Transcript Q2 Ecology PowerPoint for Marine Bio

Niche
(page 2 of Q2 marine bio research packet)
Definition of niche
The way of life or “role” a
species plays in its
environment
Scientists focus on features
that can be readily measured:
where species lives
what time of day its active
what it eats
What does the niche include?
Range of conditions the species can
tolerate
Methods by which the species
obtains resources
Number of offspring a species has
Time of reproduction
All other interactions of the species
in its environment
Fundamental Niche vs. Realized Niche
(page 2 of Q2 marine bio research packet)
Fundamental niche
Realized niche
Range of conditions a species
can potentially tolerate
Range of resources a species
actually uses
Range of conditions species can
potentially use
Species may have to restrict
activity to avoid predators
Not realistic
Competition may prevent use of
a resource
Generalists vs. Specialists
(page 2 of Q2 marine bio research packet)
Generalists
Broad niche
Specialists
Narrow niche
Tolerate wide range of
conditions
Do not tolerate a wide range
of conditions
Use a variety of resources
Use only a few resources
Virginia opossum – found
across the United States, eats
eggs, carrion, fruits, plants
Koala – lives in Australia, feeds
on the leaves of only a few
species of eucalyptus trees
Habitat (where an organism lives)
(page 3 of Q2 marine bio research packet)
Abiotic factors
Physical and chemical factors in
an environment (non-living,
never living)
Temperature, humidity, pH,
salinity, oxygen concentration,
amount of sunlight, precipitation
Influence an organism in its
environment
Biotic factors
Factors in an environment that
are or have been alive
Determines when/how the
organisms reproduces
Focus on the food a species eats
and the way it is obtained
Influence an organism in its
environment
Tolerance
(page 3 of Q2 marine bio research packet)
• Organisms can survive within a wide range of environmental conditions
• Every species has its own range of tolerance, the ability to survive and
reproduce under a range of environmental circumstances
• Scientists can graph performance vs. the values of an environmental variable
Range of Tolerance/Tolerance Curve (page 3 of Q2 marine bio research packet)
• Optimum (or optimal) range – typically several factors (pH, temperature,
salinity) must fall within an organism’s tolerance range
•
Example – The swimming speed of a species of fish is fastest at intermediate
temperatures. The fish can survive and function at temperatures outside its
optimal range but its performance is greatly reduced. The fish will not survive
below its lower limit of tolerance and upper range of tolerance (tolerance limits).
Acclimation
(page 3 of Q2 marine bio research packet)
Definition of acclimation
Some organisms can adjust their
tolerance to abiotic factors
Goldfish raised at different
temperatures have different
tolerance curves
Living at high elevations will
help you acclimate to reduced
oxygen levels (RBCs increase
in your body over time)
What is the difference between
acclimation and adaptation?
Acclimation – changes in an
organism due to environmental
factors, occur within the lifetime of
an individual organism
Adaptation – genetic change in a
species or population, occurs over
many generations
Conformers vs. Regulators
(page 3 of Q2 marine bio research packet)
Conformers (Ectotherms,
Cold-blooded)
Organisms that do not
regulate their internal
conditions
Change as the external
environment changes
Leopard gecko and frog need
a heat lamp because they
can’t regulate their body
temperature
Regulators (Endotherms,
Warm-blooded)
Organisms that use energy to control
some of their internal conditions
Keep an internal condition within the
optimal range over a wide variety of
environmental conditions
Humans are regulators of
temperature
Salmon – conformers of temp,
regulators of internal salt
concentration (spend part of their life
in salt water and part in fresh water)
Escape from Unsuitable Conditions
(page 3 of Q2 marine bio research packet)
Dormancy
Migration
State of reduced activity
Organism wants to escape
unfavorable conditions
Occurs during periods of
unfavorable environmental
conditions
Move to a more favorable habitat
Winter temperatures are too
cold for reptiles and
amphibians to tolerate. They
hide underground until the
spring.
Seasonal migration of birds to avoid
low temperatures and scarcity of food
Spring and summer spent in cooler
climates and migrate to warmer
climates in the fall
Return to cooler climate in the
spring
Resources
(page 3 of Q2 marine bio research packet)
Definition of resources
The energy and materials a
species needs to survive in
an environment
What determines the survival of a
species in a particular habitat?
Suitability of environmental
conditions
Availability of resources
Food, energy nesting sites, water,
sunlight, etc.
Resources essential to survival vary
from species to species
Competition
(page 6 of Q2 marine bio research packet)
Definition of competition
Use of the same limited
resource by two or more
species
Results from fundamental
niche overlap
One organism will likely use
the resource more efficiently
and leave less resource for the
other species
What is competitive exclusion?
One species is eliminated from a
community because of competition
for the same limited resource
Species that uses the resource
more efficiently has a
reproductive advantage
Eventually eliminates other
species
What is the competitive
exclusion principle?
• States that no two species can
occupy the same niche in the same
habitat at the same time
• Direct competition between species
almost always produces a winner
and a loser
• Losing species dies out
Classic Example - Barnacles
Competition & Community Structure
(page 6 of Q2 marine bio research packet)
Character displacement
Competitors evolve niche
differences or anatomical
differences to lessen the
intensity of competition
Darwin’s finches –
different beak sizes in
seed eating finches
reduces competition
between species
Resource partitioning
Pattern of resource use
Competition most intense between
closely related species that require the
same resources
Similar species only use part of the
available resources
Three species of warblers, each
species feeds on insects in a
different section of spruce or fir
treees
Resource partitioning
Predator-Prey Relationships
(page 8 of Q2 marine bio research packet)
Predator
The “hunter” – captures, kills,
and consumes another organism
Predator’s survival depends
on its ability to capture food
Adaptations that improve
efficiency of predators are
acted on by natural selection
Predator-prey relationships
determine relationships in food
web
Prey
The “hunted” – organism that is
captured, killed, and consumed
Prey’s survival depends on its
ability to avoid being captured
Natural selection favors
adaptations that allow prey to
avoid, escape, and ward off
predators
Energy Flow in
an Ecosystem
(page 11 of Q2 marine bio
research packet)
•
Every community has a
trophic structure (pattern of
feeding relationships)
•
One organism eats another,
molecules are metabolized,
energy is transferred
•
Trophic structure is a key
factor in community dynamics
•
Trophic levels – indicates
and organism’s position
in the sequence of energy
transfers
•
Most ecosystems only
contain 3 or 4 trophic
levels
Energy Flow in an Ecosystem
(page 11 of Q2 marine bio research packet)
• What are food chains? How do these relate to food webs?
• 10% rule of energy transfer – 10% of the total energy consumed in one
trophic level is incorporated into organisms in the next level
Energy Flow in
an Ecosystem
(page 11 of Q2 marine bio research
packet)
• Why is the percentage of
energy transfer so low?
• Some organisms in a
trophic level escape
being eaten.
• Some molecules in
the food source can’t
be broken down.
• Some energy is lost
as heat.
Biomagnification
(talk about this concept when
discussing in abiotic factors)
• The process of
bioaccumulation /
biotransfer of
contaminate from one
trophic level to the next
• Tissue concentrations of a
contaminant increase as it
passes up through the
trophic levels
• DDT, mercury, pesticides
Producers vs. Consumers
(page 13 of Q2 marine bio research packet)
Producers
1st trophic level (“primary”)
Autotrophs
Most are photosynthetic
Can be chemoautotrophs
Consumers
Heterotrophs - all animals & fungi, most
protists & bacteria
Herbivores, carnivores, omnivores
Detritivores (scavengers) – consumers
that feed on the “garbage” of an
ecosystem (ex. turkey vulture)
Decomposers – cause decay, break down
complex molecules in dead tissues and
wastes into simpler molecules