Define and give an example of biotic and abiotic factors.
Outline the importance in biodiversity in the health of an
ecosystem. What is a keystone species and how does it affect its
ecosystem? Give an example. Objectives
Slide 3
Include living and nonliving components Biotic Factors: living
things, such as plants and animals, that each play a particular
role in the ecosystem Abiotic Factors: Nonliving things, such as
moisture, temperature, wind, sunlight, and soil, which determine
what living things can survive in a particular environment
Ecosystems
Slide 4
Observation: More fish in coral reefs near marshes than out to
sea Biotic Factors: Fish, mangrove trees, other plants within marsh
Abiotic Factors: Oxygenation in mud, salinity of ocean, tidal
changes The mangrove trees protect newly hatched fish, who when
they mature swim to the reefs The ability of the mangrove tree to
survive is greatly affected by the ocean, and the fishes survival
is dependent upon the mangrove trees survival Caribbean Sea
Ecosystem
Slide 5
What is our ecosystem? Biotic Factors? Abiotic Factors? How
could each of these things affect the overall health of our
ecosystem? Example
Slide 6
Ecosystems can look similar from one year to the next, but they
are actually quite dynamic The amount of precipitation can change
the dominant plant species, which can change the communities
composition (the number of plants is similar, but the species is
different) This can change the animals that get their food from
this area As these cyclic changes occur, an ecosystem falls into
balance, which is called an approximate equilibrium What changes
occur in our ecosystem, and what is our approximate equilibrium?
Ecosystems Are Always Changing
Slide 7
The change of a biotic or abiotic factor can affect all of the
organisms in an ecosystem Changes that can affect an ecosystem:
Biodiversity Keystone Species One Factor Can Affect Change
Slide 8
Biodiversity: Assortment, or variety, of living things in an
ecosystem Rainforest: high level of biodiversity, which accounts
for more than 50% of the plant and animal species on the planet
Amount of biodiversity depends on many factors, including moisture
and temperature Biodiversity
Slide 9
Complex ecosystems are dependent on very few important parts of
the web, that when disturbed can have a significant effect on the
health of the ecosystem A species that has an unusually large
effect on its ecosystem Example: Beavers Keystone Species
Slide 10
Beavers fell trees to construct dams Change free-flowing
streams into ponds, wetlands & meadows Changes to the
ecosystem: Wider variety of fish in still water of pond Attraction
of birds that eat the above fish Insects are attracted to the pond,
which brings insect eating birds as well Waterfowl nest near the
pond, which brings in prey animals that eat the eggs Beavers can
greatly change their environment, and the loss of them can severely
impact the ecosystem Beavers
Slide 11
Slide 12
Sea Otters Sea Otters are also a keystone species, because they
eat sea urchins Sea urchins, if allowed to populate the ocean
without a predator, eat all of the available kelp The loss of kelp
means less food for crabs, snails, and geese It also means that
species of fish that hide in the kelp from predators are heavily
eaten and their numbers drop dramatically, further upsetting the
ecosystem
Slide 13
Slide 14
Outputs 1.We live in the Sonoran Desert. Name three biotic and
abiotic factors. 2.Compare with your neighbor and write down one
biotic and abiotic factor that you did not have. 3.Hummingbirds are
a keystone species in the Sonoran Desert. Give 3 reasons why you
think this is.
