TEKS 11C: Summarize the role of microorganisms in both maintaining and disrupting the health
of both organisms and ecosystems.
TEKS 11C: Summarize the role of microorganisms in both maintaining and disrupting the health
of both organisms and ecosystems.
How do microorganisms maintain the
health of ecosystems?
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Some microorganisms are decomposers that break down organic
matter into smaller pieces, eventually releasing raw nutrients back to
the ecosystem.
Some bacteria convert nitrogen and other nutrients to forms that can be
used by primary producers (plants and other photosynthetic organisms).
Specialized “oil-eating” bacteria help restore ecosystems
following oil spills.
Mycorrhizal fungi seem to
help ecosystems recover
following disturbances.
4. Use Analogies How are microorganisms similar to recycling plants?
TEKS 11C: Summarize the role of microorganisms in both maintaining and disrupting the health
of both organisms and ecosystems.
How do microorganisms disrupt the
health of ecosystems?
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Introduced fungi devastated populations of the American Chestnut in the
early 1900s. The death of the chestnut trees affected forest ecosystems
throughout the eastern United States.
The nuts of the chestnut tree were consumed by both humans and animals.
Chestnut leaves provided much nutrient content to the forest ecosystem.
Chestnut trees were replaced by oak, hickory, red maple, and sugar maple
trees throughout their range.
5. Infer The Chestnut blight fungus was accidentally introduced to the
United States around 1900. Why might microorganisms be most disruptive
when introduced to an ecosystem where they are not usually found?
(contd.)
TEKS 11C: Summarize the role of microorganisms in both maintaining and disrupting the health
of both organisms and ecosystems.
How do microorganisms disrupt the
health of ecosystems?
•
Populations of some usually harmless aquatic
microorganisms, including dinoflagellates and the
photosynthetic protist Euglena (seen here), can grow
exponentially following an influx of nutrients. Such
responses to added nutrients are called algal blooms, and
they can be very harmful to ecosystems.
• Algal blooms can block sunlight and disrupt
photosynthesis.
• Blooms of dinoflagellates, called red tides,
release toxins into the ecosystem.
• Increased rates of decomposition
following very large blooms can result
in dead zones, areas devoid of oxygen
that are inhospitable to multicellular life.
TEKS 11C: Summarize the role of microorganisms in both maintaining and disrupting the health
of both organisms and ecosystems.
Why couldn’t you survive a day
without bacteria?
•They process our wastes and make them usable again.
Without them – nothing would rot.
•They purify our water.
•Keep our soils productive
•Synthesize vitamins in our intestines
•Convert our food into useful sugars and polysaccharides
•Wage war on alien microbes that enter our digestive system
•Pluck nitrogen from the air and convert it into useful
nucleotides and amino acids for us.