MCHS BIOLOGY
Objective #5—
Biodiversity in
Ecosystems
How do the threats to biodiversity in
ecosystems show us how biodiversity is
important?
Mrs. Engelbrecht
2010-2011
MARENGO COMMUNITY HIGH SCHOOL
Biodiversity in Ecosystems
Objective #5
Objective #5a: I can explain what biodiversity is and why it is important.
Objective #5b: I can give specific examples of the 5 main threats to biodiversity: HIPPO
Objective #5c: I can explain an example of how biological magnification threatens biodiversity.
Objective #5d: I can predict how climate change can threaten biodiversity.
Activating Prior Knowledge
Go get a Biology textbook (one with a zebra on the cover). Look at the number of the textbook,
and remember it—this is the textbook you will be getting from now on.
A. Open your book to p. 116. Read the big RED headings, the big BLUE headings, and the small
RED headings on p. 116-128. Also, read all the pictures, diagrams, and captions on these pages.
Don’t read any little black words.
B. Then, in the spaces provided below, write 1-2 COMPLETE and beautifully constructed
sentences that PREDICT what information will be in that section. The first one has been done
for you as an example.
What is Biodiversity?
The Importance of Biodiversity
This section will be about the many different types
of life on earth, which is called biodiversity. There
are different types of biodiversity—genetic
diversity, which probably means the different
genes in each organism in a population; species
diversity, which maybe means the different types
of species on earth, and ecosystem diversity, which
I am going to guess refers to the many types of
ecosystems on the planet.
Extinction Rates
Factors that Threaten Biodiversity
C. Now, go back and read all the little black words on p. 116-128. As you read, go back to the
boxes above and make changes to the information you have in the boxes above. Go back and
change the example, as well, to reflect more accurate and specific information.
DO NOT write lists of copied information from the book—you should summarize in your own
words the KEY MAIN IDEAS of each section in the boxes above. Remember, knowledge is not
yours unless you can write it in your own words.
Vocabulary Practice
A. Go get 3 copies of the Word Map sheets (they’re double-sided). Create a Word Map for each
word in the box below, based on your reading and the summaries you created in your boxes
above. As you finish a map for one word, show it to your instructor for feedback.
biodiversity
habitat loss
biological magnification
introduced species
climate change
overexploitation
B. Choose ONE of the choices below to illustrate how you think the words are all connected:
1) A Concept Map (label all connectors, and it should NOT be a list of definitions—it
should make as MANY CONNECTIONS between the words as possible, and add words
if necessary. Only 1-2 words in the boxes, and one 2-3 words per connector!)
**Use the Inspiration Software on your netbook to do this!
2) A collage of pictures (Find pictures of each word AND how they’re connected on the
internet. Copy and paste them into an Open Office Writer or Word document, placing
them in key positions to show the connections. )
**To get your pictures to overlap, right-click on each picture, go to “Text
Wrapping,” and select “Behind Text.”
Then, underneath your collage, summarize how all of the words are connected, using all
the words! DO NOT write a list of definitions!
Reading for Understanding
A. As you are reading, underline any answers or parts of answers to the I can statements.
Objective #5a: I can explain what biodiversity is and why it is important.
Objective #5b: I can give specific examples of the 5 main threats to biodiversity: HIPPO
Objective #5c: I can explain an example of how biological magnification threatens biodiversity.
Objective #5d: I can predict how climate change can threaten biodiversity.
B. Mark the following as you read:
DGT = I don’t get this. I had to re-read this to try and understand it.
!! = I am surprised to find this out
?? = I have a question about this (write your question in the margin)
Biodiversity: Who Cares?
(Answer: Everyone Should!)
Did you realize that, during this entire unit, we have been discussing biodiversity, but you just
didn’t realize it? When we were learning what populations, communities, and ecosystems were, we were
indirectly talking about the amount of biodiversity on Earth. Biodiversity refers to all of the differences
that occur in life on Earth. For example, within populations, organisms of the same species have different
genes that make them different from one another. The human populations on Earth are all the same
species, yet each of us has a unique genetic combination (except for identical twins) that makes us different
from each other. In communities, there are different species living in the same area. For example, consider
a subdivision built along the Kishwaukee River—this community not only includes the humans that live in the
houses, but the fish and amphibians living in the river, as well as the bacteria and fungi in people’s houses
and in the soil. In ecosystems, there different abiotic factors that determine what types of organisms can
live in that ecosystem. This results in many different types of living things existing on our planet; only
certain types of species can live in the cold, arctic ecosystems, when compared to the different organisms
one sees in tropical rain forest ecosystems or in desert ecosystems. Thus, while the definition of biodiversity
is quite simple, the differences that biodiversity represents is quite large. It is also important that we
preserve the amount of biodiversity at every level—genetic, species, and ecosystem.
Stop & Think #1—Objective #5a
I can explain what biodiversity is and why it is important.
Using what you underlined while you read AND your note chart on p. 2 of this packet (see p. 118-120 of
your text if you realize you took poor notes the first time!), fill on the 2-column note chart below:
Question/Topic:
What is biodiversity?
Answer/Details:
Reasons why biodiversity is important:
Direct economic value:
Indirect economic value:
Aesthetic and scientific value:
As you can see, biodiversity on Earth is important for a number of reasons. However, the amount
of biodiversity is currently decreasing on Earth. The main reason for this decrease is because a lot of
species have become, or are in danger of becoming extinct, usually due to human activities. (So, this would
cause a decrease in populations. . . is this a density-independent or density-dependent factor?) This
means that the amount of biodiversity, which we just learned was very important, is being threatened.
What are those threats, and how can we stop them from decreasing biodiversity any further?
There are five main threats to biodiversity: habitat loss, introduced (or nonnative) species,
population growth, pollution, and overexploitation, and they are listed in the order of decreasing threat.
(Putting the first letters of these threats together spells the word “HIPPO,” a useful acronym for
remembering what they are.) Habitat loss occurs whenever a group of organisms’ habitat is destroyed by
human activities or disrupted in some way. Whenever an organism is brought to a new area where it did
not evolve, it is said to be an introduced, or nonnative, species. These introduced species tend to take
over an area by outcompeting the native species for resources, simply because they have no natural
predators in their new area. This will reduce the amount of biodiversity in an area, because the introduced
species will soon outnumber the native species. Population growth refers to human population growth,
and how our population on Earth is growing in an overall exponential pattern. As more and more humans
are added to the earth, they require more and more resources, mainly in the form of food, shelter, and
living space. (Think about all the resources you use on a daily basis. . . they all came from an organism or
other resource on the planet!) This means that we are using other organisms up to meet our needs, and the
overall amount of species is decreasing. Also related to population growth is the next threat to
biodiversity, pollution. With more and more of us on the planet, that means there are more opportunities
for us to pollute the earth. This pollution can range from nonbiodegradable plastics taking years to
decompose in a landfill to the oil spill on the Gulf of Mexico to a factory spewing polluting chemicals into
the atmosphere to cause acid precipitation. No matter what the type of pollution, it will decrease the
biodiversity on earth by killing organisms—either right away, or after years of pollutants trickling into
their ecosystems. Lastly, biodiversity decreases are also caused by humans overexploitation, or using an
excessive amount of organisms that have economic value. By overusing/overhunting organisms, either for
food or because they have something on them that can make humans money, we have caused the
extinction of many species, or have forced many species to the brink of extinction. Although we have
restored the numbers of some organisms that were about to go extinct, when the population sizes of these
organisms increase, they often lack the genetic diversity necessary to survive any environmental disaster
that may occur. For example, cheetahs were hunted for their fur and because people thought they ate
local livestock; their numbers dwindled to about 50 in some areas. As they became protected and were
allowed to breed again, the number of cheetahs increased, but the amount of genetic diversity did not.
(When you only have about 50 cheetahs in a population, inbreeding will occur, resulting in the same genes
being passed down to offspring more frequently.)
Stop and Think #2—Objective #5b
Objective #5b: I can give specific examples of the 5 main threats to biodiversity: HIPPO.
Fill in the chart below concerning examples of each of the main threats to biodiversity. For the second
column, you may research examples of each threat on the internet. The third column must be from your
head.
Threat to Biodiversity
Example from text, reading, or
internet
An example of the threat in
Marengo:
Habitat Loss
Introduced Species
Population Growth
Pollution
Overexploitation
While there are five main threats that are presently decreasing biodiversity, pollution was the first
factor that we noticed causing as decrease in biodiversity. Scientists were noticing that some eagle species
would lay their eggs, but the eggs would be soft and leathery, and break open easily—killing the poor
baby eagle inside. This would decrease their population size by decreasing their birth rates (not all
pollution, you see, kills organisms directly—sometimes it just makes them unable to reproduce!). They
wondered why this was happening. After some research, they learned that the problem with the eagles’
reproduction was due to a pesticide being sprayed on crops called DDT. It wasn’t that the eagles were
being directly exposed to the pesticide; rather, they were ingesting concentrated doses of the pesticide
because they were at the upper trophic levels in the food chains in their ecosystem. The pesticide was
sprayed on crops, and washed away during rains into local aquatic ecosystems. Producers then
incorporated the DDT into their tissues. Primary consumers, such as fish, then fed off the producers, and
incorporated the pesticide into their tissues, but at a much higher concentration. When the eagles ate the
fish, they incorporated the pesticide into their tissues at an even higher concentration. This affected how
the eagles laid their eggs and, ultimately, their ability to reproduce. Thus, it seems that the pesticide made
its way up the trophic levels, becoming more and more concentrated in the tissues of the organisms at the
higher trophic levels. This process is called biological magnification, or biomagnification. It decreases
the amount of biodiversity in ecosystems by causing reproductive problems in organisms, thus decreasing
the birth rate of populations so the overall number of species on Earth is decreased.
For a more detailed description of how DDT moves up the trophic levels, the consequences, and what we
can do to prevent this threat to biodiversity, click the link below and read the flyer:
http://www.sfenvironmentkids.org/toxics/bio_mag.pdf
Stop and Think #3—Objective #5c
I can explain an example of how biological magnification threatens biodiversity.
1. Re-read the picture and caption on p. 126 of your textbook. Summarize how toxins and pollutants
increase in concentration as you move up the trophic levels:
2. Why is this process called biological magnification?
3. Fill in the cause-effect chart below. You are give the primary cause; you must chain AT LEAST three
effects from the cause given. (You can have more than three.) Read the background information first
before completing the cause-effect chart.
Background info:
Dioxin or TCDD (tetra-chloro-dibenzo-dioxin) is a very toxic chlorinated hydrocarbon. It is an unintentional by-product of many
industrial processes, including waste incineration, chemical and pesticide manufacturing, and pulp and paper bleaching. It is the primary
toxic component of Agent Orange, the defoliant used in Vietnam that poisoned thousands of U.S. troops and countless thousands of
Vietnamese people. A normal level of dioxin is about 14 to 45 units per gram of blood fat. Almost everyone has some level of dioxin
because this toxic chemical is widespread in the environment and accumulates as it moves up the trophic levels.
CAUSE:
Your neighbor next door is remodeling his deck; He throws the siding he removed to put the deck up in his burn
pile along with other construction debris and sets it on fire.
EFFECT #1:
EFFECT #2:
EFFECT #3:
4. Summarize your cause and effect chart in a beautifully constructed paragraph in the space below. You
MUST use all of the words in the box below !
biological magnification
because
therefore
causes
as a result
Another process started by human pollution of the environment is climate change. A very general
definition of climate change is any significant change from what is considered the norm for a particular
climate. How are humans connected to this? Well, since the Industrial Revolution began in the early
1800s, we have been building more and more factories and industries that release so-called “greenhouse
gasses” into the atmosphere. Carbon dioxide (CO2) is one of these gases, and it traps heat in the
atmosphere. We have also been clearing more and more forests on which to built houses and develop as
agricultural land. This means that these trees, which would normally have been there to take up excess
carbon dioxide, are now gone, leaving the excess CO2 in the atmosphere. Now, when life was new billions
of years ago, CO2 and other greenhouse gases made global temperatures warm enough for life to
exist—including us! Because there is now much more carbon dioxide in the atmosphere, more heat is being
trapped there, which may cause an increase in global temperatures. This increase in temperatures will
alter energy flow patterns through ecosystems, often with dire consequences. For example, an increase in
2oC overall global temperatures would cause it to be too hot for some staple crops (i.e., corn) to be grown
in some areas, which would lead to food shortages in the long run. While some measures have been taken
by governments to reduce overall greenhouse gas emissions, it is still uncertain how these greenhouse gases
are affecting global climates.
Stop and Think #4—Objective #5d
I can predict how climate change can threaten biodiversity.
1. You just read some background information about the causes of climate change above. Read the cause
given to you below, and DESCRIBE THE EFFECTS THAT WOULD EVENTUALLY END IN A
DECREASE IN THE AMOUNT OF BIODIVERSITY. (You can have more than three!)
CAUSE:
Factories and cars are releasing large amounts of carbon dioxide into the air, while we cut down trees and clear land
of plants to build houses and create more farmland.
EFFECT #1:
EFFECT #2:
EFFECT #3:
2. Summarize your cause and effect chart in a beautifully constructed paragraph in the space below. You
MUST use all of the words in the box below !
climate change
because
therefore
causes
as a result
Making Connections—Putting It All Together
On the next page, you will find several boxes. In each box with an I can statement at the top,
answer the I can statement as specifically and thoroughly as possible IN YOUR OWN WORDS.
(Make your own meaning!)
In the large box at the bottom, connect all of the answers to the I can statements to answer the
BIG question for this objective. The answer to the BIG question must have a topic sentence, use
transition words, and the answers to the I cans must flow logically from one to the next.
Remember, here is where you SHOW ME THAT YOU UNDERSTAND—not just the answers
to the I can statements, but how all the answers are CONNECTED to each other.
Objective #5a: I can explain what biodiversity is and why it is
important.
Objective #5b: I can give specific examples of the 5 main threats to
biodiversity: HIPPO
Objective #5c: I can explain an example of how biological
magnification threatens biodiversity.
Objective #5d: I can predict how climate change can threaten
biodiversity.
How do the threats to biodiversity in ecosystems show us how important biodiversity is?
Question Levels—Practice
Look at the answer for Objective #5b. For this objective, write a level 1, 2, 3, and 4 question that
you could put on a test. Refer to the types of questions and levels sheet on the “Documents”
section of the website. (It’s also on the flow chart at the front of the room.) They can be any
format you want, but only ONE can be a multiple choice question!
Remember, a Level 1 or 2 question involves finding the answer in a reading or text; Levels 3 or 4
involve finding the answer in a student’s head.
Level 1 Question:
Level 2 Question:
Level 3 Question:
Level 4 Question:
Rating Your Understanding of the I Can Statements
Biodiversity in Ecosystems
1 = Beginning
2 = Progressing
3 = Proficient
4 = Advanced
5A. I can explain what biodiversity is
and why it is important.
5B. I can give specific examples of the
five main threats to biodiversity:
HIPPO
5C. I can explain an example of how
biological magnification threatens
biodiversity.
5D. I can predict how climate change
can threaten biodiversity.
Determine Your Understanding of the I Can Statements
1)Take the Exit Ticket provided by your instructor.
2) Check your answers when you are finished.
3) Mark whatever you did not get correct on your exit ticket.
4) Re-rate yourself on how well you have mastered the I can statements in the rubric above.
5) Staple this page to the back of your Exit Ticket and turn it in to your period’s box.