Download Ecology

Ecology
Ecology
• Ecology = the
study of the
interactions among
organisms and
their environment
Abiotic Factors
The nonliving or physical
things in an environment
are called ABIOTIC
factors.
-
-
Examples:
Sunlight
Temperature
Rainfall
Air
Soil
Earthquakes
Biotic Factors
The living or biological
things in an
environment are called
the biotic factors.
Examples:
• parasitism
• disease
• predators
• prey
• competition
Levels of Organization
• Ecologists study
organisms ranging
from the various
levels of
organization:
– Species
– Population
– Community
– Ecosystem
– Biome
– Biosphere
Levels of Organization
Species =a group of similar organisms that
can breed and produce fertile offspring
Levels of Organization
Population =group of organisms, all of the
same species, which interbreed and live in the
same area.
EX: all the turtles in Town Lake
Levels of Organization
Community = a collection of different
populations that live together
Levels of Organization
Ecosystem = a collection of interacting populations
and their physical surroundings (abiotic factors)
Levels of Organization
Biome = a group of ecosystems with the same
climate and dominant communities
Tropical rain forest
Temperate grassland
Temperate forest
Tundra
Tropical dry forest
Desert
Mountains and
ice caps
Tropical savanna
Temperate woodland
and shrubland
Northwestern
coniferous forest
Boreal forest
(Taiga)
Levels of Organization
Biosphere= the part
of the earth where life
exists including land,
water, air, and
atmosphere
• It extends from high in the
atmosphere to the bottom of
the oceans.
• If the earth could be shrunk to
the size of an apple, the
biosphere would be no thicker
than the apple's skin.
Habitat vs. Niche
HABITAT
• Place where an
organism lives
• Lots of organisms
have the same
habitat
NICHE
• Role and position a
species has in its
environment
• Organisms want a
unique niche
Habitat vs. Niche
HABITAT
• Ex: red fox’s
habitat is the
forests’ edge,
meadows, and
river bank
NICHE
• Ex: red fox’s niche is
a predator which
feeds on the small
mammals etc. that is
active at night
Symbiotic Relationships
Symbiosis =
permanent (living
together)
relationship between
two different
organisms
3 types:
1. Mutualism
2. Commensalism
3. Parasitism
Symbiotic Relationships
1. Mutualism = when
both organisms
benefit from each
other
EX: clownfish and sea
anemone
EX: lichen
EX: flower and bee
Symbiotic Relationships
2. Commensalism =
one organism
benefits, the other is
not helped or harmed
EX: pilot fish and shark
(fish eats scraps from
the shark’s food)
Symbiotic Relationships
3. Parasitism = one
organism benefits,
the other is harmed
EX: tapeworms
EX: ticks
Predation Relationships
• Predator = an animal
•
that feeds on another
animal
Prey = that animal
that is killed and eaten
EX: lion (predator) hunts
and eats the zebra
(prey)
Population Size
• Size of a population
•
•
changes over time.
Most populations
stabilize rather than
grow endlessly.
Why? Because of
demands on the
ecosystem (ex.
Enough food?)
Limiting Factors
• Limiting Factors =
any environmental
factors that limit the
size of a population
EX:
- Availability of food
- Availability of water
- Availability of oxygen
- Availability of sunlight
Density- Dependent Limiting Factors
• Limit the growth of a
•
population when the
pop gets to a certain
size
Population density =
the # of organisms in
a given area
Density- Dependent Limiting Factors
Two Main Factors
1. Competition- when a
pop gets big,
organisms compete
for available
resources
EX: group of trees
fighting for sunlight,
soil, or water
Density- Dependent Limiting Factors
2. Predation – if the
predator
population
becomes too
large, there will
not be enough
prey to support it
Density-Independent Factors
• Limit the growth of a
population regardless
of its size
EX:
- Climatic events like
extreme cold/heat,
tidal waves,
volcanoes, flooding,
drought
Density-Independent Factors
• Diseases such as HIV, influenza,
tuberculosis, Bubonic Plague, and etc.
• They kill humans without the care of the
population.
Carrying Capacity
• Carrying capacity =
•
the largest population
that a given
environment can
support over a long
period of time
Important for
conservationists in
managing wildlife
pops
Carbon Cycle
• The cycling of carbon dioxide
from the atmosphere through
the land and back.
• Processes of photosynthesis
and aerobic respiration had
this cycle balanced.
• Industrial revolution brought
about the burning of fossil
fuels which increased the
amount of CO2 released into
the atmosphere.
• This excess of CO2
(greenhouse gas) has
increased the Earth’s
atmospheric temperatures
resulting in a climate change.
Water cycle
• The cycling of water
•
from the atmosphere
down to Earth and
back to the
atmosphere.
This cycle is driven by
solar energy.
Nitrogen Cycle
• The cycling of nitrogen from
the Earth to the atmosphere
and back.
• Nitrogen cycle was in balance
but the addition of fertilizers
along with burning of fossil
fuels has unbalanced the cycle.
• Excess of nitrogen in our water
systems results in
eutrophication.
• Eutrophication is also known
as alga blooms. It ends up
killing off all the organisms in
the system.
Oxygen Cycle
• The cycling of oxygen
from the atmosphere
through
photosynthesis and
aerobic respiration.
QUESTIONS
1. Which of the following is a symbiotic
relationship where both organisms
benefit?
a. mutualism
b. commensalism
c. altruism
d. competition
Questions
2. Which of the following pairs of animals
are most likely to have a predator-prey
relationship?
a. dog and tapeworm
b. buffalo and tickbird
c. spider and fly
d. whale and barnacle
Questions
3. Some species of shark allow small fish to
enter their mouths without eating them.
Inside the mouth, the small fish feed on
debris around the teeth. The sharks get
their teeth cleaned, which reduces the risk
of decay and infection. Which term best
categorizes this relationship?
a. predation
b. mutualism
c. commensalism
d. parasitism
Questions
4. Which of the following is a densitydependent limitation on population
growth?
a. wildfire
b. competition
c. unlimited nutrients
d. severe drought
Questions
5. Which cycle is responsible for the
increase in the Earth’s atmospheric
temperatures?
a. Water
b. Nitrogen
c. Carbon
d. Oxygen