give an example of secondary succession around where you live.
Student’s answers will vary.
TEST YOURSELF
True or False
__T_ 1. Ecosystems are made up of a bunch of communities.
__T_ 2. A community includes all the species within an area.
__T_ 3. The number of species living within an ecosystem is a measure of its
biodiversity.
__F_ 4. The major difference between primary succession and secondary
succession is that primary succession occurs only on land and
secondary succession occurs in ponds and lakes.
__F_ 5. A receding (melting and moving farther north) glacier is a good
example of secondary succession.
__F_ 6. A population is a grouping of different communities.
__F_ 7. Ecosystems usually never change over time.
__T_ 8. The biosphere contains all ecosystems in an area.
Matching
A. Measures the number of
species living within an
ecosystem.
__C__ 1. Succession
__E__ 2. Population
__G__ 3. Community
__A_ 4. Biodiversity
__F__ 5. Primary Succession
__B__ 6. Organism
__H__ 7. Ecosystem
__D__ 8. Secondary Succession
B. One particular member (an
individual)- is the smallest unit.
C. Regular progression of species
replacement in an environment.
D. Example of when plants grow in
an area that had plants growing
before.
E. A group of organisms living
together in a particular place.
F. When plants grow where there
have never been plants before.
G. A number of populations living
in the same area.
H. A number of communities living
in the same area.
Fill in the Blank
secondary succession
ecosystem
population
biodiversity
primary succession
1. The number of species living within an ecosystem is a measure of its
_BIODIVERSITY_____________.
2. Plants growing in an area where there were once plants before is called
_SECONDARY SUCCESSION________.
3. A grouping of similar organisms is called _POPULATION__________.
4. An _ECOSYSTEM_______ is made up of several communities.
5. _PRIMARY SUCCESSION________ is when plants grow where there
have never been any before.
Answer the following:
1. How do you think succession is related to diversity?
The longer succession continues the more diversity there will be in
n ecosystem.
2. Which are would have a better biodiversity, a place where primary
succession is happening or an area where secondary succession is
happening? Give a reason why you think so.
Student’s answers will vary
3. How does biodiversity affect an ecosystem?
The more there is the healthier the ecosystem.