Transcript Ecosystems & Their Components

8.L.3.1
Messana
Science 8
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Dynamic – change & vary over time
Biodiversity is looked at to indicate health
A complex, interactive system that includes:
◦ 1. Biotic components (living)
 Exs: bacteria, fungi, plants, animals
◦ 2. Abiotic components (nonliving, physical
or chemical)
 Exs: water, oxygen, nitrogen, salinity, pH,
soil nutrients & composition, temperature,
amount of sunlight, precipitation
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Species = same organisms that can breed
with each other
Populations = small group of same species in
the same location/geographic area
Communities = different populations that
interact together within a certain area
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Ecosystem = communities of organisms &
their abiotic factors living together, sustained
by the continuous flow of energy
Biosphere = all ecosystems on Earth
 Population
#s fluctuate at a
predictable rate
 Supply of resources fluctuates
at a predictable rate
 Energy flows through at a
fairly constant rate
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Habitat: the place where an organism
lives. It supplies all the biotic and abiotic
factors the organism needs to survive.
Niche: an organism’s role/”job.”
what it eats, how it eats and what eats it…
If the niche of one organism overlaps the niche
of another organism, you have competition!
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What is Reginald’s habitat?
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What is Reginald’s niche?
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Measures the # of individual organisms
living in a defined space
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Carrying Capacity = the # of individuals
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Limiting Factors = things that can
that an environment can support
change within an ecosystem and will
regulate/change a population (its size,
density, distribution)
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1. Density-Dependent Factors:
◦ Affect a large population more strongly than small
◦ Triggered by density (crowding)
◦ Ex: Competition for food, shelter, territory, or mates;
predation, parasitism, disease
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2. Density-Independent Factors:
◦ Occur regardless of how large the population is
◦ Reduce size of all populations in area by same %age
◦ Ex: Weather changes, human activity – pollution,
natural disasters (fires/floods), drought
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3.Biotic Factors
4. Abiotic Factors
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Predation = an interaction between species in
which one species eats the other
Predator eats the Prey!!
Ex: Whale Shark eats plankton and small
fish
Ex: Red wolf eats deer, swamp rabbits, etc
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As prey population increases, predator
population increases (more food available)
As predator population increases, prey
population decreases (prey are easier to find,
more get eaten)
Predator-prey density fluctuates in a
predictable cycle  stable ecosystem
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Competition = occurs when 2 or more organisms
need the same resource at the same time (food,
shelter, water)
Can be among members of same or different
species
Occurs when organisms share same niche
Ex: Hawks and fox eat mice
Results in decrease in population of species that is
less adapted to compete
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Symbiotic Relationships:
Between organisms of 2 different species that
live together in direct contact
Fluctuations in populations of 1 species will
affect the other
1.Parasitism
2.Mutualism
3. Commensalism
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Parasitism = symbiotic relationship where
one organism (the parasite) benefits at the
expense of the other organism (the host)
Usually parasite does not kill host
Some parasite live within host – tapeworms
Some parasites feed on external surface of
host – fleas, aphids
Ex: Mosquito sucking blood from
animals
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Mutualism = symbiotic relationship in which
both organisms benefit & they help each
other to survive
Ex: plant roots provide food for fungi that
break down nutrients the plant needs
Ex: bacteria can digest wood and live in
digestive tracts of termites
Oxpecker Bird eats ticks and parasites, mammal
gets pest control
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Remora sharks have an adhesive disk on their
dorsal surface, with the help of which they attach
themselves to whales and then, clean the whale’s
skin and feed on the remains from the whale's food
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Commensalism = symbiotic relationship
where one organism benefits and the other is
not affected positively or negatively
Glass shrimp, which are almost completely
see through, will attach to the chocolate chip
sea star and take on its coloration. This
helps the shrimp camouflage itself so it is not
eaten by predators
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1. What are the essential components of a
habitat?
2. What are some of the “limiting factors” that
affect an organism’s survival?
3. Are wildlife populations static, or do they
tend to fluctuate, as part of an overall
“balance of nature”? Explain your answer.
4. Is nature ever really in “balance” or are
ecological systems involved in a process of
constant change?
How does this relationship help maintain balance
& stability in an ecosystem?
Let’s Find Out…
Animal Fight Club – What are they fighting for?
http://www.animalfightclub.com/
How does this relationship help maintain balance
& stability in an ecosystem?
Let’s Find Out…
Elephants Show Cooperation on Test
http://www.youtube.com/watch?v=CXcRw6Piaj8
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You will be going outside IN AN ORDERLY
AND QUIET MANNER.
Describe the school ecosystem
◦ What types of communities do you see?
◦ What populations of organisms do you
see?
◦ For three organisms, describe the habitat
and niche of each organism
What do all living organisms need?
• How might organisms in an ecosystem
interact?
• What factors would influence the size of a
population?
Do you think there is a limit to the size of a
population in an ecosystem? Explain.
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EQ: How do different factors in an ecosystem affect a population?