Download Ecology Levels of Organization Ppt

Ecology
An Introduction to Ecology and the
Biosphere
The Scope of Ecology
 High in the sky, a series
of satellites circle Earth.
 These satellites aren’t
relaying the chatter of
cell phones.
 They are transmitting
data on the annual
migration of gray
whales.
The Journey of Gray
Whales
 Leaving their calving
grounds near Baja
California, adult and
newborn gray whales
(Eschrichtius
robustus) swim side
by side on a
remarkable 8,000 km
journey.
Headed to the Arctic
 The whales are
headed to the Arctic
Ocean to feed on the
crustaceans, tube
worms and other
creatures that thrive
there in the summer.
 Satellites track their
progress.
Recovery from Brink of
Extinction
 Satellites also help
scientists track the
recovery of the blue
whale from extinction.
 A century ago, whaling
had reduced the
population to only a few
hundred.
 Today, after 70 years of
protection, more than
20,000 travel to the
Arctic each year.
Questions for Ecologists:
 What environmental
factors determine the
geographic
distribution of gray
whales?
 How do variations in
their food supply
affect the size of the
gray whale
population?
What is Ecology?
 “oikos” = home, “logos” = to study
 The scientific study of the interactions between
organisms and the environment.
Studying Ecology at the
Organism Level:
 Studies how an
organism’s structure,
physiology, and (for
animals) behavior
meet the challenges
posed by its
environment.
 Ex: How do
hammerhead sharks
select a mate?
Organism: an individual form of
life that has the ability to act or
function independently.
Population Ecology
 A population is a group
of individuals of the
same species living in an
area.
 Population ecology
analyzes factors that
affect population size
and why it changes
through time.
 Ex:What is the carrying
capacity of the Kaibab
Forest whitetail deer
population?
Community Ecology
 A community is a group
of populations of
different species in an
area.
 Community Ecology
examines how
interactions between
species, such as
predation and
competition, affect
community structure and
organization.
Ex: What factors influence
the diversity of species that
make up a forest?
Ecosystem Ecology
Ex: What factors control
photosynthetic productivity in
the savannah grassland of
Africa?
 An ecosystem is the
community of organisms
in an area and the
physical factors with
which those organisms
interact.
 Ecosystem Ecology
emphasizes energy flow
and chemical cycling
between organisms and
the environment.
Biome Ecology
 A biome is a large region
characterized by a
specific kind of climate
and certain kinds of plant
and animal communities.
 Biome Ecology focuses
on the weather and
climate patterns of an
area (biogeography) that
Ex: How would a drought
determines what kinds of
affect the population of
organisms live there.
Black-footed Ferrets in the
prairie?
Global Ecology
Ex: How does ocean
circulation affect the global
distribution of crustaceans?
 The biosphere is the
global ecosystem-the
sum of all the planet’s
ecosystems.
 Global Ecology
examines how the
regional exchange of
energy and materials
influences the
functioning and
distribution of organisms
across the biosphere.
Now You Try!
 What level would a biologist be studying if
he/she were:
- Counting the number of offspring born to a pride of
lions?
- Observing how a drought affects the number of
blossoms on a Saguaro cactus?
- Determining the effects of warming ocean
temperatures on krill populations in the Antarctic?
- Observing the behavior of Arctic wolves as they
hunt migrating caribou in the Arctic?
What would an example
be of the following?




Individual organism
Population of that organism
Community of that organism
Ecosystem of that organism
 What biotic (living) factors and abiotic (nonliving)
factors would influence where and how that
organism lives?
 What are the limiting factors in that ecosystem?
Biotic Factors in an
Ecosystem
 Biotic Factors in an
ecosystem include those
related to the activities of
living things. Ex:
 Food availability
 Diseases & parasites
 Density of the population
 Human influence
Abiotic Factors in an
Ecosystem
 Nonliving factors that
affect population size
are abiotic factors.
 Weather & Climate
 Availability of Sunlight
 Availability of Water
 pH of water/soil
 Wind
 Rocks/soil/mountains
Habitat
(an organisms’ address)
 Habitat=the area
where an
organism lives.
 This includes the
biotic and abiotic
factors that affect
it.
What is the habitat for
this bullfrog?
Niche
(an organisms’ occupation)
 Niche=full range of
physical and biological
conditions in which an
organism lives.
 It also includes the way
in which the organism
uses those conditions.
 What makes up the
niche of this bullfrog?
Does feeding by sea urchins
limit seaweed distribution?
 W.J. Fletcher, of the University of Sydney,
Australia, reasoned that if sea urchins are a
limiting biotic factor, then more seaweeds
should invade an area from which sea urchins
have been removed.
 To isolate the effect of sea urchins from that of
another seaweed-eating animal, the limpet, he
removed only urchins, only limpets, or both
from study areas adjacent to a control site.
Seaweed
Cover
100%
Both limpets and
urchins removed
80%
60%
40%
Only urchins
removed
20%
Only limpets removed
0%
Control-neither
species removed
Time-August 1983-February 1984
Conclusion
 Removing both limpets and urchins resulted in
the greatest increase in seaweed cover,
indicating that both species have some
influence on seaweed distribution.
 But, since removing only urchins greatly
increased seaweed growth while removing only
limpets had little effect, Fletcher concluded that
sea urchins have a much greater effect than
limpets on limiting seaweed distribution.